department of commerce with computer application …

76
1 MADURAI GANDHI N.M.R SUBBARAMAN COLLEGE FOR WOMEN (Affiliated at Madurai Kamaraj University) 4A, Teppakulam, Anuppanadi Road, Madurai – 625009 Ph: 0452 – 2312948 Website: www.mgnmrscollege.com Email: [email protected] DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION SEMESTER – VI INFORMATION TECHNOLOGY ( )

Upload: others

Post on 22-Mar-2022

1 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

1

MADURAI GANDHI NMR SUBBARAMAN COLLEGE FOR WOMEN

(Affiliated at Madurai Kamaraj University)

4A Teppakulam Anuppanadi Road Madurai ndash 625009 Ph 0452 ndash 2312948

Website wwwmgnmrscollegecom Email mgnmrscw2010gmailcom

DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION

SEMESTER ndash VI

INFORMATION TECHNOLOGY ( )

2

DEPARTMENT BCOM (CA) SEMESTER VI

STAFF Mrs P KAVITHA (Assistant Professor)

SUBJECT INFORMATION TECHNOLOGY

SUBJECT CODE CCADS61 CLASS III ndash BCOM (CA)

SYLABUS ndash INFORMATION TECHNOLOGY (CCADS61)

UNIT - 1

Introduction of computers ndash Generation of computers ndash Size of computers ndash Super computers ndash Mainframes ndash Mini computers ndash Work station ndash Micro computers ndash Components of computers ndash Block diagram

UNIT - II

Input devices ndash Magnetic Ink Character Recognition (MICR) ndash Optical Character Reading (OCR) ndash Optical Mark Recognition (OMR) ndash Output devices ndash Printers ndash Storage devices ndash Floppy ndash Magnetic disc ndash Optical laser disks ndash Tape drives ndash System memory ndash RAM ndash ROM ndash PROM ndash EPROM

UNIT - III

Operating System ndash Meaning ndash Functions ndash Popular Operating System ndash Step in Programming ndash Flow chart ndash Meaning ndash Uses Symbols ndash Simple flow diagrams

UNIT - IV

Computer Networks ndash Network topologies ndash Star ndash Ring ndashBus ndash LAN ndash MAN ndash WAN ndash SAN ndash Client Server ndash Peer ndash to ndash Peer ndash Wireless Networks ndash Information super Highway Internet ndash Meaning ndash uses ndash URL ndash E-mail ndash World Wide Web ndash TCPIP ndash File Transfer Protocol ndash Telnet ndash Network news

UNIT ndash V

Programming Languages - Programming Languages user today ndash Visual Programming ndashObject Oriented Programming ndash Internet Programming ndash HTML ndash XML ndash VRML ndash Java ndash ActiveX ndash uses

3

UNIT ndash I

FILL IN THE BLANKS

1 Computer is an electronic device

2 First generation computers covers the period between 1951 - 1958

3 The first electro ndash mechanical computer is Mark ndash I

4 The first fully electronic computer is ENIAC

5 Difference engine is the proposal of Charles Babbage

6 Personal Computer is a general purpose computer

7 Fourth generation computers were manufactured using VLSIC

8 ENIAC stands for Electronic Numerical Integrator and Calculator

9 UNIVAC stands for Universal Automatic Computer

10 Automatic teller machine is a special purpose computer

11 The unit in which all the arithmetic and logical operations are performed is ALU

12 The unit which controls the entire system is CU

13 CPU stands for Central Processing Unit

14 ALU stands for Arithmetic Logic Unit

15 The heart of the computer is CPU

16 The CPU performs all the process of a computer

17 The CPU made up of control unit ALU and memory

4

QUESTIONS AND ANSWERS

1What is computer or Definition of Computer

A computer is an electronic data processing device which accepts and stores data input

processes the data input and generates the output in a required format

Any digital computer carries out the following five functions

Step 1 - Takes data as input

Step 2 - Stores the datainstructions in its memory and uses them as required

Step 3 - Processes the data and converts it into useful information Step 4 - Generates the

output

Step 5 - Controls all the above four steps

2 State the advantagesof computer( or ) Characteristics of computer

High Speed

bull Computer is a very fast device

bull It is capable of performing calculation of very large amount of data

bull The computer has units of speed in microsecond nanosecond and even the picosecond

5

It can perform millions of calculations in a few seconds as compared to man who will

spend many months to perform the same task

Accuracy

Accuracy bull In addition to being very fast computers are very accurate

bull The calculations are 100 error free

bull Computers perform all jobs with 100 accuracy provided that the input is correct

Storage Capability

bull Memory is a very important characteristic of computers

bull A computer has much more storage capacity than human beings

bull It can store large amount of data

bull It can store any type of data such as images videos text audio etc

Diligence

bull Unlike human beings a computer is free from monotony tiredness and lack of

concentration

bull It can work continuously without any error and boredom

bull It can perform repeated tasks with the same speed and accuracy

Versatility

bull A computer is a very versatile machine

bull A computer is very flexible in performing the jobs to be done

bull This machine can be used to solve the problems related to various fields

6

bull At one instance it may be solving a complex scientific problem and the very next

moment it may be playing a card game

Reliability

bull A computer is a reliable machine

bull Modern electronic components have long lives

Computers are designed to make maintenance easy

Automation

bull Computer is an automatic machine

bull Automation is the ability to perform a given task automatically Once the computer

receives a program ie the program is stored in the computer memory then the program

and instruction can control the program execution without human interaction

3 State the Disadvantages limitation of computer

Dependency

bull It functions as per the userrsquos instruction thus it is fully dependent on humans

Environment

bull The operating environment of the computer should be dust free and suitable

No Feeling

bull Computers have no feelings or emotions

bull It cannot make judgment based on feeling taste experience and knowledge unlike

humans

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 2: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

2

DEPARTMENT BCOM (CA) SEMESTER VI

STAFF Mrs P KAVITHA (Assistant Professor)

SUBJECT INFORMATION TECHNOLOGY

SUBJECT CODE CCADS61 CLASS III ndash BCOM (CA)

SYLABUS ndash INFORMATION TECHNOLOGY (CCADS61)

UNIT - 1

Introduction of computers ndash Generation of computers ndash Size of computers ndash Super computers ndash Mainframes ndash Mini computers ndash Work station ndash Micro computers ndash Components of computers ndash Block diagram

UNIT - II

Input devices ndash Magnetic Ink Character Recognition (MICR) ndash Optical Character Reading (OCR) ndash Optical Mark Recognition (OMR) ndash Output devices ndash Printers ndash Storage devices ndash Floppy ndash Magnetic disc ndash Optical laser disks ndash Tape drives ndash System memory ndash RAM ndash ROM ndash PROM ndash EPROM

UNIT - III

Operating System ndash Meaning ndash Functions ndash Popular Operating System ndash Step in Programming ndash Flow chart ndash Meaning ndash Uses Symbols ndash Simple flow diagrams

UNIT - IV

Computer Networks ndash Network topologies ndash Star ndash Ring ndashBus ndash LAN ndash MAN ndash WAN ndash SAN ndash Client Server ndash Peer ndash to ndash Peer ndash Wireless Networks ndash Information super Highway Internet ndash Meaning ndash uses ndash URL ndash E-mail ndash World Wide Web ndash TCPIP ndash File Transfer Protocol ndash Telnet ndash Network news

UNIT ndash V

Programming Languages - Programming Languages user today ndash Visual Programming ndashObject Oriented Programming ndash Internet Programming ndash HTML ndash XML ndash VRML ndash Java ndash ActiveX ndash uses

3

UNIT ndash I

FILL IN THE BLANKS

1 Computer is an electronic device

2 First generation computers covers the period between 1951 - 1958

3 The first electro ndash mechanical computer is Mark ndash I

4 The first fully electronic computer is ENIAC

5 Difference engine is the proposal of Charles Babbage

6 Personal Computer is a general purpose computer

7 Fourth generation computers were manufactured using VLSIC

8 ENIAC stands for Electronic Numerical Integrator and Calculator

9 UNIVAC stands for Universal Automatic Computer

10 Automatic teller machine is a special purpose computer

11 The unit in which all the arithmetic and logical operations are performed is ALU

12 The unit which controls the entire system is CU

13 CPU stands for Central Processing Unit

14 ALU stands for Arithmetic Logic Unit

15 The heart of the computer is CPU

16 The CPU performs all the process of a computer

17 The CPU made up of control unit ALU and memory

4

QUESTIONS AND ANSWERS

1What is computer or Definition of Computer

A computer is an electronic data processing device which accepts and stores data input

processes the data input and generates the output in a required format

Any digital computer carries out the following five functions

Step 1 - Takes data as input

Step 2 - Stores the datainstructions in its memory and uses them as required

Step 3 - Processes the data and converts it into useful information Step 4 - Generates the

output

Step 5 - Controls all the above four steps

2 State the advantagesof computer( or ) Characteristics of computer

High Speed

bull Computer is a very fast device

bull It is capable of performing calculation of very large amount of data

bull The computer has units of speed in microsecond nanosecond and even the picosecond

5

It can perform millions of calculations in a few seconds as compared to man who will

spend many months to perform the same task

Accuracy

Accuracy bull In addition to being very fast computers are very accurate

bull The calculations are 100 error free

bull Computers perform all jobs with 100 accuracy provided that the input is correct

Storage Capability

bull Memory is a very important characteristic of computers

bull A computer has much more storage capacity than human beings

bull It can store large amount of data

bull It can store any type of data such as images videos text audio etc

Diligence

bull Unlike human beings a computer is free from monotony tiredness and lack of

concentration

bull It can work continuously without any error and boredom

bull It can perform repeated tasks with the same speed and accuracy

Versatility

bull A computer is a very versatile machine

bull A computer is very flexible in performing the jobs to be done

bull This machine can be used to solve the problems related to various fields

6

bull At one instance it may be solving a complex scientific problem and the very next

moment it may be playing a card game

Reliability

bull A computer is a reliable machine

bull Modern electronic components have long lives

Computers are designed to make maintenance easy

Automation

bull Computer is an automatic machine

bull Automation is the ability to perform a given task automatically Once the computer

receives a program ie the program is stored in the computer memory then the program

and instruction can control the program execution without human interaction

3 State the Disadvantages limitation of computer

Dependency

bull It functions as per the userrsquos instruction thus it is fully dependent on humans

Environment

bull The operating environment of the computer should be dust free and suitable

No Feeling

bull Computers have no feelings or emotions

bull It cannot make judgment based on feeling taste experience and knowledge unlike

humans

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 3: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

3

UNIT ndash I

FILL IN THE BLANKS

1 Computer is an electronic device

2 First generation computers covers the period between 1951 - 1958

3 The first electro ndash mechanical computer is Mark ndash I

4 The first fully electronic computer is ENIAC

5 Difference engine is the proposal of Charles Babbage

6 Personal Computer is a general purpose computer

7 Fourth generation computers were manufactured using VLSIC

8 ENIAC stands for Electronic Numerical Integrator and Calculator

9 UNIVAC stands for Universal Automatic Computer

10 Automatic teller machine is a special purpose computer

11 The unit in which all the arithmetic and logical operations are performed is ALU

12 The unit which controls the entire system is CU

13 CPU stands for Central Processing Unit

14 ALU stands for Arithmetic Logic Unit

15 The heart of the computer is CPU

16 The CPU performs all the process of a computer

17 The CPU made up of control unit ALU and memory

4

QUESTIONS AND ANSWERS

1What is computer or Definition of Computer

A computer is an electronic data processing device which accepts and stores data input

processes the data input and generates the output in a required format

Any digital computer carries out the following five functions

Step 1 - Takes data as input

Step 2 - Stores the datainstructions in its memory and uses them as required

Step 3 - Processes the data and converts it into useful information Step 4 - Generates the

output

Step 5 - Controls all the above four steps

2 State the advantagesof computer( or ) Characteristics of computer

High Speed

bull Computer is a very fast device

bull It is capable of performing calculation of very large amount of data

bull The computer has units of speed in microsecond nanosecond and even the picosecond

5

It can perform millions of calculations in a few seconds as compared to man who will

spend many months to perform the same task

Accuracy

Accuracy bull In addition to being very fast computers are very accurate

bull The calculations are 100 error free

bull Computers perform all jobs with 100 accuracy provided that the input is correct

Storage Capability

bull Memory is a very important characteristic of computers

bull A computer has much more storage capacity than human beings

bull It can store large amount of data

bull It can store any type of data such as images videos text audio etc

Diligence

bull Unlike human beings a computer is free from monotony tiredness and lack of

concentration

bull It can work continuously without any error and boredom

bull It can perform repeated tasks with the same speed and accuracy

Versatility

bull A computer is a very versatile machine

bull A computer is very flexible in performing the jobs to be done

bull This machine can be used to solve the problems related to various fields

6

bull At one instance it may be solving a complex scientific problem and the very next

moment it may be playing a card game

Reliability

bull A computer is a reliable machine

bull Modern electronic components have long lives

Computers are designed to make maintenance easy

Automation

bull Computer is an automatic machine

bull Automation is the ability to perform a given task automatically Once the computer

receives a program ie the program is stored in the computer memory then the program

and instruction can control the program execution without human interaction

3 State the Disadvantages limitation of computer

Dependency

bull It functions as per the userrsquos instruction thus it is fully dependent on humans

Environment

bull The operating environment of the computer should be dust free and suitable

No Feeling

bull Computers have no feelings or emotions

bull It cannot make judgment based on feeling taste experience and knowledge unlike

humans

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 4: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

4

QUESTIONS AND ANSWERS

1What is computer or Definition of Computer

A computer is an electronic data processing device which accepts and stores data input

processes the data input and generates the output in a required format

Any digital computer carries out the following five functions

Step 1 - Takes data as input

Step 2 - Stores the datainstructions in its memory and uses them as required

Step 3 - Processes the data and converts it into useful information Step 4 - Generates the

output

Step 5 - Controls all the above four steps

2 State the advantagesof computer( or ) Characteristics of computer

High Speed

bull Computer is a very fast device

bull It is capable of performing calculation of very large amount of data

bull The computer has units of speed in microsecond nanosecond and even the picosecond

5

It can perform millions of calculations in a few seconds as compared to man who will

spend many months to perform the same task

Accuracy

Accuracy bull In addition to being very fast computers are very accurate

bull The calculations are 100 error free

bull Computers perform all jobs with 100 accuracy provided that the input is correct

Storage Capability

bull Memory is a very important characteristic of computers

bull A computer has much more storage capacity than human beings

bull It can store large amount of data

bull It can store any type of data such as images videos text audio etc

Diligence

bull Unlike human beings a computer is free from monotony tiredness and lack of

concentration

bull It can work continuously without any error and boredom

bull It can perform repeated tasks with the same speed and accuracy

Versatility

bull A computer is a very versatile machine

bull A computer is very flexible in performing the jobs to be done

bull This machine can be used to solve the problems related to various fields

6

bull At one instance it may be solving a complex scientific problem and the very next

moment it may be playing a card game

Reliability

bull A computer is a reliable machine

bull Modern electronic components have long lives

Computers are designed to make maintenance easy

Automation

bull Computer is an automatic machine

bull Automation is the ability to perform a given task automatically Once the computer

receives a program ie the program is stored in the computer memory then the program

and instruction can control the program execution without human interaction

3 State the Disadvantages limitation of computer

Dependency

bull It functions as per the userrsquos instruction thus it is fully dependent on humans

Environment

bull The operating environment of the computer should be dust free and suitable

No Feeling

bull Computers have no feelings or emotions

bull It cannot make judgment based on feeling taste experience and knowledge unlike

humans

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 5: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

5

It can perform millions of calculations in a few seconds as compared to man who will

spend many months to perform the same task

Accuracy

Accuracy bull In addition to being very fast computers are very accurate

bull The calculations are 100 error free

bull Computers perform all jobs with 100 accuracy provided that the input is correct

Storage Capability

bull Memory is a very important characteristic of computers

bull A computer has much more storage capacity than human beings

bull It can store large amount of data

bull It can store any type of data such as images videos text audio etc

Diligence

bull Unlike human beings a computer is free from monotony tiredness and lack of

concentration

bull It can work continuously without any error and boredom

bull It can perform repeated tasks with the same speed and accuracy

Versatility

bull A computer is a very versatile machine

bull A computer is very flexible in performing the jobs to be done

bull This machine can be used to solve the problems related to various fields

6

bull At one instance it may be solving a complex scientific problem and the very next

moment it may be playing a card game

Reliability

bull A computer is a reliable machine

bull Modern electronic components have long lives

Computers are designed to make maintenance easy

Automation

bull Computer is an automatic machine

bull Automation is the ability to perform a given task automatically Once the computer

receives a program ie the program is stored in the computer memory then the program

and instruction can control the program execution without human interaction

3 State the Disadvantages limitation of computer

Dependency

bull It functions as per the userrsquos instruction thus it is fully dependent on humans

Environment

bull The operating environment of the computer should be dust free and suitable

No Feeling

bull Computers have no feelings or emotions

bull It cannot make judgment based on feeling taste experience and knowledge unlike

humans

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 6: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

6

bull At one instance it may be solving a complex scientific problem and the very next

moment it may be playing a card game

Reliability

bull A computer is a reliable machine

bull Modern electronic components have long lives

Computers are designed to make maintenance easy

Automation

bull Computer is an automatic machine

bull Automation is the ability to perform a given task automatically Once the computer

receives a program ie the program is stored in the computer memory then the program

and instruction can control the program execution without human interaction

3 State the Disadvantages limitation of computer

Dependency

bull It functions as per the userrsquos instruction thus it is fully dependent on humans

Environment

bull The operating environment of the computer should be dust free and suitable

No Feeling

bull Computers have no feelings or emotions

bull It cannot make judgment based on feeling taste experience and knowledge unlike

humans

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 7: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

7

4 Write an essay on the various generations of the computers

First GenerationComputers

The period of first generation was from 1946-1959 The computers of first generation

used vacuum tubes as the basic components for memory and circuitry for CPU (Central

Processing Unit) These tubes like electric bulbs produced a lot of heat and the

installations used to fuse frequently Therefore they were very expensive and only large

organizations were able to afford it

In this generation mainly batch processing operating system was used Punch

cards paper tape and magnetic tape was used as input and output devices The

computers in this generation used machine code as the programming language

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 8: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

8

The main features of the first generation are

bull Vacuum tube technology

bull Unreliable

bull Supported machine language only

bull Very costly

bull Generated a lot of heat

bull Slow input and output devices

bull Huge size

bull Need of AC

bull Non-portable

bull Consumed a lot of electricity

Some computers of this generation were

ENIAC

bull EDVAC

bull UNIVAC

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 9: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

9

bull IBM-701

bull IBM-650

Second GenerationComputers

The main features of second generation are

Use of transistors

bull Reliable in comparison to first generation computers

bull Smaller size as compared to first generation computers

bull Generated less heat as compared to first generation computers

bull Consumed less electricity as compared to first generation computers

bull Faster than first generation computers

bull Still very costly

bull AC required

bull Supported machine and assembly languages

Some computers of this generation were

IBM 1620

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 10: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

10

bull IBM 7094

bull CDC 1604

bull CDC 3600

bull UNIVAC 1108

Third Generation Computers

The main features of third generation are

IC used

bull More reliable in comparison to previous two generations

bull Smaller size

bull Generated less heat

bull Faster

bull Lesser maintenance

bull Costly

bull AC required

bull Consumed lesser electricity

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 11: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

11

bull Supported high-level language

Some computers of this generation were

IBM-360 series

bull Honeywell-6000 series

bull PDP (Personal Data Processor)

bull IBM-370168

bull TDC-316

Fourth Generation Computers

The main features of fourth generation are

VLSI technology used

bull Very cheap

bull Portable and reliable

bull Use of PCs

bull Very small size

bull Pipeline processing

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 12: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

12

bull No AC required

bull Concept of internet was introduced

bull Great developments in the fields of networks

bull Computers became easily available

Fifth Generation Computers

AI includes

Robotics

bull Neural Networks

bull Game Playing

bull Development of expert systems to make decisions in real-life situations

bull Natural language understanding and generation

The main features of fifth generation are

ULSI technology

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 13: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

13

bull Development of true artificial intelligence

bull Development of Natural language processing

bull Advancement in Parallel Processing

bull Advancement in Superconductor technology

bull More user-friendly interfaces with multimedia features

bull Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are

Desktop

bull Laptop

bull NoteBook

bull UltraBook

bull ChromeBook

5 What are the different types of computers

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 14: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

14

PC (Personal Computer)

A PC can be defined as a small relatively inexpensive computer designed for an

individual user PCs are based on the microprocessor technology that enables

manufacturers to put an entire CPU on one chip Businesses use personal computers for

word processing accounting desktop publishing and for running spreadsheet and

database management applications At home the most popular use for personal

computers is playing games and surfing the Internet Although personal computers are

designed as single-user systems these systems are normally linked together to form a

network In terms of power now-a-days high-end models of the Macintosh and PC offer

the same computing power and graphics capability as low-end workstations by Sun

Microsystems Hewlett-Packard and Dell

Workstation

Workstation is a computer used for engineering applications (CADCAM) desktop

publishing software development and other such types of applications which require a

moderate amount of computing power and relatively high quality graphics capabilities

Workstations generally come with a large high-resolution graphics screen large amount

of RAM inbuilt network support and a graphical user interface Most workstations also

have mass storage device such as a disk drive but a special type of workstation called

diskless workstation comes without a disk drive Common operating systems for

workstations are UNIX and Windows NT Like PC workstations are also single-user

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 15: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

15

computers like PC but are typically linked together to form a local-area network

although they can also be used as stand-alone systems

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users

simultaneously

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting

hundreds or even thousands of users simultaneously Mainframe executes many programs

concurrently and supports many simultaneous execution of programs

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 16: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

16

Supercomputer

Supercomputers are one of the fastest computers currently available Supercomputers are

very expensive and are employed for specialized applications that require immense

amount of mathematical calculations (number crunching) For example weather

forecasting scientific simulations (animated) graphics fluid dynamic calculations

nuclear energy research electronic design and analysis of geological data (eg in

petrochemical prospecting)

6 What are the components of a computer system

All types of computers follow the same basic logical structure and perform the following

five basic operations for converting raw input data into information useful to their users

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 17: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

17

Input Unit

This unit contains devices with the help of which we enter data into the computer This

unit creates a link between the user and the computer The input devices translate the

information into a form understandable by the computer

CPU (Central Processing Unit)

CPU is considered as the brain of the computer CPU performs all types of data

processing operations It stores data intermediate results and instructions (program) It

controls the operation of all parts of the computer

CPU itself has the following three components

ALU (Arithmetic Logic Unit)bull

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 18: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

18

Memory Unitbull

Control Unitbull

Output Unit The output unit consists of devices with the help of which we get the

information from the computer This unit is a link between the computer and the users

Output devices translate the computers output into a form understandable by the users

7 Distinguish between analog and digital computer

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 19: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

19

UNIT ndash II

FILL IN THE BLANK

1A dot matrix printer is an output device

2 A Laser printer is non ndash Impact printer

3 A daisy wheel has 96 characters

4 There are 12 rows in a punched card

5 There are 85 columns in a punched card

6 Data entry can be performed with OMR

7 MICR stands for Magnetic Ink Character Recognition

8 OCR stands for Optical Character Reading

9 MICR technology used in the Banking sectors

10 Dot ndash matrix is an impact printer

11 Magnetic disk is made up of Aluminium

12 The primary memory of a personal computer consists of ROM and RAM

13 RAM stands for Random Access Memory

14 ROM stands for Read Only Memory

15 Example of non-volatile memory ROM

16 Example of volatile memory RAM

17 Memory which is programmed once cannot be modified in PROM

18 EEPROM can be erased by exposing it to Ultra violet radiation

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 20: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

20

19 EPROM stands for Erasable Programmable Read Only Memory

20 Secondary memory is also known as Auxillary memory

21 A floppy disk contains circular tracks and sectors

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 21: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

21

QUESTIONS AND ANSWERS

1 What is a peripheral device

Input device is any peripheral (piece of computer hardware equipment to provide data

and control signals to an information processing system such as a computer or other

information appliance Input device Translate data from form that humans understand to

one that the computer can work with Most common are keyboard and mouse

2 What are the different types of input devices

1 Keyboard

2 Mouse

3 Touchpad

4 Scanner

5 Digital Camera

6 Microphone

7 Joystick

8 Graphic Tablet

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 22: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

22

9 Touch Screen

10 Webcam

1 Keyboard

Keyboards are the most common type of input device Before keyboards interaction with

computers was generally carried out using punch cards and paper tape Most English

language keyboards use the QWERTY layout for the alphabetic keys which are

surrounded by number symbol function and other key types By pressing the relevant

keys a user can feed data and instructions to the computer

2 Mouse

A mouse interacts with a computer through a process known as point and click

Essentially when a user moves the mouse on the mouse pad the pointer moves in a

corresponding direction on the computers monitor screen The concept of a computer

mouse has its roots in the trackball a related pointing device invented in 1946 that used a

roller ball to control a pointer Most modern computer mice have two buttons for

clicking and a wheel in the middle for scrolling up and down documents and web pages

3 Touchpad

Also known as a trackpad a touchpad is a common substitute for a computer mouse It is

essentially a specialized surface that can detect the movement of a users finger and use

that information to direct a pointer and control a computer Touchpads were first

introduced for laptops in the 1990s and its now rare to find a laptop without one

4 Scanner

The word scanner can be used in a number of different ways in the computer world but

here I am using it to refer to a desktop image scanner Essentially a scanner is an input

device that uses optical technology to transfer images (or sometimes text) into a

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 23: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

23

computer where the signal is converted into a digital image The digital image can then

be viewed on a monitor screen saved edited emailed or printed

5 Digital Camera

Digital cameras are used to capture photographs and videos independently Later these

photo and video files can be transferred to a computer by connecting the camera directly

with a cable removing the memory card and slotting it into the computer or through

wireless data transfer methods such as Bluetooth Once the photos are on the computer

they can be saved edited emailed or printed

6 Microphone

A microphone captures audio and sends it to a computer where it is converted to a digital

format Once the audio has been digitized it can be played back copied edited

uploaded or emailed Microphones can also be used to record audio or to relay sounds

live as part of a video chat or audio stream

7 Joystick

Joysticks are commonly used to control characters and vehicles in computer video games

Essentially a joystick is a handle that pivots on a base and sends its angle or direction to

the computer as data Many video gaming joysticks feature triggers and buttons that can

be pressed to use weapons or projectiles in games

8 Graphic Tablet

Also known as digitizers graphic tablets are input devices used for converting hand-

drawn artwork into digital images The user draws with a stylus on a special flat surface

as if they were drawing on a piece of paper The drawing appears on the computer screen

and can be saved edited or printed While scanners can only create digital images from

drawings graphic tablets offer greater control and versatility for artists by allowing them

to see their drawing appear live on their monitor as they create it

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 24: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

24

9 Touch Screen

Many devices nowadays use a touch screen rather than a mouse as a way for users to

point drag or select options on a screen As the name suggests a touch screen is a touch-

sensitive monitor screen that reacts to fingers moving across it Touch screens are

particularly common in portable devices such as tablets palmtops laptops and

smartphones

10 Webcam

Webcams are different from digital cameras in two ways Firstly they cannot operate

independently from a computer and second they have no inbuilt memory Although

webcams can capture photographs and videos they are more often used to live-stream

videos or facilitate video chats

3What is output device

An output device is any piece of computer hardware equipment used to communicate the

results of data processing carried out by an information processing system (such as a

computer) which converts the electronically generated information into humanreadable

form

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 25: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

25

4 What are the different types of output devices

1 Monitor

2 Printer

3 Headphones

4 Computer Speakers

5 Projector

6 GPS

7 Sound Card

8 Video Card

9 Braille Reader

10 Speech-Generating Device

1 Monitor

Mode Visual

Function A monitor consists of a screen circuitry a power supply buttons to adjust

screen settings and a casing that contains all of these components A monitor displays

data from a computer onto a screen so the user can interact with the data via a digital

interface

Popular Brands Acer Alienware Apple Asus Dell HP LG Lenovo Samsung

2 Printer

Mode Print

Function The function of a printer is to create a copy of whatever is sent from the

computer to the printer Printers take electronic data sent from a computer and generate a

hard copy

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 26: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

26

Popular Brands Brother Canon Epson

3 Headphones

Mode Sound

Function Headphones output audio from a computer through two individual headphones

for a single listener Also known as earphones headphones allow you to listen to audio

without disrupting other people in the vicinity

Popular Brands Sennheiser JBL Bose Sony Skullcandy

4 Computer Speakers

Mode Sound

Function Computer speakers are hardware devices that transform the signal from the

computers sound card into audio Speakers create sound using internal amplifiers that

vibrate at different frequencies according to data from the computer This produces

sound

Popular Brands Audioengine Logitech Razer Harman

5 Projector

Mode Visual

Function As its name suggests this output device projects computer images or video

onto a wall or screen

Popular Brands BenQ Sony Optoma Epson

5 Explain the working principle of CRT

CRT technology uses electron guns that must be at distances of over one foot from

the screen The inside surface of thescreen iscoated with dots ofphosphors which glow

when a stream of electrons from the electron gun strike themOn a colour monitor these

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 27: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …

27

dots are in groups of three red greenand blue Three electron guns are used to set the

dots glowingand the human eyes blend the dots that are glowing to create allthe

colours CRT technology is used with computer systems thatare not frequently moved

from one place to another Computersthatused this technology include desktop

computersminicomputers mainframes and supercomputers

6 Explain the working principle of Flat screen Technologies

The technology used for CRT display tends to be bulky in sizeand hence difficult

to move around Therefore in order to createsmall portable computers flat paneldisplay

technology is used

7 What is printer

Printers are a primary output device used to prepare permanent documents There are

various kinds of printers

a) Impact printers

b) Non ndash Impact printers

8 Explain about Dot Matrix Printer

It prints characters as combination of dots Dot matrix printers are the most

popular among serial printers These have a matrix of pins on the print head of the printer

which form the character The computer memory sends one character at a time to be

printed by the printer There is a carbon between the pins amp the paper The words get

printed on the paper when the pin strikes the carbon There are generally 24 pins

9 Explain about Line Printer

A line printer is an impact printer which makes use of a continuous feed of

paper and prints one line of text at a time Although they have been replaced in most

28

instances by high-speed laser printers they are still used in some business as they are

low cost and have the ability to print on multi-part forms

A high-speed printer capable of printing an entire line at one time A fast line

printer can print as many as 3000 lines per minute The disadvantages of line

printers are that they cannot print graphics the print quality is low and they are very

noisy

10 Explain about Daisy Wheel printer

A daisy-wheel printer works on the same principle as a ball-head typewriter

The daisy wheel is a disk made of plastic or metal on which characters stand out in relief

along the outer edge To print a character the printer rotates the disk until the desired

letter is facing the paper

Daisy wheel printing was used in electronic typewriters word processors and

computers from 1972 The daisy wheel is considered to be so named because of its

resemblance to the daisy flower By 1980 daisy wheel printers had become the

dominant technology for high-quality text printing

11 Explain about chain printer

An early line printer that used type slugs linked together in a chain as its printing

mechanism The chain spins horizontally around a set of hammers When the desired

character is in front of the selected print column the corresponding hammer hits the

paper into the ribbon and onto the character in the chain Chain and train printers gave

way to band printers in the early 1980s

When the required character in the chain has revolved to the selected print column

the hammer pushes the paper into the ribbon and against the type slug of the letter or

digit

29

12 Explain about Thermal Printer

A thermal printer is a printer that makes use of heat in order to produce the image

on paper

Due to quality of print speed and technological advances it has become

increasingly popular and is mostly used in airline banking entertainment retail grocery

and healthcare industries Thermal printing does not make use of ink or toner unlike

many other printing forms but largely depends on thermal papers for producing

the imagesThey are also quiet popular in creating labels owing to speed of printing

Advantages of Thermal printers

1 No involvement of cartridges or ribbons and thus organizations can save investment by

using thermal printers

2 Easier to use as there are less buttons and use of software involved

3 Popular in noise-free environments and are great for offices

4 Largely inexpensive and come in various models and sizes

5 More efficient and faster in printing monochromic ones compared to other forms of

printing

6 More durable compared to other printers

Disadvantages of Thermal printers

1 Unlike standard printers thermal printers usually do not print out colors well

2 If they become too heated to operate the ink consumed would be more and the printing

may not be precise

3 Printhead could be harmed by the high heat used while printing often resulting on cost

to repair when it break down

30

13 Explain about Ink jet Printer

It prints characters by spraying patterns of ink on the paper from a nozzle or jet It prints

from nozzles having very fine holes from which a specially made ink is pumped out to

create various letters and shapes The ink comes out of the nozzle in a form of vapors

After passing through a reflecting plate it forms the desired lettershape at the desired

place

14 Explain about Laser Printer

Laser Printer is a type of printer that utilizes a laser beam to produce an image on a

drum The light of the laser alters the electrical charge on the drum wherever it hits The

drum is then rolled through a reservoir of toner which is picked up by the charged

portions of the drum Finally the toner is transferred to the paper through a combination

of heat and pressure

laser printers are non-impact printers they are much quieter than dotmatrix or daisy-

wheel printers They are also relatively fast although not as fast as some dot-matrix or

daisy-wheel printers The speed of laser printers ranges from about 4 to 20 pages of text

per minute (ppm) A typical rate of 6ppm is equivalent to about 40 characters per second

(cps)

15 What is Plotter and its types

A plotter is a printer that interprets commands from a computer to make line drawings

on paper with one or more automated pens Unlike a regular printer the plotter can draw

continuous point-to-point lines directly from vector graphics files or commands As a

rule plotters are much more expensive than printers

Flatbed plotters

In flatbed plotters the writing pen moves in both x and y-axis directions across the

surface of the paper This type of plotter consists of a flat surface on which the paper is

31

placed in a stationary position and it is the pen that moves to create drawing or images

The pen can be of different sizes and colors in flatbed plotters

Drum Plotters

There are other types of plotters called drum plotters in which drum or a cylindrical

surface rotates in the vertical direction while the pen moves in another axis to create an

image or other output Moreover the width of the final print-out is limited by the width

of a drum while there is no limit to the length of the paper

16 Explain about Primary memory

Primary Memory-

1 RAM Random Access Memory (RAM) is a memory scheme within the computer

system responsible for storing data on a temporary basis so that it can be promptly

accessed by the processor as and when needed It is volatile in nature which means that

data will be erased once supply to the storage device is turned off RAM stores data

randomly and the processor accesses these data randomly from the RAM storage RAM

is considered random access because you can access any memory cell directly if you

know the row and column that intersect at that cell

2 ROM (Read Only Memory) ROM is a permanent form of storage ROM stays active

regardless of whether power supply to it is turned on or off ROM devices do not allow

data stored on them to be modified

17 Explain about secondary memory

Secondary Memory- Stores data and programs permanently its retained after the power

is turned off 1 Hard drive (HD) A hard disk is part of a unit often called a disk drive

hard drive or hard disk drive that store and provides relatively quick access to large

amounts of data on an electromagnetically charged surface or set of surfaces

32

2 Optical Disk an optical disc drive (ODD) is a disk drive that uses laser light as part of

the process of reading or writing data to or from optical discs Some drives can only read

from discs but recent drives are commonly both readers and recorders also called

burners or writers Compact discs DVDs and Blu-ray discs are common types of optical

media which can be read and recorded by such drives Optical drive is the generic name

drives are usually described as CD DVD or Bluray followed by drive writer

etc There are three main types of optical media CD DVD and Blu-ray disc CDs can

store up to 700 megabytes (MB) of data and DVDs can store up to 84 GB of data Blu-

ray discs which are the newest type of optical media can store up to 50 GB of data This

storage capacity is a clear advantage over the floppy disk storage media (a magnetic

media) which only has a capacity of 144 MB 4 3 Flash Disk A storage module made of

flash memory chips A Flash disks have no mechanical platters or access arms but the

term disk is used because the data are accessed as if they were on a hard drive The disk

storage structure is emulated

17 Compare between RAM and Hard disk

33

18 Different between RAM and ROM

19 Define a) PROM b) EPROM c) EEPROM

PROM - (programmable read-only memory) is a memory chip on which data can be

written only once Once a program has been written onto a PROM it remains there

forever Unlike main memory PROMs retain their contents when the computer is turned

off

EPROM - (erasable programmable read-only memory) is a special type of PROM

that can be erased by exposing it to ultraviolet light Once it is erased it can be

reprogrammed An EEPROM is similar to a PROM but requires only electricity to be

erased

EEPROM - (electrically erasable programmable read-only memory) Pronounced e-

e-prom an EEPROM is a special type of PROM that can be erased by exposing it to an

electrical charge Like other types of PROM EEPROM retains its contents even when

the power is turned off Also like other types of ROM EEPROM is not as fast as RAM

34

20 What is a virtual memory

Virtual memory is a feature of an operating system that enables a computer to be

able to compensate shortages of physical memory by transferring pages of data from

random access memory to disk storage This process is done temporarily and is designed

to work as a combination of RAM and space on the hard disk

21 Explain the Working of Magnetic Disk Drive

A magnetic disk is a storage device that uses a magnetization process to write

rewrite and access data It is covered with a magnetic coating and stores data in the form

of tracks spots and sectors Hard disks zip disks and floppy disks are common examples

of magnetic disks

The primary computer storage device Increasingly magnetic disks are being

replaced by SSDs (see SSD) Like magnetic tape disks are magnetically recorded and

can be re-recorded over and over Disks contain rotating platters with a mechanical arm

that moves a readwrite head across their surface For more details see hard

disk and hard disk interfaces

Tracks and Spots

A disks surface is divided into concentric tracks (circles within circles) and the

thinner the tracks the more storage The data bits are recorded as magnetic spots on the

tracks and the smaller the spot the greater the storage

Sectors

Tracks are further divided into sectors which hold a block of data that is read or

written at one time for example READ SECTOR 782 WRITE SECTOR 5448 In order

to update the disk one or more sectors are read into the computer changed and written

back to disk The operating system figures out how to fit data into these fixed spaces

Modern disks have more sectors in the outer tracks than the inner ones because the

35

outer radius of the platter is greater than the inner radius (see CAV) See magnetic

tape and optical disc

22 Briefly explain a Floppy disk

A floppy disk is a storage medium that consists of a thin and flexible magnetic

disk inside a plastic carrier Widely used since the 1970s until the early 2000s they have

gradually been replaced by other storage devices with greater capacity

A floppy disk is a magnetic storage medium for computer systems The floppy

disk is composed of a thin flexible magnetic disk sealed in a square plastic carrier In

order to read and write data from a floppy disk a computer system must have a floppy

disk drive (FDD) A floppy disk is also referred to simply as a floppy Since the early

days of personal computing floppy disks were widely used to distribute software

transfer files and create back-up copies of data When hard drives were still very

expensive floppy disks were also used to store the operating system of a computer

A number of different types of floppy disks have been developed The size of the floppy

got smaller and the storage capacity increased However in the 1990s other media

including hard disk drives ZIP drives optical drives and USB flash drives started to

replace floppy disks as the primary storage medium

36

UNIT ndash III

FILL IN THE BLANKS

1OS stands for Operating System

2 Operating System is a system software

3 Windows is the latest operating system

4 Algorithm is a set of well defined logical steps

5 Multi user allows to support more than one process at the same time

6 Single user allows only one process at a time

7 Command user to allows a user an interact with the operating system through a set of

commands

8 Graphical user to allows a user by pointing and clicking the objects that appear on the

screen

9A programming is a planning process to solve a problem by using computer

10 A program is a detailed set of instruction

37

QUESTIONS AND ANSWERS

1Define Operating System

Operating system refers to the collection of softwares that manages hardware

resources of a computer and provides collective services to the user Different types of

Computer Operating Systems refer to the collection of various softwares Every computer

possesses an operating system to run other programs present in it

2 What are the functions of an operating system

bull Protected and supervisor mode

bull Allows disk access and file systems Device drivers Networking Security

bull Program Execution

bull Memory management Virtual Memory Multitasking

bull Handling IO operations

bull Manipulation of the file system

bull Error Detection and handling

bull Resource allocation

bull Information and Resource Protection

3 Explain any three popular operating system used today

DOS Stands for Disk Operating System DOS was the first operating system used

by IBM-compatible computers It was originally available in two versions that were

essentially the same but marketed under two different names PC-DOS was the version

developed by IBM and sold to the first IBM-compatible manufacturers MS-DOS was

the version that Microsoft bought the rights to and was bundled with the first versions of

Windows

DOS uses a command line or text-based interface that allows the user to type

commands By typing simple instructions such as pwd (print working directory)

38

and cd (change directory) the user can browse the files on the hard drive open files and

run programs While the commands are simple to type the user must know the basic

commands in order to use DOS effectively (similar to Unix) This made the operating

system difficult for novices to use which is why Microsoft later bundled the graphic-

based Windows operating system with DOS

UNIX is an operating system which was first developed in the 1960s and has been

under constant development ever since By operating system we mean the suite of

programs which make the computer work It is a stable multi-user multi-tasking

system for servers desktops and laptops

UNIX systems also have a graphical user interface (GUI) similar to Microsoft

Windows which provides an easy to use environment However knowledge of UNIX

is required for operations which arent covered by a graphical program or for when

there is no windows interface available for example in a telnet session

Linux has been around since the mid-1990s and has since reached a user-base that spans

the globe Linux is actually everywhere Its in your phones your thermostats in your

cars refrigerators Roku devices and televisions It also runs most of the Internet all of

the worldrsquos top 500 supercomputers and the worldrsquos stock exchanges

But besides being the platform of choice to run desktops servers and embedded systems

across the globe Linux is one of the most reliable secure and worry-free operating

systems available

Here is all the information you need to get up to speed on the Linux platform

39

4 Distinguish between single user and multi user operating systems

40

5 Distinguish between Command user interface and Graphical user interface

41

6 What is a program

A computer program is a collection of instructions that can be executed by a

computer to perform a specific task Most computer devices require programs to function

properly A computer program is usually written by a computer programmer in a

programming language

7 What are source and object program

Source program or source code is the original program written by the

programmer It is a text-based document In the source program the programmer writes

the instructions the computer should perform He writes these instructions using a

computer programming language such as Java CNET etc Programmer can easily

understand and read the syntax of these programming languages Furthermore the

written source code has to be according to the correct conventions and rules of that

particular programming language

Object Program or the object code is a machine executable file The computer or

the machine does not understand the source program or the source code Therefore the

compiler converts the source program into an object program In other words the object

program is the output of the compiler It has instructions for the machine in the form of

binary digits Therefore it is a machine-readable code As the machine understands this

object program it is a machine-executable code Additionally if the programmer does

any changes to the source program it is necessary to compile it to make those changes

appear in the object program

42

8 Define Algorithm

In mathematics and computer science an algorithm is a finite sequence of well-

defined computer-implementable instructions typically to solve a class of problems or to

perform a computation

9 Explain the various symbols used in flowchart

43

10Explain the steps involved in writing a program

Step 1 starting the problem

Step 2 Development of Algorithm

Step 3 Flow charting

Step 4 coding

Step 5 Debugging

Step 6 testing

11 What is a flowchart What are its uses

A flowchart is a graphical representations of steps It was originated from

computer science as a tool for representing algorithms and programming logic but had

extended to use in all other kinds of processes Nowadays flowcharts play an extremely

important role in displaying information and assisting reasoning They help us visualize

complex processes or make explicit the structure of problems and tasks A flowchart

can also be used to define a process or project to be implemented

44

11 Distinguish between system flowchart and program flow chart

45

UNIT ndash IV

FILL IN THE BLANKS

1Cable is the oldest and most common transmission Line

2 Bus network the ends are not connected

3 LAN stands for Local Area Network

4 WAN stands for Wide Area Network

5 MAN stands for Metropolitan Area Network

6 SAN stands for Storage Area Network

7 Protocol is a set of rules

8 FTP enables files to be transferred between computers

9 HTTP refers to Hyper Text Transfer Protocol

10 World Wide Web is made of documents created with a language called HTML

11 URL stands for Uniform Resource Locator

12 Network of Network is called Internet

13 Telnet enables to work between any host and any terminal

46

QUESTIONS AND ANSWERS

1What is a Network

computer network is an interconnection of two or more computers through the use

of cables telephone lines radio transmitter satellites and other wireless

telecommunication devices which goal is to successfully communicate to each other

through information interchange and resource sharing A network is a set of technologies

including the media used to connect computers together as well as the software and

hardware used to construct and operate it These media are the copper wire fiber optic

cable or radio frequency in the case of a wireless technology The network allows many

users to access shared data programs software movies pictures MP3s e-books and

many others almost instantly

2 What are the features of networking

To e-mails and Internet chat the company employees and officers enjoy the

benefit of teleconferencing one of the best technologies that evolves because of

networking technology Through teleconferencing the companies meeting is no longer

limited to physical presence of the attendee but anywhere and anytime she or he can join

the meeting virtually The attendee just need a computer connected to the networks or

Internet to make this high-tech way of communicating possible In a teleconference

settings data audio and video signals travel across a Local Area Network

(LAN)through the use of wires access points hubs switches or across the networkrsquos

Internet

Videoconferencing audio-conferencing and data-conferencing

3 What is a network topology

Network Topology is the schematic description of a network arrangement connecting

various nodes(sender and receiver) through lines of connection

4 What are the different types of network topologies

47

Bus topology

Bus topology is a network type in which every computer and network device is

connected to single cable When it has exactly two endpoints then it is called Linear Bus

topology

Features of Bus Topology

1 It transmits data only in one direction

2 Every device is connected to a single cable

Advantages of Bus Topology

1 It is cost effective

2 Cable required is least compared to other network topology

3 Used in small networks

4 It is easy to understand

5 Easy to expand joining two cables together

48

Disadvantages of Bus Topology

1 Cables fails then whole network fails

2 If network traffic is heavy or nodes are more the performance of the network

decreases

3 Cable has a limited length

4 It is slower than the ring topology

RING Topology

It is called ring topology because it forms a ring as each computer is connected to

another computer with the last one connected to the first Exactly two neighbours for

each device

Features of Ring Topology

1 A number of repeaters are used for Ring topology with large number of nodes

because if someone wants to send some data to the last node in the ring topology

with 100 nodes then the data will have to pass through 99 nodes to reach the

100th node Hence to prevent data loss repeaters are used in the network

2 The transmission is unidirectional but it can be made bidirectional by having 2

connections between each Network Node it is called Dual Ring Topology

49

3 In Dual Ring Topology two ring networks are formed and data flow is in

opposite direction in them Also if one ring fails the second ring can act as a

backup to keep the network up

4 Data is transferred in a sequential manner that is bit by bit Data transmitted has to

pass through each node of the network till the destination node

Advantages of Ring Topology

1 Transmitting network is not affected by high traffic or by adding more nodes as

only the nodes having tokens can transmit data

2 Cheap to install and expand

Disadvantages of Ring Topology

1 Troubleshooting is difficult in ring topology

2 Adding or deleting the computers disturbs the network activity

3 Failure of one computer disturbs the whole network

STAR Topology

In this type of topology all the computers are connected a single hub through a cable

This hub is the central node and all others are connected to the central node

50

Features of Star Topology

1 Every node has its own dedicated connection to the hub

2 Hub acts as a repeater for data flow

3 Can be used with twisted pair Optical Fibre or coaxial cable

Advantages of Star Topology

1 Fast performance with few nodes and low network traffic

2 Hub can be upgraded easily

3 Easy to troubleshoot

4 Easy to setup and modify

5 Only that node is affected which has failed rest of the nodes can work smoothly

Disadvantages of Star Topology

1 Cost of installation is high

2 Expensive to use

3 If the hub fails then the whole network is stopped because all the nodes depend on

the hub

4 Performance is based on the hub that is it depends on its capacity

51

MESH Topology

It is a point-to-point connection to other nodes or devices All the network nodes

are connected to each other Mesh has n(n-1)2 physical channels to link n devices

There are two techniques to transmit data over the Mesh topology they are

1 Routing

2 Flooding

MESH Topology Routing

In routing the nodes have a routing logic as per the network requirements Like

routing logic to direct the data to reach the destination using the shortest distance Or

routing logic which has information about the broken links and it avoids those node etc

We can even have routing logic to re-configure the failed nodes

HYBRID Topology

It is two different types of topologies which is a mixture of two or more

topologies For example if in an office in one department ring topology is used and in

another star topology is used connecting these topologies will result in Hybrid Topology

(ring topology and star topology)

52

Features of Hybrid Topology

1 It is a combination of two or topologies

2 Inherits the advantages and disadvantages of the topologies included

Advantages of Hybrid Topology

1 Reliable as Error detecting and trouble shooting is easy

2 Effective

3 Scalable as size can be increased easily

4 Flexible

Disadvantages of Hybrid Topology

1 Complex in design

2 Costly

5 What are the network protocols

53

Network Protocols are a set of rules governing exchange of information in an easy

reliable and secure way Before we discuss the most common protocols used to transmit

and receive data over a network we need to understand how a network is logically

organized or designed

6 Describe the World Wide Web

The World Wide Web (WWW) commonly known as the Web is an information

system where documents and other web resources are identified by Uniform Resource

Locators (URLs such as httpswwwexamplecom) which may be interlinked

by hypertext and are accessible over the Internet[1][2] The resources of the WWW are

transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by

a software application called a web browser and are published by a software application

called a web server

7 What is an e-mail

Electronic mail (email or e-mail) is a method of exchanging messages (mail) between

people using electronic devices Email entered limited use in the 1960s Email operates

across computer networks primarily the Internet Todays email systems are based on

a store-and-forward model Email servers accept forward deliver and store messages

Neither the users nor their computers are required to be online simultaneously they need

to connect typically to a mail server or a webmail interface to send or receive messages

or download it

8 Mention the advantages and disadvantages of e-mail

Advantages

1 Email is a free tool Once you are online there is no further expense that you need

to spend on in order to send and receive messages

54

2 Email is quick Once you have finished composing a message sending it is as

simple as clicking a button Email especially if an email system is integrated into

the network is sent delivered and read almost immediately

3 Email is simple It is easy to use Once your account is set up composing sending

and receiving messages is simple Also email allows for the easy and quick access

of information and contacts

4 Email allows for easy referencing Messages that have been sent and received can

stored and searched through safely and easily It is a lot easier to go through old

email messages rather than old notes written on paper

5 Email is accessible from anywhere ndash as long as you have an internet connection

Whether or not you are in the office or on the field or even overseas you can

access your inbox and go through your messages

6 Email is paperless and therefore beneficial for the planet Not only can you

reduce the costs of paper you are actually reducing the damage paper usage does

to the environment

7 Email allows for mass sending of messages An effective medium to utilize to get

your message out there you can send one particular message to several recipients

all at once

8 Email allows for instant access of information and files You can opt to send

yourself files and keep messages so that you have a paper trail of conversations

and interactions you have online just in case you may need them in the future

Disadvantages

1 Email could potentially cause information overload Some messages may be

dismissed or left unread especially if there are a lot coming in and the network has

not integrated some sort of email alert system into the computers at work

55

2 Email lacks a personal touch While some things are better off sent as written and

typed messages some things should be verbally relayed or written by hand in a

note or letter

3 Email can be disruptive Going through each email can be disruptive to work as it

does require a bit of time This disruption is decreased through the utilization of an

email alert system

4 Email cannot be ignored for a long time The thing with email is that it needs

constant maintenance If you ignore it more and more messages will enter your

inbox until it gets to the point that your inbox is no longer manageable

5 Email can cause misunderstandings Because email does not include nonverbal

communication recipients may misinterpret the senderrsquos message This is

particularly true of senders fail to go through their messages before they send

them

6 Email messages can contain viruses Itrsquos best to be aware of this possibility so that

you are careful when opening messages from people you donrsquot know or when

downloading attachments

7 Email should be kept short and brief This is especially difficult if you are one to

send messages that are too long

8 Email requires timely responses While some people tend to disregard messages

those that require responses should be replied to as soon as they are received and

read If not urgent and important messages may be left untended

9 What is LAN

Local Area Network (LAN) is an interconnection of personal computers that are

close to each other usually in the same building campus or area In a LAN one or more

computers can serve as a ldquoserverrdquo (the main computer) while the computers connected to

it are called workstations or client PCs The server

56

serves a storehouses for software and data that are shared by many users who are

connected to it through cables or antenna (for wireless connection) The user is

usually using the workstation

This is the term used for a computer connected to the main computer called server

In real setting there are many workstations connected to a server To use this

workstation the user is required to enter a login name and its corresponding password

This kind of set-up is applied to protect the software resources and confidential

information that can be found in the whole network The term used for this application is

called

system security

10 What is WAN

The Wide Area Network (WAN) is an interconnection of many computers that are

located from different cities or countries WAN is made up of two or more LAN which

are separated by geographic distance and linked through phone lines microwave towers

and communication satellites Wide Area Network allows users to share computer

hardware software information or data even if they are separated by a long distance The

user can send(upload) or receive (download) data information software pictures

57

images MP3seBooks and movies through the network In a network environment the

users can possibly work together for a particular project All users can see the changes

made by other users For example a company may have its main office and

manufacturing plant in one city or province and its marketing office in another city Each

site needs resources such as data programs or projects to work to locally but it also

needs to share data with the other sites To accomplish this need of data communication

the company can use a WAN setup This is possible because some telecommunication

network usually a phone company or an Internet Service Provider (ISP) will link the

different LANs of the company that are located in different cities so that it can

communicate to each other

11 What are MAN and SAN

The metropolitan area network (MAN) is a large-scale network that connects

multiple corporate LANs together across a wide geographical area such as by regions

Usually the users are sharing resources with other regional resources This type of

networks are not owned by one company but usually owned by two or more different

companies The network devices and communication equipments of Metropolitan Area

58

Networks are maintained by the network provider that offers network services to

corporate customers

12 Describe Wireless Networks in detail

Wireless LAN is so common today Even Wireless MAN and Wireless WAN are

prevalent in todays present technology We can see and hear how this present emerging

technology works to make our life better and better A wireless network simply enables

people to communicate anytime and anywhere and access application and information

without being required to connect to the network using wires or cables This literally

provides freedom of movement and the ability to extend applications to different parts of

a building cities or practically anywhere in the world For example if I want to connect

to the Internet to research some topics of interest or opening my e-mail and yet free-of-

charge I will simply bring my Laptop to Robinsons Robinsons mall provides free access

to the Internet wirelessly You can try it You will enjoy it

59

13 Explain TCPIP

The TCPIP relationship is similar to sending someone a message written on a puzzle

through the mail The message is written down and the puzzle is broken into pieces Each

piece then can travel through a different postal route some of which take longer than

others When the puzzle pieces arrive after traversing their different paths the pieces may

be out of order The Internet Protocol makes sure the pieces arrive at their destination

address The TCP protocol can be thought of as the puzzle assembler on the other side

who puts the pieces together in the right order asks for missing pieces to be resent and

lets the sender know the puzzle has been received TCP maintains the connection with the

sender from before the first puzzle piece is sent to after the final piece is sent

14 What is Telnet

Telnet developed in 1969 is a protocol that provides a command line interface for

communication with a remote device or server sometimes employed for remote

management but also for initial device setup like network hardware Telnet stands for

Teletype Network but it can also be used as a verb to telnet is to establish a connection

using the Telnet protocol

Telnet can be used to test or troubleshoot remote web or mail servers as well as for

remote access to MUDs (multi-user dungeon games) and trusted internal networks

15 What is Internet

The Internet is a worldwide system of connected networks Each network consists of

millions of computers servers routers and printers You can think of the Internet like the

telephone network or the interstate highway system You may have even heard people

refer to the Internet as the Information Super Highway The networks that make up the

Internet may be owned and maintained by different companies but messages and data

move across all of them without regard to ownership because they all use the same

protocol or language to communicate

60

16 How does Internet work

Information moves across the Internet much like UPS delivers packages When you order

something it could be boxes in multiple packages because one box would be too large to

deliver A message or webpage is broken down into packets to be delivered to your

computer Each packet has addressing information so that it knows where it is going

Your message or webpage could be broken down into many packets and each packet will

have the address and the number of the packet so that when it gets to its final destination

your computer or email server will know how to put the packet together to make a

meaningful message

17 What is FTP and how does it work

FTP stands for File Transfer Protocol In a nutshell FTP is used to transfer computer

files Yoursquove probably used FTP before even if you didnrsquot realize it If you have

downloaded something from the Internet such as a new version of an application it is

very possible that you used FTP to do so

FTP is also frequently used as a way to transfer web pages FTP allows new web

pages created by an individual to show up on the Internet FTP essentially transfers these

web page files to the computer server so others can access them FTP can also be used to

download files or programs from the Internet to your computer When you download

these files you are transferring them from other servers through FTP

FTP can allow you to transfer files over any two computers as long as they both

have an Internet connection You can share folders that contain data like music Word

documents and more

How does File Transfer Protocol Work

When files are transferred through FTP one of two actions is happening ndash

uploading or downloading Uploading involves transferring files from a personal

computer to a server Downloading involves transferring a file from a server to a personal

61

computer FTP uses TCPIP (Transmission Control ProtocolInternet Protocol) to transfer

your files TCPIP is basically the language that the Internet uses to carry out commands

If you are going to use File Transfer Protocol in order to download files you

should keep security concerns in mind Files downloaded from the Internet may have

viruses that can harm your computer

One way to use FTP is to go through an FTP client FTP clients may make it safer

for your computer to downloadupload files and help you avoid malware and viruses

Some FTP clients are pricey while some are completely free Using an FTP client is not

a necessary step for transferring folders but it may make uploading and downloading

files easier to do

18 What is a URL

The URL is the key to navigate or explore the World Wide Web When we

provide a URL to the Web browser by typing it on its Address box the Web browser will

find the URLrsquos web page and then transfers the web page to our computer The content of

the Web page will appear on our computerrsquos screen through the window of the Web

browser We can also go to a particular Web page by clicking the hyperlink of a

particular URL The hyperlink is usually written in our Web page with an underline on

it

62

UNIT ndash V

FILL IN THE BLANKS

1Machine Language is machine dependent

2 High level language is machine in-dependent

3 High level language is more English

4 Machine Language is written by using 0s and 1s

5 Assembly language is written by using mnemonic code

6 Fifth generation languages are also called Natural language

7 All computer execute Machine language program

8 LISP is not a procedural language

9 BASIC is an interpreted language

10 FORTRAN is most oriented to scientific programming

11 RPG is a report generator

12 SQL is a problem oriented language

13 FORTRAN stands for Formula Translator

14 COBOL stands for Common Business Oriented Language

15 PL1 stands for Programming Language 1

16 BASIC stands for Beginners All purpose Symbolic Instruction Code

17 VB is a Visual Programming Language

18 C++ is an Internet Programming Language

63

QUESTIONS AND ANSWERS

1What is a Programming Language

A program is a set of instructions that tells a computer what to do in order to come

up with a solution to a particular problem Programs are written using a programming

language A programming language is a formal language designed to communicate

instructions to a computer There are two major types of programming languages low-

level languages and high-level languages

2 What is a Machine Language

Machine code is the only language a computer can process directly without a previous

transformation Currently programmers almost never write programs directly in machine

code because it requires attention to numerous details that a high-level language handles

automatically Furthermore it requires memorizing or looking up numerical codes for

every instruction and is extremely difficult to modify

True machine code is a stream of raw usually binary data A programmer coding

in machine code normally codes instructions and data in a more readable form such

as decimal octal or hexadecimal which is translated to internal format by a program

called a loader or toggled into the computers memory from a front panel

8B542408 83FA0077 06B80000 0000C383

FA027706 B8010000 00C353BB 01000000

B9010000 008D0419 83FA0376 078BD989

C14AEBF1 5BC3

64

3 What is an Assembly Language

Few programmers write programs in low level assembly language but it is still used for

developing code for specialist hardware such as device drivers

It is easy distinguishable from a high level language as it contains few recognisable

human words but plenty of mnemonic code

Advantages

bull Can make use of special hardware or special machine-dependent instructions (eg

on the specific chip)

bull Translated program requires less memory

bull Write code that can be executed faster

bull Total control over the code

bull Can work directly on memory locations

Example The same Fibonacci number calculator as above but in x86-64 assembly

language using ATampT syntax

_fib

movl $1 eax

fib_loop

cmpl $1 edi

jbe fib_done

movl eax ecx

addl ebx eax

movl ecx ebx

subl $1 edi

jmp fib_loop

fib_done

65

ret

4 Different types of high level language

No particular knowledge of the hardware is needed as high level languages create

programs that are portable and not tied to a particular computer or microchip

These programmer friendly languages are called lsquohigh levelrsquo as they are far

removed from the machine code instructions understood by the computer

Examples include C++ Java Pascal Python Visual Basic

Advantages

bull Easier to modify as it uses English like statements

bull Easierfaster to write code as it uses English like statements

bull Easier to debug during development due to English like statements

bull Portable code ndash not designed to run on just one type of machine

5 What are the different types of low level language

A low-level language is a programming language that provides little or no

abstraction of programming concepts and is very close to writing actual

machine instructions

Two examples of low-level languages are assembly and machine code

6 What is a compiler

A compiler is a special program that processes statements written in a particular

programming language and turns them into machine language or code that a

66

computers processor uses Typically a programmer writes language statements in a

language such as Pascal or C one line at a time using an editor The file that is created

contains what are called the source statements The programmer then runs the appropriate

language compiler specifying the name of the file that contains the source statements

When executing (running) the compiler first parses (or analyzes) all of the

language statements syntactically one after the other and then in one or more successive

stages or passes builds the output code

7 What is an Interpreter

Interpreter is a program that executes instructions written in a high-level language There

are two ways to run programs written in a high-level language The most common is

to compile the program the other method is to pass the program through an interpreter

8 What is an Assembler

67

The Assembler is used to translate the program written in Assembly language into

machine code The source program is a input of assembler that contains assembly

language instructions The output generated by assembler is the object code or machine

code understandable by the computer

9 Distinguish between compiler and interpreter

A compiler is a program that translates a source program written in some high-

level programming language (such as Java) into machine code for some computer

architecture (such as the Intel Pentium architecture) The generated machine code can be

later executed many times against different data each time

An interpreter reads an executable source program written in a high-level

programming language as well as data for this program and it runs the program against

the data to produce some results One example is the Unix shell interpreter which runs

operating system commands interactively

68

10 What is a source program

The programmer writes the source program using higher level language Therefore it is

easily readable by the humans Source programs usually contain meaningful variable

names and helpful comments to make it more readable A machine cannot directly

execute a source program A compiler helps to transform source program to executable

code to execute by the machine Alternatively is to use an interpreter It executes a

source program line by line without pre-compilation

11 What is an object program

Object program is usually a machine executable file which is the result of compiling a

source file using a compiler Apart from machine instructions they may include

debugging information symbols stack information relocation and profiling information

Since they contain instructions in machine code they are not easily readable by humans

69

But sometimes object programs refer to an intermediate object between source and

executable files

12 Distinguish between source program and object program

13 What are the advantages and disadvantages of machine language

Advantages Disadvantages

Machine language

makes fast and

efficient use of the

computer

All operation codes

have to be

remembered

It requires no All memory

70

Advantages Disadvantages

translator to translate

the code It is

directly understood

by the computer

addresses have to be

remembered

It is hard to amend or

find errors in a

program written in

the machine

language

14 What are the advantages and disadvantages of Assembly language

Advantages Of Assembly Language

1 Programs written in machine language are replaceable by mnemonics which are

easier to remember

2 Memory Efficient

3 It is not required to keep track of memory locations

4 Faster in speed

5 Easy to make insertions and deletions

6 Hardware Oriented

7 Requires fewer instructions to accomplish the same result

Disadvantages Of Assembly Language

1 Long programs written in such languages cannot be executed on small sized

computers

71

2 It takes lot of time to code or write the program as it is more complex in nature

3 Difficult to remember the syntax

4 Lack of portability of program between computers of different makes

5 No SDKs (System Development Kit)

15 Distinguish between high level language and Assembly language

high level language

- High level languages are easily understandable

- The programs that are developed in high level language are portable

- In case of high level languages debugging of the code is easy and the program written is

not machine dependent

Assembly language

- Although Assembly level languages are not easy to understand they are relatively easier

as compared to machine level languages

- The programs written in this language are not portable and the debugging process is

also not very easy

- The programs developed in assembly language are thoroughly machine dependent

16 Distinguish between machine language and assembly language

72

17 Describe Visual Programming

It is a method of creating programs by making connections between objects by clicking

on diagrams drawing pointing and icons It enables users to think more about solving

73

the problem that about handing the programming language The learning of syntax and

actual writing of code is very much less

18 Describe Object-Oriented Programming

A recent approach to software development is object oriented programming

It attempts to completely alter traditional software development methods It has the

potential for satisfying some of the enormous demands for more sophisticated software

19 Describe Internet Programming Language

Thousands of internet data and information sites around the world are text-based only

that is the users see no graphics animations and hear no sound But the world wide web

permits all of this To build such multimedia sites on the web a number of recently

developed programming language and standards are used

20 Explain HTML

Hypertext Markup Language (HTML) is the standard markup language for documents

designed to be displayed in a web browser HTML describes the structure of a web

page semantically and originally included cues for the appearance of the

document HTML elements are the building blocks of HTML pages

HTML is the main markup language of the web It runs natively in every browser and is

maintained by the World Wide Web Consortium

21 What is XML

bull XML stands for eXtensible Markup Language

bull XML is a markup language much like HTML

bull XML was designed to store and transport data

bull XML was designed to be self-descriptive

74

bull XML is a W3C Recommendation

XML tags identify the data and are used to store and organize the data rather than

specifying how to display it like HTML tags which are used to display the data XML is

not going to replace HTML in the near future but it introduces new possibilities by

adopting many successful features of HTML

XML Usage

A short list of XML usage says it all minus

bull XML can work behind the scene to simplify the creation of HTML documents for

large web sites

bull XML can be used to exchange the information between organizations and

systems

bull XML can be used for offloading and reloading of databases

bull XML can be used to store and arrange the data which can customize your data

handling needs

bull XML can easily be merged with style sheets to create almost any desired output

bull Virtually any type of data can be expressed as an XML document

22 Explain VRML

VRML (Virtual Reality Modeling Language) is a language for describing three-

dimensional ( 3-D ) image sequences and possible user interactions to go with them

Using VRML you can build a sequence of visual images into Web settings with which a

user can interact by viewing moving rotating and otherwise interacting with an

apparently 3-D scene For example you can view a room and use controls to move the

room as you would experience it if you were walking through it in real space

75

To view a VRML file you need a VRML viewer or browser which can be a plug-

in for a Web browser you already have Among viewers you can download for the

Windows platforms are blaxxuns CC Pro Platinums Cosmo Player WebFX

WorldView and Fountain Whurlwind and Voyager are two viewers for the Mac

23What is JAVA

Java is a general-purpose concurrent object-oriented class-based and the runtime

environment(JRE) which consists of JVM which is the cornerstone of the Java platform

This blog on What is Java will clear all your doubts about why to learn java features

and how it works

In this What is Java blog I would be covering following topics

bull What is Java used for

bull History of Java

bull What is Java

bull Features of Java

bull Components in Java

What is Java used for

Before I answer the question what is Java used for let me brief you about why you

should choose Java Java is highly popular and has dominated this field from early 2000rsquos

till the present 2018

Java has been used in different domains Some of them are listed below

bull Banking To deal with transaction management

bull Retail Billing applications that you see in a storerestaurant are completely

written in Java

76

bull Information Technology Java is designed to solve implementation

dependencies

bull Android Applications are either written in Java or use Java API

bull Financial services It is used in server-side applications

bull Stock market To write algorithms as to which company they should invest in

bull Big Data Hadoop MapReduce framework is written using Java

bull Scientific and Research Community To deal with huge amount of data

24 Write a short note on

a) Small talk ndash It is the first Object oriented programming language It is specially

developed for the Object oriented programming It was developed by Alan Kay in 1970

at Xerox corporation It uses a keyboard for entering text but all other tasks are performed

with mouse

b) ActiveX ndash ActiveX is a set of object-oriented programming technologies and tools that

Microsoft developed for Internet Explorer

ActiveX is a set of controls or reusable components that enables programs or

content of almost any type to be embedded within a web page

  • 1 Keyboard
  • 2 Mouse
  • 3 Touchpad
  • 4 Scanner
  • 5 Digital Camera
  • 6 Microphone
  • 7 Joystick
  • 8 Graphic Tablet
  • 9 Touch Screen
  • 10 Webcam
  • 1 Monitor
  • 2 Printer
  • 3 Headphones
  • 4 Computer Speakers
  • 5 Projector
    • Flatbed plotters
    • Drum Plotters
      • Bus topology
      • Bus topology is a network type in which every computer and network device is connected to single cable When it has exactly two endpoints then it is called Linear Bus topology
        • Features of Bus Topology
        • Advantages of Bus Topology
        • Disadvantages of Bus Topology
          • RING Topology
            • Features of Ring Topology
            • Advantages of Ring Topology
            • Disadvantages of Ring Topology
              • STAR Topology
              • In this type of topology all the computers are connected a single hub through a cable This hub is the central node and all others are connected to the central node
                • Features of Star Topology
                • Advantages of Star Topology
                • Disadvantages of Star Topology
                  • MESH Topology
                    • MESH Topology Routing
                      • HYBRID Topology
                        • Features of Hybrid Topology
                        • Advantages of Hybrid Topology
                        • Disadvantages of Hybrid Topology
                          • How does File Transfer Protocol Work
                            • A low-level language is a programming language that provides little or no abstraction of programming concepts and is very close to writing actual machine instructions
                            • Two examples of low-level languages are assembly and machine code
                            • Advantages Of Assembly Language
                            • Disadvantages Of Assembly Language
                              • XML Usage
                              • What is Java used for
Page 28: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 29: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 30: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 31: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 32: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 33: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 34: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 35: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 36: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 37: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 38: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 39: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 40: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 41: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 42: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 43: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 44: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 45: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 46: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 47: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 48: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 49: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 50: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 51: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 52: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 53: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 54: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 55: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 56: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 57: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 58: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 59: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 60: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 61: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 62: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 63: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 64: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 65: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 66: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 67: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 68: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 69: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 70: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 71: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 72: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 73: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 74: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 75: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …
Page 76: DEPARTMENT OF COMMERCE WITH COMPUTER APPLICATION …