department of commerce with computer application …
TRANSCRIPT
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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 ( )
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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)
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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
-
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
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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
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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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
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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
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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
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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
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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
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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
-