Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Notes: Fundamentals of Computing

(ETCS 111)

Unit 1

B Tech First Semester

Compiled by:

Prof. Shafiq ul Abidin, Department of IT

HMR Institute of Technology & Management

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

1. What is a computer?Computer is a device that transforms data into meaningful information. Data can be anything like marks obtained by you in various subjects. It can also be name, age, sex, weight, height, etc. of all the students in a class.

Computer can also be defined in terms of functions it can perform. A computer can i) accept data, ii) store data, iii) process data as desired, and iv) retrieve the stored data as and when required and v) print the result in desired format.

The major characteristics of a computer are high speed, accuracy, diligence, versatility and storage.

Fig: The block diagram of computer

The computer performs basically five major operations of functions irrespective of their size and make. These are

1) it accepts data or instruction by way of input,

2) it stores data,

3) it can process data as required by the user,

4) it gives results in the form of output, and

5) it controls all operations inside a computer.

We discuss below each of these operations.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

1. Input: this is the process of entering data and programs into the computer

system.

2. Control Unit (CU): The process of input, output, processing and storage is

performed under the supervision of a unit called 'Control Unit'. It decides when to

start receiving data, when to stop it, where to store data, etc. It takes care of step

-by-step processing of all operations in side the computer.

3. Memory Unit: Computer is used to store data and instructions.

Arithmetic Logic Unit (ALU): The major operations performed by the ALU are

addition, subtraction, multiplication, division, logic and comparison.

Output: This is the process of producing results from the data for getting useful

information.

The ALU and the CU of a computer system are jointly known as the central processing

unit (CPU). You may call CPU as the brain of any computer system.

2. Peripheral DevicesPeripheral devices are connected to the computer externally. These devices are used

for performing some specific functions.

Peripheral devices are as follows:

1. Input Devices

2. Output Devices

3. Other Peripherals

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: Different Peripheral Devices of Computer

Input Devices

Input devices accept data and instructions from the user. Following are the examples of

various input devices, which are connected to the computer for this purpose.

1.Keyboard

2. Mouse

3. Light Pen

4. Optical/magnetic Scanner

5. Touch Screen

6. Microphone for voice as input

7. Track Ball8. Joy Stick

9. Scanner

10. Digital Camera

Keyboard:

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

A keyboard (as shown in figure) is the most common input device. Several kinds of

keyboards are available, but they resemble each other with minor variations. The

keyboard in most common use is the QWERTY board.

Generally standard keyboard has 104 keys. In these keyboards, the cursor control keys

are duplicated to allow easier use of the numeric pad.

Mouse:

A mouse is an electro-mechanical, hand-held device (as shown in figure). It is used as a

pointer. It can perform functions like selecting menu commands, moving icons, resizing

indows, starting programs, and choosing options.

Fig: Mouse

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

The most common mouse uses an internal, magnetically coated ball, to detect the

movement of the mouse across a flat surface, usually a desktop. Now a days Optical or

laser mouse is used to detect the movement. All windows based applications today are

designed to work with a mouse. A mouse is used to replace hard -to-remember key

combinations with easier "Point and Click" actions. However, it cannot substitute all

keyboard operations. It can be alternative for commands based operations.

Light Pen:

An input device that utilizes a light-sensitive detector to select objects on a display

screen. A light pen is similar to a mouse (as shown in figure), except that with a light

pen you can move the pointer and select objects on the display screen by directly

pointing to the objects with the pen.

Fig: Light Pen

Optical Scanner:

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

These devices are used for automatic data collection. The devices of this category

completely eliminate manual input of data. For example, the bar-code reader is actually

just a special type of image scanner. An image scanner translates printed images into

an electronic format that can be stored in a computer’s memory, and with the right kind

of software, one can alter a stored image. Another example of scanner is optical

character recognition (OCR) device, used by banks to convert the scanned image of a

typed or printed page into text that can be edited on the computer.

Scanner: In computing, an image scanner—often abbreviated to just scanner, although the term is ambiguous out of context (barcode scanner, CAT scanner, etc.)—is

a device that optically scans images, printed text, handwriting, or an object, and

converts it to adigital image. Commonly used in offices are variations of the

desktop flatbed scannerwhere the document is placed on a glass window for

scanning. Hand-held scanners, where the device is moved by hand, have evolved from

text scanning "wands" to 3D scanners used for industrial design, reverse engineering,

test and measurement,orthotics, gaming and other applications. Mechanically-driven

scanners that move the document are typically used for large-format documents, where

a flatbed design would be impractical.

Modern scanners typically use a charge-coupled device (CCD) or a contact image

sensor (CIS) as the image sensor, whereas drum scanners, developed earlier and still

used for the highest possible image quality, use a photomultiplier tube (PMT) as the

image sensor. A rotary scanner, used for high-speed document scanning, is a type of

drum scanner that uses a CCD array instead of a photomultiplier. Non-contactplanetary

scanners essentially photograph delicate books and documents. All these scanners

produce two-dimensional images of subjects that are usually flat, but sometimes solid;

3D scanners produce information on the three-dimensional structure of solid objects.

Digital cameras can be used for the same purposes as dedicated scanners. When

compared to a true scanner, a camera image is subject to a degree of distortion,

reflections, shadows, low contrast, and blur due to camera shake (reduced in cameras

with image stabilisation). Resolution is sufficient for less demanding applications. Digital

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

cameras offer advantages of speed, portability and non-contact digitizing of thick

documents without damaging the book spine. As of 2010 scanning technologies were

combining 3D scanners with digital cameras to create full-color, photo-realistic 3D

models of objects.[citation needed]

In the biomedical research area, detection devices for DNA microarrays are called

scanners as well. These scanners are high-resolution systems (up to 1 µm/ pixel),

similar to microscopes. The detection is done via CCD or a photomultiplier tube.

Scanners usually attach to your personal computer with a Small Computer System Interface ( SCSI ). An application such as PhotoShop uses the TWAIN program to read in the image.

Some major manufacturers of scanners include: Epson, Hewlett-Packard, Microtek, and Relisys.

Fig: Scanner

Touch Screen:

Touch panel displays and pads are now being offered as alternatives to keyboard. Here

the input can be given through the computer screen, that accepts the input through

monitor; users touch electronic buttons displayed on the screen or they may use light

pen.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: Touch Screen

Micro Phone:

Microphone is an input device, which takes voice as input. The voice communication is more

error-prone than information through keyboard. There are two types of microphones available

(as shown in figure ):

Fig: Desktop microphone and Hand-held Microphone

Track Ball:

Trackball, a pointing device, is a mouse lying on its back (as shown in figure ). To move

the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand.

There are usually one to three buttons next to the ball, which you use just like mouse

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

buttons. The advantage of trackballs over mouse is that the trackball is stationary so it

does not require much space to use it. In addition, you can place a trackball on any type

of surface, including your lap. For both these reasons trackballs are popular pointing

devices for portable computers.

Fig: Track Ball

Joystick:

A joystick is an input device consisting of a stick that pivots on a base and reports its

angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal control device in the cockpit of many civilian and military

aircraft, either as a center stick or side-stick. It often has supplementary switches to

control various aspects of the aircraft's flight.

Joysticks are often used to control video games, and usually have one or more push-

buttons whose state can also be read by the computer. A popular variation of the

joystick used on modern video game consoles is the analog stick. Joysticks are also

used for controlling machines such as cranes, trucks, underwater unmanned vehicles,

wheelchairs, surveillance cameras, and zero turning radius lawn mowers. Miniature

finger-operated joysticks have been adopted as input devices for smaller electronic

equipment such as mobile phones.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: Joystick and its Components

Digital Camera: A digital camera (or digicam) is a camera that encodes digital

images and videosdigitally and stores them for later reproduction.[1] Most cameras sold

today are digital,[2] and digital cameras are incorporated into many devices ranging

from PDAsand mobile phones (called camera phones) to vehicles.

Digital and film cameras share an optical system, typically using a lens with a

variablediaphragm to focus light onto an image pickup device. [3] The diaphragm and

shutter admit the correct amount of light to the imager, just as with film but the image

pickup device is electronic rather than chemical. However, unlike film cameras, digital

cameras can display images on a screen immediately after being recorded, and store

and delete images from memory. Many digital cameras can also record moving videos

with sound. Some digital cameras can crop and stitch pictures and perform other

elementary image editing.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

A digital camera is a similar to a traditional film-based camera, but it captures

images digitally. When you take a picture with a digital camera, the image is recorded

by a sensor, called a "charged coupled device" or CCD. Instead of saving the picture

on analog film like traditional cameras, digital cameras save photos in digital memory.

Some digital cameras have built-in memory, but most use an SD or Compact

Flash card.

Digital cameras have several advantages over their analog counterparts. While film rolls

typically hold about 24 pictures, memory cards have the capacity to store several

hundred or even several thousand pictures on a single card. Therefore, photographers

can be much more liberal in the shots they take. Since the images are captured digitally,

unwanted images can be deleted directly on the camera. Most digital cameras also

include a small LCD screen that shows a live preview of the image, which makes it

easier to capture the perfect picture. These cameras usually include an option to record

video as well.

Output Devices

Output devices return processed data that is information, back to the user. Some of the commonly used output devices are:

1. Monitor (Visual Display Unit)2. Printers3. Plotter4. Speakers

Monitor:

Out of all the output devices, monitor (as shown in figure) is perhaps the most important

output device because people interact with this device most intensively than others.

Computer information is displayed, visually with a video adapter card and monitor.

Information processed within the CPU, that needs to be visually displayed, is sent to

video adapter. The video adapter converts information from the format used, in the

same manner as a television displays information sent to it by a cable service.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: CRT and LCT Monitor

Two basic types of monitors are used with microcomputers, which are as follows:

1. CRT2. LCD

Cathode Ray Tube (CRT): CRT or Cathode Ray Tube Monitor is the typical monitor

that you see on a desktop computer. It looks a lot like a television screen, and works the

same way. This type uses a large vacuum tube, called cathode ray tube (CRT).

Liquid Crystal Displays (LCD): This type of monitors are also known as flat panel

monitor. Most of these employ liquid crystal displays (LCDs) to render images. These

days LCD monitor are very popular. When people talk about the capabilities of various

monitors, one critical statistic is the resolution of the monitor. Most monitors have a

resolution of at least 800 x 600 pixels. High-end monitors

can have resolutions of 1024 x 768 pixels or even 1280 x 1024 pixels. Thus monitors

are available either in low resolution or in high resolution.

Printer:

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

After a document is created on the computer, it can be sent to a printer for a hard copy

(printout). Some printers offer special features such as colored and large page formats.

Some of the most commonly used printers are:

1. Laser Printer

2. Ink Jet Printer

3. Dot Matrix Printer

4. Line Printer

Laser Printer: A laser printer produces high quality print that one normally finds in

publishing. It is extremely fast and quiet. Moreover, the operation of a laser printer is

easy with automatic paper loading and no smudging or messing up of ink ribbons. The

fastest laser printer can print up to 200 pages per minute in monochrome (black and

white) and up to 100 pages per minute in colour.

Fig: Laser Printer

Ink- Jet Printer: An ink-jet printer creates an image directly on paper by spraying ink

through as many as 64 tiny nozzles. Although the image it produces is not generally

quite as sharp as the output of a laser printer, the quality of ink-jet images is still high.

In general, ink-jet printer offers an excellent middle ground between dot matrix and laser

printer. Like laser printer, an ink-jet printer is quiet and convenient, but not particularly

fast.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Typically, an ink-jet printer is more expensive than a dot-matrix printer, but costs only

half as much as a laser printer.

Fig: Ink – Jet Printer

Dot Matrix Printer: The dot matrix printer was very popular at one point of time. It is a

very versatile and inexpensive output device. In dot matrix printer the print head

physically "hits" the paper through the ribbon and produces text (or images) by

combinations of dots; hence the name dot matrix printer. Its speed is measured in characters per second (CPS). Although it is less expensive, it is louder, slower and

produces lower print quality.

Fig: Dot Matrix Printer

Line Printer: A line printer is generally used with large computer systems to produce

text based data processing reports. Line printers are high-speed printers with speeds

ranging anywhere from 100 to about 3800 lines per minute. In the past, print quality on

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

line printers was not high. Developments in technology are improving the print quality on

line printers. These are in the cost range of lacs of Rupees.

Fig: Line Printer

Impact Printer & Non-Impact Printer

Impact Printer: An impact printer is a type of printer that operates by striking a metal or

plastic head against an ink ribbon. The ink ribbon is pressed against the paper, marking

the page with the appropriate character, dot, line, or symbol. Common examples of

impact printers include dot matrix, daisy-wheel printers, and ball printers.

Dot matrix printers work by striking a grid of pins against a ribbon. Different characters

are printed by using different pin combinations. Daisy-wheel printers use a circular

wheel with "petals" that each have a different character or symbol on the end. In order

to print each character, the wheel spins to the appropriate petal and a hammer strikes

the petal against the ribbon and the page. Similarly, ball printers use a spherical ball

with raised characters on the outside. The ball spins to each character before printing it

on the page.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

While impact printers still have some uses (such as printing carbon copies), most

printers are nownon-impact printers. These printers, such as laser and inkjet printers

are much quieter than impact printers and can print more detailed images.

Non Impact Printer : Early printers, such as dot matrix and daisywheel printers were

called impact printers, since they operated by striking an ink ribbon against the paper.

Most modern printers, including inkjet and laser printers, don't include an ink ribbon and

are considered to be non-impact printers.

Non-impact printers are generally much quieter than impact printers since they don't

physically strike the page. For example, inkjet printers spray tiny drops of ink onto the

page, while laser printers use a cylindrical drum that rolls electrically charged ink onto

the paper. Both of these methods are non-impact and provide an efficient printing

process that produces little sound. The low impact nature of inkjet and laser printers

also means they are less likely to need maintenance or repairs than earlier impact

printers.

An impact printer is a printer that strikes a print head against an ink ribbon to mark the

paper. Common examples include dot matrix and daisy-wheel printers.

Fig: Images of Non Impact Printers

Plotter:

A plotter is a special kind of output device that, like a printer, produces images on

paper, but does so in a different way. Plotters are designed to produce large drawings

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

or images, such as construction plans for buildings or blueprints for mechanical objects.

A plotter can be connected to the port normally used by a printer.

An array of different colored pens in a clip rack and a robotic arm is part of plotter. The

instructions that a plotter receives from a computer consist of a color, and beginning

and ending coordinates for a line. With that information, the plotter picks up the

appropriate pen through its arm, positions it at the beginning coordinates drops the pen

down to the surface of the paper and draws to the ending coordinates. Plotters draw

curves by creating a sequence of very short straight lines.

Plotters usually come in two designs:

1. Flat Bed: Plotters of small size to be kept on table with restriction of paper size.

2. Drum: These plotters are of big size using rolls of paper of unlimited length.

Fig: Flat Bed and Drum Plotter

Speaker:

Speakers (as shown in figure) are another type of output device, which allow you to

listen to voice like music, and conversation with people.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: Speaker

Direct Data Entry Devices : - MICR, OMR, OCR

Optical Mark Recognition (OMR):  (also called optical mark reading and OMR) is the

process of capturing human-marked data fromdocument forms such as surveys and

tests.

OMR is basically a system that gathers information by using a hardware device that

detects a reflection or an absence of reflection from a card or piece of paper. OMR

enables the processing of hundreds or thousands of documents every hour

automatically.

OMR processing is popular for tests, where students receive a special card containing

several empty circles and a packet that contains the questions and possible answers to

each of the questions. The student must complete the test by using a pencil to fill in

each blank circle with what he or she believes is the correct answer. For example, if the

answer is "B", the student would have to fill in the "B Circle" in order to get the answer

correct.

Once the card or form has been completed a user would feed the cards into a system

that grades or gathers information from the card. An example of an OMR system is the

Scanmark 5500 from Scantron, a system that is capable of processing 5,500

documents every hour.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: Sample of OMR

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Uses and Advantages of OMR

The main advantages of OMR technology are as follows:

OMR scanning is fast: An OMR scanner can maintain a throughput of 2000 to 10,000

forms per hour. This activity can be controlled and processed by a single PC

workstation, which can handle any volume the scanner can generate. Increasing the

throughput simply requires upgrading the scanner.  Double entry is not required.

OMR scanning is accurate:  It consistently provides unmatched accuracy when reading

data, exceeding the accuracy of expert key-entry clerks because it eliminates

transcription errors.

OMR scanning is cost effective: With OMR technology, organizations can accomplish a

wide variety of administrative tasks rapidly and accurately from a central location, with

minimum initial and ongoing outlay of funds.

OMR scanning is easy to implement and support : Compared to many PC network

installations, OMR scanners' need for ongoing technical support is minimal. OMR

scanners also solve most system availability issues: data can be recorded on an OMR

form even when a PC or network goes down. If questions arise, a source form is

available to validate results.

Optical Character Recognition (OCR): Often abbreviated OCR, optical character

recognition refers to the branch of computer science that involves reading text from

paper and translating the images into a form that the computer can manipulate (for

example, into ASCII codes). An OCR systemenables you to take a book or a magazine

article, feed it directly into an electronic computer file, and then edit the file using a word

processor.

All OCR systems include an optical scanner for reading text, and

sophisticated software for analyzing images. Most OCR systems use a combination

of hardware (specialized circuit boards) and software to recognize characters, although

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

some inexpensive systems do it entirely through software. Advanced OCR systems can

read text in large variety of fonts, but they still have difficulty with handwritten text.

The potential of OCR systems is enormous because they enable users to harness the

power of computers toaccess printed documents. OCR is already being used widely in

the legal profession, where searches that once required hours or days can now be

accomplished in a few seconds.

Applications of OCR : OCR engines have been developed into many kinds of object

oriented OCR applications, such as receipt OCR, invoice OCR, check OCR, legal billing

document OCR.

They can be used for:

Data entry for business documents, e.g. check, passport, invoice, bank statement

and receipt

Automatic number plate recognition

Automatic insurance documents key information extraction

Extracting business card information into a contact list

More quickly make textual versions of printed documents, e.g. book

scanning for Project Gutenberg

Make electronic images of printed documents searchable, e.g. Google Books

Converting handwriting in real time to control a computer (pen computing)

Defeating CAPTCHA anti-bot systems, though these are specifically designed to

prevent OCR[4][5][6]

Assistive technology for blind and visually impaired users

Magnetic Ink Character Recognition (MICR) : MICR is a character-recognition

technology used mainly by the banking industry to ease the processing and clearance

of cheques and other documents. The MICR encoding, called the MICR line, is at the

bottom of cheques and other vouchers and typically includes the document-type

indicator, bank code, bank account number, cheque number, cheque amount, and a

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

control indicator. The technology allows MICR readers to scan and read the information

directly into a data-collection device. Unlikebarcodes and similar technologies, MICR

characters can be read easily by humans. The MICR E-13B font has been adopted as

the international standard inISO 1004:1995,[1] but the CMC-7 font is widely used in

Europe.Magnetic ink character recognition is a technology used to verify the legitimacy

or originality of paper documents, especially checks. Special ink, which is sensitive to

magnetic fields, is used in the printing of certain characters on the original documents.

Information can be encoded in the magnetic characters.

There are two major MICR fonts in use: E-13B and CMC-7. E-13B has a 14 character

set, while CMC-7 has 15—the 10 numeric characters, plus control characters.

The MICR E-13B font is the standard in Australia, Canada, the United Kingdom, the

United States, and other countries. (The "13" in the font's name comes from the 0.013-

inch grid used to design it.[2]) 0.013-inch is one typographic point. Besides decimal

digits, it also contains the following symbols: ⑆ (transit: used to delimit a bank

branch routing transit number), ⑇ (amount: used to delimit a transaction amount), ⑈ (on-

us: used to delimit a customer account number), and ⑉ (dash: used to delimit parts of

numbers—e.g., routing numbers or account numbers).

Major European countries, including France and Italy, use the CMC-7 font, developed

by Groupe Bull in 1957.

The use of MICR can enhance security and minimize the losses caused by some types

of crime. If a document has been forged - for example, a counterfeit check produced

using a color photocopying machine, the magnetic-ink line will either not respond to

magnetic fields, or will produce an incorrect code when scanned using a device

designed to recover the information in the magnetic characters. Even a legitimate check

can be rejected if the MICR reader indicates that the owner of the account has a history

of writing bad checks.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Retailers commonly use MICR readers to minimize their exposure to check fraud.

Corporations and government agencies also use the technology to speed up the sorting

of documents.

MICR characters are printed in the form of either an e-13b or cmc-7 font.  each font

series is made up of a series of numbers and symbols specifically designed for

readability on check sorting machines which read at extremely high rates of speed.   the

symbols provide a beginning and ending point for each group of numbers allowing the

machine to quickly determine what each series of number signifies.  line placement,

character placement, skew and quality are several critical components of printing micr;

the line must be precisely positioned in the micr clear band area.  to create consistency

in the check clearing process it is critical that each character is readable and that the

printing methods are reliable.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

What is resolution?

Resolution is the term used to describe the number of dots, or pixels, used to display an

image.

Higher resolutions mean that more pixels are used to create the image, resulting in a

crisper, cleaner image.

The display, or resolution on a monitor, is composed of thousands of pixels or dots. This

display is indicated by a number combination, such as 800 x 600. This indicates that

there are 800 dots horizontally across the monitor, by 600 lines of dots vertically,

equaling 480,000 dots that make up the image you see on the screen.

Refers to the sharpness and clarity of an image. The term is most often used to

describe monitors, printers, and bit-mapped graphic images. In the case of dot-

matrix and laser printers, the resolution indicates the number of dots per inch. For

example, a 300-dpi (dots per inch) printer is one that is capable of printing 300

distinct dotsin a line 1 inch long. This means it can print 90,000 dots per square inch.

For graphics monitors, the screen resolution signifies the number of dots (pixels) on the

entire screen. For example, a 640-by-480 pixel screen is capable of displaying 640

distinct dots on each of 480 lines, or about 300,000 pixels. This translates into different

dpi measurements depending on the size of the screen. For example, a 15-

inch VGAmonitor (640x480) displays about 50 dots per inch.

Printers, monitors, scanners, and other I/O devices are often classified as high

resolution, medium resolution, orlow resolution. The actual resolution ranges for each of

these grades is constantly shifting as the technology improves.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Storage Devices

Primary Memory : Primary memory is computer memory that is accessed directly by

the CPU. This includes several types of memory, such as the processor cache and

system ROM. However, in most cases, primary memory refers to system RAM.

Alternatively referred to as internal memory, main memory, and primary

memory, primary storage is a storage location that holds memory for short periods of

times while the computer running. For example, computer RAM and cache are both

examples of a primary storage device. This storage is the fastest memory in your

computer and is used to store data while it's being used. For example, when you open a

program data is moved from the secondary storage into the primary storage.

RAM stands for Random Access Memory and t is read/write memory. Information can

be written into and read from a RAM. It is a volatile memory. It retains the stored

information as long as it is supplied with power. When power supply is switched off or

interrupted the stored information in the RAM is lost. RAMs of various capacities are

available for example, 1K, 4K, 16K, 64K, 1M, 4M and so on.

Types of RAMsThere are two important types of RAMs - static RAM and dynamic RAM. Static RAMs

retain stored information as long as power supply is on . But a dynamic RAM loses its

stored information in a very short time even though the power supply is on. Therefore,

dynamic RAMs have to be refreshed periodically, generally every 2 millisecond. The

dynamic RAMs are cheaper and have high packing density and moderate speed. They

consume less power. They are used where large capacity memories are needed. Static

RAMs are costlier and consume more power. They do not need refreshing circuiting.

They have higher speed than dynamic RAMs. Static RAM and dynamic RAM are also

written as SRAM and DRAM.

Difference between SRAM AND DRAM

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

SRAM (Static RAM)1. SRAM is a static RAM because each bit of SRAM remains stored until

power supply to the computer goes off.

2. For SRAM each bit is stored in flip-flop.3. SRAM does not need any extra circuit for maintaining bit value (logic 1 or

0) in flip-flops.4. With respect to same size of DRAM, SRAM can store fewer amounts of

data.5. SRAM cells are large with respect to DRAM cells. 6. SRAM is faster than DRAM because SRAM does not need any refreshing

circuit before accessing the bits of SRAM.7. This memory is made of transistors.8. It is very costly as compared to DRAM.9. It has less storage density.

DRAM (Dynamic RAM)1. DRAM is called dynamic RAM, because each bit of DRAM needs to be

refreshed periodically.2. For DRAM each bit is stored in capacitors.3. DRAM needs extra circuits for maintaining each bit value.4. With respect to same size of SMAR, DRAM can store more amounts of data.5. DRAM cells are smaller with respect to SRAM cells.6. DRAM is slower because it needs refreshing periodically before accessing

bits in the cell.7. This memory is made of capacitors.8. It is relatively much cheaper.9. It has higher storage density.

Read Only MemoryROM stands for Read Only Memory and it is a permanent type memory. It contents are

not lost when power supply is switched off. The user cannot write into a ROM. Its

contents are written into at manufacturing time. ROMs store permanent programs and

other types of information which are needed by the computer to execute user programs.

ROMs store function such as sine, cosine, logarithm, square root, exponential and code

conversion tables, etc. An example of a ROM is Toshiba Mask ROM, TCS 534000, 512

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

KX8 bits again. There are two subsections of ROM such as - PROM and CD ROM

which are described below:

PROMs (PROGRAMMABLE ROMs)

Programmable ROMs called PROMs are also available. Further, different types of

PROMs such as Erasable PROM called EPROM, electrically erasable PROM called

E2PROM are available. Users can write information in PROMs, EPROMs and

E2PROMs. Once programmed the recorded information into an EPROM or E2PROM

can be erased to record different information, whereas in a PROM the information once

written by the user can not be changes. Such information is required while executing

user programs. An example of PROM is 74S287.

A variation of ROM chip is programmable read only memory. ROM chip are supplied by

the computer system manufacture and it is not possible for a customer to modify the

programs stored inside the ROM chip. However, it is possible for a user to customize a

system by converting his own programs to micro programs and storing them in a PROM

chip. Once the users programs are stored in a PROM chip, they can usually be

executed in a fraction of the time previously required. PROMs are programmed to

record information using a special facility known as a pro-programmer. However, once

the chip has been programmed, the recorded information can not be changed, i.e. the

PROM becomes a ROM and it is only possible to read the stored information. PROM is

also non-volatile storage, i.e. the stored information remains intact even if power is

switched off.

EPORM (ERASABLE PROGRAMMABLE READ ONLY MEMORY)Once information is stored in a ROM or a PROM chip it can not be changed or altered.

However, there is another type of memory chip called erasable programmable read only

memory that overcomes this problem. As the name implies, it is possible to erase

information stored in an EPROM chip the chip can be reprogrammed to store new

information usinging a special prom-programmer facility. Information stored in an 

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

EPROM chip is erased by exposing the chip for some time to ultraviolet light. When an

EPROM is in use, information can only be read and the information remains on the chip

until it is erased. EPROMs are mainly used by R & D personnel because they frequently

change the micro programs to test the efficiency of the computer system with new

programs.

E2PROM (ELECTONICALY ERASABLE PROGRAMMABLE ROM )It is also called flash BIOS, in this type of memory high voltage electric pulses are used

to erase information content in the ROM. New information can be recorded in ROM by

special software program although there is a limit to the number of times that can be

programmed. E2PROM chip allows user to upgrade their BIOS.

DIFFERENCE BETWEEN PRIMARY MEMORY AND SECONDARY MEMORY

PRIMARY MEMORY

1. Primary memory is purely made of electronic devices either by transistor or capacitor.

2. It can directly communicate with CPU (Central Processing Unit) hence it is called main memory. 

3. It is relatively faster than secondary memory. 4. It is needed basically by the system itself for processing functions. 5. It is relatively much costly than secondary memory. 6. It has less memory space as compared to the secondary memory.

SECONDARY MEMORY

1.       It is not purely made of electronic devices.2.       It cannot directly communicate with CPU hence it is called auxiliary

memory.3.      It is comparatively slower than primary memory.4.      It is needed basically by users for storing of data and information

permanently.          5.       It is comparatively much cheaper than primary memory.6.       It has a huge memory space as compared to primary memory.

DIFFERENCE BETWEEN RAM AND ROM

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

RAM (RANDOM ACCESS MEMORY)1. RAM is both read and write enable means users can write into and read

from a RAM.2. RAM is volatile in nature means its content gets erased when power

supply to the computer is switched off.3. A user can write information in RAM temporarily.4. It is necessary for holding of data at the time of processing.

ROM (READ ONLY MEMORY)

1. ROM is only read enable.2. It is very much permanent like such as secondary memory.3. Normally users cannot write anything into ROM other than E2PROM.4. It is necessary only at the time of starting up (Booting) of the computer.5. Contents are written at the time of manufacturing.6. ROM contains functions such as sine, cosine, square root, logarithm, code

conversion table, exponential tables, etc.

Cache MemoryCache memory, also called CPU memory, is random access memory (RAM) that a

computer microprocessor can access more quickly than it can access regular RAM. 

As the microprocessor processes data, it looks first in the cachememory and if it finds

the data there (from a previous reading of data), it does not have to do the more time-

consuming reading of data from larger memory. 

Cache memory is fast and it is expensive. It is categorized in levels that describe its

closeness and accessibility to the microprocessor. Level 1 (L1) cache, which is

extremely fast but relatively small, is located close to the processor.  Level 2 (L2) cache

is located half-way between the process and the system bus; it is fairly fast and

medium-sized. Level 3 (L3) cache is relatively large and close to RAM. 

Types of Secondary Memories

Hard Disk

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

A magnetic disk on which you can store computer data. The term hard is used to

distinguish it from a soft, or floppy, disk. Hard disks hold more data and are faster

than floppy disks. A hard disk, for example, can store anywhere from 10 to more than

100 gigabytes, whereas most floppies have a maximum storagecapacity of 1.4

megabytes.

A single hard disk usually consists of several platters. Each platter requires

two read/write heads, one for each side. All the read/write heads are attached to a

single access arm so that they cannot move independently. Each platter has the same

number of tracks, and a track location that cuts across all platters is called a cylinder.

For example, a typical 84 megabyte hard disk for aPCmight have two platters (four

sides) and 1,053 cylinders.

In general, hard disks are less portable than floppies, although it is possible to

buy removable hard disks.

A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard disk drive,"

that stores and provides relatively quick access to large amounts of data on an

electromagnetically charged surface or set of surfaces.

A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard disk drive,"

that stores and provides relatively quick access to large amounts of data on an

electromagnetically charged surface or set of surfaces. Today's computers typically

come with a hard disk that contains several billion bytes (gigabytes) of storage.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fig: Hard Disk

Define cylinder, track and sector of a hard disk

A disk is divided into tracks, cylinders, and sectors. A track is that portion of a disk

which passes under a single stationary head during a disk rotation, a ring 1 bit wide.

A cylinder is comprised of the set of tracks described by all the heads (on separate

platters) at a single seek position. Each cylinder is equidistant from the center of the

disk. A track is divided into segments of sectors, which is the basic unit of storage.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

On Sun systems a sector is 512 bytes (1 disk block) of data, with header and trailer

information. The latter make it possible for the controller to identify sectors, detect data

errors, and perform error corrections when necessary. The actual layout of a disk sector

will vary depending on the controller, but should look something like that shown in Fig.

2.3. There are two Preambles and a Postamble (whose sizes may vary due to rotational

speed, etc., and are disk dependent). The Header field lets the controller know where

the head is positioned, and the ECC field is for error correction.

The number of sectors per track varies with the radius of the track on the platter. The

outermost tracks is larger and can hold more sectors than the inner ones. These outer

tracks also spin faster under the head than do the inner ones, because while the

angular speed remains the same, the larger circumference results in more sectors

spinning by in the same period for the outer tracks. Disk blocks are numbered starting at

the outermost track, so put the data you expect to access most often on partition, or

slice, 0.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Magnetic Tape

Magnetic tape is a medium for magnetic recording, made of a thin magnetizable

coating on a long, narrow strip of plastic. It was developed in Germany, based

on magnetic wire recording. Devices that record and play back audio and video using

magnetic tape are tape recorders and video tape recorders. A device that stores

computer data on magnetic tape is a tape drive (tape unit, streamer).

Magnetic tape revolutionized broadcast and recording. When all radio was live, it

allowed programming to be prerecorded. At a time whengramophone records were

recorded in one take, it allowed recordings in multiple parts, which mixed and edited

with tolerable loss in quality. It is a key technology in early computer development,

allowing unparalleled amounts of data to be mechanically created, stored for long

periods, and to be rapidly accessed.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Today, other technologies can perform the functions of magnetic tape. In many cases

these technologies are replacing tape. Despite this, innovation in the technology

continues and tape is still widely used.

Over years, magnetic tape can suffer from deterioration called sticky-shed syndrome.

Caused by absorption of moisture into the binder of the tape, it can render the tape

unusable.

Fig: Magnetic Tape

Sequential MediumThe major drawback of tape is its sequential format. Locating a specific record requires

reading every record in front of it or searching for markers that identify predefined

partitions. Although most tapes are used for archiving rather than routine updating,

some drives allow rewriting in place if the byte count does not change. Otherwise,

updating requires copying files from the original tape to a blank tape (scratch tape) and

adding the new data in between.

Blu Ray Disk

Blu-ray is an optical disc format designed to display high definition video and store large

amounts of data.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Blu-ray is the successor to DVD. The standard was developed collaboratively by

Hitachi, LG, Matsushita (Panasonic), Pioneer, Philips, Samsung, Sharp, Sony, and

Thomson. It became the default optical disk standard for HD content and optical data

storage after winning a format war with HD-DVD, the format promoted by Toshiba and

NEC.

The format's name comes from the fact that a blue laser reads from and writes to the

disc rather than the red laser of DVD players. The blue laser has a

405 nanometer (nm)wavelength that can focus more tightly than the red lasers used for

writable DVD. As a consequence, a Blu-ray disc can store much more data in the same

12 centimeter space. Like the rewritable DVD formats, Blu-ray uses phase

change technology to enable repeated writing to the disc.

Blu-ray's standard storage capacity is enough to store a continuous backup copy of

most people's hard drives on a single disc. Initially, the format had a 27 gigabyte (GB)

single-sided capacity and 50 GB on dual-layer discs. Single-sided Blu-ray discs can

store up to 13 hours of standard video data, compared to single-sided DVD's 133

minutes. In July 2008, Pioneer announced that they had found a way to increase

capacity to 500 GB by creating 20-layer discs. These discs are not, however, expected

to be commercially available in the near future.

Blu-ray also features data streams at 36 megabits per second (Mbps), fast enough for

high quality video recording. Blu-ray discs will not play on current CD and DVD players,

because those players lack the blue-violet laser required to read the discs. If the

appropriate lasers are included, however, Blu-ray players can play the other two

formats. Blu-ray disc players (BDPs) are available from a number of anufacturers,

including Panasonic, Pioneer, Samsung and Sony. Sony's Playstation 3 also has a Blu-

ray drive installed.

What is Blu-ray?Blu-ray, also known as Blu-ray Disc (BD) is the name of a new optical disc format that is

rapidly replacing DVD. The format was developed to enable recording, rewriting and

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

playback of high-definition video (HD), as well as storing large amounts of data. The

format offers more than five times the storage capacity of traditional DVDs and can hold

up to 25GB on a single-layer disc and 50GB on a dual-layer disc.

Why the name Blu-ray?The name Blu-ray is derived from the underlying technology, which utilizes a blue-violet

laser to read and write data. The name is a combination of "Blue" (blue-violet laser) and

"Ray" (optical ray). According to the Blu-ray Disc Association the spelling of "Blu-ray" is

not a mistake, the character "e" was intentionally left out so the term could be registered

as a trademark. 

The correct full name is Blu-ray Disc, not Blu-ray Disk (incorrect spelling) The correct

shortened name is Blu-ray, not Blu-Ray (incorrect capitalization) or Blue-ray (incorrect

spelling) The correct abbreviation is BD, not BR or BRD (wrong abbreviation)

Who developed Blu-ray?What Blu-ray formats are planned?

As with conventional CDs and DVDs, Blu-ray plans to provide a wide range of formats

including ROM/R/RW. The following formats are part of the Blu-ray Disc specification: 

BD-ROM - read-only format for distribution of HD movies, games, software, etc.

BD-R - recordable format for HD video recording and PC data storage.

BD-RE - rewritable format for HD video recording and PC data storage.

There's also plans for a BD/DVD hybrid format, which combines Blu-ray and DVD on

the same disc so that it can be played in both Blu-ray players and DVD players.

How much data can you fit on a Blu-ray disc?

A single-layer disc can hold 25GB.

A dual-layer disc can hold 50GB.

To ensure that the Blu-ray Disc format is easily extendable (future-proof) it also includes

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

support for multi-layer discs, which should allow the storage capacity to be increased to

100GB-200GB (25GB per layer) in the future simply by adding more layers to the discs.

How much video can you fit on a Blu-ray disc?

Over 9 hours of high-definition (HD) video on a 50GB disc.

About 23 hours of standard-definition (SD) video on a 50GB disc.

Generation of Computers

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

First Generation (1940-1956) Vacuum TubesThe first computers used vacuum tubes for circuitry and magnetic drums for memory,

and were often enormous, taking up entire rooms. They were very expensive to operate

and in addition to using a great deal of electricity, generated a lot of heat, which was

often the cause of malfunctions.

First generation computers relied on machine language, the lowest-level programming

language understood by computers, to perform operations, and they could only solve

one problem at a time. Input was based on punched cards and paper tape, and output

was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing

devices. The UNIVAC was the first commercial computer delivered to a business client,

the U.S. Census Bureau in 1951.

Fig : A UNIVAC computer at the Census Bureau.Image Source: United States Census Bureau

Second Generation (1956-1963) Transistors

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Transistors replaced vacuum tubes and ushered in the second generation of computers.

The transistor was invented in 1947 but did not see widespread use in computers until

the late 1950s. The transistor was far superior to the vacuum tube, allowing computers

to become smaller, faster, cheaper, more energy-efficient and more reliable than their

first-generation predecessors. Though the transistor still generated a great deal of heat

that subjected the computer to damage, it was a vast improvement over the vacuum

tube. Second-generation computers still relied on punched cards for input and printouts

for output.

Second-generation computers moved from cryptic binary machine language to

symbolic, or assembly, languages, which allowed programmers to specify instructions in

words. High-level programming languages were also being developed at this time, such

as early versions of COBOL and FORTRAN. These were also the first computers that

stored their instructions in their memory, which moved from a magnetic drum to

magnetic core technology.

The first computers of this generation were developed for the atomic energy industry.

Third Generation (1964-1971) Integrated CircuitsThe development of the integrated circuit was the hallmark of the third generation of

computers. Transistors were miniaturized and placed on silicon chips,

called semiconductors, which drastically increased the speed and efficiency of

computers.

Instead of punched cards and printouts, users interacted with third generation

computers through keyboards andmonitors and interfaced with an operating system,

which allowed the device to run many different applications at one time with a central

program that monitored the memory. Computers for the first time became accessible to

a mass audience because they were smaller and cheaper than their predecessors.

Fourth Generation (1971-Present) MicroprocessorsThe microprocessor brought the fourth generation of computers, as thousands of

integrated circuits were built onto a single silicon chip. What in the first generation filled

an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

1971, located all the components of the computer—from the central processing unitand

memory to input/output controls—on a single chip. In 1981 IBM introduced its first

computer for the home user, and in 1984 Apple introduced the Macintosh.

Microprocessors also moved out of the realm of desktop computers and into many

areas of life as more and more everyday products began to use microprocessors.

As these small computers became more powerful, they could be linked together to form

networks, which eventually led to the development of the Internet. Fourth generation

computers also saw the development of GUIs, the mouseand handheld devices.

Fifth Generation (Present and Beyond) Artificial IntelligenceFifth generation computing devices, based on artificial intelligence, are still in

development, though there are some applications, such as voice recognition, that are

being used today. The use of parallel processing and superconductors is helping to

make artificial intelligence a reality. Quantum computation and molecular and

nanotechnology will radically change the face of computers in years to come. The goal

of fifth-generation computing is to develop devices that respond to natural

language input and are capable of learning and self-organization.

Computer Languages

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Languages are a means of communication. Normally people interact with each other

through a language. On the same pattern, communication with computers is carried out

through a language. This language is understood both by user and the machine. Just as

every language like English, Hindi has its grammatical rules; every computer language

is bound by rules known as SYNTAX of that language. The user is bound by that syntax

while communicating with the computer system.

Computer languages are broadly classified as:

1. Low Level Language:

2. High Level Languages

Low Level Languages :The term low level means closeness to the way in which

machine understand. The low level languages are:

a. Machine Language:This is the language (in the form of 0’s and 1’s, called binary numbers) understood

directly by the computer. It is machine dependent. It is difficult to learn and even more

difficult to write programs.

b. Assembly Language:

This is the language where the machine codes comprising of 0’s and 1’s are substituted

by symbolic codes (called mnemonics) to improve their understanding. It is the first

step to improve programming structure. Assembly language programming is simpler

and less time consuming than machine level programming, it is easier to locate and

correct errors in assembly language than in machine language programs. It is also

machine dependent. Programmers must have knowledge of the machine on which the

program will run.

High Level Languages : You know that low level language requires extensive

knowledge of the hardware since it is machine dependent. To overcome the limitation,

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

high level language has been evolved which uses normal English like, easy to

understand statements to solve any problem. Higher level languages are computer

independent and programming becomes quite easy and simple.

Various high level languages are given below:

BASIC (Beginners All Purpose Symbolic Instruction Code): It is widely used, easy to learn general purpose language. Mainly used in microcomputers in earlier days.

COBOL (Common Business Oriented Language): A standardized language used for commercial applications.

FORTRAN (Formula Translation): Developed for solving mathematical and scientific problems. One of the most popular languages among scientific community.

C: Structured Programming Language used for all purpose such as scientific application, commercial application, developing games etc.

C++: Popular object oriented programming language, used for general purpose.

JAVA

LISP

Prolog

Introduction to Software

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

As you are aware, computer cannot do anything on its own. It is the user who instructs

computer; what to do, how to do and when to do. In order to perform any task, you have

to give a set of instructions in a particular sequence to the computer. These sets of

instructions are called Programs. Software refers to a set of programs that makes the

hardware perform a particular set of tasks in particular order. Software can be classified

mainly into following categories and sub-categories are shown in Figure

Fig: Classification of Software

System software:System software  is any computer software that provides the infrastructure over which

programs can operate, i.e. it manages and controls computer hardware so that

application software can perform. Operating systems, such as GNU, Microsoft

Windows, Mac OS X or Linux, are prominent examples of system software.

System software is software that basically makes the computer work. Besides operating

systems, other examples are anti-virus software, communication software and printer

drivers. Without the system software the computer doesn't work. In contrast to system

software, software that allows you to do things like create text documents, play games,

listen to music, or surf the web is called application software.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

In general application software are programs that enable the end-user to perform

specific, productive tasks, such as word processing or image manipulation. System

software performs tasks like transferring data from memory to disk, or rendering text

onto a display device.

Types of system software

System Software can be classified as operating system, device drivers and utility

software. An operating system creates an interface between user and the system

hardware, while other system software will refine or allow greater interaction with the

machine's hardware.

System software helps run the computer hardware and computer system. It includes

operating systems, device drivers, diagnostic tools, servers, windowing systems,

utilities, language translator, data communication programs, data management

programs and more. The purpose of systems software is to insulate the applications

programmer as much as possible from the details of the particular computer complex

being used, especially memory and other hardware features, and such accessory

devices as communications, printers, readers, displays, keyboards, etc.

Specific kinds of system software include:

Loading programs

Operating systems (and their components, many of which are classified as

system software)

Device drivers

Linkers

Utility software

Desktop environment / Graphical user interface

Shell

BIOS

Hyper visors

Boot loaders

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

If system software is stored on non-volatile memory such as integrated circuits, it is

usually termed firmware.

One characteristic in which most system software differ from application software is

machine dependency

»         e.g. assembler translates mnemonic instructions into machine code

»         e.g. compilers must generate machine language code

»         e.g. operating systems are directly concerned with the management of

nearly all of the resources of a computing system

There are some aspects of system software that do not directly depend upon the type of

computing system

»         e.g. general design and logic of an assembler

»         e.g. code optimization techniques

 When you switch on the computer the programs stored in ROM are executed which

activates different units of your computer and makes it ready for you to work on it. This

set of programs can be called system software.

System software means sets of programs, responsible for running the computer,

controlling various operations of computer systems and management of computer

resources. Operating System (OS) falls under this category.

An operating system is a system software that provides an interface for a user to

communicate with the computer, manages hardware devices (disk drives, keyboard,

monitor, etc), manages and maintains disk file systems and supports application

programs. Some popular Operating systems are UNIX, Windows and Linux.

Although operating system provides all the features users need to use and maintain

their systems, inevitably, they still do not meet everyone’s expectations. This has led to

another type of system software called "Utilities". These are programs that bridge the

gap between the functionality of an OS and the needs of users. Utility programs are a

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

broad category of software such as compress (zip)/uncompress (unzip) files software,

anti virus software, split and join files software, etc.

Single User Operating Systems :- DOS, MSDOS, CP/M and early versions of MacMultiuser Systems: - Windows NT, Windows XP, Unix, Linux, Zenix

Application Software:

Application software is a set of programs, which are written to perform specific tasks, for

example: An application package for managing library known as library information system is used to manage information of library such as: keeping book details, account

holder details, book issue details, book return details etc. Another application package

for managing student details is called student’s information system, manages

student’s roll no, name, parents name, address, class, section, processing of

examination results etc. Application software can be broadly classified into two types:

1. Generalized packages (Off-the-shelf)

2. Customized packages

Generalized Packages : These are user friendly softwares written to cater to user’s

very general needs such as preparing documents, drawing pictures, database to

manage data/information, preparing presentations, play games etc. It is a group of

programs that provide general purpose tools to solve specific problems. Some of the

generalized packages are listed below:

Word Processing Software(for preparing documents): Word Perfect, MS-Word,

OpenOffice.org Writer

Spreadsheets (Data Analysis): Lotus Smart suites, MSExcel, OpenOffice.org

Calc, Apple Numbers

Presentations : Presentation Graphics, MS-PowerPoint, OpenOffice.org Impress

Database Management System: MS-Access, OpenOffice.org Base, MS-SQL

Server, ORACLE

Graphics Tools: Paint shop pro, Adobe Photoshop

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Customized Packages : These are the applications that are customized (or developed)

to meet the specific requirements of an organization/institution.

For Example: Student information details, Payroll packages, inventory control etc.These

packages are developed using high-level computer language.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Language Translators

Languages translators are of three types: Compiler, Interpreter, Assembler

Compiler

A Compiler is a computer program that translates code written in a high level

language to a lower level language, object/machine code. The most common reason for

translating source code is to create an executable program (converting from a high level

language into machine language).

Advantages of using a compiler

Source code is not included, therefore compiled code is more secure than interpreted

code

Tends to produce faster code than interpreting source code

Produces an executable file, and therefore the program can be run without need of

the source code

Disadvantages of using a compiler

 Object code needs to be produced before a final executable file, this can be a slow

process

 The source code must be 100% correct for the executable file to be produced

Fig: Compiler

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Interpreter

An interpreter program executes other programs directly, running through program code

and executing it line-by-line. As it analyses every line, an interpreter is slower than

running compiled code but it can take less time to interpret program code than to

compile and then run it — this is very useful when prototyping and testing code.

Interpreters are written for multiple platforms, this means code written once can be run

immediately on different systems without having to recompile for each. Examples of this

include flash based web programs that will run on your PC, MAC, games console and

Mobile phone.

Advantages of using an Interpreter

Easier to debug(check errors) than a compiler

Easier to create multi-platform code, as each different platform would have an

interpreter to run the same code

Useful for prototyping software and testing basic program logic

Disadvantages of using an Interpreter

 Source code is required for the program to be executed, and this source code can

be read making it insecure

 Interpreters are generally slower than compiled programs due to the per-line

translation method

Assembler

An assembler translates assembly language into machine code. Assembly language

consists of mnemonics for machine opcodes so assemblers perform a 1:1 translation

from mnemonic to a direct instruction. For example:

LDA #4  converts to  0001001000100100

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Conversely, one instruction in a high level language will translate to one or more

instructions at machine level.

Advantages of using an Assembler:

Very fast in translating assembly language to machine code as 1 to 1 relationship

Assembly code is often very efficient (and therefore fast) because it is a low level

language

Assembly code is fairly easy to understand due to the use of English-like mnemonics

Disadvantages of using Assembler:

 Assembly language is written for a certain instruction set and/or processor

 Assembly tends to be optimised for the hardware it's designed for, meaning it is

often incompatible with different hardware

 Lots of assembly code is needed to do relatively simple tasks, and complex

programs require lots of programming time

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Define linker and loader

In high level languages, some built in header files or libraries are stored. These libraries

are predefined and these contain basic functions which are essential for executing the

program. These functions are linked to the libraries by a program called Linker. If linker

does not find a library of a function then it informs to compiler and then compiler

generates an error. The compiler automatically invokes the linker as the last step in

compiling a program.

Not built in libraries, it also links the user defined functions to the user defined libraries.

Usually a longer program is divided into smaller subprograms called modules. And

these modules must be combined to execute the program. The process of combining

the modules is done by the linker.

Loader: Loader is a program that loads machine codes of a program into the system

memory. In Computing, a loader is the part of an Operating System that is responsible

for loading programs. It is one of the essential stages in the process of starting a

program. Because it places programs into memory and prepares them for execution.

Loading a program involves reading the contents of executable file into memory.  Once

loading is complete, the operating system starts the program by passing control to the

loaded program code. All operating systems that support program loading have loaders.

In many operating systems the loader is permanently resident in memory. 

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Exercise

1. What is a computer? Draw a block diagram to illustrate the basic organisation of a computer system and explain the functions of various units.

2. What is an input device? Briefly describe varioius important input devices.

3. Discuss two basic types of monitors CRT and LCD.

4. What is a software? Discuss its various categories with the help of diagram.5. Distinguish between system and application software.6. Write short notes on:(a) Laser Printer(b) High level language(c) Compiler(d) Plotter7. Write a note on Computer language and its classification.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Notes: Fundamentals of Computing

(ETCS 111)

Unit 2

B Tech First Semester

Compiled by:

Prof. Shafiq ul Abidin, Department of IT

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Introduction to Operating System

What is OS?

An operating system (OS) is a collection of software that manages computer hardware

resources and provides common services for computer programs. The operating

system is an essential component of the system software in a computer system.

Application programs usually require an operating system to function.

There are two types of OS

Single User Operating System (Example - DOS, MSDOS, CP/M and earlier versions

of Mac)

Multiuser Operating System (Examples - Windows 2000, Windows XP, Unix, Linux)

Types of Operating Systems:

Real-time

A real-time operating system is a multitasking operating system that aims at executing

real-time applications. Real-time operating systems often use specialized scheduling

algorithms so that they can achieve a deterministic nature of behavior. The main

objective of real-time operating systems is their quick and predictable response to

events. They have an event-driven or time-sharing design and often aspects of both. An

event-driven system switches between tasks based on their priorities or external events

while time-sharing operating systems switch tasks based on clock interrupts.

Multi-user

A multi-user operating system allows multiple users to access a computer system at the

same time. Time-sharing systems and Internet servers can be classified as multi-user

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

systems as they enable multiple-user access to a computer through the sharing of time.

Single-user operating systems have only one user but may allow multiple programs to

run at the same time.

Multi-tasking vs. single-tasking

A multi-tasking operating system allows more than one program to be running at the

same time, from the point of view of human time scales. A single-tasking system has

only one running program. Multi-tasking can be of two types: pre-emptive and co-

operative. In pre-emptive multitasking, the operating system slices the CPU time and

dedicates one slot to each of the programs. Unix-like operating systems such as Solaris

and Linux support pre-emptive multitasking, as does AmigaOS. Cooperative

multitasking is achieved by relying on each process to give time to the other processes

in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-

tasking. 32-bit versions of both Windows NT and Win9x, used pre-emptive multi-tasking.

Mac OS prior to OS X used to support cooperative multitasking.

Distributed

Further information: Distributed system

A distributed operating system manages a group of independent computers and makes

them appear to be a single computer. The development of networked computers that

could be linked and communicate with each other gave rise to distributed computing.

Distributed computations are carried out on more than one machine. When computers

in a group work in cooperation, they make a distributed system.

Embedded

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Embedded operating systems are designed to be used in embedded computer systems.

They are designed to operate on small machines like PDAs with less autonomy. They

are able to operate with a limited number of resources. They are very compact and

extremely efficient by design. Windows CE and Minix 3 are some examples of

embedded operating systems.

Operating systems can be classified as follows:

Multi-user

Allows two or more users to run programs at the same time. Some operating systems

permit hundreds or even thousands of concurrent users.

A multi-user operating system is a computer operating system (OS) that allows multiple

users on different computers or terminals to access a single system with one OS on it.

These programs are often quite complicated and must be able to properly manage the

necessary tasks required by the different users connected to it. The users will typically

be at terminals or computers that give them access to the system through a network, as

well as other machines on the system such as printers. A multi-user operating system

differs from a single-user system on a network in that each user is accessing the same

OS at different machines.

Multiprocessing

Supports running a program on more than one CPU.

Refers to a computer system's ability to support more than one process (program) at the

same time. Multiprocessing operating systems enable several programs to run

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

concurrently. UNIX is one of the most widely used multiprocessing systems, but there

are many others, including OS/2 for high-end PCs. Multiprocessing systems are much

more complicated than single-process systems because the operating system must

allocate resources to competing processes in a reasonable manner.

Refers to the utilization of multiple CPUs in a single computer system. This is also

called parallel processing.

Multitasking

Allows more than one program to run concurrently.

A multitasking operating system is a system that is created to perform multiple tasks

and processes at the same time. In this Operating system, multiple software run at the

same time and they function efficiently.

A multitasking operating system is used to handle or run multiple programs

simultaneously. They can either support pre-emptive or cooperative multitasking. Pre-

emptive multitasking involves doling out time to the applications by the operating system

while in cooperative multitasking; the operating system waits for the program to give

back control.

Multithreading

Allows different parts of a single program to run concurrently.

A multitasking operating system is a system that is created to perform multiple tasks

and processes at the same time. In this Operating system, multiple software run at the

same time and they function efficiently.

A multitasking operating system is used to handle or run multiple programs

simultaneously. They can either support pre-emptive or cooperative multitasking. Pre-

emptive multitasking involves doling out time to the applications by the operating system

while in cooperative multitasking; the operating system waits for the program to give

back control.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Real Time

Responds to input instantly. General-purpose operating systems, such as DOS and

UNIX, are not real-time.

A real-time operating system is an operating system intended to serve real-time

application requests. It must be able to process data as it comes in, typically without

buffering delays. Processing time requirements are measured in tenths of seconds or

shorter. ...

Batch ProcessingAn example of batch processing is the way that credit card companies process billing.

The customer does not receive a bill for each separate credit card purchase but one

monthly bill for all of that month s purchases. The bill is created through batch��

processing, where all of the data are collected and held until the bill is processed as a

batch at the end of the billing cycle.

The opposite of batch processing is transaction processing or interactive processing. In

interactive processing, the application responds to commands as soon as you enter

them.

Executing a series of non interactive jobs all at one time. The term originated in the

days when users entered programs on punch cards. They would give a batch of these

programmed cards to the system operator, who would feed them into the computer.

Batch jobs can be stored up during working hours and then executed during the evening

or whenever the computer is idle. Batch processing is particularly useful for operations

that require the computer or a peripheral device for an extended period of time. Once a

batch job begins, it continues until it is done or until an error occurs. Note that batch

processing implies that there is no interaction with the user while the program is being

executed.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Difference Between Real Time System and Online System

Online activity may be real time sometimes but there are online systems that are not real time Real time systems are those where the user gets immediate response to his reaction and there is no time delay If you are typing something and it appears on the screen of another person online after a lag of few micro seconds, it is online but not real time

Time SharingTime sharing is a technique which enables many people, located at various terminals, to

use a particular computer system at the same time. Time-sharing or multitasking is a

logical extension of multiprogramming. Processor's time which is shared among multiple

users simultaneously is termed as time-sharing. The main difference between

Multiprogrammed Batch Systems and Time-Sharing Systems is that in case of

Multiprogrammed batch systems, objective is to maximize processor use, whereas in

Time-Sharing Systems objective is to minimize response time.

Multiple jobs are executed by the CPU by switching between them, but the switches

occur so frequently. Thus, the user can receives an immediate response. For example,

in a transaction processing, processor execute each user program in a short burst or

quantum of computation. That is if n users are present, each user can get time

quantum. When the user submits the command, the response time is in few seconds at

most.

Operating system uses CPU scheduling and multiprogramming to provide each user

with a small portion of a time. Computer systems that were designed primarily as batch

systems have been modified to time-sharing systems.

Advantages of Timesharing operating systems are following

Provide advantage of quick response. Avoids duplication of software. Reduces CPU idle time.

Disadvantages of Timesharing operating systems are following.

Problem of reliability. Question of security and integrity of user programs and data.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Problem of data communication.

Distributed operating System

Distributed systems use multiple central processors to serve multiple real time

application and multiple users. Data processing jobs are distributed among the

processors accordingly to which one can perform each job most efficiently.

The processors communicate with one another through various communication lines

(such as high-speed buses or telephone lines). These are referred as loosely coupled

systems or distributed systems. Processors in a distributed system may vary in size and

function. These processors are referred as sites, nodes, computers and so on.

The advantages of distributed systems are following.

With resource sharing facility user at one site may be able to use the resources available at another.

Speedup the exchange of data with one another via electronic mail. If one site fails in a distributed system, the remaining sites can potentially continue

operating. Better service to the customers. Reduction of the load on the host computer. Reduction of delays in data processing.

Types of Mobile Operating Systems

When you purchase a mobile device the manufacturer will have chosen the operating

system for that specific device.  Often, you will want to learn about the mobile operating

system before you purchase a device to ensure compatibility and support for the mobile

applications you want to use.

9 Popular Mobile Operating Systems

1. Android OS (Google Inc.)

The Android mobile operating system is Google's open and free software stack that

includes an operating system, middleware and also key applications for use on mobile

devices, including smartphones. Updates for the open source Android mobile operating

system have been developed under “dessert-inspired” codenames (Cupcake, Donut,

Eclair, Gingerbread, Honeycomb, Ice Cream Sandwich) with each new version arriving

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

in alphabetical order with new enhancements and improvements.

2. Bada (Samsung Electronics)

Bada is a proprietary Samsung mobile OS that was first launched in 2010. The

Samsung Wave was the first smartphone to use this mobile OS. Bada provides mobile

features such as multipoint-touch, 3D graphics and of course, application downloads

and installation.

3. BlackBerry OS (Research In Motion)

The BlackBerry OS is a proprietary mobile operating system developed by Research In

Motion for use on the company’s popular BlackBerry handheld devices. The BlackBerry

platform is popular with corporate users as it offers synchronization with Microsoft

Exchange, Lotus Domino, Novell GroupWise email and other business software, when

used with the BlackBerry Enterprise Server.

4. iPhone OS / iOS (Apple)

Apple's iPhone OS was originally developed for use on its iPhone devices. Now, the

mobile operating system is referred to as iOS and is supported on a number of Apple

devices including the iPhone, iPad, iPad 2 and iPod Touch. The iOS mobile operating

system is available only on Apple's own manufactured devices as the company does

not license the OS for third-party hardware. Apple iOS is derived from Apple's Mac OS

operating system.

5. MeeGo OS (Nokia and Intel)

A joint open source mobile operating system which is the result of merging two products

based on open source technologies: Maemo (Nokia) and Moblin (Intel).  MeeGo is a

mobile OS designed to work on a number of devices including smartphones, netbooks,

tablets, in-vehicle information systems and various devices using Intel Atom and ARMv7

architectures.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

6. Palm OS (Garnet OS)

The Palm OS is a proprietary mobile operating system (PDA operating system) that was

originally released in 1996 on the Pilot 1000 handheld. Newer versions of the Palm OS

have added support for expansion ports, new processors, external memory cards,

improved security and support for ARM processors and smartphones. Palm OS 5 was

extended to provide support for a broad range of screen resolutions, wireless

connections and enhanced multimedia capabilities and is called Garnet OS.

. Symbian OS (Nokia)

Symbian is a mobile operating system (OS) targeted at mobile phones that offers a

high-level of integration with communication and personal information management

(PIM) functionality. Symbian OS combines middleware with wireless communications

through an integrated mailbox and the integration of Java and PIM functionality (agenda

and contacts). Nokia has made the Symbian platform available under an alternative,

open and direct model, to work with some OEMs and the small community of platform

development collaborators. Nokia does not maintain Symbian as an open source

development project.

8. webOS (Palm/HP)

WebOS is a mobile operating system that runs on the Linux kernel. WebOS was initially

developed by Palm as the successor to its Palm OS mobile operating system. It is a

proprietary Mobile OS which was eventually acquired by HP and now referred to as

webOS (lower-case w) in HP literature. HP uses webOS in a number of devices

including several smartphones and HP TouchPads. HP has pushed its webOS into the

enterprise mobile market by focusing on improving security features and management

with the release of webOS 3.x. HP has also announced plans for a version of webOS to

run within the Microsoft Windows operating system and to be installed on all HP

desktop and notebook computers in 2012.

9. Windows Mobile (Windows Phone 7)

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Windows Mobile is Microsoft's mobile operating system used in smartphones and mobile devices – with or without touchscreens. The Mobile OS is based on the Windows CE 5.2 kernel. In 2010 Microsoft announced a new smartphone platform called Windows Phone 7.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

DISK Operating System

DOS Internal Commands

These commands are automatic loaded into the memory when operating system is loaded into the memory. Thus these are also called memory-resident commands. The command available are all combined together and are stored in Command.com file, which is a executable command file. These internal command are further grouped according to their properties. These are as follows.

Genral purposeFile related commands Directory related commands

1. CLS2. DIR 3. VER4. VOL5. DATE6. TIME

7. COPY CON8. TYPE9. COPY10. REN11. DEL

12. MD13. CD14. RD

General purpose commands

1. CLS:- (Clear the screen) This command is used to clear the screen or wipe out every thing written on the screen.

Syntax:-    C:\> CLS   and press Enter

2. DIR:- (Directory) Dir command is used for listing files and directories present in the current disk.

Syntax:-  C:\> DIR [/switches]

Example:-   C:\> DIR /P

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

 

Switches:-

/P Page wise

/W Widths wise

/S List all files and directory of subdirectories

/AH Display directory with hidden files

/AS Display directory with system files

/AD Display only directories present in current drive

3. VER:-(Version) Version numbers indicates that which edition of DOS we are working on.

Syntax:-  C:\> VER   press enter

Output:-C:\>VER

Windows 98 [Version 4.10.2222]

4. VOL:-(Volume) Displays the disk volume label and serial number, if it exist.

Syntax:- C:\> VOL  press enterOutput:-C:\>VOL

Volume in drive C is JAI

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Volume Serial Number is 3E42-1907

5. DATE:- Display the current Date

Syntax:-  C:\> DATEC:\>DATECurrent date is Fri 02-15-2002Enter new date (mm-dd-yy):

Type DATE without parameters to display the current date setting anda prompt for a new one. Press ENTER to keep the same date.Note:- We enter new date in the format of MM-DD-YY.

6. TIME:- Display current time

Syntax:- C:\> TIMEC:\>TIMECurrent time is 8:38:47.70aEnter new time:

Type TIME with no parameters to display the current time setting and a prompt for a new one. Press ENTER to keep the same time.

Note:- We enter the time in the format of 24 hour clock.

File related commands

7. COPY CON:- This command gives the facility to create a new text file.

Syntax:-  C:\> COPY CON <Filename>C:\>COPY CON Rose.txtA clock in a office can never get stolenToo many employees watch it all the time^Z1 file(s) copied

After copy con we must specify a suitable file name. Press enter. Start typing the informations of the file. After gathering the information we press ^Z (CTRL+Z) button or F6 button to save the file. After pressing enter key computer will show a message like 1 file(s) copied. This means that file is stored in the disk. Suppose we don't want to save the file or we just want to abort from file creation job, then we simply press ^C (CTRL+C) button to abort without saving the file, intend of pressing

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

^Z button.

Notes:-  1. Never forget to give a suitable filename              2. You can use extension as .TXT for denoting the file as Text file.

8. TYPE:- This command is used to display the contents or text of any file to the display device.

Syntax:- C:\> TYPE <Filename>A:\>TYPE GULAB.TXTA clock in a office can never get stolenToo many employees watch it all the time

9. COPY :-  Copy command is used for copy any file to another location or to copy the files to another directory. This command may also be used for copying any file to another disk with different file name.

Syntax:-  C:\> COPY <Source filename> <Target file name> C:\>COPY ROSE.TXT ROSE.MSG         1 file(s) copied

TO copy a file from hard disk to floppy diskC:\>COPY Rose.txt A: 1 file(s) copied

To copy a file from Floppy Disk to Hard diskA:\>COPY LOTUS.TXT C:\1 file(s) copied

10. REN:- (Rename) This command is used to change the name of any file or directory.

Syntax:- C:\> REN <Source filename> <Target filename>C:\>REN ROSE.TXT GULBAL.TXTIf we get successfully C:\ that means filename or directory name is get changed. Either it will show the error message.

To changing the filename present in floppy diskC:\>REN A:\ROSE.TXT GULAB.TXT

Note that you cannot specify a new drive or path for your destination.

11. DEL:- This command is used for erasing any file from the disk.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Syntax:- C:\> DEL <Filename>C:\>DEL LOTUS.TXTIf it successfully erase the file from dosk then C:\> prompt will be appear, either computer will show an error message.

Note:- /P option is used for permission before deleting the file.

Directory related commands

12. MD:- (Make Directory)- This command allows to create a new directory.

Syntax:- C:\> MD <Dirname>C:\> MD REPORTC:\>

Now this directory can be used for keeping various sort of reports. Under this directory we can create another directory which is known as subdirectory.

13. CD:- (Change Directory):- We can enter or exit from any directory using this command.

Syntax:- To access any directoryC:\> CD <Directory name>C:\> CD REPORTC:\REPORT>

Prompt will change with the directory name. If we keep two dots after CD command than we will exit from the directory.

Syntax:-C:\> CD..C:\REPORT> CD..C:\>

14. RD:-(Remove directory):- This command is used when we want to remove any unusable directory form our disk.

Syntax:- C:\> RD <Directory name>C:\> RD REPORT

15. PATH:- This command is used for display or sets directories for executable files.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Synatx:- C:\> PATH This command display current path settings.

C:\> PATH=C:\WINDOWS\COMMAND;C:\WINDOWS\;C:\TC

this command will sets the directories windows, the command subfolder of windows and TC folder for executable files. Operating system will look for executable files in these directories.

NOTE:- If we need any help for above DOS commands the we put a '/?' symbol after writting the command at DOS prompt .

     Example:- C:\> DIR/?  or  C:\> COPY/?

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

DOS External Commands

External commands are known as Disk residence commands. Because they can be store with DOS directory or any disk which is used for getting these commands. Theses commands help to perform some specific task. These are stored in a secondary storage device. Some important external commands are given below-

MORE MOVE FIND DOSKEY

MEM FC DISKCOPY FORMAT

SYS CHKDSK ATTRIB

XCOPY SORT LABEL

1. MORE:-Using TYPE command we can see the content of any file. But if length of file is greater than 25 lines then remaining lines will scroll up. To overcome through this problem we uses MORE command. Using this command we can pause the display after each 25 lines.

Syntax:- C:\> TYPE <File name> | MOREC:\> TYPE ROSE.TXT | MOREorC:\> DIR | MORE

2. MEM:-This command displays free and used amount of  memory in the computer.

Syntax:- C:\> MEMthe computer will display the amount of memory.

3. SYS:- This command is used for copy system files to any disk. The disk having system files are known as Bootable Disk, which are used for booting the computer.

Syntax:- C:\> SYS [Drive name]C:\> SYS A:System files transferred This command will transfer the three main system files COMMAND.COM, IO.SYS, MSDOS.SYS to the floppy disk.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

4. XCOPY:- When we need to copy a directory instant of a file from one location to another the we uses xcopy command. This command is much faster than copy command.

Syntax:- C:\> XCOPY < Source dirname >  <Target dirname>C:\> XCOPY  TC TURBOC

5. MOVE:- Move command is used for moving one file or multiple files from one location to another location or from one disk to another disk.

Syntax:- C:\> MOVE  <file name>  <path name>C:\SONGS> MOVE   *.MP3   C:\ SONGS\OLD SONGS\

C:\>

6. FC:-(File Compare) This command is capable for comparing two set of files and display difference between two files.

Syntax:- C:\> FC <First set of file>  <Second set of file>C:\> FC ROSE.TXT GULAB.TXT

7.CHKDSK:-(Check disk) - This command is used to check the status of a disk and show the report of result status.

Syntax:- C:\> CHKDSK

C:\>CHKDSK

CHKDSK has NOT checked this drive for errors.You must use SCANDISK to detect and fix errors on this drive.

Volume JAI created 10-19-2001 7:14pVolume Serial Number is 3E42-1907

4,203,073,536 bytes total disk space381,988,864 bytes available on disk

4,096 bytes in each allocation unit1,026,141 total allocation units on disk93,259 available allocation units on disk

651,264 total bytes memory610,784 bytes free

Instead of using CHKDSK, try using SCANDISK. SCANDISK can reliably detectand fix a much wider range of disk problems.

8. SORT:- This command is useful when we want to sort a file. When we run this command the result can be get to display device or file.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Syntax:- C:\> SORT /R  < Input file name>  <output file name>Suppose we have a file Player.txt which having the list of a cricket player team and we want to sort the list of players, then we uses this commandC:\> SORT  Player.txt

If we not specify the output file name then result will show to the screen.

/R- switch is used for sorting the file in descending order like from Z to A or from 9 to 0.

9. FIND:- The FIND command is used to search a file for a text string. 

Syntax:- C:\> FIND "String to search" <File name>C:\TEST>find "office" gulab.txt

---------- gulab.txtA clock in a office can never get stolen

10. DISKCOPY:- DISKCOPY copies the contents of a floppy disk to another.

Syntax:- C:\> DISKCOPY  <Drive1>  <Drive2>C:\> DISKCOPY  A:   B:

This command will be copy all contents of A drive to B drive.

11. ATTRIB:- Sets the various type of attribute to a file. Like Read only, Archive, Hidden and System attribute.

Syntax:- C:\> ATTRIB [± r] [± a] [± h] [± s] <File name>here r  -  for read only,  a-  for archive, h  -  for hidden, s -  for hidden attribute.C:\> ATTRIB +r  Gulab.txt

This command will change the attribute of file gulab.txt to read only mode. To remove the read only attribute we will follow this command.C:\> ATTRIB -r Gulab.txt

12. LABEL:- If you are not happy with the volume label of hard disk, you can change it.

Syntax:- C:\> LABELC:\>LABELVolume in drive C is JAIVolume Serial Number is 3E42-1907Volume label (11 characters, ENTER for none)? INFOWAY

13. DOSKEY:- Once we install doskey , our dos will star to memorize all commands we uses. We can recall those commands using up or down arrow keys. It also gives the facility to create macros, which creates a short key for long keyword or command. 

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Key function for Doskey are given as-

UP,DOWN arrows recall commands

Esc clears current command

F7 displays command history

Alt+F7 clears command history

F9 selects a command by number

Alt+F10 clears macro definitions

Syntax:- C:\> DOSKEYDOSKey installed

Creating Macros:-C:\>doskey t=time

C:\>tC:\>timeCurrent time is 3:39:05.97pEnter new time:

To list out all macros defined just type DOSKEY/MACROS at dos prompt and press enter.C:\>DOSKEY/MACROS$D=dateT=time

14. FORMAT:- This command creates new Track & Sectors in a disk. Every

Syntax:- C:\> FORMAT  [drive name] [/S]C:\> FORMAT A:this command will create new track & sectors.C:\> FORMAT A: /SThis command will transfer system files after formatting the disk.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Windows 2000

Windows 2000 (W2K) is a 1st commercial version of Microsoft's evolving Windows

operating system. Previously called Windows NT 5.0, Microsoft emphasizes that

Windows 2000 is evolutionary and "Built on NT Technology." Windows 2000 is

designed to appeal to small business and professional users as well as to the more

technical and larger business market for which the NT was designed.

The Windows 2000 product line consists of four products:

Windows 2000 Professional, aimed at individuals and businesses of all sizes. It includes

security and mobile use enhancements. It is the most economical choice.

Windows 2000 Server, aimed at small-to-medium size businesses. It can function as a

Web server and/or a workgroup (or branch office) server. It can be part of a two-way

symmetric multiprocessing system. NT 4.0 servers can be upgraded to this server.

Windows 2000 Advanced Server, aimed at being a network operating system server

and/or an application server, including those involving large databases. This server

facilitates clustering and load-balancing. NT 4.0 servers with up to eight-way SMP can

upgrade to this product.

Windows 2000 Datacenter Server, designed for large data warehouses, online

transaction processing (OLTP), econometric analysis, and other applications requiring

high-speed computation and large databases. The Datacenter Server supports up to

16-way SMP and up to 64 gigabytes of physical memory.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Windows 2000 is reported to be more stable (less apt to crash) than Windows 98/NT

systems. A significant new feature is Microsoft's Active Directory, which, among other

capabilities, enables a company to set up virtual private networks, to encrypt data

locally or on the network, and to give users access to shared files in a consistent way

from any network computer.

Windows 2000 and Windows NT

Windows NT 4.0 and Windows 2000 are two operating systems created by Microsoft

and marketed for business users. The two operating systems were released several

years apart: Windows NT 4.0 in 1996, and Windows 2000 in 2000. Owing in part to the

significant amount of time that passed between the releases of the two operating

systems, Windows 2000 has several features that Windows NT 4.0 does not.

Windows Administrative Tools

Task Scheduler

The Task Scheduler enables you to automatically perform routine tasks on a chosen

computer. The Task Scheduler does this by monitoring whatever criteria you choose to

initiate the tasks

Component Services

Component Services. Configure and administer Component Object Model (COM)

components. Component Services is designed for use by developers and

administrators.

Event Viewer

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Event Viewer. View information about significant events, such as a program starting or

stopping, or a security error, which are recorded in event logs.

Print Management

Print Management. Manage printers and print servers on a network and perform other

administrative tasks.

Local Security

Windows Firewall with Advanced Security. Configure advanced firewall settings on both

this computer and remote computers on your network.

System Configuration

System Configuration. Identify problems that might be preventing Windows from running

correctly.

Windows Utilities

Paint

WordPad

Calculator

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Calculator picks up a bunch of new functionality, including this handy mortgage calculator.

Windows 7 also includes a Sticky Notes application.

Windows Calendar

Windows DVD Maker

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Windows Media Player

Windows Fax and Scan

Microsoft Safety Scanner

Help protect your PC and remove malicious software (including Blaster, Sasser, and

Mydoom).

Windows Live Movie Maker 2011

Craft video footage, photos, and music into a movie, then share it with your friends.

Skype for Windows

Keep in touch with the people you care about most. Video Call or Chat, Skype helps

you get together.

Windows   7 USB DVD Download Tool

Allows you to install a downloaded copy of Windows 7 onto your computer directly from

the USB flash drive or DVD.

Microsoft Touch Pack for Windows   7

A collection of games and applications for your Windows touch-enabled PC, including

Blackboard, Surface Globe, and Collage.

Windows System Registry

The Windows Registry is a hierarchical database that stores configuration settings and

options on Microsoft Windows operating systems. It contains settings for low-level

operating system components and for applications running on the platform that have

opted to use the registry. ...

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Overview of Linux OS

The Birth of Linux

On August 25, 1991, a Finn computer science student named Linus Torvalds made the

following announcement to the Usenet group comp.os.minux:

What is Linux?

Linux is, in simplest terms, an operating system. It is the software on a computer that enables

applications and the computer operator to access the devices on the computer to

perform desired functions. The operating system (OS) relays instructions from an

application to, for instance, the computer's processor. The processor performs the

instructed task, then sends the results back to the application via the operating system.

Explained in these terms, Linux is very similar to other operating systems, such as

Windows and OS X.

But something sets Linux apart from these operating systems. The Linux operating

system represented a $25 billion ecosystem in 2008. Since its inception in 1991, Linux

has grown to become a force in computing, powering everything from the New York

Stock Exchange to mobile phones to supercomputers to consumer devices.

As an open operating system, Linux is developed collaboratively, meaning no one

company is solely responsible for its development or ongoing support. Companies

participating in the Linux economy share research and development costs with their

partners and competitors. This spreading of development burden amongst individuals

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

and companies has resulted in a large and efficient ecosystem and unheralded software

innovation.

Over 1,000 developers, from at least 100 different companies, contribute to every kernel

release. In the past two years alone, over 3,200 developers from 200 companies have

contributed to the kernel--which is just one small piece of a Linux distribution.

This article will explore the various components of the Linux operating system, how they

are created and work together, the communities of Linux, and Linux's incredible impact

on the IT ecosystem.

Where is Linux?

One of the most noted properties of Linux is where it can be used. Windows and OS X

are predominantly found on personal computing devices such as desktop and laptop

computers. Other operating systems, such as Symbian, are found on small devices

such as phones and PDAs, while mainframes and supercomputers found in major

academic and corporate labs use specialized operating systems such as AS/400 and

the Cray OS.

Linux, which began its existence as a server OS and Has become useful as a desktop

OS, can also be used on all of these devices.

Linux is already successful on many different kinds of devices, but there are also many

technological areas where Linux is moving towards, even as desktop and server

development continues to grow faster than any other operating system today.

Linux Architecture

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Linux System Architecture is consists of following layers

Hardware layer - Hardware consists of all peripheral devices (RAM/ HDD/ CPU etc). Kernel - Core component of Operating System, interacts directly with hardware,

provides low level services to upper layer components. Shell - An interface to kernel, hiding complexity of kernel's functions from users. Takes

commands from user and executes kernel's functions. Utilities - Utility programs giving user most of the functionalities of an operating

systems.

Components of Linux System

Linux Operating System has primarily three components

Kernel - Kernel is the core part of Linux. It is responsible for all major activities of this operating system. It is consists of various modules and it interacts directly with the underlying hardware. Kernel provides the required abstraction to hide low level hardware details to system or application programs.

System Library - System libraries are special functions or programs using which application programs or system utilities accesses Kernel's features. These libraries

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

implements most of the functionalities of the operating system and do not requires kernel module's code access rights.

System Utility - System Utility programs are responsible to do specialized, individual level tasks.

Linux File Structure

In Linux all files organized into directories and directories are connected through the

hierarchical order. The Linux file structure branches into several directories beginning

with a root ( / ) directory.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

root - The root directory presents in all file system structure is the ancestor of all files

in the file system.

bin – It holds the essential command and binaries files needed to run the system in

single user mode.

home - It holds all the directories/ subdirectories of users.

usr – contains user applications and supporting files.

File Permission in Linux

In Linux, a file may have read, write and execute permission. When a file is created then

it is automatically given read and write permission for the owner.

There are three categories of users who can have access to a file or directory.

Owner

Group

Others

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Permissions is granted by using a set of octal number program. Each authorization is

associated to a number:

Read( r) = 4

Write (w) = 2

Execute ( x) = 1

Each category has its own set of read, write and execute permission for example

- r w x r w x r w x Owner Group Others

First dash shows file types whereas first set of rwx is for owner, second set of rwx for group and third set of rwx for others.

Command for File Permission

Change Mode Command is used to change the permission.

chmod

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

chmod 777 myfile

This command sets the r/w/x permissions for all (owner, group and others).

chmod 766 filename

This command sets r/w/x permissions for owner and r/w permissions for group and

others.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Basic Linux Commands

ls Used to display the Lists of files and directory without information.ls –l Used to display the list of files and directory with complete information such

as permissions, owner, time etc.rm data1        Deletes the file data1 in the current directory. rm –rf dirname  Used to remove a directory including subdirectory and files.rmdir temp             Removes the directory temp.mkdir temp            Creates the directory temp.cd                           Changes directories.cd ..                        To exit from current directory.pwd                        (Print Working Directory) Shows what directory (folder) you are in.man                        This command is used to display the manual about any command. man pwd                You will see the manual for the pwd command.info                      This command is used to display the information about any command. info pwd                You will see the information for the pwd command.clear  Clears the terminal screen.cat Used to view the contents of a file and it is also used for

creating a new file with some contentscat <file name> To view file contentscat > newfilename Press enter,then you can write something in the file and then to

save the file contents press ctrl+d then enter.cp Used to copy something in a destination file or directory. cp sourcepath destinationpathmv Used to move one file or directory from one place to another

place. mv source destinationwho By this command you can see the user name and their ip

addresses, who have loged in on your serverwho am i This command shows you the logged in terminal number and

user name and

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

more detailed informationuseradd username Used to create a new user. passwd Used to give a password of a user.userdel username Used to remove a user from linux.groupadd grpname Used to add a new group.groupdel grpname Used to delete a group.cal Used to display the calendar of current month and year.cal month year Used to display the calendar of given month and year.cal year Used to display the calendar of complete year.

RPM Package Manager

Red Hat Package Manager or RPM Package Manager (RPM) is a package

management system. The name RPM variously refers to the .rpm file format, files in this

format, software packaged in such files, and the package manager itself. RPM was

intended primarily for Linux distributions; the file format is the baseline package format

of the Linux Standard Base.

RPM was originally written in 1997 by Erik Troan and Marc Ewing, based on pms, rpp,

and pm experiences.

Deb Packages

Debian packages are standard Unix/Linux archieves that include two tar archives

optionally compressed with gzip (zlib), Bzip2, lzma, or xz (lzma2): one archive holds the

control information and another contains the program data.

Debian packages can be converted into other packages and vice versa using alien, and

created from source code using CheckInstall or Debian Package Maker.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

HMR Institute of Technology & Management

Notes: Fundamentals of Computing

(ETCS 111)

Unit 3

B Tech First Semester

Compiled by:

Prof. Shafiq ul Abidin, Department of IT

HMR Institute of Technology & Management

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Flowchart

A flowchart is a diagram that represents a process or algorithm. The steps are

represented by a series of boxes or other specialized symbols, then connected with

arrows.

A flowchart is a type of diagram that represents an algorithm, workflow or process,

showing the steps as boxes of various kinds, and their order by connecting them with

arrows. This diagrammatic representation illustrates a solution model to a given

problem. Flowcharts are used in analyzing, designing, documenting or managing a process or program in various fields.

Basic Flowchart Symbols

The Process Symbol represents any process, function, or action and is the most frequently used symbol in flowcharting.

The Document Symbol is used to represent any type of hard copy input or output (i.e. reports).

Offpage Connector Symbols are used to indicate the flowchart continues on another page. Often, the page number is placed in the shape for easy reference.

The Input/Output Symbol represents data that is available for input or resulting from processing (i.e. customer database records).

Comment Symbols are used when additional explanation or comment is required. This symbol is usually connected to the symbol it is explaining by a dashed line.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

The Decision Symbol is a junction where a decision must be made. A single entry may have any number of alternative solutions, but only one can be chosen.

The Connector Symbol represents the exit to, or entry from, another part of the same flowchart. It is usually used to break a flow line that will be continued elsewhere. It's a good idea to reference page numbers for easy location of connectors.

Arrows are used to show the flow of logic / data (→ , ← , ↓)

Advantages and Limitations of Flowchart

Advantages:

It provides an easy way of communication because any other person besides

the programmer can understand the way they are represented.

It represents the data flow.

It provides a clear overview of the entire program and problem and solution.

It checks the accuracy in logic flow.

It documents the steps followed in an algorithm.

It provides the facility for coding.

It provides the way of modification of running program.

They shows all major elements and their relationship.

Limitations:

1. Sometimes, the program logic is quite complicated. In that case, flowchart becomes complex and clumsy.

2. Alterations and Modifications: If alterations are required the flowchart may require re-drawing completely.

3. Reproduction: As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Draw a flowchart to find the sum of the first 50 natural numbers.

Draw a flowchart to find the largest of three numbers A, B, and C.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Draw a flowchart for computing factorial N (N!)

Where N! = 1?2?3?....N .

Flowchart for calculating area of a triangle.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Flowchart to find odd or even number

Flowchart to find leap year

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Computer Network

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

A network consists of two or more computers that are linked in order to share resources

(such as printers and CDs), exchange files, or allow

electronic communications.

The computers on a network may be linked through cables, telephone lines, radio

waves, satellites, or infrared light beams.

A computer network or data network is a telecommunications network that allows

computers to exchange data. In computer networks, networked computing devices

(network nodes) pass data to each other along data connections. The connections

(network links) between nodes are established using either cable media or wireless

media. The best-known computer network is the Internet.

Network devices that originate, route and terminate the data are called network nodes.

[1] Nodes can include hosts such as servers and personal computers, as well as

networking hardware. Two devices are said to be networked when a device is able to

exchange information with another device.

Computer networks support applications such as access to the World Wide Web,

shared use of application and storage servers, printers, and fax machines, and use of

email and instant messaging applications. Computer networks differ in the physical

media used to transmit their signals, the communications protocols to organize network

traffic, the network's size, topology and organizational intent.

Types of Networks

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

There are different types of computer networks. Some of the common ones include;

1. Local Area Network LAN – These types of computer networks connect network

devices over a relatively short distance. Quite often, a networked office building,

home or school contains a single LAN although it is normal to come across a

building that contains a few small LANs. On a few occasions, a LAN may also

span over a group of nearby buildings. Such computer networks are usually

owned by one organisation.

2. Wide Area Network WAN – As the name suggests, a WAN spans over a large

physical distance. It may be regarded as a collection of LANs dispersed over a

geographical area. The internet is a very good example of a WAN. LANs are

connected to a WAN through a device referred to as a router. In IP networking,

both the LAN and WAN addresses are maintained by the router. Most WANs

exist under distributed or collective ownership and management and unlike the

LANs, are not necessarily owned by one organisation.

3. Metropolitan Area Network MAN – This is a network that spans over a physical

area like a city that is smaller than a WAN but larger than a LAN. Quite often,

such computer networks are owned and operated by single entities such as

government bodies or large corporations.

Network Topologies

The mesh network topology employs either of two schemes, called full mesh and partial

mesh. In the full mesh topology, each workstation is connected directly to each of the

others. In the partial mesh topology, some workstations are connected to all the others,

and some are connected only to those other nodes with which they exchange the most

data.

The tree network topology uses two or more star networks connected together. The

central computers of the star networks are connected to a main bus. Thus, a tree

network is a bus network of star networks.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Logical (or signal) topology refers to the nature of the paths the signals follow from node

to node. In many instances, the logical topology is the same as the physical topology.

But this is not always the case. For example, some networks are physically laid out in a

star configuration, but they operate logically as bus or ring networks.

The following sections discuss the physical topologies used in networks and other related topics.

Linear Bus Star Tree (Expanded Star) Considerations When Choosing a Topology

Linear Bus

A linear bus topology consists of a main run of cable with a terminator at each end (See

fig. 1). All nodes (file server, workstations, and peripherals) are connected to the linear

cable.

Fig Linear Bus topology

Advantages of a Linear Bus Topology

Easy to connect a computer or peripheral to a linear bus.

Requires less cable length than a star topology.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Disadvantages of a Linear Bus Topology

Entire network shuts down if there is a break in the main cable.

Terminators are required at both ends of the backbone cable.

Difficult to identify the problem if the entire network shuts down.

Not meant to be used as a stand-alone solution in a large building.

Star

A star topology is designed with each node (file server, workstations, and peripherals)

connected directly to a central network hub, switch, or concentrator (See fig. 2).

Data on a star network passes through the hub, switch, or concentrator before

continuing to its destination. The hub, switch, or concentrator manages and controls all

functions of the network. It also acts as a repeater for the data flow. This configuration is

common with twisted pair cable; however, it can also be used with coaxial cable or fiber

optic cable.

Fig. Star topology

Advantages of a Star Topology

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Easy to install and wire.

No disruptions to the network when connecting or removing devices.

Easy to detect faults and to remove parts.

Disadvantages of a Star Topology

Requires more cable length than a linear topology.

If the hub, switch, or concentrator fails, nodes attached are disabled.

More expensive than linear bus topologies because of the cost of the hubs, etc.

Tree or Expanded Star

A tree topology combines characteristics of linear bus and star topologies. It consists of

groups of star-configured workstations connected to a linear bus backbone cable (See

fig. 3). Tree topologies allow for the expansion of an existing network, and enable

schools to configure a network to meet their needs.

Fig Tree topology

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Advantages of a Tree Topology

Point-to-point wiring for individual segments.

Supported by several hardware and software venders.

Disadvantages of a Tree Topology

Overall length of each segment is limited by the type of cabling used.

If the backbone line breaks, the entire segment goes down.

More difficult to configure and wire than other topologies.

Considerations When Choosing a Topology

Money. A linear bus network may be the least expensive way to install a

network; you do not have to purchase concentrators.

Length of cable needed. The linear bus network uses shorter lengths of cable.

Future growth. With a star topology, expanding a network is easily done by

adding another concentrator.

Cable type. The most common cable in schools is unshielded twisted pair, which

is most often used with star topologies.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Protocols

A protocol is a set of rules that governs the communications between computers on a

network. In order for two computers to talk to each other, they must be speaking the

same language. Many different types of network protocols and standards are required

to ensure that your computer (no matter which operating system, network card, or

application you are using) can communicate with another computer located on the next

desk or half-way around the world. The OSI (Open Systems Interconnection) Reference

Model defines seven layers of networking protocols. The complexity of these layers is

beyond the scope of this tutorial; however, they can be simplified into four layers to help

identify some of the protocols with which you should be familiar

Network protocol - Within computer science, a communications protocol is a system of

digital rules for message exchange within or between computers. Communicating

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

systems use well-defined formats for exchanging messages. Each message has an

exact meaning intended to provoke a particular response of the receiver.

HTTP- HyperText Transfer Protocol - An Internet-based protocol for sending and

receiving webpages.

HTTP defines how messages are formatted and transmitted, and what actions

Web servers and browsers should take in response to various commands. For

example, when you enter a URL in your browser, this actually sends an

HTTP command to the Web server directing it to fetch and transmit the

requested Web page.

HTTPS- Hyper Text Transfer Protocol Secure (HTTPS) is a secure version of

the Hyper Text Transfer Protocol (http). HTTPS allows secure ecommerce

transactions, such as online banking.

When a user connects to a website via HTTPS, the website encrypts the session

with a Digital Certificate. A user can tell if they are connected to a secure website

if the website URL begins with https:// instead of http://.

FTP is an acronym for File Transfer Protocol. As the name suggests, FTP is

used to transfer files between computers on a network. You can use FTP to

exchange files between computer accounts, transfer files between an account

and a desktop computer, or access online software archives. Keep in mind,

however, that many FTP sites are heavily used and require several attempts

before connecting.

FTP is the easiest way to transfer files between computers via the internet, and

utilizes TCP, transmission control protocol, and IP, internet protocol, systems to

perform uploading and downloading tasks.

SMTP stands for Simple Mail Transfer Protocol. It's a set of communication

guidelines that allow software to transmit email over the Internet. Most email

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

software is designed to use SMTP for communication purposes when sending

email, and It only works for outgoing messages. When people set up their email

programs, they will typically have to give the address of their Internet service

provider's SMTP server for outgoing mail. There are two other protocols - POP3

and IMAP - that are used for retrieving and storing email.

PPP (Point-to-Point Protocol) is a protocol for communication between two

computers using a serial interface, typically a personal computer connected by

phone line to a server. For example, your Internet server provider may provide

you with a PPP connection so that the provider's server can respond to your

requests, pass them on to the Internet, and forward your requested Internet

responses back to you. PPP uses the Internet protocol (IP) (and is designed to

handle others).

It is sometimes considered a member of the TCP/IP suite of protocols. Relative

to the Open Systems Interconnection (OSI) reference model, PPP provides layer

2 (data-link layer) service. Essentially, it packages your computer's TCP/IP

packets and forwards them to the server where they can actually be put on the

Internet.

POP is short for Post Office Protocol, a protocol used to retrieve e-mail from a

mail server. Most e-mail applications (sometimes called an e-mail client) use the

POP protocol, although some can use the newer IMAP (Internet Message

Access Protocol).

There are two versions of POP. The first, called POP2, became a standard in the

mid-80's and requires SMTP to send messages. The newer version, POP3, can

be used with or without SMTP.

TCP ( Transmission Control Protocol) is a set of rules (protocol) used along with

the Internet Protocol (IP) to send data in the form of message units between

computers over the Internet. While IP takes care of handling the actual delivery

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

of the data, TCP takes care of keeping track of the individual units of data (called

packets) that a message is divided into for efficient routing through the Internet.

IP Internet Protocol (IP) is the method or protocol by which data is sent from one

computer to another on the Internet. Each computer (known as a host) on the

Internet has at least one IP address that uniquely identifies it from all other

computers on the Internet. 

Network Transmission Media

Transmission media is a pathway that carries the information from sender to receiver.

We use different types of cables or waves to transmit data. Data is transmitted normally

through electrical or electromagnetic signals.

An electrical signal is in the form of current. An electromagnetic signal is series of

electromagnetic energy pulses at various frequencies. These signals can be transmitted

through copper wires, optical fibers, atmosphere, water and vacuum Different Medias

have different properties like bandwidth, delay, cost and ease of installation and

maintenance. Transmission media is also called Communication channel.

Types of Transmission Media

Transmission media is broadly classified into two groups.

1. Wired or Guided Media or Bound Transmission Media

2. Wireless or Unguided Media or Unbound Transmission Media

  Wired or Guided Media or Bound Transmission Media: Bound transmission media

are the cables that are tangible or have physical existence and are limited by the

physical geography. Popular bound transmission media in use are twisted pair cable,

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

co-axial cable and fiber optical cable. Each of them has its own characteristics like

transmission speed, effect of noise, physical appearance, cost etc.

Wireless or Unguided Media or Unbound Transmission Media: Unbound

transmission media are the ways of transmitting data without using any cables. These

media are not bounded by physical geography. This type of transmission is called

Wireless communication. Nowadays wireless communication is becoming popular.

Wireless LANs are being installed in office and college campuses. This transmission

uses Microwave, Radio wave, Infra red are some of popular unbound transmission

media.

                      

Coaxial Cable

Single copper conductor in the center surrounded by a plastic layer for insulation and a braided metal outer shield

Twisted pair

Four pairs of wires twisted to certain specifications. Available in shielded and unshielded versions.

Fiber-optic –

A cable, consisting of a center glass core surrounded by layers of plastic, that transmits

data using light rather than electricity.

Atmosphere/Wireless

Uses Electromagnetic waves. whose frequency range is above that of microwaves, but

below that of the visible spectrum.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Choose Media based on :

• Wiring configurations

• Distance and location limitations

• Speed

• Reliability

• Security• Budget

Network Devices

Network devices / hardware may also be known as network equipment, computer

networking devices. Units which are the last receiver or generate data are called hosts

or data terminal equipment.

All these terms refer to devices facilitating the use of a computer network. Specifically,

they mediate data in a computer network.

There are number of network devices few of them are as follows:

Routers

A router is a network device that connects together two or more networks. A common

use of a router is to join a home or business network (LAN) to the Internet (WAN).

The router will typically have the Internet cable plugged into it, as well as a cable, or

cables to computers on the LAN.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Alternatively, the LAN connection might be wireless (WiFi), making the device a

wireless router. (A wireless router is actually a router and wireless switch combined)

Routers work at the network layer (layer 3) of the Open Systems Interconnection (OSI)

reference model for networking to move packets between networks using their logical

addresses (which, in the case of TCP/IP, are the IP addresses of destination hosts on

the network). Because routers operate at a higher OSI level than bridges do, they have

better packet-routing and filtering capabilities and greater processing power, which

results in routers costing more than bridges.

A router is a network device that connects together two or more networks.

A common use of a router is to join a home or business network (LAN) to the Internet

(WAN).

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

The router will typically have the Internet cable plugged into it, as well as a cable, or

cables to

HUB

Networks using a Star topology require a central point for the devices to connect.

Originally this device was called a concentrator since it consolidated the cable runs from

all network devices. The basic form of concentrator is the hub.

As shown in Figure; the hub is a hardware device that contains multiple, independent

ports that match the cable type of the network. Most common hubs interconnect

Category 3 or 5 twisted-pair cable with RJ-45 ends, although Coax BNC and Fiber Optic

BNC hubs also exist. The hub is considered the least common denominator in device

concentrators. Hubs offer an inexpensive option for transporting data between devices,

but hubs don't offer any form of intelligence. Hubs can be active or passive.

An active hub strengthens and regenerates the incoming signals before sending the

data on to its destination.

Passive hubs do nothing with the signal.

Switches

Switches are a special type of hub that offers an additional layer of intelligence to basic,

physical-layer repeater hubs. A switch must be able to read the MAC address of each

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

frame it receives. This information allows switches to repeat incoming data frames only

to the computer or computers to which a frame is addressed. This speeds up the

network and reduces congestion.

Switches operate at both the physical layer and the data link layer of the OSI Model.

Bridges

A bridge is a network device that typically links together two different parts of a LAN.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Whereas a router is usually used to link a LAN to a WAN (such as the Internet), a bridge

links independent parts of a LAN so that they act as a single LAN.

A bridge is used to join two network segments together, it allows computers on either

segment to access resources on the other. They can also be used to divide large

networks into smaller segments. Bridges have all the features of repeaters, but can

have more nodes, and since the network is divided, there is fewer computers competing

for resources on each segment thus improving network performance.

Bridges can also connect networks that run at different speeds, different topologies, or

different protocols. But they cannot, join an Ethernet segment with a Token Ring

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

segment, because these use different networking standards. Bridges operate at both

the Physical Layer and the MAC sublayer of the Data Link layer. Bridges read the MAC

header of each frame to determine on which side of the bridge the destination device is

located, the bridge then repeats the transmission to the segment where the device is

located.

Network Interface Card (NIC)

Any computer that is to be connected to a network, needs to have a network interface

card(NIC).

Most modern computers have these devices built into the motherboard, but in some

computers you have to add an extra expansion card (small circuitboard)

Modem

Before the days of broadband Internet connections, most computers connected to the

Internet via telephone lines (dial-up connections).

The problem with using telephone lines is that they are designed to carry voices, which

are analogue signals. They are not designed for digital data.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

The solution was to use a special device to join the digital computer to the analogue

telephone line. This device is known as a modem.

Introduction to Database Management

In an organization, the data is the most basic resource. To run the organization efficiently, the proper organization and management of data is essential. The formal definition of the major terms used in databases and database systems is defined in this section.

Data

The term data may be defined as known facts that could be recorded and stored on Computer Media. It is also defined as raw facts from which the required information is produced.

Information

Data and information are closely related and are often used interchangeably. Information is nothing but refined data. In other way, we can say, information is processed, organized or summarized data. According to Burch et. al., "Information is data that have been put into a meaningful and useful content

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

and communicated to a recipient who uses it to made decisions". Information consists of data, images, text, documents and voice, but always in a meaningful content. So we can say, that information is something more than mere data.

Data are processed to create information. The recipient receives the information and then makes a decision and takes an action, which may triggers other actions.

In these days, there is no lack of data, but there is lack of quality information. The quality information means information that is accurate, timely and relevant, which are the three major key attributes of information.

Accuracy: It means that the information is free from errors, and it clearly and accurately reflects the meaning of data on which it is based. It also means it is free from bias and conveys an accurate picture to the recipient.

Timeliness: It means that the recipients receive the information when they need it and within the required time frame.

Relevancy: It means the usefulness of the piece of information for the corresponding persons. It is a very subjective matter. Some information that is relevant for one person might not be relevant for another and vice versa e.g., the price of printer is irrelevant for a person who wants to purchase computer.

So, organization that have good information system, which produce information that is accurate, timely and relevant will survive and those that do not realize the importance of information will soon be out of business.

Database

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

A database is a collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal way. The data are stored in such a way that they are independent of the programs used by the people for accessing the data. The approach used in adding the new data, modifying and retrieving the existing data from the database is common and controlled one.

It is also defined as a collection of logically related data stored together that is designed to meet information requirements of an organization. We can also define it as an electronic filling system.

The example of a database is a telephone directory that contains names, addresses and telephone numbers of the people stored in the computer storage.

Databases are organized by fields, records and files. These are described briefly as follows:

Fields

It is the smallest unit of the data that has meaning to its users and is also called data item or data element. Name, Address and Telephone number are examples of fields. These are represented in the database by a value.

Records

A record is a collection of logically related fields and each field is possessing a fixed number of bytes and is of fixed data type. Alternatively, we can say a record is one complete set of fields and each field have some value. The complete information about a particular phone number in the database represents a record. Records are of two types fixed length records and variable length records.

Files

A file is a collection of related records. Generally, all the records in a file are of same size and record type but it is not always true. The records in a file may be of fixed length or variable length depending upon the size of the records contained in a file. The telephone directory containing records about the different telephone holders is an example of file.

Database Management System (DBMS)

DBMS is a program or group of programs that work in conjunction with the operating system to create, process, store, retrieve, control and manage the data. It acts as an interface between the application program and the data stored in the database.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Alternatively, it can be defined as a computerized record-keeping system that stores information and allows the users to add, delete, modify, retrieve and update that information.

The DBMS performs the following five primary functions:

Define, create and organise a database: The DBMS establishes the logical relationships among different data elements in a database and also defines schemas and subschemas using the DDL.

Input data: It performs the function of entering the data into the database through an input device (like data screen, or voice activated system) with the help of the user.

Process data: It performs the function of manipulation and processing of the data stored in the database using the DML.

Maintain data integrity and security: It allows limited access of the database to authorised users to maintain data integrity and security.

Query database: It provides information to the decision makers that they need to make important decisions. This information is provided by querying the database using SQL.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Beyond Syllabus

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Number System in computerA set of values used to represent different quantities is known as Number System". For example, a number system can be used to represent the number of students in a class or number of viewers watching a certain TV program etc. The digital computer represents all kinds of data and information in binary numbers. It includes audio, graphics, video, text and numbers. The total number of digits used in a number system is called its s base or radix. The base is written after the number as subscript such as 51210.

Some important number systems are as follows.

Decimal number system Binary number system Octal number system Hexadecimal number system

The decimal number system is used in general. However, the computers use binary number system. The octal and hexadecimal number systems are used in the computer.

Decimal Number SystemThe number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands and so on.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Each position represents a specific power of the base (10). For example, the decimal number 1234 consists of the digit 4 in the units position, 3 in the tens position, 2 in the hundreds position, and 1 in the thousands position, and its value can be written as

(1x1000)+ (2x100)+ (3x10)+ (4xl)(1x103)+ (2x102)+ (3x101)+ (4xl00)1000 + 200 + 30 + 41234

As a computer programmer or an IT professional, you should understand the following number systems which are frequently used in computers.

  S.N.

   Number System and Description

1. Binary Number System Base 2. Digits used : 0, 1

2. Octal Number System Base 8. Digits used : 0 to 7

3. Hexa Decimal Number System Base 16. Digits used : 0 to 9, Letters used

A to F

Binary Number SystemCharacteristics of binary number system are as follows:

Uses two digits, 0 and 1. Also called base 2 number system Each position in a binary number represents a 0 power of the base (2). Example 20

Last position in a binary number represents a x power of the base (2). Example 2x where x represents the last position - 1.

Example

Binary Number : 101012

Calculating Decimal Equivalent:

Step Binary Number Decimal Number

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Step 1 101012 ((1 x 24) + (0 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10

Step 2 101012 (16 + 0 + 4 + 0 + 1)10

Step 3 101012 2110

Note : 101012 is normally written as 10101.

Octal Number SystemCharacteristics of octal number system are as follows:

Uses eight digits, 0,1,2,3,4,5,6,7. Also called base 8 number system Each position in an octal number represents a 0 power of the base (8). Example 80

Last position in an octal number represents a x power of the base (8). Example 8x where x represents the last position - 1.

Example

Octal Number : 125708

Calculating Decimal Equivalent:

Step Octal Number Decimal Number

Step 1 125708 ((1 x 84) + (2 x 83) + (5 x 82) + (7 x 81) + (0 x 80))10

Step 2 125708 (4096 + 1024 + 320 + 56 + 0)10

Step 3 125708 549610

Note : 125708 is normally written as 12570.

Hexadecimal Number SystemCharacteristics of hexadecimal number system are as follows:

Uses 10 digits and 6 letters, 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. Letters represents numbers starting from 10. A = 10. B = 11, C = 12, D = 13, E = 14, F =

15. Also called base 16 number system

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Each position in a hexadecimal number represents a 0 power of the base (16). Example 160

Last position in a hexadecimal number represents a x power of the base (16). Example 16x where x represents the last position - 1.

Example

Hexadecimal Number : 19FDE16

Calculating Decimal Equivalent:

Step Binary Number Decimal Number

Step 1 19FDE16 ((1 x 164) + (9 x 163) + (F x 162) + (D x 161) + (E x 160))10

Step 2 19FDE16 ((1 x 164) + (9 x 163) + (15 x 162) + (13 x 161) + (14 x 160))10

Step 3 19FDE16 (65536+ 36864 + 3840 + 208 + 14)10

Step 4 19FDE16 10646210

Note : 19FDE16 is normally written as 19FDE.

Number System ConversionThere are many methods or techniques which can be used to convert numbers from one base to another. We'll demonstrate here the following −

Decimal to Other Base System Other Base System to Decimal Other Base System to Non-Decimal Shortcut method − Binary to Octal Shortcut method − Octal to Binary Shortcut method − Binary to Hexadecimal Shortcut method − Hexadecimal to Binary

Decimal to Other Base SystemSteps

Step 1 − Divide the decimal number to be converted by the value of the new base. Step 2 − Get the remainder from Step 1 as the rightmost digit (least significant digit) of

new base number. Step 3 − Divide the quotient of the previous divide by the new base.

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Step 4 − Record the remainder from Step 3 as the next digit (to the left) of the new base number.

Repeat Steps 3 and 4, getting remainders from right to left, until the quotient becomes zero in Step 3. The last remainder thus obtained will be the Most Significant Digit (MSD) of the new base number.

Example −

Decimal Number: 2910

Calculating Binary Equivalent −

Step Operation Result Remainder

Step 1 29 / 2 14 1

Step 2 14 / 2 7 0

Step 3 7 / 2 3 1

Step 4 3 / 2 1 1

Step 5 1 / 2 0 1

As mentioned in Steps 2 and 4, the remainders have to be arranged in the reverse order so that the first remainder becomes the Least Significant Digit (LSD) and the last remainder becomes the Most Significant Digit (MSD).

Decimal Number − 2910 = Binary Number − 111012.

Other Base System to Decimal SystemSteps

Step 1 − Determine the column (positional) value of each digit (this depends on the position of the digit and the base of the number system).

Step 2 − Multiply the obtained column values (in Step 1) by the digits in the corresponding columns.

Step 3 − Sum the products calculated in Step 2. The total is the equivalent value in decimal.

Example

Binary Number − 111012

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Calculating Decimal Equivalent −

Step Binary Number Decimal Number

Step 1 111012 ((1 × 24) + (1 × 23) + (1 × 22) + (0 × 21) + (1 × 20))10

Step 2 111012 (16 + 8 + 4 + 0 + 1)10

Step 3 111012 2910

Binary Number − 111012 = Decimal Number − 2910

Other Base System to Non-Decimal SystemSteps

Step 1 − Convert the original number to a decimal number (base 10). Step 2 − Convert the decimal number so obtained to the new base number.

Example

Octal Number − 258

Calculating Binary Equivalent −

Step 1 − Convert to DecimalStep Octal Number Decimal Number

Step 1 258 ((2 × 81) + (5 × 80))10

Step 2 258 (16 + 5 )10

Step 3 258 2110

Octal Number − 258 = Decimal Number − 2110

Step 2 − Convert Decimal to BinaryStep Operation Result Remainder

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Step 1 21 / 2 10 1

Step 2 10 / 2 5 0

Step 3 5 / 2 2 1

Step 4 2 / 2 1 0

Step 5 1 / 2 0 1

Decimal Number − 2110 = Binary Number − 101012

Octal Number − 258 = Binary Number − 101012

Shortcut method - Binary to OctalSteps

Step 1 − Divide the binary digits into groups of three (starting from the right). Step 2 − Convert each group of three binary digits to one octal digit.

Example

Binary Number − 101012

Calculating Octal Equivalent −

Step Binary Number Octal Number

Step 1 101012 010 101

Step 2 101012 28 58

Step 3 101012 258

Binary Number − 101012 = Octal Number − 258

Shortcut method - Octal to BinarySteps

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Step 1 − Convert each octal digit to a 3 digit binary number (the octal digits may be treated as decimal for this conversion).

Step 2 − Combine all the resulting binary groups (of 3 digits each) into a single binary number.

Example

Octal Number − 258

Calculating Binary Equivalent −

Step Octal Number Binary Number

Step 1 258 210 510

Step 2 258 0102 1012

Step 3 258 0101012

Octal Number − 258 = Binary Number − 101012

Shortcut method - Binary to HexadecimalSteps

Step 1 − Divide the binary digits into groups of four (starting from the right). Step 2 − Convert each group of four binary digits to one hexadecimal symbol.

Example

Binary Number − 101012

Calculating hexadecimal Equivalent −

Step Binary Number Hexadecimal Number

Step 1 101012 0001 0101

Step 2 101012 110 510

Step 3 101012 1516

Fundamentals of Computing (ETCS 111) Prof. Shafiq ul Abidin

Binary Number − 101012 = Hexadecimal Number − 1516

Shortcut method - Hexadecimal to Binary

Steps

Step 1 − Convert each hexadecimal digit to a 4 digit binary number (the hexadecimal digits may be treated as decimal for this conversion).

Step 2 − Combine all the resulting binary groups (of 4 digits each) into a single binary number.

Example

Hexadecimal Number − 1516

Calculating Binary Equivalent −

Step Hexadecimal Number Binary Number

Step 1 1516 110 510

Step 2 1516 00012 01012

Step 3 1516 000101012