introduction to computers.ppt

Data Processing

Data

• Data consists of raw facts typically about physical phenomena or business transactions.

• Data are objective measurements of the attributes (the characteristics) of entities (such as people, places, things and events).

Information

• Information is a collection of facts organized (or processed) in such a way that they have additional value.

• Processed data is information.

Module-1

• Introduction to computers – Overview – Computer Architecture – Input output and storage devices

What is computer? - The word “computer” comes from word compute, which means to calculate.- Computer is an electronic device that takes input from its user, stores, processes data and generates the required output as per the processing instructions given to it by the user.

• “An automatic electronic apparatus for making calculations or controlling operations that are expressible in numerical or logical terms”.(Oxford Dictionary)

Overview Of Computer

• Generation Of Computers • Characteristics of Computers• Limitation of Computer• Classification of Computer

Generations of computers• 5 Main generations

1. First Generation( 1942-1955)2. Second Generation( 1955-1964)3. Third Generation( 1964-1975)4. Fourth Generation( 1975-1989)5. Fifth Generation (1989-Present)

First generation(1942-1955)• Hardware: Vacuum Tubes• Software: Machine Language (Binary Language)• Features -The vacuum tube computers were very big in size.-These computers use to dissipate lot of heat.-Rate of failure was more as vacuum tubes burn out

very frequently.-Electric power consumption was very large.-Air conditioning required-used for scientific purposes• Examples: ENIAC, EDVAC, EDSAC, UNIVAC 1

Second Generation(1955-1964)

• Hardware: Transistors• Software: High Level Languages, eg: FORTRAN,

COBOL• Features are- Very small in size as compared to first generation.- Dissipate lesser heat than first generation- Rate of failure was lesser than vacuum tubes

computers.- Electric power consumption was lesser than first

generation.

- Used for commercial purposes- Air-conditioning required.• Examples: LARC (Livermore Atomic Research

Computer)

Third Generation Computers(1964-1975)

• Hardware: Integrated Circuits(IC)• Software: High Level Languages, eg: PASCAL, BASIC,

VISUAL BASIC, C, C++, Java• Main features-more compact as compared to second generation.-these computers use to dissipate lesser heat than second

generation.-Failure of IC was rare.-Electronic power consumption was far lesser.-Different languages were developed.

• Used for both scientific and commercial purposes

• Air-conditioning required• Examples: Mainframe, Minicomputers

Fourth Generation(1975-1989)

• Hardware: Microprocessor made up of LSI and VLSI.

• Software: Advanced Java, HTML, XML, SQL• Features-More compact as compared to third

generation.-These computers use to dissipate lesser heat

than third generation.

-Failure rare is negligible-Air-conditioning is not required.-Electric power consumption was far lesser.-Sophisticated languages like query languages are developed.•Examples: Personal Computers

Fifth Generation (1989-Present)

• Hardware: Ultra Scale Large Integration (USLI), optical disks

• Software: Artificial Intelligence, PROLOG, OPSS, Mercury

• Features- Less prone to hardware failure- User- friendly features- Air-conditioning not required• Examples: Portable PCs, Laptop, Palmtop

Characteristics of Computers1. Speed: Computer is very fast and accurate device. It can process millions and millions of instructions within seconds.

2. Accuracy: Computer results are highly accurate.

3. Memory: Computers have a large amount of memory to hold a very large amount of data or information.

4. Programmed Intelligence: Computer themselves as such are dumb terminals. But they are programmed in such a way that they can perform those operations which have been fed into them in the form of executable programs.

5. Diligence: Computer is free from problems like lack of concentration, and confusions etc. Computer may never be

confused like humans.6. Versatility: We can perform many different types of tasks on

computer. One moment it might be busy in calculating the statistical data for annual performance evaluation of a business organization and next moment it might be working on playing movies.

7. Power of Remembrance: Unlike humans, computer can store things for unlimited period of time

Types of Computers

There are three basic kinds of computers: • Analog computers• Digital Computers• Hybrid computer

Analog computers

• Analog computers are analog devices. That is, they have continuous states rather than discrete numbered states.

• Generally used in industrial process controls and to measure physical quantities such as pressure, temperature etc.

• Performs computations using electric resistance, voltage etc.

• Operating speed is faster than digital computer but memory capacity is less.

Analog Computer

Digital Computer

• A digital computer uses discrete states. A binary digital computer uses two discrete states, such as positive/negative, high/low, on/off, used to represent the binary digits zero and one.

• Digital computer stores data in the form of digits.

• Commonly used for data processing and problem solving using specific programs.

Hybrid Computer• Is a mixture of analog and digital computer.• Some functions were performed in digital part

and some in analog part.• Used to process both continuous and discrete

data.• Generally used for weather forecasting and

industrial process control.

Difference between Analog and Digital computer

Analog Computer Digital Computer

1. Contains a huge network of electronic components

2. Widely used in engineering and scientific jobs

3. It is costly4. Suitable for programming

1. Contains less electronic components

2. Used in commercial purposes.

3. Less costly4. Difficult for programming

Classification based on processing and storing capabilities and size

1. Micro computers2. Mini computers3. Main frame computers4. Super computers5. Note book/Laptop 6. Tablet PC7. PDA

1.Micro computers• Small processing computers and can do a variety of

jobs such as storage of data, calculations, control and output.

• Meant for single individuals• Also called personal computers / PCs.• I st Microcomputer- IBM PC• Small in size and cost is less compared to others

• Characteristics of Micro-Computer1. Speed: 100 Kilo instructions per second2. Word length: 8 to 16 bits3. Storage: 64 kilobytes to 640 kilobytes4. Functions: Word processing, Graphics,

Science etc.5. Peripherals used: Floppy disks, hard disks,

key board, V.D.U Printers.

2.Mini Computers

• Fabricated for general purposes.• Smaller in size.• Commonly used for business, education and

government depts.• 1st Minicomputer introduced by Digital Equipment

Corporation(DEC)

• Characteristics of Mini Computer1. Speed: 500 Kilo instructions per second2. Word length: 16 bits3. Storage: 256 Kilo bytes to 1024 Kilo Bytes4. Functions: Engineering, Scientific5. Peripherals used: Line printers, Hard disc, Magnetic tapes

3.Main frame Computers• More powerful.• All high level languages are available for main

frame computers.• Can be used in banks, insurance companies,

hospitals and railways.• It placed in central location with several user

terminals connected to it, and terminals act as access stations.

• Characteristics Of Mainframe Computer1. Speed: 1000 to 10000 Kilo instructions per

second2. Word length: 32 to 60 bits3. Storage: 2 Mega Bytes to 16 Mega Bytes4. Functions: Scientific, engineering, designs,

railway and airlines reservations etc.5. Peripherals used: Hard disc, Line printer, Laser Printer.

4. Super Computers

• Most powerful and expensive computer.• Very fast in operations • Designed for complicated scientific jobs• Main users- Military organizations, major R&D

centres, chemical laboratories and universities• Manufactures of Super Computers – IBM, Silicon

Graphics, Fujitsu and Intel.

• Characteristics Of Super Computers1. Speed: 10000 Kilo instructions per second2. Word length: 64 to 96 bits3. Storage: 8 Mega Bytes to 64 Mega Bytes4. Functions: Space research, weather, designing5. Peripherals used: Hard disk, Laser Printer or very high speed printers

5. Notebook

• Popularly known as laptop• Battery operated personal computers.• Portable• Have large storage space

6. Tablet PC

• Is a mobile computer looks like a writing slate but uses a stylus pen or your finger tip to write on the touch screen.

7. PDA

• Personal Digital Assistant• Is a small palm sized hand held computer

which has a small colour touch screen with audio and video features.

Components of Computer

• Components or entities of computers can be classified into two broad categories as:

· Hardware· Software

Hardware

• Hardware refers to any physical component of a computer.

• For example, CPU, Monitor, Keyboard, Hard Disk, Floppy Disk, Printer, etc. are physical components and thus, is hardware.

Software

• Software refers to the programs, which are required to operate the computer.

• An analogy of hardware can be the book, which you are reading, and then software would be the text written on this book.

• Another analogy could be ‘brain’ is hardware but ‘memory stored in brain’ is software.

• E.g. of software, which you come across daily, are: Windows, Internet Explorer or any other Browser, Messenger etc.

Computer Architecture

• A computer system has the following main components:

1. Input Unit/Devices2. Output Unit/Devices3. Central Processing Unit includes ALU and CU.4. Memory Unit/Storage Devices

Organization/ Architecture of computer

Input Device Output Device

Secondary storage

Primary storage

Control Unit

ALU

Input Devices

• Hardware used – to enter data– and instructions

Input Devices

Input Device

• Mouse• Keyboard• Track ball• Joy Stick• Touch screen

• Light Pen • Digitizer• Web Cam• Scanner• Voice input• OMR

The Input device is used for input the information and The Input device is used for input the information and to change this instruction in binary form for to change this instruction in binary form for acceptance by the computer.acceptance by the computer.

Keyboard :- It is the CUI (Character user interface) user friendly device. It contain alphabets, digits, special character and some control keys.

Every key board is compatible with standard 101-key keyboard with QWERTY layout.

1.Keyboard

Types of Keyboard:- Serial Keyboard :- A serial keyboard sends

the data ,bit by bit, in a serial manner these serial data is converted into the parallel data.

Parallel Keyboard:- While a keyboard sends the data as a byte in parallel form and all the bits are sent simultaneously on different lines.

Keys

• Function Keys: 10-12 F keys at the top of the key board

• Arrow keys, Page Up, Page Down, Home, and End-known as cursor movement keys as it move the cursor around onscreen.

• Ctrl and Alt keys: these keys make the other keys on the keyboard act different from the way they act eg: Ctrl+S –shortcut to save

• Esc Save: Can be use to back out of or quit whatever you are currently doing

• Print Screen/SysRq: this key send a copy of your screen to your printer. In windows, this sends the screen image to the windows clipboard, a temporary storage area for data.

• Pause/ Break: It used to stop your computer from performing the same task over and over again.

2. Mouse

• Used to position your cursor, navigate through documents, enter commands and more.

• Functions - Pointing - Clicking - Dragging

3.Track ball & Space ball

• Basically an upside down mouse.• Instead of sliding the mouse, we can roll the

ball.• Doesn’t require much desk space.

4. Bar Code Reader

• It scans a bar code image and converts it into an alphanumeric values which is fed into the computer to which the bar code reader is connected.

• The laser bean scanning technology has been used for reading bar codes.

5.Joy stick

• Used for playing arcade games in computer.• It has a base with a lever sticking out of it and

lever has a few buttons for firing weapons and accelerating.

6. Touch Screen• A touch screen is an electronic visual display

that can detect the presence and location of a touch within the display area.

7. Light Pen

• A light pen looks like a pen light with a cable attaching it to the system unit.

• We can point the pen directly at objects on the screen and then press the pen tip against the screen to click or drag.

8. Graphic Tablet• It is an input device used to create graphics.• It is commonly used at CAD terminals, engineering

workstations and other data entry sites. • It contains 100 of copper wire embedded below the

surface. A stylus (an electronic pen) is provided for drawing.

9. Web Cam• A webcam is a video capture device connected to a

computer or computer network, often using a USB port or, if connected to a network, ethernet or Wi-Fi.

• The most popular use is for video telephony, permitting a computer to act as a videophone or video conferencing station.

10.Scanner• Scanner is an optical device that can input any

graphical matter and display it back. • The common optical scanner devices are Magnetic

Ink Character Recognition (MICR), Optical Mark Reader (OMR) and Optical Character Reader (OCR).

1.Magnetic Ink Character Recognition (MICR): - This is widely used by banks to process large volumes of cheques and drafts.

2.Optical Mark Reader (OMR): used for checking OMR sheets.

3.Optical Character Recognition (OCR): - This technique unites the direct reading of any printed character.

Output device

Hardware that conveys information to one or more people.

It is an electro mechanical device - accepts processed data from the

computer - transforms data into user

understandable form

What is an output device?

Output Device

• Monitor• Printer• Plotter• Speakers• Modem

Monitor or VDU (Video Display Unit)

• Monitors also called display unit

• 2 types of display screen technology

i. Cathode Ray Tube (CRT)ii. Liquid Crystal

Display(LCD)

i) Cathode Ray Tube: • Electron gun -electronic beam-creates

image –falls on a phosphate coated glass display screen.

ii) Liquid Crystal Display: •CRT is replaced with LCD•LCD make monitors more compact and slimmer.•Low energy consumption than CRT

Printer• It is an important output device which can be

used to get a printed copy of the processed text or result on paper

• Printers are evaluated on the basis of image quality, speed and cost of operation.

Types of printers

i) Depending on their speed, printing technology and printing quality, printers are classified into,

i. impact ii. non-impact printers

Impact Printers

• using oldest printing technology• Impact printers use the familiar typewriter

approach of hammering a typeface against the paper and inked ribbon.

• Common forms are dot matrix, daisy wheel and line printers

Non-impact Printers

• Non-impact printers do not hit or impact a ribbon to print.

• They use electro-static chemicals and ink-jet technologies.

• Laser printers, thermal printers, page printers and Ink-jet printers are of this type.

Plotter

• Used to produce larger pictures or images such as -drawing graphics, - making maps, - construction plans for buildings, - plotting contour lines - detailing of civil engineering structures or blue prints for machine

components.

Types of Plotter

• 2 types on the basis of technology,i. Pen Plotter/ Flat bed Plotter: draw images

with multi coloured pensii. Electrostatic Plotter/ Drum Plotter: work on

same technology as laser printers

MODEM

• Modulator Demodulator• Both an input and out put device• A modem is a device that connects your computer to

the outside world.• 2 types: External modem and internal modem.

• External modem: it is connected to the computer through a serial port and to the telephone system with a standard telephone jack. It indicates transmission of data.

• Internal modem: is a circuit board that is plugged into one of the computer’s expansion slot. It doesn’t indicate transmission of data.

What is the system unit?

The Casecontainingelectroniccomponentsused to processdata

CPU• The CPU is attached to the Main memory

and this combination is the main basis of the modern general purpose computer.

• It has 2 main tasks - to control the fetching and interpretation

of instructions from memory and the movement of data between memory and the CPU.

- to carry out the instructions

CPU have two main component 1. Control Unit2. Arithmetic Logic Unit

Control Unit

• It is a most complex unit and work as a Traffic police.

• It controls -the fetching of instructions from main memory-execution of the instructions-passing of data to and from the Arithmetic/

Logical Unit for computation.

Arithmetic Logic Unit

-It perform logical and Arithmetic functions like Add, Subtract, Multiply, Divide, Compare, Shift and rotate.

What are two main components on the motherboard?

Central Processing Unit (CPU)Central Processing Unit (CPU)Also called a processor

MemoryMemory

4. Memory Unit/ Storage Devices

• Consists of • A. Main Memory or Primary storage• B. External Memory/ Auxiliary Memory/

Secondary Storage

MemoryMemory

Primary memory Secondary Memory

RAM ROM

EEPROM

DRAM

SRAM

PROM

EPROM

A. Main Memory or Primary storage

• Main memory stores programs and data when computer is running

• Memory is a set of chips that stores data or instructions.

• Data can be stored temporarily or permanently.• PCs use several different kinds of memory but the

two very important are Read only Memory (ROM) and Random Access Memory (RAM).

Random Access Memory (RAM):

• Part of memory can be accessed for reading and writing.

• RAM holds data and instructions which the CPU needs to work with.

• Fast access• This data is held temporarily, it is volatile, its contents

are erased when the computer is switched off or power failure occurs.

Read Only Memory (ROM):

• - Memories can only be read, and not possible to write the data.

• - ROMs can be written only at the time of manufacture

• - It permanently stores its data even when computer is switched off.

• - It is non-volatile because its contents are never erased.

Cache Memory

• Are small , high speed memories that function between CPU and main memory

• Faster than main memory• Very costly

B. External Memory/ Auxiliary Memory

• Also called secondary storage• External memory holds large quantities of

information too large for storage in main memory.

• It used to keep a permanent copy of programs and data.

Storage

• The process of saving data and instructions permanently is known as storage. Data has to be fed into the system

• All data and instructions are stored here before and after processing.

Storage device1) Magnetic drivesa. Hard diskb. Floppyc. Zip drived. Magnetic Tapes

2) Optical drivesa. CD ROMb. HD-DVDc. Blu-Ray

3) Solid state devices - Flash Memory - Smart Card - Solid State disks

Magnetic Storage Devices

• Most common form of storage• They are magnetized storage media on which digital

or analog information is recorded as electro magnetic symbols.

• All magnetic drives work the same

Working Magnetic Storage Devices

• Data storage and retrieval– Media is covered with iron oxide– Read/write head is a magnet– Magnet writes charges on the media

• Positive charge is a 1• Negative charge is a 0

– Magnet reads charges– Drive converts charges into binary

Magnetic Storage Devices

Floppy DiskFloppy Disk

Hard DiskHard Disk

TapeTape

What is a hard disk?

– Provides greater storage capacity than a floppy disk, Zip disk, or

USB flash drive

Illustrated Hard Disk

What is a floppy disk?

– Thin, flexible disk enclosed in rigid plastic shell

– Low capacity and cheap

– Highly prone to dust and scratching

Zip drives•Similar to floppy disks but with thicker magnetic disks.•Introduced to overcome the liumitations of floppy disks•Faster than floppy disks

Magnetic Tapes:•Used in the 1980s and 1990s as back up devices•Due to their slow speed they are become virtually obsolete.

Optical drives

• Is a type of storage medium that stores content in digital form, which is read and written by a low density laser .

What is a compact disc?

– Flat, round, portable metal disc

• CD-ROM• DVD-ROM

HD DVD•High density mostly single sided, double layered optical disks which can hold up to 15 GB on a single layer and 30 GB on a dual layer disc.

Blu-Ray•High density optical storage media•Mainly used for high definition video and storing data

What is a USB flash drive?

– Provides much greater storage capacity than a floppy disk or Zip® disk

– Small and lightweight enough to be transported on a keychain or in a pocket

Solid State Devices

• Data is stored physically• No magnets or laser• Very fast• Eg: Flash memory, Smart Cards and Solid

state disks

Flash memory– Found in cameras and USB drives– Combination of RAM and ROM– Long term updateable storage

Smart cards– Credit cards with a chip– Chip stores data– Eventually may be used for cash– Hotels use for electronic keys

• Solid-state disks– Large amount of SDRAM– Extremely fast– Volatile storage– Require battery backups

Consists of a seriesof instructions thattells the computer

what to do

Consists of a seriesof instructions thattells the computer

what to do

Computer Software

What is software?

Also called aprogram

Also called aprogram

What is system software?

– Programs that control or maintain the operations of the computer and its devices

What is application software?

Presentation Graphics

Spreadsheet

Database

Word Processing

Programs that perform specific tasks for users

Who is a programmer?Someone who develops application or system

software

• Programmer writesinstructions todirect computer toprocess data intoinformation

Javascript program

Resulting Internet application

Limitations of Computer

1. It cannot think intelligently like human being.2. It can neither take decision nor can correct

wrong instructions3. It is maintained and updated by a

programmer or user4. It has no feelings and ethics5. It cannot work without power