Unit-1 Introduction to Computers

INFORMATION TECHNOLOGY MANAGEMENT

Content:
Introduction Evolution of Computers Generation of Computer Basic Computer Organization Types of computer Computer Application

What Is A Computer?
A computer is an electronic device, operating under the control of instructions (software) stored in its own memory unit, that can accept data (input), manipulate data (process), and produce information (output) from the processing.

Devices that comprise a computer system

Monitor (output) Speaker (output) System unit (processor, memory) Printer (output)

Storage devices Mouse (input) (CD-RW, Floppy, Hard disk, zip,)

Scanner (input)

Keyboard (input)

What Does A Computer Do?

Computers can perform four general operations, which comprise the Information Processing Cycle.
Input Process Output Storage

Evolution of Computer

Abacus
Chinese invented calculating device called ABACUS Perform addition and subtraction Rules memorized by the user Regular arithmetic problems can be done

 beads on the rods to count and calculate still widely used in Asia!

PASCALS CALCULATING MACHINE (PASCALINE)

Blaise Pascal a French mathematician developed mechanical calculating machine called Pascals calculating machine in 1642 A.D First real desktop calculating device that could add and subtract. Construct of set of toothed wheels or gears.

Each wheel having 0 through 9.

Arithmetic operation performed by turning these wheels.

Concept still seen in conventional electric meter

and taxi meter.

LEIBNITZS IMPROVED PASCAL MACHINE

Pascal machine perform only addition and subtraction operation
Pascal machine was improved in 1673, Introduced wheel could perform multiplication, division and square root operation.

HOLLERITHIS CARD READING MACHINE

Dr.Herman Hollerith came up with the concept of punch card.

Developed a card reading machine and used punched cards for

tabulating and calculating data, Data was being compiled and analyzed.

CHARLES BABBAGES ENGINE.

Charles Babbage (1792-1871) made a machine called Difference Engine. Evaluate accurate algebraic expression and mathematical tasks up to 20 decimal places,

This machine is also called as Babbage's difference engine

Later adopted by insurances companies for computing life tables.

Modified the device in 1833.

Modified device is called Analytical engine

It had memory unit, arithmetic operators. Producers the o/p in punched card format. Parts and working principle of Analytical Engine similar to today computer. Charles Babbage is called Father of computer

MARK-I DIGITAL COMPUTER

All calculating machines invented were basically mechanical machine. First electro-mechanical computer developed in 1937 by Howard Aiken. Used Hollerith's punched cards and principle of computer stated by Charles Babbage

Automatically perform a sequence of arithmetic

operators.

It was an electromechanical device.

FIRST ELECTRONICS COMPUTER (ABC)

Dr.John Atanasoff and Clifford Berrys developed first electronic computer. It is called as ABC. Use vaccum tubes for storage ,

arithmetic and logical function.

It could solve simultaneous equation. It could perform 500 addition or 350

multiplication in one second.

ELECTRONIC NUMERICAL INTEGRATOR AND CALCULATOR (ENIAC)

Electronic computer
Developed by Prof.Presper Eckert and John Mauchly. Produced in 1940 for U.S.army

Perform 300 multiplication/second was the fastest machine.

(ENIAC)

ELECTRONIC DISCRETE VARIABLE AUTOMATIC COMPUTERS(EDVAC)

First electronic stored program
computer developed by Dr. John Neumann in 1949. Sequence of instructions and data can be stored in memory for the purpose of automatically directing the flow of operations.

Features of EDVAC different form ENIAC are: 1.Use of binary and electronic arithmetic operators. 2.Internal storage of instructions were written in digital forms.

MANCHESTER MARK-I
Small experimental computer. Performs operation based on stored program.

Designed Manchester university by a group of scientist headed by

prof.M.H.A.Newman. Limited to stored data and instruction.

MICROPROCESSOR
Microprocessor chip INTEL 4004 was developed in 1969 by INTEL. Perform only few instruction and very small amount of data. 1971 INTEL 8008 MP was developed. Foundation for development of personal computer(pc).

PERSONAL COMPUTERS
First pc (with MP)developed in 1974.

In 1977 first successful micro computer (pc) developed by a

young technician named Steve Wozniak. This was called the computer Apple-1

Generation of Computers
Computer can classified in to five types according to generations . First generation computer . Second generation computer . Third generation computer . Fourth generation computer . Fifth generation computer

First generation computer

Period : 1946 1956

1st Generation (1946 - 1959) : Vacuum Tubes

Main processing device : Vacuum tubes
Gave off so much heat that even if they were cooled by air conditioners IBM Punched Card (input) Input and output media were punched cards and magnetic tapes
Magnetic Tapes (output) Vacuum Tubes (memory)

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Vacuum tubes

UNIVAC

ENIAC

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Punched cards

First generation computer

Advantages : . It was the only electronic device . First device to hold memory Disadvantages : . Too bulky . Vaccum tubes burn frequently . They were producing heat . Maintenance problems

Too bulky

Second generation computer

Period : 1956 1963
Main processing device : Transistor Storage media : Magnetic disc

2nd Generation (1956 - 1963) : Transistor

An electronic switch that alternately allow or disallow electronic signal to pass, replaces vacuum tubes

Much smaller than vacuum tubes, draw less power, and generate less heat, conduct electricity faster.

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Minicomputer

Second generation computer

Advantages :
. Size reduced considerably
. Very fast . Very much reliable

Disadvantages :
. They over heated quickly . Maintenance problems

Third generation computer

Period : 1964 1971

Main processing device : IC (integrated circuit)

Storage media : Floppies

3rd Generation (1964 - 1971) : Integrated Circuit

An electronic circuit that packages transistors and other electronic components into one small silicon chip called semiconductor. The number of transistors that is placed on a single chip has increased, shrinking both the size and cost of computers. Keyboards and monitors were used. Magnetic disks were used widely as secondary storage

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Third generation computer

Advantages :
. ICs are very small in size
. Improved performance . Production cost is low

Disadvantages :
. ICs are sophisticated

Fourth generation computer

Period : 1971 present
Main processing device : ICs with VLSI
(Very Large Scale Integration)

Storage media : Floppies, CDs.

4th Generation (1971-Present) : Microprocessor

A silicon chip on which transistors are integrated onto it. Microprocessor can do all the processing of a full-scale computer smaller in size , faster in speed. These circuit integrations are known as Largescale integrated (LSI) and Very Large-scale integrated (VLSI) circuits Microprocessors led to the invention of personal computers.
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ICs with VLSI (Very Large Scale Integration)

Fourth generation computer

Advantages :
. It is a compact
. Less power consumption . Production cost is low

Disadvantages :
. No artificial intelligent.

Fifth generation computer

Period : Present and beyond

Main processing device : Super large scale

integrated chips and ICs with parallel processing

Advantages : Artificial intelligence Expert system

5th Generation (Present & Beyond) : Artificial Intelligence

Artificial Intelligence (AI) concerns with making computers behave and think like humans. The branch of computer science that deal with writing computer programs that can solve problems creatively AI studies include robotics, expert systems, games, etc..

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. First generation computer . Second generation computer

Vacuum tubes

Transistors

. Third generation computer . Fourth generation computer

ICs
. Fifth generation computer

ICs with VLSI

ICs with parallel processing

Basic Computer Organization

Layers of a Computing System

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Communications devices

Central Processing Unit Control unit Input devices Arithmetic/ logic unit Output devices

Register storage area Memory

Secondary storage

Basic Computer Organization

Central processing unit (CPU) A hardware component that performs computing functions utilizing the ALU, control unit, and registers. Arithmetic/logic unit (ALU) Performs mathematical calculations and makes logical comparisons Control unit Sequentially accesses program instructions, decodes them, coordinates flow of data in/out of ALU, registers, primary and secondary storage, and various output devices

 Registers High-speed storage areas used to temporarily hold small units of program instructions and data immediately before, during, and after execution by the CPU Primary storage Holds program instructions and data

The characteristics of a computer are:

1. Speed 2. Reliability 3. Storage

4. Accuracy 5. Automation 6. Functionality 7. Diligence 8. Versatility

1. Speed: computer process the data at an unimaginable speed. The speed of the computer ranges up to Nano seconds.

2. Reliability: The next important characteristic of a computer is its reliability. we can always rely on the information given by a computer. 3. Storage: The memory capacity of a computer is measured in in bits and bytes. Large amount of the data can be stored in computer and retrieved. Memory capacity of the computer ranges in Giga bytes.

4. Accuracy: Accuracy of the computer is very high it performs calculation with greater accuracy

in less time.
5. Automation: a computer allows automation for any process designed in the from of a program. A program can be executed any number of times to repeat the process.

6. Functionality: Computer can performs many kinds of jobs. They not process the data but also can be used for playing music, movies, and printing jobs. It finds its applications in all most all the fields. 7. Diligence: A computer never gets tired. 8. Versatility: Perform different operations

Units of Data storage

Bit - the smallest unit of data that a computer uses. It can be used to represent two states of information, such as Yes or No. Byte - is equal to 8 Bits. A Byte can represent 256 states of information, for example, numbers or a combination of numbers. 1 Byte could be equal to one character.

Bits on Bytes
1 byte 1 kilobyte (K / Kb) 1 megabyte (M / MB) 1 gigabyte (G / GB) 1 terabyte (T / TB) = 8 bits = 1,024 bytes = 1,048,576 bytes = 1,073,741,824 bytes = 1,099,511,627,776 bytes

 Fact 1: Kilobyte 1 Kilobyte would be equal to this paragraph you are reading, whereas 100 Kilobytes would equal an entire page.

 Fact 2: Megabyte One of those old 3-1/2 inch floppy disks can hold 1.44 Megabytes or the equivalent of a small book.

 Fact 2: Megabyte 100 Megabytes might hold a couple volumes of Encyclopedias. 650 Megabytes is about the amount of data that will fit on a CD-ROM disk.

 Fact 3: Gigabyte 1 Gigabyte of data is almost twice the amount of data that a CD-ROM can hold. 1 Gigabyte could hold the contents of about 10 yards of books on a shelf. 100 Gigabytes could hold the entire library floor of academic journals.

 Fact 4: Terabyte To put it in some perspective, a Terabyte could hold about 3.6 million 300 Kilobyte images or maybe about 300 hours of good quality video. A Terabyte could hold 1,000 copies of the Encyclopedia Britannica.

Types of Computers

Types of computer
Type of computer

Digital computer

Analog computer

Hybrid Computer

Micro Computer

Main frame Computer

Super Computer

Mini Computer

Home

PC

Analog computer
o Analog computer operates on measuring methods. o The input data is a physical quantity like temp, pressure, speed, velocity. o It measures magnitude, temp, pressure, speed, velocity etc. o Signals are continuous of (0 to 10 V) o Used for scientific and engineering purpose o Output is continuous and presented graphically

Analog computer

Digital Computers
o Digital computer operates on counting methods o The input data is represented by a number. These are used for the logical and arithmetic operations. o Signals are two level of (0 V or 5 V) o Accuracy unlimited o Output is continuous but obtain when computation is completed.

Hybrid Computer
Hybrid computers are computers that exhibit features of analog computers and digital computers. Hybrid computer accepts analog signals, converts them to digital and processes them in digital form. This integration is obtained by digital to analog and analog to digital converter

 It accepts a continuously varying input, which . is then converted into a set of discrete values for digital processing.

Micro Computer
Desktop or portable Personal or business computers Affordable Many available components Can be networked

Micro Computer
o Micro computer are the smallest computer system. o There size range from calculator to desktop size. o Its CPU is microprocessor. o Application : - Personal computer, Multi user system, Offices. o Used as front-end processor for mainframe.

Mini Computer
o These are also small general purpose system. o More powerful and most useful as compared to micro computer. o Mini computer are also known as mid range computer . o Application :- Universities, Factories, Labs.

Mini computer

Main Frame Computer

o Mainframes are used by companies to provide centralized storage, processing, and management for large amounts of data. o Provides faster processing and greater storage area. o The word main frame comes from the metal frames. o Application Host computer, Central data base server, COMMERCIAL, SCIENTIFIC, MILITARY These are largest enterprise computers. Supports complex computation on massive data.

Super Computer
o Super computer are those computer which are designed for scientific job like weather forecasting and artificial intelligence etc. o Fastest and expensive. o A super computer contains a number of CPU which operate in parallel to make it faster. o Application weather forecasting, weapons research and development.

Super computer

Laptops & Smaller

LAPTOP (OR NOTEBOOK): Briefcase type package, very portable, can be inexpensive, can connect to other computers or networks HAND-HELD (OR PALMTOP): Sub-miniature, wireless computer. Growing in sophistication and connectivity.

Workstation

Tablet

Handheld PC(PDA)

Smart phone

Computers Progress
UNIVAC (1951-1970)
(1968 vers.)

Circuits

Integrated Circuits 512 K 1.3 MHz 100 MB Hard Drive

Mits IBM PC Macintosh Pentium Altair (1981) (1984) IV (1975) 2 Intel Intel 8088 Motorola Intel P-IV 8080 Microchip 68000 Microchip 29,000 - 7.5 million Microchip Transistors transistors 265 Bytes 256 KB 2 KHz 4.77 MHz Floppy Drives 256 MB 3200 MHz = 3.2 GHz Hard Drive, Floppy, CD-Rom Small Tower $1000 $2000

RAM Memory Speed Storage

8 Floppy Floppy Drive Drive

Size

Whole Room

Briefcase
(no monitor)

Briefcase Two + Monitor shoeboxes

(integrated monitor)

Cost

$1.6 million $750

$1595

~$4000

Data and Information

All computer processing requires data, which is a collection of raw facts, figures and symbols, such as numbers, words, images, video and sound, given to the computer during the input phase. Computers manipulate data to create information. Information is data that is organized, meaningful, and useful.

During the output Phase, the information that has been created is put into some form, such as a printed report.
The information can also be put in computer storage for future use.

Word Processing

Word Processing software is used to create and print documents. A key advantage of word processing software is that users easily can make changes in documents.

Electronic Spreadsheets

Electronic spreadsheet software allows the user to add, subtract, and perform user-defined calculations on rows and columns of numbers. These numbers can be changed and the spreadsheet quickly recalculates the new results.

Database Software

Allows the user to enter, retrieve, and update data in an organized and efficient manner, with flexible inquiry and reporting capabilities.

Presentation Graphics

Presentation graphic software allows the user to create documents called slides to be used in making the presentations. Using special projection devices, the slides display as they appear on the computer screen.

Computer Application
Office Automation Industry and Engineering Health care Education Banking Commerce Simulations Education Space Entertainment

Practice Questions:
1. List out the various computer generations along with their basic characteristics and examples. 2. Explain basic computer architecture and its components in detail. 3. What are various types of computers? 4. Write a note on computer application with respect to multiple disciplines. 5. How computerization helps in various departments like finance, marketing, human resource and operations

You have a very powerful mind that can make anything happen as long as you keep yourself centered.

Dr. Wayne W. Dyer

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