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UNIT - 1; COMPUTER HISTORY, , , , , , Learning Objectives :, After learning the Unit the students will be able to:, , > learn about the various inventions in computers, , > understand the technological changes occurs in computer in terms of hardware and, software, , > Identify and classify computers in its various categories, , > understand the basic difference between various types of computers, , > differentiate computers according to the way they process data, according to their size, and the function performed., , , , , , , , As we have seen that since its inception computer has been evolved a lot for the last couple, of decades. In earlier days a computer was such a big machine that required space like a complete, room and hence its maintenance cost was very much far away from a common man. A common, man could not have thought to have a computer for his personal use. But now-a-days one in every, three person is using computer in one way or the other. From bulky machine to as small as like a, SIM card, this is possible because of the ever changing technological world., , The old adage “Necessity Is the mother of inventions” holds true for computer also because, computers are invented as a result of man’s search for fast, accurate and reliable calculating, devices,, , The Evolution of Computers is defined in terms of various eras. Let us take a look of them:, , A) MANUAL ERA:, , The earliest device that qualifies as a digital, computer is the ‘Abacus’. This device allows the user seeeeeeees, to represent numbers by the position of beads on a rack., Simple addition and subtraction can be carried out rapidly, and efficiently by positioning the beads on the rack, appropriately, Although Abacus was invented around, , 600 B.C. and was used by the Chinese and Egyptians, it is still, being used in Far East., , Another manual calculating device Tle, to speed up the multiplication process was T28, John Napier’s bone or Cardboard Multiplication Tes, Calculator developed by Scottish man named tHe, , , , John Napier. A complete set of Napier bone’s Bho, consists of rods , one for each of the digit 0 to 9 i ane, called bones, with number carried on them. eee, It was designed in the 17" Century and they first 98, appeared in print in 1614, SET OF ROD, , B) MECHANICAL ERA :, , The first mechanical calculator was developed by Wilhelm Schickhard , a professor at the, University of Tubingen., , In 1642, the young French philosopher and mathematician, Blaise Pascal developed another mechanical adding machine, called Pascaline, which could add and subtract numbers.

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Pascaline used a system of gears and wheels., , Later in year 1671 Baron Gottfried Wilhelm Von Leibiniz of Germany developed a similar, mechanical calculator that could also perform multiplication and division., , In early 19" Century a Frenchman Joseph Jacquard invented a loom that used punched cards, to automatically control the manufacturing of patterned cloth., , Charles Babbage , a 19" Century professor at Cambridge University,, is considered to be the Father of Modern Digital Computers., Babbage designed a Difference Engine in year 1822, which was, capable of performing automatic multistep calculation and, can produced reliable mathematical and statistical tables, automatically. In the year 1842, Babbage conceived the new, idea of Analytical Engine, that was intended to be completely, automatic. It was capable of performing the basic arithmetic, functions for any mathematical problem at an average speed, of 60 additions per minute. The Analytical Engine, incorporated many features of modern computers including, punched card instructions, internal memory , an arithmetic, unit to perform calculation any many other number of principals, which have been shown to be fundamental to the design of any digital computer., , , , , , Analytical Engine was programmable and in order to write program Babbage employed ada, Augusta Lovelace (daughter of poet Lord Byron), who became the first programmer in the, world., , , , , , , , in the late 19" century a young statistician Harmen Hollerith,, , the inventor of Punched Card Tabulating Machine , used it for, , processing Census data. Later in 1911, by merging several, other firms, he formed IBM Corporation., , In 20" Century, under the direction of George Stibitz of, , Bell Telephone Laboratories, five large scale computer, , were developed by using Electromechanical Relays and were called as Bell Relay cantare:, These computers were capable to perform calculations with a high speed and accuracy., , The Mark-| computer, the world first general purpose mechanical digital computer was, developed by Howard H. Aiken, a professor of Physics at Harvard University, in collaboration with, IBM, Its designed was based on he technique already developed for punched card machinery. This, machine was also known as Automatic Sequence Controlled Calculator, and may be regarded as, the first realization of Babbages’ Analytical Engine., , , , C) ELECTRONIC ERA :, , The first electronic computer using 45 vacuum tubes (valves) for internal logic and capacitors, for storage and having the concept of binary system was developed by John Vincent Atanasoff and, his assistant Clifford Berry in 1939. This prototype of automatic electronic calculator was known as, Atanasoff-Berry Computer or ABC, capable of solving variables with a high degree of accuracy., , In 1946, an all electronic version of Mark-! called Electronic Numerical Integrator And, Calculator (ENIAC) was developed by J. Presper Eckert and John W. Mauchly at the University of, Pennsylvania, USA. It was the first large scale fully electronic computer installed at Marryland to, cater the military need., , The basic behind the stored program digital computers was developed by Dr. John Von, Neumann. And in 1952 by using the concepts of stored program, John Von Neumann with his, collaborator H.H. Goldsteine designed Electronic Discrete Variable Automatic Calculator (EDVAC). It, was John Von Neumann who introduced the idea od storing both instructions and data in the binary, form.

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In 1949, at Cambridge University, a group of British Scientists headed by professor Maurice, Wilkes developed Electronic Delay Storage Automatic Calculator (EDSAC), that was capable of, performing Addition operation in 1500 microseconds and multiplication operation in 4000, microseconds., , The UNIversal Automatic Computer (UNIAC) was first digital computer, produced by many, companies like IBM, Universal Accounting Company, General Electronic Corporation etc . It was first, commercial large scale digital computer produced in 1951., , During the period of late 1940’s and early 1950's many other stored program computers like, JOHNIAC, MANIAC, ILLIAC etc were developed., , 1.1 GENERATION OF COMPUTERS, , Generation in computer era provides a framework for the growth of computer industry and, generally characterizes the major developments in the computer industry. The modern computer, era can be divided into Five generations distinguished by the basic electronic component within the, computer. Each new logic unit let the computers faster in speed, smaller in size, more reliable and, less expensive than their predecessors. Modern computers came in a variety of shapes, sizes and, costs., , Computers were developed in Five different phases known as the Generation of Computers., Let’s discuss one by one in a little detail :, , First Generation (1942-1955) The computers of this generation used Electronic Valves, {an array of Vacuum Tubes) as the basic component for memory and circuitry for central processing, unit. These vacuum tubes were a fragile glass device like electric bulb, that could control and, amplify electronic signals. They produced a lot of heat and, were prone to frequent fusing/ damaging of the installations., Therefore, they were used very expensive and could be, afforded onlyby very large organizations., , Advantages :, , i) these computers were the fastest calculating device of their, time. They could perform computations in milliseconds., , ii) vacuum tube technology made possible the advent of, electronic digital computers., , , , Disadvantages :, , i) Too bulky in size, , ii) Air conditioning required to control the temperature, iii) Prone to frequent hardware failure., , iv) Commercial production was difficult and costly., , v) Slow input and output operations., , USEFUL POINTS :, Period : 1942-1955, Component used : Vacuum tubes, Speed : milliseconds, Maximum memory capacity : 2000 inch, Mean-time before failure : minutes, Peripherals :, © 1/0: Punched cards, Paper tape, Magnetic tape, Printer (online), © Secondary Storage : Punched Cards, Paper Tape, Magnetic Drum, Magnetic Disk etc

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© Operating System : Mainly Batch Processing, , © Languages ; Machine Code and Electric Wired board, , © Application Areas : Payroll Processing, Record Keeping etc., , © Example : ENIAC, EDVAC, EDSAC and IBM 650 ( the first modern digital computer produced on, mass scale), , Second Generation (1955-1964) The second generation computer used Semi-conductor, transistor instead of vacuum tubes after the invention of transistor by a team led by William, Shockley., , This generation computers used transistors which were cheaper,, , consumed less power, more compact in size, more reliable and “, faster than the vacuum tubes used in first generation computers. }, , Advantages :, , i) Smaller in size as compared to first generation computers, li) More reliable, , iii) Less heat generated., , iv) Less prone to hardware failure, , v) Wider commercial use, , , , , Disadvantages :, i) Air conditioning required, ji) Manual assembly of individual components into a functioning unit was a cumbersome task., , USEFUL POINTS :, © Period : 1955-1964, * Component used : Transistors, Speed ; microseconds, Maximum memory capacity : 128000 inch, Mean-time before failure : days, Peripherals :, 0 1/0: Paper tape, Magnetic tape, Visual Display Unit, © Secondary Storage : Paper Tape, Magnetic Drum, Magnetic Disk etc, © Operating System : Multiprogramming, Time-Sharing and Real Time processing, © Languages : Assembly Language, High Level Languages like FORTRON, COBOL etc, © Application Areas ; Batch -oriented application like Billing, Payroll processing, Updating, Inventory etc., * Example : IBM 1401, IBM 7090, IBM 1620, IBM 7094, IBM 700 series, CDC 1604, CDC 3600,, UNIVAC 1108, , Third Generation (1964-1975) The third generation computers used Integrated Circuits (or IC, Chips) in which many transistors, resistors, capacitors and other, , components (circuit elements) are fabricated or integrated and packaged, , together into a very small surface of silicon known as Chips., , This new microelectronic technology was called Integrated Circuits., , The IC was invented by Jack Kilby in 1958