C R ORIGIN AND EVOLUTION
OMPUTE
The word “computer” is derived from the word com compute pute.. Com Compute puter r lite litera rall lly y means ans a mac machin hine whic which h does does calc calcul ulat atio ion n or comp comput utat atio ion. n. But But its its lite litera rall mean meanin ing g is insu insuff ffic icie ient nt to desc descri ribe be the the actual meaning of computer. Basically, the computer is a device that stores, processes and retr retrie ieve ves s (ext (extra ract cts) s) info inform rmat atio ion n in a very very shor shortt time. Today, it is used in every sphere of human activity.
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History About 5000 years ago Greek invented a calculating machine called Abacus. This was regarded as the first digital digital compute computer. r. Later Later, in 1614; 1614; the Logarith Logarithm m table table was invented by John Napier. In 1642, a French scientist, Blade Pascal invented a device for additions. This This was improv improved ed by Godfre Godfrey y Libnit Libnittis tis,, who who was the the inventor of the multiplication device in 1673. Both these devices were not foolproof at there performance. Thus later in 1820, another scientist named Mr. Charles Charles Thomas, Thomas, develop developed ed prototyp prototype e of today’s today’s calculator calculator with with improv improved ed facili facilitie ties. s. In 1822 1822,, Charl Charles es Babag Babage, e, a Briti British sh scientist, who was the professor of mathematics, designed a “differe “difference nce engine” engine” for the Royal Royal Society Society,, which which was meant meant for addition and multiplication. Since, its performance could
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not overcome the Charles Babage expectations, he deve develo lope ped d a mo more re effi effici cien entt mach machin ine e whic which h also also had had the the facilities facilities to do addition addition and multiplic multiplication ation,, called called “analytic “analytical al engi engine ne”. ”. Char Charle les s Baba Babage ge is cons consid ider ered ed as the the “fat “fathe her r o modern computer” for his harsh effort and work which lead to the the evoluti lutio on of com omp puters. rs. By 1920 920, mach achine ines that worked on electricity came into being and it greatly increased the speed and efficiency. The 1970s could be called as the era of the minicomputer. These were progressively smaller and cheaper machines than the the standa andard rd main ainfram frame e era era com ompu putters. rs. The The stan tandard ard mainframe of the 1970s shrunk from a room full of cabinets and tape drives to a decorative office machine perhaps 3 to 5 feet long and 3 to 4 feet high. In 1980, Apple realized the Apple II computer, the first true true comm commer erci cial al PC. PC. It was was a smal smalll desk deskto top p mach machin ine e that that
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runs BASIC. This machine had a major impact on the educational market. In 1981, all of this changed. The PC was released by IBM, and Lotus developed 1-2-3 based on the Visi-Calc spreadsheet program. This program became the first of the Killer Applications (killer apps) that industry had to run. The PC became an overnight success.
COMPUTER GENERATIONS Based on the increasing technology of the computers, it can be divided into five generations: generations:
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FIRST GENERATION COMPUTER 4
Computers of the first generation were based on the vacuum tube technology, as shown in figure (a). In 1822, Charles Babbage, a professor of mathematics at Cam Cambrid ridge Univer ivers sity ity, dev devise ised a machin chine e call calle ed the “Difference machine” meant to perform simple comp comput utat atio ions ns need needed ed fo for r sett settin ing g up trig trigon onom omet etri ric c and and logarithmic tables. Hence, he was known as the “Father o modern day computers”. After the World War II, there was in need need of adva advanc nced ed calc calcul ulat ator or fo for r calc calcul ulat atio ion. n. By that that time, many mechanical desk calculators were introduced. In 1946, the the Univ Unive ersit sity of Pensylv sylvan ania ia intr intro oduc duced the world’s first electronic computer ENIAC (Electronic Numerical Integrator and Calculating Machine). The ENIAC per perfo for rmed 5000 addi addittion ion per sec second, ond, consum sumed 150 150 kilowatts of power. Although, it had many other limitations as such. It was so huge and generated so much heat that it needed to be water cooled. Its weight was 30 tonnes (approx.) and there were about 18,000 electronic valves.
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ENIAC ENIAC was follow followed ed by EDSAC EDSAC (Elect (Electron ronic ic Dela Delay y Storag Storage e Auto Autom matic atic Comp Comput uter er)) in 1950 1950 and and UN UNIV IVAC AC (Uni (Unive vers rsal al Accounting Computer) in 1951.
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Fig (a): Vacuum Tube 7
In general, the first computer generation computer faced the following limitations: 1.Low operating speed. 2.Restricted computing capacity. 3.High power consumption. 4.Short life span. 5.Large space requirement. 6.Generate much heat that needed to be water cooled.
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SECOND GENERATION COMPUTERS
In the year 1950-51, the vacuum tubes were replaced by tran transi sist stor ors. s. This This decr decrea ease sed d the the size size and and incr increa ease sed d the the efficiency manifold (many & varied). If the computer in first
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generation could perform about 500 tasks per second, then the second generation computers could be able to perform around 5 lakh tasks. The use of computer increased from 1 st generation to 2nd generation.
Fig (b): ( b): Transisto Transistor r 9
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THIRD GENERATION COMPUTERS Third generation computers were introduced in the early 60’s. The basic distinguishing characters of the 3 rd generation computers from the other generation compute computers rs were the introduc introduction tion to the IC’s (Integra (Integrated ted circuits). It is an arrangement where micro sized crystals are connected on a surface using tiny metal strings. In IC’s several logical gates are fabricated on a single piece of silico silicon. n. Size Size of the the compu computer ters s was furt further her reduc reduced, ed, computing power increased, cost reduced. In this generation SSI (Small scale integrated) to MSI (Medium scale integrator) then to LSI (Large scale integrator). IC helped in making the computer much & more compact and inc increas rease ed the the sto storage age capac apacit ity y. Us Usin ing g vario ariou us
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terminals, terminals, more than one person was able to work on the same same comp comput uter ers s simu simult ltan aneo eous usly ly.. IBM3 IBM360 60 seri series es and and IBM370/168 belonged to the third generation computers.
Fig (c): Integrated Circuit (IC) 11
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FOURTH GENERATION COMPUTERS
By the end of 1970, 4 th generation computers computers emer emerge ged d with with a lot lot of revo revolu luti tion onar ary y inno innova vati tion ons. s. VLSI VLSI tech techno nolo logy gy of IC’s IC’s made made it poss possib ible le to mak make comple complete te circu circuit it of ALU ALU (Arith (Arithme metic tic and Logic Logic Unit) Unit) and and CU (Con (Contr trol ol unit unit)) with within in a sing single le chip chip whic which h comp compri rise se of the the main main part part of comp comput uter er call called ed CPU CPU (Central Processing Unit). Silicon chips were introduced as microprocessors in the fourth generation computers. Circuit space got reduced as a result & it could finally be kept on a table top. Compar Compared ed to the the other other gener generati ation on compu compute ters, rs, the the size and prize were brought down remarkably in the
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fourth generation. This increased the popularity and accessibility of computers among the general public. It came came to be incre increasi asing ngly ly emplo employe yed d for acces accessin sing g knowle knowledge dge and and enter entertai tainm nmen ent. t. Apple Apple series series one one & two, Intel 4004 etc, belong to this generation.
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Fig (d): Basic Block Diagram of a Computer System
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FIFTH GENERATION COMPUTERS
The computers being developed presently belong to the fifth generation. The most significant aspect of this generation of computers is expected to be the “artificial intelligence”. The chips used in these computers are “Very Large Scale Integrated” circuit (VLSI) with high power & efficiency. Besides VLSI there is LSI, ULSI types of chips which are also being used in fifth generation computers. Japanese and Americans are working on it. The fifth generation computers might well have the ability to recognize voice, read written matter and possibly, think on its own.
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