Thursday, June 24, 2010

COMPUTER GENERATION



you know that the evolution of computer started from 16th century and resulted in the form of that we see today.The present day computer,howerever, has also undergone rapid change during the last fifty years.Computer are classified into different generation.They are:
1.First Generation Computer(1943-1958):-
First generation of computer used Thermion valves.These computer were large in size and writing programs on them was difficult..They use vaccum tubes as memory device and they have 1 to 4kb storage capacity.They use machine level programming language. Some name of 1st generation computer are:-
a.ENIAC b.EDVAC,
c.EDSAC d.UNIVAC-1

2.Second Generation Computer(1959-1965):-
Around 1955 a device called Transistor replaced the bulky electric tubes in the first generation computer.Transistors are smaller than electric tubes and have higher operating speed.They have no filament and require no heatinf. Manufacturing cost was also very low.Thus the size of the computer got reduced considerably.Magnetic core memory was used as internal storage. Some name of 2nd generation of computer are:-
a. IBM 1620 b.IBM 1401
c. CDC 3600

3.Third Generation Computer(1966-1973):-
The third generation computers were introduced in 1996.They used Intergrated Circuits(Ics).These are popularly known as chips.A single IC has many transitors,registers and capactiors built on a single thin slice of silicon.Magnetic disks were used as secondary memory. Some of the computer of the 3rd generation of computer are:-
a. IBM-360 b.ICL-1900
c. IBM-370 d. VAX-750

4.Fourth generation computer (1974-1990):-
The present day computers that you see today are the fourth generation computers that started around 1974.It uses large scale Intergrated Circuits(LSIC) buil on a single silicon chip called microprocessors.Due to the development of microprocessor it is possible to place computer's central processing unit(CPU) on single chip.These computers are called microcomputers.Later very large scale Intergated Circuits(VLSIC) rrplaced LSICs.Some of the computer of the 4th generation of computer are:-
a.8086 b.8088
c.80286Sx d.80386Dx
e.Pentium I f.Pentium II

5.Fifth Generation Computer(1990-upward):-
The computers having artifical intelligence and high processing capacity undergoing on the development stage from 1990 are said to be fifth generation computer. It can perform large number parallel processing.ULSI(Ultra Large Scale Integration) as CPU component and AI(Arificial Intelligence) are main features of this generation.

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