Monday, August 10, 2020

Computer Basics: Computer Generations

Computer Generations

1st Computer Generations: 1946-1959

  • The computers of this generation where ENIAC, EDVAC, EDSAC, Ferrant, Manchester, Mark 1, UniAc etc.
  • The main component used in these computers was vacuum tube (a switching device which replaced gear & excels)

2nd Computer Generations: 1959-1965

  • The most popular invention of the 2nd generation computer, as well as 20th centuries, was a transistor (Switching device replaced vacuum tube).
    it was invented by scientists of Bell laboratory, U.S.A named:
    1. William Shockley
    2. John Bardeen
    3. Walter Brattain
  • In the 1st part of the 2nd generation, we used Ge transistor and in the 2nd part Si.
    Ge & Si both are semiconductor materials i-e, not a very good conductor and not a very bad conductor.
  • Ge was replaced by Si because the chemical bonding and melting-point of Ge were less than Si.
    In 1963, DEC(Digital Equipment Corporation, USA) introduced the first 32-bits main Frame computer.

3rd Computer Generations: 1965-1971

  • The most popular invention of the third generation computer was IC (Integrated circuit). It was invented by Jack St. Clair an Engineer in Terias Instrument USA in 1958.
  • Advantages of Integrated Circuit:
    1. Smaller Computer
    2. Low-cost computer
    3. Reliability
  • According to pins agreement, there are mainly two types of IC’s:-
    1. DIP (Dual In-Line Package): Up to 24 pins agreement
    2. PGA (Pin Grid Array): more than 100 pins arrangement
  • According to transistor implementation the types of ICs in the 3rd generation where
    1. S.S.I – Small scale Integration: 1 to 10 transistor
    2. M.S.I – Medium Scale Integration: 11 to 100 transistor
  • The computer of this generation is called supercomputer. The 1st supercomputer where made in 1964 named CDC-6600 (Control Data Corporation, USA) and ILLIAC-IV made by Burroughs, USA.

4th Computer Generations: 1971-1980

  • This is the period of enhancement in IC Technology Semiconductor Memory, microprocessor etc.
    IC Technologies:
  • According to transistors implementations the types of IC in the 4th generation where:
    1. L.S.I – Large Scale Integration – 101 to 1000 transistor
    2. V.L.S.I – Very Large Scale Integration – 1001 to 10000 transistor
    3. U.L.S.I – Ultra Large Scale Integration) – more than 10001 transistor
  • Semiconductor Materials:-
    The memory which is made of semiconductor materials such as:
    1. RAM: Random Access Memory
    DRAM: Dynamic RAM
    SRAM: Static RAM
    2. ROM: Read Only Memory
    PROM: Programmable PROM
    EPROM: Erasable PROM
    EAROM: Electricity Alterable PROM
  • Note: The 1st semiconductor memory was DRAM, which could hold only 256bits in 1970.
  • Microprocessor:
    The single chip processor is termed as the 1st microprocessor was made by Intel a 4-bits microprocessor Chip in 1971.
    Intel 4004 – 4 bits – Microcomputer
    Intel 8008 – 8 bits – Microcomputer
    Intel 8080 – (8-12)bits – Microcomputer

5th Computer Generations: 1980 -till today

  • This is the period of enhancement in ICs Technologies, Semiconductor memory microprocessor as well as in AI(Artificial Intelligence).
  • Artificial Intelligence:
    AI is the branch of computer science which is used to period machines, Robotics that will emulate the human thought process.

The following table shows concluded information about all Five computer generations:

S.No Computer Generations Period of Computer Generation Description of Computer Generations
1 First Generation 1946-1959 Vacuum tube based
2 Second Generation 1959-1965 Transistor-based
3 Third Generation 1965-1971 Integrated Circuit based
4 Fourth Generation 1971-1980 VLSI microprocessor based
5 Fifth Generation 1980-till today ULSI microprocessor based


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