Generations of Computer :

1.      There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period.

The main five generations of computer are:





First Generation

Period: 1946-1959. Vacuum Tube Based.


Second Generation

Period: 1959-1965. Transistors Based.


Third Generation

Period: 1965-1971. IC (Integrated Circuit) Based.


Fourth Generation

Period: 1971-1980. VLSI (Very Large Scale Integrated) Based.


Fifth Generation

Period:1980-onwards. ULSI (Ultra Large Scale Integrated) Based.

1st Generation(1946-1959):

First Generation Computers uses vacuum tubes, magnetic tapes drivers and magnetic core was developed.ENIAC() was the First digital computer. It uses 18,000 vacuum tubes. its size was too larger. It was developed by two scientists Mauchly and Echert at the Census Department of United States. Examples of first generation computers are ENIVAC and UNIVAC-1.


§  Vacuum tube technology made possible to make electronic digital computers.

§  These computers could calculate data in millisecond.


§  The computers were very large in size.

§  They were not very reliable.

§  Air conditioning was required.

§  They consumed a large amount of energy.

§  Non-Portable.

§  Very slow speed.

§  Used punch cards for input.

§  Used machine language only.

§  They produced too much heat and energy.

2nd Generation (1959-1965):

The second generation computers used transistors. The scientists at Bell laboratories developed transistor in 1947. These scientists include John Barden, William Brattain and William Shockley. The size of the computers was decreased by replacing vacuum tubes with transistors. The examples of second generation computers are IBM 7094 series, IBM 1400 series and CDC 164 etc.


§  Smaller in size as compared to the first generation computers.

§  The 2nd generation Computers were more reliable.

§  Better portability as compared to the first generation computers.

§  Better speed and could calculate data in microseconds.


§  Costly and not versatile.

§  Only used for specific purposes.

§  Constant maintenance was required

3rd Generation(1965-1971):

The computers of third generation used integrated circuits (IC’s) in place of transistors. The IC was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient. In this generation remote processing, time-sharing, multi-programming operating system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation.


§  Smaller in size as compared to the previous computers.

§  They were more reliable.

§  Used less energy.

§  Maintenance cost was low because hardware failure is rear.

§  Less expensive.

§  Used mouse and keyboard for input.


§  Air conditioning was required.

§  The latest technology required for the manufacturing of IC chips.

4th Generation(1971-1980):

After 1971 the fourth generation computers were built. The fourth generation computers were the extension of third generation technology. The fourth generation computers emerged with development of the VLSI (Very Large Scale Integration).With the help of VLSI technology microprocessor came into existence. The computers were designed by using microprocessor, as thousands of integrated circuits were built onto a single silicon chip. It became more powerful and reliable.


§  Smaller in size as compared to the previous generations.

§  More powerful and reliable than previous generations.

§  No air conditioning required.

§  Cheapest among all generations.

§  Totally general purpose

§  Less need to repair the Computers.


§  The latest technology is required for manufacturing of Microprocessors.

5th Generation(1980-Onwards):

Fifth generation computers are in developmental stage which is based on the artificial intelligence (AI). The idea of fifth generation computer was developed by Japan’s Ministry of International Trade and Industry in 1982. Computers can understand spoken words & imitate human reasoning. Scientists are constantly working to increase the processing power of computers. They are trying to create a computer with real IQ with the help of advanced programming and technologies. So we can say that the fifth generation computers will have the power of human intelligence.

§  Smaller in size.

§  More powerful, reliable and easy to handle.

§  VLSI (Very Large Scale Integrated) is replaced by ULSI(Ultar Large Scale Integrated).

§  The fifth generation is a more updated, clean and easy to use

§  Having capabilities of parallel processing.

§  Having extra high processing speed.

§  Wireless facility is provided.


§  If Computers have their own brain then they can harm the humans.


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