Generations of Computer

Different generations of the computer are as follows:

First Generation Computers (1942-1955)

The beginning of commercial computer age is from UNIVAC (Universal Automatic Computer). It was developed by the Census Department of United States and developed by two scientists MAUCHLY and ECKERT in 1947.

First-generation computers were used during 1942-1955. They were based on vacuum tube, which was a glass (tube) that controlled and amplified the electronic signals.


  • Vacuum tubes were the only electronic component available during those days.
  • Vacuum tube technology made possible to make electronic digital computers.
  • These computers could calculate data in a millisecond.


  • These were very large.
  • Consumed a large amount of energy.
  • Heated very soon due to thousands of vacuum tubes.
  • Not reliable Air conditioning was required.
  • Constant maintenance was required.
  • Non-portable.
  • Costly commercial production.
  • Limited commercial use.
  • Quite slow speed.
  • Limited programming capabilities.
  • Used Machine language only.
  • Used magnetic drums which provide very less facility of data storage.
  • Punch cards for input.
  • Not versatile.
  • Very faulty.

Second Generation Computers (1955-1964)

Three scientists of Bell Laboratories developed transistor by 1948. These scientists include J. Baardeen, H.W. Brattain and W. Shockley. Transistor is a small device that transfers electronic signals across a resistor. The transistor was used in the computer by 1956 in second-generation computers.


  • Smaller in size as compared to first-generation computers.
  • More reliable More energy-efficient Were not heated because of less energy.
  • Wider commercial use.
  • Better portability.
  • Better speed, could calculate data in a microsecond.
  • Used faster peripherals like tape drives, magnetic disks, line printer etc.
  • Used Assembly language instead of Machine language.
  • Accuracy improved.


  • Air conditioning was required.
  • Constant maintenance was required.
  • Commercial production was difficult.
  • Also only used for specific purposes.
  • Costly
  • Not versatile.
  • Punch cards were used for input.

Third Generation Computers (1964-1975)

Jack Kilby developed the integrated circuit (IC) in 1958. An IC combined three electronic components onto a small silicon disc, Scientists later managed to fit even more components on a single chip called a semiconductor. Computers became ever smaller as a result. Operating System was also produced at that time.


  • Smaller in size as compared to the previous generation.
  • More reliable.
  • Less energy used.
  • Produced less heat as compared to previous generation computers.
  • More good speed could calculate data in nanoseconds.
  • Used fan for heat discharge and so to prevent from damaging.
  • Maintenance cost was low because hardware failure is rare.
  • Totally general-purpose.
  • Could be used for high-level languages.
  • Good storage
  • Versatile too an extent.
  • Less expensive.
  • Better accuracy
  • Commercial production increased.
  • Used Mouse, Keyboard for input.


  • Air conditioning was required.
  • High sophisticated technology required for the manufacturing of IC Chips.

Fourth Generation Computers (1975-Present)

In this generation, microprocessors were used. The microprocessor is a small chip containing thousands of ICs on it. It greatly reduced the size of the computer.


  • Very small in size.
  • Less power consumption.
  • Less heat generated.
  • Large fan for heat discharging and thus to keep cold.
  • No air conditioning is required.
  • Best speed to read instructions i.e. one billionth per second.
  • Reliable and Powerful.
  • Totally general-purpose.
  • Commercial production.
  • Less need of repairing.
  • Cheapest among all generations.
  • All types of high-level languages can be used in this type of computers.


  • High sophisticated technology required for manufacturing microprocessors.

Fifth Generation (Present and Beyond)

Scientists are now working on the 5th generation computers using recent engineering advances. Computers can understand spoken words instructions and imitate human reasoning. The ability to translate a foreign language is also moderately possible with fifth-generation computers. Japan’s work is considered important in this direction, which has chosen PROLOG (Programming in logic) language as its operating system.

Scientists are working to increase the speed of the computer. They are trying to create a computer with real IQ with the help of advanced programming and technologies.

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