Generation of Computer, Computer Science notes

Here we are trying to collect notes of generation of computer of grade 11 computer science subject.

– In simple words, generation of computer is step ahead in technology used in manufacturing of the computers.
– Based on the period of development and the features incorporated, the computers are classified into different generations- from first generation to fifth generation computer.
– However, each generation is characterized by a major technological advancement which changed the way computer operate.

1. First Generation of Computer (1946-1955)

Technology usedVacuum Tubes
InputPunched Cards
OutputPunched Cards
LanguageMachine Language
StoragePunched Paper Tape
  • The first generation of computer used vacuum tubes for circuitry and magnetic drums for memory. The input to the computer was through punched cards and paper tapes. The output was displayed as printouts.
  • Vacuum tubes was invented by Lee De Forest in 1980 A.D. Each vacuum tube consumed about half a watt power. The vacuum tubes allowed flow of electrons in only one direction.
  • The instructions were written in machine language. Machine language used 0’s and 1’s for coding of the instructions. The first generation computer could solve one problem at a time.
  • The computation time was in milliseconds. These computers were enormous in size and required a large room for installation.
  • Example of first generation computer are : ENIAC, EDSAC, EDVAC, LEO, UNIVAC-I, IBM701, IBM650 etc.

2. Second Generation of Computer (1956-1965):

Technology usedTransistors
InputPunched Cards
LanguageAssembly Language
StorageMagnetic Cores
  • The computer which used transistors as memory device were grouped into second generation computer.
  • Transistors replaced the vacuum tubes of the first generation of computer.
  • Transistors allowed computers to become smaller, faster, cheaper, energy efficient and reliable.
  • The 2nd generation computer used magnetic core technology for primary memory.
  • The instructions were written using the assembly language.(ADD, SUB).
  • It is easier to write instructions in assembly language, as compared to writing instructions in machine language.
  • The computation time was in microseconds.
  • Transistors are smaller in size compared to vacuum tubes thus the size of the computer was also introduced.
  • Example of 2nd generation computer are: RCA 501,IBM 1620, IBM 1401, IBM 7094, Mark III, IBM 650.

3. Third Generation of Computer (1966-1975):

Technology usedIntegrated Circuits
LanguageHigh Level Language
StorageImproved Disk Storage
  • IC was the memory device used in third generation computer.
  • The operating speed in this generation computer increased up to nanosecond range.
  • The internal storage capacity of computer of this generation increased and bout one half million characters could be accommodated in the computer of this generation.
  • Programming was done with high level language.
  • Computer started to use keyboard as input device and monitor as output device. Before third generation computer were not equipped with monitor and keyboard.
  • The size of these computers was quite small compared to the second generation computers.

We can categorize the IC into following types on the basis of number of electronic components used on them.

  1. SSI (Small Scale Integration): it is the types of IC where upto 100 electronic components were used per IC.
  2. MIS (Medium Scale Integration): where 100 to 3000 electronic components were used per IC.
  3. LSI (Large Scale Integration): where 3000 to 1 lakh electronic components were used per IC.
  4. VLSI (Very LSI): where 1 lakh to 10 lakh electronic components were used per IC.
  5. ULSI (Ultra LSI): where more than 10 lakh electronic components were used per IC.

4. Fourth Generation of Computer (1975- Present):

Technology usedVery large scale integrated circuits(VLSIC), Microprocessor
LanguageHigh level language
StorageHard disk
  • The operating speed increased up-to pico second and even beyond it. Speed began to be measured in terms of MIPS (million of instruction per second).
  • Microprocessor was the memory devices used in these computer.
  • These computers were very user friendly and even the software used in these computer are the friendly.
  • From this generation onward multi-processing, multiprogramming, distributed computing were possible.
  • The internal storage capacity increased up-to 1GB and it’s still increasing.
  • The computer were available for general purpose as well as for special purpose.
  • The computer were smaller in size and less expensive than previous generation computer.
  • Power consumption and Heat emission has been less than previous generation computer.
  • Computer have become portable because of the  development of Personal or Desktop computer, laptop, Notebook etc.
  • Example: IBM PC, Apple, Pentium PC etc.

5. Fifth Generation of Computer (coming generation):

This generation of computer have not come yet in reality, but computers scientist are trying since 1990 A.D. It is said that the computer of this generation will use AI (Artificial Intelligence) and bio-chips as memory device so that they can think and decide like a human being. This computer will have power of sense, logic and decision making capacity.

Features of this computer are as follows:

  • They will be capable of fully parallel processing.
  • Computer will use super conductor memory like bio-chips so that the speed will be very fast.
  • The computers will be intelligent and knowledge base because of AI.
  • Instead of HLL, natural language like English, Nepali, Hindi etc. will be used giving instruction and making computer program.
  • They try to simulate the human way of thinking and reasoning.

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