In computer terminology, the word generation is described as a stage of technological advancement or innovation. According to the kind of processor installed in a machine, the development of computer can be divided into five distinct generations:
- First Generation Computer (1945-1954)
- Second Generation Computer (1955-1964)
- Third Generation Computer (1965-1979)
- Fourth Generation Computer (1980-present)
- Fifth Generation Computer (present and beyond)
First Generation Computer (1945-1954)
• These computer were based on vaccum tube technologgy.
• Paper tape, punch card were used for input and printout display for output.
• Acoustic delay lines were used as main memory and magnetic drum as secondary storage.
• Machine language used for coding of the instructions.
• No programmed operating system were used.
• Operating frequency was very few kilohertz.
• Computation time was in milliseconds.
• They were enormous in size and lack of versatility.
• eg:- UNIVAC, ENIAC, and EDSAC.
Second Generation Computer (1955-1964)
• They were based on transistor technology.
( A transistor is made up of semiconductor material like germanium and silicon)
• They used magnetic core technology for primary memory and magentic tape, magnetic disk for secondary storage.
• Input was through punch card and output using printouts
• They used the concept of stored program, where instructions were stored in the memory of computer.
• Assembly Language was used.
• Batch operating system was used.
• Computational time was in microseconds.
• They generate less amount of heat, more expensive and smaller than first generation computer.
• eg:- IBM 1401, PDP-8, CDC 1604.
Third Generation Computer (1965-1979)
• These computer were based on Integrated Circuit (IC) technology.
(Note: IC is made up of a very thin silicon wafer which contains a numerous transistor, registers and capacitors.)
• Keyboard and monitor were used to interact with computers instead of punch card and printouts.
• Semiconductor memory used for internal storage.
• Started to use multi-programming Operating system like UNIX.
• High level languages were used instead of machine and Assembly language.
• Their size were quite small compared to second generation computers.
• They produces less heat and didn`t require dedicated cooling system.
• They become accessible to mass audience and were produced commercially.
• eg:- IBM 370, PDP11, NCR 395.
Fourth Generation Computer (1980-present)
• These computer were microprocessor based computer using large scale Integration(LSI) and Very large scale Integration (VLSI) Technology.
• Semiconductor memory replaced the magnetic core memory, resulting in fast random access to memory.
• Secondary storage device like magentic disks became smaller in size and larger in capacity.
• This generation of computer supported Graphical User Interface (GUI) operating system.
(Note: GUI is user-friendly interface that allows user to interact with the computer via menus and icons.)
• High level programming languages are used.
• Fast processing speed and computation time is in picoseconds.
• Smaller in size and widely available for commercial purpose.
• eg:- Cray-1, Apple II, Intel pcs.
Fifth Generation Computer (present and beyond)
• Ultra Large Scale Integration (ULSI) technology based biochips will be used as processing components.
• Input and output will be in the form of speech and graphics images.
• They are intented to cope with natural language.
• They are based on Artificial Intelligence (AI).
• The research and advancement in quantum computation and molecular and nano-technology could be utilized in fifth generation computer.
Differences between Generations of computers:
