There are six generations of computers are given below:-
(a) First Generation Computers: The Computers which are invented between 1949 and 1955 are called First generation computers. First Generation Computers used vacuum tubes as the main working component. These computers were are huge in size, consumed a lot of electricity. Large air condition where necessary because the computers generated heat. In the First generation, programmers use machine language.
(b) Second Generation Computers: The Computers which are developed between 1956 and 1965 are called Second Generation Computers. Second Generation Computers used transistors instead of vacuum tubes. The use of transistors made Computers smaller, faster, more reliable and cheaper. These Computers generated less heat, consumed low electricity. Magnetic tapes and disk used in Second Generation Computers as secondary storage devices. In Second Generation Programmers use machine language as well as assembly language.
(c) Third Generation Computers: The Computers invented between 1996 and 1975 are called Third Generation Computers. Third Generation Computers used integrated Circuits as their main working component. The use of IC made Computers smaller, faster, more reliable and cheaper. These Computers consumed low power. In this Computers High-Level Language has appeared. These Computers have less human labour.
E.g IBM 360 series, ICL 1900 series, IBM 370 x 168, ICL 1900, Honey well model 6000 series
(d) Fourth Generation Computers: The Computers invented after 1976 are called Fourth Generation Computers. Fourth Generation Computers used a microprocessor as their main working component which makes the computer smaller and faster. In Fourth Generation Computers Micro Computer series such as IBM and Apple developed and different types of secondary memory with large storage capacity and faster access developed. In this Generation portable Computer are developed and also great development in data communication.
(e) Fifth Generation Computers: The Computers invented between 1984 and 1999 are called Fifth Generation Computers. In this period computer technology achieved most superiority and parallel processing which was until limited to vector processing and pipelining, Where hundreds of processor could all work on various parts of a single program.
(f) Sixth Generation Computers: The Computers invented between 1999 to till date are called Sixth Generation Computers. This present Generation of Computer technology is highly related with parallel computing and several growth areas have been noticed in this area in both hardware part and in the better understanding of how to develop an algorithm to make use of massively parallel architecture.