• First Generation (Year 1946 - 1959)
• Second Generation (Year 1959 - 1965)
• Third Generation (Year 1965 - 1971)
• Fourth Generation (Year 1971 - 1980)
• Fifth Generation (Year 1980- Onwards)
First Generation (1946 - 1959)-
First-generation computers were vacuum tube-based computers popular in the period 1946-1959. These vacuum-based computers were expensive, extremely large, and less cost-effective as they consumed a lot of electricity. The language used for storing and processing data was machine language. Some of the first-generation computers are:
Electronic Numerical Integrator and Calculator (ENIAC) built at the University of Pennsylvania in the year 1946 by John Eckert and John Mauchly. Electronic Discrete Variable Automatic Computer (EDVAC) developed in 1950 at Cambridge University. UNIVAC-1 developed in 1951.
Second Generation (1959 - 1965)-
The computers from 1959- 1965 were transistor-based second generation computers. In this generation, vacuum tubes were replaced by more durable transistors. Transistors are more compact than vacuum tubes as they are made up of semiconductors. Some of the computers of the second generations are:
IBM 1620- Its size was smaller as compared to the first-generation computers, used mostly for scientific purposes. IBM1401- used for business applications. CDC3600- used for scientific purposes.
Third Generation (Year 1965 - 1971)-
The third-generation computers from 1965 to 1971 were Integrated Circuit (IC) based. These ICs are more compact than a transistor and were called chips. Single ICs has many transistors, resistors and capacitors, placed on a single thin of silicon. So, the computer built of such components became smaller. Some of the computers developed during this period were-
IBM360- developed by IBM in the year 1964. PDP8- developed by DEC in the year 1965.
Fourth Generation (1971 - 1980)-
The computers from the period 1971-1980 were Very Large Scale Integrated (VLSI) microprocessor-based fourth generation computers. VLSI circuits were used in these computers. VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of the fourth generation. As a result, fourth-generation computers became more powerful, compact, reliable, and affordable giving rise to personal computer (PC) revolution. In this generation time sharing, real-time networks, and distributed operating systems were used. All the high-level programming languages like C, C++, DBASE etc., were developed during this generation.
Fifth Generation (1980- Onwards)-
The fifth generation of computers developed 1980 onwards were Ultra Large Scale Integrated (ULSI) microprocessor-based. In this generation, the VLSI technology was replaced by more advanced ULSI technology. ULSI is a set of ten million electronic components into a single chip. This technology is based on parallel processing with hardware and software support. A key advancement of this generation is machine learning/artificial learning.