First Generation (1946-1959)

    *.Vacuum tubes were used for the basic       component of memory and circuitry for CPU.
    *.Batch processing operating system, punched card, Paper Tape, Magnetic Tape Input and Output device were used.
    *.Machine codes and electric wired board languages were used.
    *.Used for scientific; later simple business system.
    *.Some computers of this generation were: ENIAC ; EDVAC; UNIVAC; IBM-701 ; IBM-650

Second Generation (1959-1965)

    *.Instead of Vacuum tubes Transistors were used.
    *.Magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices.
    *.Main memory was 100KB.
    *.Assembly language and high-level programming language like FORTRAN, COBOL were used.
    *.Used for extensive business applications, engineering design optimization scientific research.
    *.Some computers of this generation were: IBM 1620; IBM 7094 ; CDC 1604 ; CDC 3600 ; UNIVAC 1108

Third Generation (1965-1971)

    *.Integrated circuits were used in place of transistors. A single IC has many transistors, resistors and capacitors along with the associated circuitry.
    *.Remote processing, Time-sharing, Real-time, Multi-programming Operating System were used.
    *.High-level languages FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68, etc were used.Used for Database management system and online systems.
    *.Some computers of this generation were: IBM-360 series; Honeywell-6000 series; PDP (Personal Data Processor); IBM-370/168; TDC-316.

Fourth Generation(1971-1980)

    *.Very Large Scale Integrated (VLSI) circuits were used .These are more powerful, compact, reliable and affordable which gave rise to personal computers.4thgeneration
    *.C, C++, DBASE etc, all these higher level languages were used in this generation.
    *.Concept of internet was introduced, computers became easily available.
    *.Some computers of this generation were: DEC 10; STAR 1000; PDP 11; CRAY-1 (Super Computer); CRAY-X-MP (Super Computer)

Fifth Generation(1980-till date)

    *.VLSI technology became ULSI (Ultra Large Scale Integration) technology.
    *.In this generation AI(Artificial Intelligence) concept is introduced which is an emerging branch of Computer Science that interprets means and methods of making computers think like human beings.
    *.Higher level languages like C, C++, Java, .Net are used.
    *.Some computers types of this generation are: Desktop ; Laptop ; NoteBook ; UltraBook ; ChromeBook