#java tutorials for beginners by deepak

History Of Computers:- before 18th century - Abacus, Slide Rule, Pascals Calculator, Leibnitz's Calculator; in 18th century - Difference Engine, Analytical Engine; in 19th century - Five Generations Of Computers Generations Of Computers :- 1. First Generation Of Computers (1942 - 1954) : The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and the installations used to fuse frequently. Therefore, they were very expensive and only large organizations were able to afford it. The computers in this generation used machine code as the programming language. Some computers of this generation were −    ENIAC    EDVAC    UNIVAC    IBM-701    IBM-650 2. Second Generation Of Computers (1952 - 1964) : In this generation, transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes. In this generation, assembly language and high-level programming languages like FORTRAN, COBOL were used. The computers used batch processing and multiprogramming operating system. Some computers of this generation were −    IBM 1620    IBM 7094    CDC 1604    CDC 3600    UNIVAC 1108 3. Third Generation Of Computers (1964 - 1962) :- The computers of third generation used SSI and MSI Integrated Circuits (ICs) in place of transistors. A single IC has many transistors, resistors, and capacitors along with the associated circuitry. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation. Some computers of this generation were −    IBM-360 series    Honeywell-6000 series    PDP (Personal Data Processor)    IBM-370/168    TDC-316 4. Fourth Generation Of Computers (1972-1989) : Computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. All the high-level languages like C, C++, DBASE etc., were used in this generation. Some computers of this generation were −    DEC 10    STAR 1000    PDP 11    CRAY-1(Super Computer)    CRAY-X-MP(Super Computer) 5. Fifth Generation Of Computers (1989 - Present) : In the fifth generation, VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets the means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc., are used in this generation. Some computer types of this generation are -    Desktop    Laptop    NoteBook    UltraBook    ChromeBook