Generation of Computer

First Generation Computer (1942-1955) - Vacuum tubes          The computer using vacuum tubes as the electronic devices are called first generation computer. Vacuum tubes were developed by Lee deforest in 1908s.          The vacuum tubes were used as CPU components; acoustic delay for main memory, magnetic tape and magnetic drum for secondary memory. data and instructions were fed into the system using punched cards. the instructions were written in Machine level Language (MLL) because high level languages were introduced later.           First generation computers were mainly used for scientific computations. Examples : ENIAC, EDSAC, EDVAC, UNIVAC-I, IBM 701, IBM 700 series. THE MAIN FEATURES OF FIRST GENERATION COMPUTER ARE: These computers were the fastest of their time. They were programmed using machine language. The electronic digital computers were introduced due to the vacuum tube technology. They were extremely large and occupied a very large space. The operating speed was measured in milliseconds. Second Generation Computer (1955-1965) - Transistor      Second Generation computer started after the invention of transistors by Trio group (John Braden, william Shockley and Walter Brattain) in 1947 at bell laboratories in U.S.      Transistor were used as CPU component; magnetic core for main memory. Magnetic drum, Magnetic tape and magnetic disk were secondary storage media used in second generation. Punched card were still popular and widely used for preparing programs and data to be fed to these computers.      The first generation computers were mainly used for scientific computations, but second generating computer were used in payroll, inventory control, marketing and production planning. Example : IBM 7090, IBM 7094I, IBM 7094II, CDC 1604, IBM 1620, IBM 1401 THE MAIN FEATURES OF SECOND GENERATION COMPUTER ARE: They required less electricity and emitted less heat. They were smaller than first generation computer, requiring smaller space. They were more reliable and accurate than the first generation computer. They had faster and larger primary and secondary storage in comparison to the first generations computer. They were much easier to program and use than first generation computer. Hence they had wider commercial use. Assembly language and high level programming language like FORTAN, COBOL were introduced.   Third Generation Computer (1965-1975) - Integrated Circuit (IC)         The third generation computers replaced transistors with 'Integrated circuits (IC) popularly knows as chips. IC was developed by Jack St clair Kilby and roberrt Noyce in 1958.         ICs, ie. SSI (Small scale integration) and MSI (Medium scale integration) were used for CPU components in the beginning of third generation computer uses magnetic core for main memory but later on semiconductor memories were used. Magnetic disk and Magnetic tape were used as secondary memory. Cache memory was also introduced Multiprocessing, multi pgrogramming, multi user system were introduced. the concept of virtual memory was also introduced, Keyboard and Video display terminals were introduced for input and the output data.        FORTRAN and  COBAL were standardized by ANSI and were referred to as ANSI FORTRAN AND ANSI COBAL and time sharing operating system used PL/1, PASCAL, BASIC were notable high level language of the third generating . They used both scientific and commercial applications. THE MAIN FEATURES OF THIRD GENERATION COMPUTER ARE: They were much smaller than second generation computer so it requires smaller space. they had faster primary and auxiliary memory as compared to second generation computers. they consumed much less power than second generation computers. the operating speed of computer was nanoseconds. they were reliable, better performance and has larger storage capacity. the size of computer became much smaller.   Forth Generation Computer (1975-1975) - (LSI) & (VLSI)       The forth generation of computer used LSI (Large scale integration) and VLSI (very large scale integration) circuits for internal operations.        A signals silicon chip of LSI or VLSI has thousands of ICs built on it. this chip reduced the physical size of the computer and increased their power, efficiency and reliability. The speed of operation is measured in Pico second. because of the VLSI technology, ti becomes possible to build many computing function on a single chip.        The microprocessor, which is the main component of fourth generation computer is semiconductor device consisting of electronic logic circuits manufactured by using VLSI technique. then in 1971, American Intel corporation developed first microprocessor (microchip) called 4004 microprocessor. today such a microprocessor contains millions of transistors. It is capable of performing various computing functions and making decisions to change the sequence of program execution. Since 1973, many American companies started to manufacture microcomputers. for examples IBM PC, Apple/Macintosh, Wang Laser, Letron etc. ICL 2950/10 (international computer limited company) was brought in Nepal for census 2038 B.S.          The semiconductor memories (Ram and Rom) are used as primary storage and magnetic disk (floppy disk, hard disk), optical disk (CD-ROM, CD RW, CD-R, CD-R/W) as flash memory and used as secondary storage.           The forth generating computers are user friendly due to development of operating system and application software. As smaller computers but more powerful, they could be linked together, or network, to share memory space, software, information and communicate with each other. So, these computers are mostly used in offices, home, teaching and other organization. Fifth Generation Computer (Coming Generation) - (ULSI) Ultra large Scale Integration.           The fifth generation computers under development stage. they will use super conductor technology. the two future devices are Gallium Arsenide (GaAs) and bio-chips. theses machines incorporated ultra large scale integration (ULSI) and contains millions of components into a single IC. the development of super conductors was declared by Jan in 1978. they will increase the capacity of computer with millions of times.          The computers using bio-chips will be able to understand natural language, speak command, capacity to see their surrounding and will have thinking power called Artificial intelligence (AI). In contrast to present DIPS (data information processing system) the fifth generation computer will have KIPS (Knowledge information processing system) and Prolog is expected to play and important role for this. the computers will understand natural languages and transited foreign language also. there are different programs under way to develop fifth generation computer. ICOT program in Japan. MCC and DARPA project of USA. Alvey project of UK THE MAIN FEATURES OF FIFTH GENERATION COMPUTER ARE: The development of the fifth generation of computer system is characterized mainly by the acceptable of parallel processing. These computers will use super conductor technology. the tow future devices are Gallium Arsenide and biochips. These Machines will incorporate Ultra Large Scale Integrating (ULSI) The cost of hardware and software will decrease. These computers will have artificial intelligence.

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