COMPUTER GENERATIONS

                       

Generation is a computer terminology which means change in technology of computer being used. Initially, it meant change in the technology of hardware but now it also includes change in technology of software which together makes up an entire computer system

There are total five generations of computer known till date each discussion has been discussed in detail along with its time period.

Following are the five generation of computers

1) First Generation Computers

The period of first generation computers was from 1946 to 1959. They used vacuum tubes as a basic component of memory and circuitry for central processing unit (CPU). These tubes were very expensive. They required a lot of electricity and they generated a lot of heat. Therefore, they required a large cooling down system made from air conditioners. They were unreliable. This generation computers required continuous replacement of tubes. In this generation mainly batch processing system were used. Punch card, paper tape and magnetic tape were used as input and output devices. They used machine language only. Their sizes were huge and they were non-portable. They were used for only scientific purposes. They run only scientific applications. They were used only at commercial level and only high level organization could afford them. They were very costly. They were difficult to use.

 SOME REPRESENTATIVE SYSTEMS

    ·         EDVAC

    ·         EDSAC

    ·         UNIVAC I

    ·         IBM 701

                            

                               

2) Second Generation Computer

The period of second generation computers was from 1959 to 1965. In this generation transistors were used which were cheaper than vacuum tubes. 240 transistors were used instead of one vacuum tube. They consumed less power than first generation computers. They were used at commercial level only.  They were more compact in size. They were still very costly. They were more reliable and faster than first generation computers made of vacuum tubes. In this generation computers magnetic cores were used as primary memory and magnetic disks were used as secondary memory. In this generation assembly language and high level languages such as FORTRAN and COBOL were used. They used batch processing operating systems.

Some Representative Systems

    ·         IBM-1620

    ·         IBM-7094

    ·         CDC-1604

    ·         CDC-3600

    ·         UNIVAC-1108

     

             

3) Third Generation computer

The period of third generation was from 1965 to 1971. The major invention in the third generation computer was the development of integrated circuits (IC’s). A single IC chip contained thousands of transistors, resistors and capacitors. They used IC’s with MSI (Medium Scale Integration) technology. These computers were smaller in size than the first and second generation computers. They were faster than first and second generation computers. They were less expensive and consumed less energy. They were reliable and portable. It was user-friendly and easy to upgrade. They became very common in medium to large scale business. These computers used magnetic core memory as internal storage. Larger capacity disks and magnetic tapes were used as secondary storage devices. These computers used keyboards and monitors. They were multitasking. They used multi-processing, multi-programming and time sharing operating systems.  High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation.

Some Representative Systems

    ·         IBM-360

    ·         DEC

    ·         PDP-8

    ·         UNIVAC-1108

    ·         UNIVAC-9000

    ·         IBM-370

                                     

                                    

           

4) Fourth Generation Computer

The period of this computer generation was from 1971 to 1980. They were smaller than first, second and third generation computers. They were affordable, reliable and easy to use PC’s. They were more powerful than first, second and third generation computers. At that time they were called as super computers. They were totally general purpose machines. They were easier to produce commercially and easier to upgrade than first, second and third generation computers. In these computers rapid software development was also possible. Fourth generation of computers started with the invention of microprocessor. It revolutionized the computer world. Advancements were made in IC’s technology. LSI (large scale integrated) circuits and VLSI (very large scale integrated) circuits were designed which contributed towards the invention of microprocessors, which made it possible to make micro-computers. Computer of this generation used semi-conductor memory which increased the internal storage of the computers. These computers had high processing speed. All the high-level languages like C, C++, DBASE etc., were used in this generation. Operating systems for PC’s with graphical user inter phase were made and multiple windows on a single terminal screen was possible.

Some Representative Systems

    ·        DEC 10

    ·        STAR 1000

    ·        PDP 11

    ·        PDP 8

    ·        IBM 360/370

        

5) Fifth Generation Computers

The period of fifth generation computers is from 1980 till now. These computers are portable, cheaper, reliable and more powerful. They are easy to use and rapid software development is possible. They are totally general purpose. In this generation VLSI circuits became ULSI (ultra large scale integrated) circuits which made it possible to make microprocessors having ten million components on single chip. Fifth generation computing devices, based on artificial intelligence (AI), are still in development stage. Though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and super conductors is helping to make AI a reality. AI is an emerging branch in computer science, which interprets means and methods to make computer think like a human being. It uses all high level languages like C++ and JAVA. Quantum computation, molecular and Nano-technology will radically change the face of computers in future. The goal of fifth generation computing is to develop such devices that will be able to respond to natural language input and capable of learning and self-organization.

Some Representative Systems

    ·         IBM notebooks

    ·         Pentium PC’s

    ·         Laptop

    ·         Ultra book

    ·         Tablets