Saturday, March 1, 2014

GENERATIONS OF COMPUTERS

    Each generation of computer is designed base i technological development, resulting in better cheaper and smaller computers that are more powerful, faster and efficient than their predecessors.

FIRST GENERATION            :       VACUUM TUBES  (1940 - 1956)

      SOFTWARE TECHNOLOGY - The instructions were written in machine language Machine language use Os and Is for coding of the instructions.
the first generation computers could solve one problem at a time.

     COMPUTING CHARACTERISTICS - the computation was in the milliseconds.

     PHYSICAL APPEARANCE  - these computers were enormous and required a large room for installation.

     APPLICATION -  They were used for scientific applications as they were the fastest computing device  of their time.

Examples .  Universal Automatic Computer (UNIVAC)
                  Electronic Numerical Integrator and Calculator (ENIAC)
                  Electronic Discrete variable Automatic Computer  (EDVAC)

      The first generation computers used vacuum tubes for circuitry and magnetic drum a for memory. the input to the computer was through punched cards and paper tapes the output was displayed as printout.



SECOND GENERATION      :   TRANSISTOR ( 1956 -1963 )

         SOFTWARE TECHNOLOGY    -  the instructions were written using the assembly language.

        COMPUTING CHARACTERISTICS    -  The Computation time was in microseconds.

         PHYSICAL APPEARANCE   - Transistors are smaller in size compared to vacuum tubes, thus, the  size of   the computers was also reduced.

         APPLICATION               -       the cost of commercial production f these computers was very high, though less than the first generation computers. The transistors had to be assembled manually is second generation computers.

         examples. PDP - 8 , 1b,1401, CDC 1604

 the second generation computers used magnetic core technology for primary memory. they used magnetic tapes and magnetic disks for secondary Storage. The input was still through punch cards and the output using printouts. They used the concept if a stored program, where instructions were stored in the memory of computer.


THIRD GENERATION   -  INTEGRATED CIRCUITS ( 1964 - 1971 )



Software Technology, the keyboard and the monitor were interfaced through the operating system. Operating System allowed different application to run at the same time. High - level languages were used extensively for programming, instead of machine language and assembly language.

COMPUTING CHARACTERISTICS  -  The computation time was in nanoseconds.

PHYSICAL APPEARANCE                   -  The size of these computers was quite small compared to Second generation computers.

APPLICATION COMPUTERS             -  Became accessible to mass audience. Computers were produces commercially and were smaller and cheaper than their predecessors.

      Examples : IBM 370, PDP II

          In an IC chip, multiple transistors are placed on a silicon chip. Silicon is a type of semiconductor. The use of IC chip increased the speed and the efficiency of computer, manifold, The keyboard and monitor were used to interact with the third generation computer, instead of the punched cards and printouts.


FOURTH GENERATION  MICROPROCESSORS (1971 - PRESENT)


SOFTWARE TECHNOLOGY - Several new Operating System like the MS - DOS and MS -              
                                                      WINDOWS Develop during this time. Third Generation of computers
                                                     supported graphical user interface. GUI is a user - Friendly interface that
                                                     allows user to to interact with the computer via minus and icons. High
                                                     level programming languages are used for the writing of the programs. -


COMPUTING CHARACTERISTICS  - The computations time is in microseconds.

PHYSICAL APPEARANCE  - They are smaller than the previous computers and some can fit it the Palm.

APPLICATION    -  .They became widely available for commercial purposes, personal computers became                                     available to home user.





FIFTH GENERATION  


      Artificial intelligence the goal of fifth generation computing is to developed computers that are capable of learning and self organization. The fifth generation computers use SLSI CHIPS that are able to store millions of components on a single chip. These computers have large memory requirements. These generation of computers have large memory requirements.Then use parallel Processing that results to faster processing speed. The fifth generation computers are based on artificial intelligence they try to simulate the human way of thinking and reasoning. Artificial intelligence includes areas like expert system, natural language processing, speech recognition, voice recognition, robotics.



HARDWARE SPECIFICATION

           Hardware Specifications dictate the limits and maximum capacity of the hardware of device depending on a given criteria or unit of measurement.
             Ex. CPU clock Rate  - 3.3 GHz

       " The hardware specifications of a computer will vary depending on what an individual user will be doing with it. A person that wants to use their computer for graphically intense games or video editing will need a totally different configuration than somebody that just wants to browse the internet and type word documents."

WHAT IS A COMPUTER SYSTEM?

           A computer system is one that is able to take a set of inputs, process them and create a set of outputs, this is done by a combination of hardware and software.

          The Computer System is composed of the Hardware and the Software. under hardware are the I/O Devices, CPU and Memory, Under Software are the OS and the Applications.

         Types of Computer:

          *  Analog Computer
          *  Mini Computer
          *  Main Frame
          *  Super Computer

SYSTEM DEVELOPMENT PROGRAM SOFTWARES

System Development Program Software

Compliers                 -    used to create software
PC Platforms            -    defined by a processor and an operating system
Wintel Platforms       -     are backward compatible allowing programs for earlier Microsoft platforms to be                                         run on  modern system.

 Before choosing a platform, we consider this:

- availability of appropriate commercial applications software for the platform.
- compatibility of the platform.