Jan 6, 2008

What is Computer?

A computer is a device that accepts information (in the form of digitalized data) and manipulates it for some result based on a program or sequence of instructions on how the data is to be processed. Complex computers also include the means for storing data (including the program, which is also a form of data) for some necessary duration. A program may be invariable and built into the computer (and called logic circuitry as it is on microprocessors) or different programs may be provided to the computer (loaded into its storage and then started by an administrator or user). Today's computers have both kinds of programming.
The two principal characteristics of a computer are:
  • It responds to a specific set of instructions in a well-defined manner.
    • It can execute a prerecorded list of instructions (a program).

    Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.

    All general-purpose computers require the following hardware components:

  • memory : Enables a computer to store, at least temporarily, data and programs.
  • mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.
  • input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.
  • output device : A display screen, printer, or other device that lets you see what the computer has accomplished.
  • central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.
  • In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.

    Computers can be generally classified by size and power as follows, though there is considerable overlap:

  • personal computer : A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.
  • workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.
  • minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.
  • mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.
  • supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.
  • Most histories of the modern computer begin with the Analytical Engine envisioned by Charles Babbage following the mathematical ideas of George Boole, the mathematician who first stated the principles of logic inherent in today's digital computer. Babbage's assistant and collaborator, Ada Lovelace, is said to have introduced the ideas of program loops and subroutines and is sometimes considered the first programmer. Apart from mechanical calculators, the first really useable computers began with the vacuum tube, accelerated with the invention of the transistor, which then became embedded in large numbers in integrated circuits, ultimately making possible the relatively low-cost personal computer.

    Modern computers inherently follow the ideas of the stored program laid out by John von Neumann in 1945. Essentially, the program is read by the computer one instruction at a time, an operation is performed, and the computer then reads in the next instruction, and so on. Recently, computers and programs have been devised that allow multiple programs (and computers) to work on the same problem at the same time in parallel. With the advent of the Internet and higher bandwidth data transmission, programs and data that are part of the same overall project can be distributed over a network and embody the Sun Microsystems slogan: "The network is the computer."

    1 comment:

    1. Nice attempt. But why don't you try this in Kannada where there are not enough resources for people who want to learn?

      ReplyDelete

    Popular Posts