Introduction

They have started invading our life. They are almost everywhere, offices, schools, colleges… our homes! They are called computers.  Just as the inventions of the train and the motor car revolutionized the way we travel from one place to another, computers have revolutionized the way we remember, write or communicate. Not only do they help us to draft a letter, a report or a book, but also to send it anywhere even without using any paper! They can like a radio or television also be used to share our thoughts, our emotions, our creations with many people, all at once.

A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.

A computer is an information-processing machine, an electronic device, manufactured in a factory, that can perform many functions-till now done by humans only. It can see, listen, read, write, speak, show, learn, remember, think, analyze and decide. In short, it can communicate intelligently. It can do so not only with humans but also with other computers. It needs electricity from the main power line to be alive. Without electricity, a computer is a dead body. If a computer is connected to a UPS (Uninterrupted Power Supply) or a battery, it can work for a short duration even when there is no electricity.

Just as our body has many organs, each of which has a particular function, the body of a computer is also made up of several parts. Like our brain that controls other parts of our body, in a computer there is a device called microprocessor that allows it to take decisions and control its various parts. We have memory to retain information and ways to do various tasks, so has a computer. We have a face, a mouth and limbs to express ourselves, a computer has a screen (just like that of TV) that acts like its face, a device called mouse is like its limb which can also write,draw and paint, and a small or sing. We have eyes,ears,nose and skin to help us to know our environment . Similarly, a computer has a operating system through which you can instruct it to perform various tasks. Some computers can also hear voices, see objects and sense touch through a microphone, a camera and a touch screen.