Descriptive Text

COMPUTERS
Computers are machines that handle information automatically.They can perform calculation and process data. computers can work with numbers to solve problems in a few seconds. Computers can remember a great deal of information and make pratically no mistakes. That is why computers are widely used in place such as banks, offices and complaint.

Computers work like calculators. but most calculators can do only one thing at time. We tell them what to do by pressing various button. To do the same work, we can give a series of instructions to a computer. We call this program. if we set up a program, the computer can provide other information such list, numbers, letters, words or even graphs or pictures. once provide a  program, the computer can do all this work automatically without further help or instruction.
All computers have three basic parts :

1. input and output.
2. A central Processing Unit
3. A memory

The I/O make it possible for people to communicate with computers. There are several kinds of I/O. One of them is a videoterminal. the video terminal has typewriter like keyboard and a screen like a television screen. we can see the output of the computer on the screen.
If we need a permanent record of a computer's output, a printer will make it. And if the computers main memory cannot hold enough information, magnetic disk or tapes can be used for this purpose. the computer then can turn the information stored on the disk or tapes into numbers or letters.