WHAT IS A COMPUTER?

COMPUTER LITERACY

Informed citizens of our information-dependent society shoud be computer-literate, which means that they should be able touse computers as everyday problem-solvingdevices. They should be aware of the potential of computers to influence the quality of life.

There was a time when only priviliged people had an oppor­tunity to learn the basics, called the three R's: reading, writing, and arithmetics. Now, as we are quickly becoming an informa­tion-becoming society, it is time to restate this right as the right to learn reading, writing and computing. There is little doubt that computers and their many applications are among the most sig­nificant technical achievements of the century. They bring with them both economic and social changes. "Computing" is a con­cept that embraces not only the old third R, arithmetics, but also a new idea — computer literacy.

In an information society a person who is computer-literate need not be an expert on the design of computers. He needn't even know much about how to prepare programs which are the instructions that direct the operations of computers. All of us are already on the way to becoming computer-literate. Just think of your everyday life. If you receive a subscription magazine in the post-office, it is probably addressed to you by a computer. If you buy something with a bank credit card or pay a bill by check, computers help you process the information. When you check out at the counter of your store, a computerassists the checkout clerk and the store manager. When you visit your doc­tor, your schedules and bills and special services, such as labo­ratory tests, are prepared by computer. Many actions that you have taken or observed have much in common. Each relates tosome aspect of a data processingsystem.

WHAT IS A COMPUTER?

A computer is a machine with an intricate network of elec­tronic circuits that operate switches or magnetize tiny metal cores. The switches, like the cores, are capable of being in one or two possible states, that is, on or off; magnetized or demag­netized. The machine is capable of storing and manipulating numbers, letters, and characters (symbols).

Английский язык. Основы компьютерной грамотности 14

The basic idea of a computer is that we can make the ma­chine do what we want by inputting signals that turn certain switches on and turn others off, or magnetize or do not magne­tize the cores.

The basic job of computers is processing of information. For this reason computers can be defined as devices which accept information in the form of instructions, called a program, and characters, called data, perform mathematical and / or logical operations on the information, and then supply results of these operations. The program, or part of it, which tells the comput­ers what to do and the data, which provide the information needed to solve the problem, are kept inside the computer in a place called memory.

It is considered that computers have many remarkable pow­ers. However most computers, whether large or small, have three basic capabilities.

First, computers have circuits for performing arithmetic op­erations, such as: addition, subtraction, division, multiplication and exponentiation.

Second, computers have a means of communicating with the user. After all, if we couldn't feed information in and get results back, these machines wouldn't be of much use. Some of the most common methods of inputting information are to use ter­minals, diskettes, disks and magnetic tapes. The computer's input device (a disk drive or tape drive) reads the information into the computer. For outputting information two common devices used are: a printer, printing the new information on paper, and a cathode-ray-tube display, which shows the results on a TV-like screen.

Third, computers have circuits which can make decisions. The kinds of decisions which computer circuits can make are not of the type: "Who would win the war between two coun­tries?" or "Who is the richest person in the world?" Unfortu­nately, the computer can only decide three things, namely: Is one number less than another? Are two numbers equal? and, Is one number greater than another?

A computer can solve a series of problems and make thou­sands of logical decisions without becoming tired. It can find the solution to a problem in a fraction of the time it takes a human being to do the job.

15 Unit 1. Information-Dependent Society

A computer can replace people in dull, routine tasks, but it works according to the instructions given to it. There are times when a computer seems to operate like a mechanical 'brain', but its achievements are limited by the minds of human beings. A computer cannot do anything unless a person tells it what to do and gives it the necessary information; but because electric pulses can move at the speed of light, a computer can carry out great numbers of arithmetic-logical operations almost instan­taneously. A person can do the same, but in many cases that person would be dead long before the job was finished.