Ответьте на вопросы, используя информацию текста.
1. What is a computer?
2. What are the main functions of a computer?
3. What is the basic task of a computer?
4. What decisions can the computer make?
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WHAT IS A COMPUTER?
A computer is a machine with an intricate network of electronic circuits thatoperate 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 andmanipulating numbers, letters, and characters (symbols).
The basic idea of a computer is that we can make the machine do what wewant by inputting signals that turn certain switches on and turn others off, ormagnetize or do not magnetize the cores.
The basic job of computers is processing of information.
For this reasoncomputers can be defined as devices which accept information in the form ofinstructions, called a program, and characters, called data, performmathematical and / or logical operations on the information, and then supplyresults of these operations.
The program, or part of it, which tells thecomputers what to do and the data, which provide the information needed tosolve the problem, are kept inside the computer in a place called memory.
It is considered that computers have many remarkable powers.
Howevermost 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, ifwe couldn't feed information in and get results back, these machineswouldn't be of much use.
Some of the most common methods of inputtinginformation are to use terminals, diskettes, disks and magnetic tapes.
Thecomputer's input device (a disk drive or tape drive) reads the information intothe computer.
For outputting information two common devices used are: aprinter, printing the new information on paper, and a cathode-ray-tubedisplay, which shows the results on a TV-like screen.
Third, computers have circuits which can make decisions.
The kinds ofdecisions which computer circuits can make are not of the type: "Who wouldwin the war between two countries?"
or "Who is the richest person in theworld?"
Unfortunately, the computer can only decide three things, namely: Isone number less than another?
Are two numbers equal?
and, Is one numbergreater than another?
A computer can solve a series of problems and make thousands of logicaldecisions without becoming tired.
It can find the solution to a problem in afraction of the time it takes a human being to do the job.
A computer can replace people in dull, routine tasks, but it works according tothe instructions given to it.
There are times when a computer seems tooperate like a mechanical 'brain', but its achievements are limited by theminds of human beings.
A computer cannot do anything unless a person tellsit what to do and gives it the necessary information;
but because electricpulses can move at the speed of light, a computer can carry out greatnumbers of arithmetic-logical operations almost instantaneously.
A personcan do the same, but in many cases that person would be dead long beforethe job was finished.