A computer is a machine with an intricate network of electronic circuits that operate switches or magnetize tiny metal cores. The I switches, like the cores, are capable of being in one of two possible I states, that is, on or off; magnetized or demagnetized. The machine is capabele of storing and manipulating numbers, letters, and characters. The basic ideal is 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 that magnetize the cores.
The basic job of a computer is processing of information. For this reason, computer 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.
Computers are thought to have many remakable powers. However, most computers, whether large or small have three basic capabilities. First, computers have circuits for performing arithetic operations, such as: addition, subtraction, division, multiplication and exponentiation. Second, computers have a means of communicatiing with the user. After all, if we couldn’t feed information in and get results back, these machines wouldn’t be of much use. However, certain computers (commonly minicomputers and microcomputers) are used to control directly things such as robots, aircraft navigation systems, medical instruments,etc
Some of the most common methods of inputting information are to use puched cards, magnetic tape, disks, and terminals. The computer’s input device (which might be a card reader, a tape drive or disk drive, depending on the medium used in inputting information) reads the information into the computer.
For outputting information, two common devices used are a printer which prints the new information on paper, or a CRT display screen which shows the results on a TV-like a screen.
Third,computer have circuits which can make dicisions. The kinds of decisions which computer cirsuits can make are not of the type:” Who would win a war between two countries?” or “Who is the richest person in the world?” Unfortunately, the computer can only decide three things, named: 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 hundreds, even thousands, of logical decisions without becoming tired or bored. It can find the solution to a problem in a fraction of time it takes a human being to do the job. A computer can replace people in dull, routine tasks, but it has no originality; it works according to the instructions given to it and cannot exercise any value judgements. 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 appropriate information; but because electric pulses can move at the speed of light, a computer can carry out vast numbers of arithmetic logical operhinstantaneously. A person can do everything a computer can do, but in many cases that person would be dead long before the job was finished.