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What is a computer?

The word computer comes from a Latin word which means to count. A computer is a machine with a complex network of electronic circuits that operate switches or magnetize tiny metal cores. The switches, like the cores, are capable of being in one of two possible states, that is, on and off; magnetized or demagnetized. The machine is capable of storing and manipulating numbers, letters, and characters. The basic idea of the 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 or do not magnetize the cores.

The basic job of computers is the 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 data, which provide the information needed to solve the problem, are kept inside the computer in a place called memory.

Some of the most common methods of inputting information are to use punched cards, magnetic tape, disks, and terminals. The computer’s input device (which may 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 screen.

There are different kinds of computers. Some do only one job over and over again. These are special-purpose computers. But there are some computers that can do many different jobs. They are called general-purpose computers. These are the “big brains” that solve the most difficult problems of science. They answer questions about rockets and planes, bridges and ships – long before these things are even built. Computers help our space program, our business and industry, medicine and education. They are powerful tools which help to change our life and the world around us.

Computer system

A computer system is a collection of components that work together to process data. The purpose of a computer system is to make it as easy as possible for you to use a computer to solve problems. A functioning computer system combines hardware elements with software elements. The hardware elements are the mechanical devices in the system , the machinery and the electronics that perform physical functions.

The software elements are the programs written for the system; these programs perform logical and mathematical operations and provide a means for you to control the system. Documentation includes the manuals and listings that tell you how to use the hardware and software.

Collectively these components provide a complete computer system: system hardware + system software + system documentation = computer system. Usually, a computer system requires these basic hardware items: the computer, which performs all data processing; a terminal device, used like a typewriter for two-way communication between the user and the system; and a storage medium for storing programs and data.



Computer systems that that provide (or use) have a magtape device, because magnate device is an industry – standard storage device.

Peripheral devices are categorized as input/output (I/O) devices since the functions they perform provide information (input) to the computer, accept information (output) from the computer, or do both. Line printers are output devices because they perform only output operations.

Terminals and storage devices are input/output devices because they perform both input and output operations.

System software is an organized set of supplied programs that effectively transform the system hardware components into usable tools. These programs include operations, functions, and routines that make it easier for you to use the hardware to solve problems and produce results.

For example, some system programs store and retrieve data among the various peripheral devices. Others perform difficult or lengthy mathematical calculations. Some programs allow you to create, edit, and process application programs of your own.

System software always includes an operating systems, which is the “intelligence” of the computer system. Usually the system software includes one or several language processors.

 

 


Date: 2015-12-11; view: 544


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