Computer as a concept

In the developed world of the 20^th century, man lives surrounded by a bewildering variety of machines on which his way of life and even life itself depends. These machines can be simple or complex, minute or enormous. Some, like a sewing machine, are for specific applications while other, like electric drill, can be used for a variety of purposes. Some machines, though designed for a specific purpose, are components in many different machines; for instance, the electric motor gives the electric drill its flexibility. This is because the purpose of the motor – to provide power – is fundamental in many applications.

Another fundamental aspect of twentieth-century life is the vast amount and variety of information that surrounds man from media such as the telephone and radio. This has transformed everyday life as much as engines and motors. There are many machines developed to handle the information, for example television cameras to record pictures, transmitters to send these pictures to television receivers in people’s homes.

The ease of using machines also varies and is not always related to their complexity. For example, some, like refrigerators, can work untended, and little skill or training is required to use a television set or a tin-opener; whereas considerable aptitude, instruction and practice is needed to fly an airplane or use a potter’s wheel. The amount of skill and training required might depend on the circumstances of use – driving a motorcar on a country road is a skill relatively easily acquired compared to driving a racing car on a grand prix circuit. Knowledge of the principles behind the operation of a machine may be useful. It is possible to drive a car without knowing anything about what happens under the bonnet, although one can probably drive better for knowing something about mechanics.

Computers are machines, which handle information, and they are based on relatively simple principles. Knowledge of these principles helps one to understand computers and make better use of them.

Computers which deal with numerical information can be divided into three classes: (1) digital, in which the representation of numbers and the calculations on them are performed by counting processes (e.g. by counting teeth on gear wheels or counting electrical impulses); (2) analogue, in which the representation of numbers and the calculations on them are performed my measuring processes (e.g. in electronic computers by measuring voltages); and (3) hybrid, in which both kinds of process are used. Nowadays the word computer, unless qualified, normally means ‘electronic digital computer’; ‘electronic’ because in most computers electronic processes have replaced all others because of their speed, reliability and cheapness, “digital” because the exactness of digital processes implies a greater potential for accuracy.

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Дата добавления: 2015-07-20