Combining the Parts

Combining the Parts

Combining the parts The main store, the arithmetic unit, and the control unit together with a group of registers, form what is called the central processor. Surrounding the central processor we have the input and output units together with the backing store. These are known as the peripheral units. Some peripherals can provide both input and output, such as Visual Display Units (VDUS).

We can now see in a very general way the method by which the computer works. Information in a specially prepared form is fed into the input unit where it is 'read' by a device which turns it into a series of electrical pulses. The computer then 'writes' down this information, that is, transfers it to a storage unit. The information that is stored is of two kinds: data, and instructions.

A list of instructions forms a program, and when the program is started, data is transferred into the arithmetic unit and calculations are carried out at a very high speed. All activities within the computer are supervised by the control unit. The central processor is made up from several thousand transistors, together with other electrical components. Peripheral units are usually electrically- driven, mechanical devices.

Reproduced from "How it Works" Ladybird Series