Functional units.
Describe the basic functional units of a computer.
Each element of functional
elements is given bellow:
Input:
Most computers cannot accept data in
forms customary to human communication such as speech or hand-written documents.
It is necessary, to present data to the computer in a way that provides easy
conversion into its own electronic pulse-based forms. This is commonly achieved
by typing data into keyboard devices that convert it into machine-sensible
forms. A keyboard device is one of many kinds of input device.
Storage:
Data and Instructions enter main
storage. The instructions dictate action to be taken on the data. Results of
action will be held until they are required for output. Main storage is
supplemented by less costly auxiliary storage, also called backing storage, eg.
hard disk for mass storage purposes. Backing serves an important role in
holding “maintained data”.
Control:
The processor controls the
operation of the computer. It fetches instructions from main storage,
interprets them and issues the necessary signals to the components making up
the system. It directs all hardware operations necessary in obeying
instructions. At one time most computers actually had a separate electronic
unit, called the control unit, to perform the control function.
Processing:
Instructions are obeyed and
necessary arithmetic operations, etc are carried out on the data. In addition
to arithmetic the processor also performs so called “logic” operations. These
operations take placed at incredibly high speeds, eg. 10 million numbers may be
in one second.
Output:
Result are taken from main
storage and fed to an output device. This may be a printer.
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