How a Computer Works


A computer is a fabulous instrument that turns human inputs into electronic information that it then can store or share/distribute through various output devices.
A computer performs (if instructed to do so) the steps shown in the diagram below, using information that a user provides (such as a typed sentence): 
All of the equipment (hardware) and the instructions (software) needed to complete the above steps are described in the next section.
 
Processing
Amazingly, the information that the user inputs into a computer is processed so that it becomes a simple code made up of only two digits: zero and one!
For all its complexity, a computer is only able to handle these two choices. This is because it is based on electrical signals that have only two options (such as either on or off).
But computers compensate for this very simple code by using it in huge quantities. A single unit of this zero/one code is called a bit. Grouping 8 bits together makes a unit of information called a byte.
Typing a single page of typed text on a computer requires a minimum of about 20 kilobytes (20 KB or 20,000 bytes) of information to be stored. Good quality digital photographs are usually 1 megabyte (1 MB or 1,000,000 bytes) or larger. So a computer is a very “busy” machine indeed!

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