5. Information processing

In order for computers to turn data into information, they must work their way through three stages. 

These are Input, Processing and Output.

Input

The input stage of computing is concerned with getting the data needed by the program into the computer.  Input devices are used to do this.  The most commonly used input devices are the mouse and the keyboard.

Processing

The program contains instructions about what to do with the input.  During the processing stage the computer follows these instructions using the data which has just been input.  What the computer produces at the end of this stage, the output, will only be as good as the instructions given in the program.  In other words, if garbage has been put into the program, garbage is what will come out of the computer.  This is known as GIGO, or 'Garbage In, Garbage Out'

Output

The output stage of computing is concerned with 'giving out' processed data as information in a form that is useful to the user.  Output devices are used to do this.  The most commonly used output devices are the screen, which is also called a monitor or visual display unit (VDU) and the printer.