How a computer processes information

All computers carry out the same sequence of events over and over again, which can be represented as:

INPUT - PROCESS - OUTPUT

This means that information in the form of data is input to the computer, the data is processed according to specific instructions and then output. This may be:

  • Input - a character key pressed on the keyboard input to the computer as a binary number.
  • Process - processed by the processor to be stored in a memory location.
  • Output - the binary number is presented to a video card to be converted into the same character and displayed on the monitor screen.

At the very heart of the computer is the Central Processing Unit (CPU), which carries out a list of instructions to bring in the data via the input circuits, process it as required and pass it to the output circuits. The process and the CPU is shown in the diagram below. 

Click on it to animate:

 

The diagram above is applicable to any computer however small or large.

The Control Unit interprets and issues commands to the computer

The Main Memory is a storage area, which can store data ready to be processed or passed to the output circuits and instructions waiting to be passed one by one to the control unit.

The Auxiliary Storage area will have items like discs and tapes, which will hold data and instructions so that the main memory area does not get too clogged up. If a set of instructions needs to be carried out over and over again at different times, the set can be saved as a program on auxiliary storage and returned to main memory when required.

The CPU can be several boards with discrete components, as in a Mainframe computer or one integrated circuit (IC), as in a PC. Either way it is a very important item and will set how well, and how fast, processing of data can take place.

The whole computer can be compared to items of the human body as discussed later in this Unit.

More about how a computer processes information: