A computer system has three main parts: input, which accepts data from devices like keyboards and sensors; processing, where the central processing unit follows instructions from a program to transform input data; and output, which communicates the processed results to users through displays or printouts. An example is a microwave oven, which takes cooking instructions as input, processes the food accordingly, and outputs a signal when finished.

1. Computer Systems
A computer system is an electronic
machine and there are three main parts
to it.
Information
Data
Input Process Output

2. Input
Accepts data and instructions from an
input device, such as a:
•keyboard or mouse;
•sensor;
•or buttons and switches.

3. Process
Processing is done by the computer’s
central processing unit (CPU).
It follows a sequence of instructions
provided by a program and will involve
turning the data into something else.

4. Output
Once the data has been processed the
computer will communicate the result to
the user.
This might be displayed on a screen or on a
print out.

5. Example
A Microwave Oven.
Input = use buttons or a dial to set the
temperature and cooking time.
Process = the food will be cooked at the
temperature and duration set.
Output = the microwave will heat the food and
make a sound when it has finished.