Introduction to computer systems.

Electronic computers were developed from digital electronics technology. Some of the revolutionary aspects that emerged from this branch of electronics, that are now inherent in modern computer systems are:

Some basic examples of the above are:

Numerically encoded data.

The text that you are reading in this document is stored and transmitted as numeric codes, e.g. the word “computer” is stored with the following numbers (written in decimal), “ 99, 111, 109, 112, 117, 116, 101, 114”.

Processing speed.

If you open even a very large text file, your computer can retrieve the codes, convert them to text characters and display them on the screen in a fraction of a second.

Decision making.

Numerical codes are also used for storing image data, but when the computer receives these codes, it processes them in a completely different way to text files. i.e. Rather than creating text characters, it generates coloured dots to produce an image on the screen.


Mobile phone apps can change your phones function to applications such as a sat nav, music player, camera or internet browser etc. It’s the same microprocessor running each of these applications, which is just given different program instructions for each task.

The aim of this section is not to explain in any detail how a computer performs each of the above tasks. It is simply to establish the basic principles on which the technology is based.