teach-ict.com logo

THE education site for computer science and ICT

2. Multi-tasking

You are probably very familiar with this kind of operating system, as it is what runs on most personal computers.

Examples of a multi-tasking operating system includes Windows, OS X, Linux and Android.

A multi-tasking operating system allows more than one program to run at the same time - or at least they appear to run concurrently as far as the user is concerned.

The diagram below shows a number of programs loaded into memory, where they are called a 'process'.

processes in memory

A multi-tasking operating system arranges for every process in memory to run in the CPU once they are ready to do so, switching between processes from different applications to keep them all up to date.

The CPU is able to process billions of instructions per second, so this switching of processes is not apparent to the user.


Multi-tasking operating systems are useful because they allow users to run multiple applications at the same time. These can range from graphic and word processing applications to music players and web browsers. In addition, there will be many system background tasks also running.


The part of the operating system that manages all of these processes is called the scheduler, (read about the scheduler here)

Challenge see if you can find out one extra fact on this topic that we haven't already told you

Click on this link: What is a multi tasking operating system