7. Multi tasking operating system

When you are working on the computer you probably have a web browser open, an email or instant messaging system open and one or more applications such as a word processor, spreadsheet or graphics package open.

You are able to do this because your operating system will switch the application modules in and out of RAM as you are using them and return them temporarily to the hard disk when they are open but not being accessed.

This is called multi tasking.