Computers are used for many reasons and in many different places. They may be of different sizes and processing power, but all computers have some features in common. In order for most computers to perform useful functions, there are three things that have to work together:
1. Hardware – the physical components, both internal and external, that make up a computer.
2. Operating System – a set of computer programs that manages the hardware of a computer. An operating system controls the resources on a computer, including memory and disk storage. An example of an operating system is Windows XP.
3. Application Software – programs loaded on the computer to perform a specific function using the capabilities of the computer. An example of application software is a word processor or a computer game.