Most of us spend the majority of our day at a laptop or desktop computer at school or at work and also in our free time. Even though we seldom think about it, TV sets, microwave ovens and washing machines all have microprocessors controlling them.

Working with the computer is easier when you understand how it and its so-called peripheral devices work. In addition to the hardware, the computer also needs software, that is, various programs, of which the most important one is the operating system (such as Microsoft Windows, Linux Ubuntu and Apple Mac OS X). Without an operating system, the computer is useless. This chapter discusses the devices and software that are the most important to the operation of the computer.