1. Introduction

Computers today are all around us in one form or another. You are probably sitting in your classroom reading this text. Just have a think about all of the different computers that are nearby:

• Mobile phone
• Calculator
• Watch
• Interactive white board
• Projector
• Printer
• Desktop computer
• Laptop

As you can see, computers come in all shapes and sizes and are often built into other devices. However, all computers share some common features which we will cover in the next few pages.