Computers are a major element of our society, and they exist in so many places that we tend to forget they are there. In simple terms, all computers are made up of four basic functions:

• Data input
• Data output
• Processing
• Storage

Although the packaging of these functions takes very different shapes, from smartphones and digital video recorders (DVRs) to routers, laptops, and tower computers, they all share these functions at the most basic layer.