At the core of every computer is a microprocessor, a device that has been called the greatest invention of the century. The dictionary defines the microprocessor as "a semiconductor central processing unit usually contained on a single integrated circuit chip." More important than what a microprocessor is, is what a microprocessor can do.

The microprocessor is also known as a central processing unit, or CPU. The CPU actually runs the programs in a device, be it a computer, personal digital assistant (PDA), or cell phone; but the CPU depends on instructions from other microcomponents to tell it what to do. These instructions usually come from a software program that is stored in memory.

The CPU directs computer operations by sending control signals, memory addresses, and data from one area of the computer to another by using interconnected pathways called a bus. At locations along the bus are input...