How Computers Work, Ninth Edition

Chapter 6. How a Microprocessor Works

THE easiest way to visualize how computers work is to think of them as enormous collections of switches, which is really what they are—switches in the form of microscopic transistors etched into a slice of silicon. But for the moment, think of a computer as a giant billboard made up of columns and rows of lights—thousands of them. Then imagine a control room behind that billboard in which there is a switch for every one of the light bulbs on the sign. By turning on the correct switches, you can spell your name or draw a picture.

But suppose there are “master switches” that control dozens of other switches. Instead ...