Probably nothing has influenced our lives more in the past 50 years than the invention of the electronic computer. Today computers are nearly ubiquitous. They are in our homes, our cars, our microwaves, our cellular phones, and even in our toys. Tiny computers called microprocessors are responsible for controlling many of the common appliances that we use every day from the automatic coffee maker to the hi-fi VCR. One way to get a sense of the pervasive nature of modern computers is see how these machines are depicted in art. Click on the arrows below to browse through the computer art gallery. See if you can identify with any of these humorous depictions of how computers influence modern life.

 Computer Art Gallery

Why is it that computers have become such an integral part of modern life? One answer to this question might be that computers are both flexible and efficient. Consider the first quality: flexibility. Computers are truly universal machines. Unlike other machines such as cars, can openers, or washing machines, computers can be used to solve a variety of problems. By simply changing the instructions that control the computer, these machines can be transformed from a video arcade to a word processor. In this module, we will examine the structure of a computer and discover why these machines can be so flexible.

Now consider the second quality: efficiency. Computers are certainly efficient at tasks which require many mathematical calculations and tasks which can be expressed in the form of an algorithm. Of course, computers are not efficient at all tasks. No one has ever seen a computer plant a garden or write a novel. However, many common tasks are well suited to computers, and that is why we see such a variety of pictures in the computer art gallery above. In this module, we will also discover why computers are efficient calculators and why computers require tasks to be expressed as algorithms. (For more information on algorithms, see the Algorithms module.)

By the end of this module, you should be able to do the following:

• Explain the various ways data is represented in computer memory
• Reproduce the truth tables for the AND, OR, and NOT gates
• Trace the logic of circuits composed of a few simple gates
• Describe the behavior of the following circuits: the decoder, the latch, and the adder
• Write simple programs in machine code.