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What Is A Computer?

© Copyright 1998, Jim Loy

What is a computer? Something that computes? Maybe, maybe not. Try this quiz. Which of these are computers:

  1. Pencil and paper
  2. Abacus
  3. Calculator
  4. Programmable calculator
  5. Your personal computer
  6. An earthworm
  7. A person

Definitions may vary. But, essentially, the first three are not computers. A pencil and paper are memory and I/O (input/output). An abacus is memory and I/O. A calculator is memory, calculating device, and I/O. That's pretty close. The last four are computers. And the key word in that list is "programmable."

A program is a list of instructions. And a computer executes programs. They also have to interact with the real world (I/O is helpful). But executing programs is the distinguishing feature of a computer.

Of course, earthworms and humans are more than computers. In fact, they often program themselves, especially humans. And they do other things, too.


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