What is an Automaton?
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The word automaton is Greek. That might not surprise you at all. After all, the very concept of theoretical computer science probably seems like Greek to you at this point. Automaton has the same root as automatic. One of its meanings, according to Webster's New World Dictionary of the American Language is "an apparatus with a concealed mechanism that enables it to move or work of itself." In other words, an automaton is a device that functions automatically.
We interact with automata daily (automata is the plural of automaton). Coke dispensers, ATM machines, and automatic car washes are all automata. Aha, you might think. Maybe the theory of computer science is pretty simple after all. You've been operating Coke machines since you were old enough to wheedle your grandparents out of money. If learning the theory of computing is as easy operating a Coke machine, you're in business.
Let's think about those candy and soda machines for a moment. Could we design one? What goes on inside such a machine as we plug plug coins into it? Somehow, it must be able to remember how much money has been inserted at each point in order to continue accepting coins until enough money has been accumulated to dispense the product. So, for example, if we start by inserting a quarter, the machine must remember that it has "seen" $0.25 so far. It is not important that it was a quarter it saw, but rather that so far it has accumulated $0.25.
Now suppose you insert a nickel after having started with a quarter. At this point, the machine must remember that it has now accumulated $0.30. If, on the other hand, you had inserted a dime instead, it would need to remember that it had now accumulated $0.35.
Example -- A candy bar dispensing machine
To see an example of how an automatic dispensing machine could be designed, click on the example heading.
