The computer: a definition.

From: William R. Buckley <wrb_at_wrbuckley.com>
Date: Wed Nov 19 15:50:25 2003

>From Daniel I. A. Cohen's book, Introduction To Compuer Theory,
pp 788

>>Definition. If a Turning Machine (TM) has the property that for every
word
>>it accepts, at the time it halts, it leaves one solid string of a's and
b's on
>>its Tape starting in cell i, we call it a computer. The input string we
call
>>the input (or, string of input numbers), and we identify it as a sequence
>>of nonnegative integers. The string left on the Tape we call the output
>>and identify it also as a sequence of nonnegative integers.

The discussion continues,

"Now we finally know what a computer is. Those expensive boxes of
electronics sold as computers are only approximations to the real McCoy.
For one thing, they almost never come with an infinite memory like a true
TM."

William R. Buckley
Received on Wed Nov 19 2003 - 15:50:25 GMT