As someone who was a Gerard O'Neill http://www.ssi.org/obit.html fan long before he even knew who Turing/Von Neumann/etc., were, of course, I was talking about the latter. Cheers, RAH ------- http://en.wikipedia.org/wiki/Von_Neumann_machine Von Neumann machine
From Wikipedia, the free encyclopedia.
A von Neumann machine is either of two different machines popularized by
the famous mathematician John von Neumann.
General-purpose computer
A von Neumann machine is a model created by John von Neumann for a
computing machine that uses a single storage structure to hold both the set
of instructions on how to perform the computation and the data required or
generated by the computation. Most modern computers use this von Neumann
architecture.
Universal constructor
The term von Neumann machine also refers to the idea of a self-reproducing
machine, which was first examined in a rigorous manner and popularized by
John von Neumann who called it a "Universal Constructor." In principle, if
a machine (for example an industrial robot) could be given enough
capability, raw material and instructions then that robot could make an
exact physical copy of itself. The copy would need to be programmed in
order to do anything. If both robots were reprogrammable, then the original
robot could be instructed to copy its program to the new robot. Both robots
would now have the capability of building copies of themselves.
These machines could be used to explore--or conquer--the universe. The
fact that we haven't seen any from other civilizations is a contributing
element of the Fermi paradox. One of the predictions of some proponents of
nanotechnology is very small Von Neumann machines which, should they become
out of control, would advance over the planet as a "grey goo".
Since such a machine is capable of reproduction, it could arguably qualify
as a life-form.
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R. A. Hettinga