[TUHS] [TUHS} RIP Claude Shannon

Doug McIlroy doug at cs.dartmouth.edu
Sun Feb 25 01:51:19 AEST 2018

So many memories. The "ultimate machine" (which was brought out and
demonstrated from time to time while I was at the Labs) was built in
collaboration with Ed Moore (he of Moore-model automata, who published
"Dijkstra's algorithm" for shortest paths a year before Dijkstra) and
(I believe) Dave Hagelbarger. Moore endowed the machine with a longevity
property seldom remarked on: majority logic so that any electrical
component can be removed without harming its observable behavior.

Shannon moved to MIT from Bell Labs some weeks before I moved the
other way, so I only met him much later when he visited the Unix room
(an excuse, albeit weak, for this distant detour from TUHS). By that
time Shannon was descending into Alzheimer's fog, but his wife who
accompanied him was a memorably curious and perceptive visitor. I have
wondered what role she may have played as a sounding board or more in
Shannon's research.

As a child, I used to ski on the 50-foot hill that was the lawn of the
mansion that Shannon would buy when he moved to Massachusetts. We kids
would ski down and climb back up. Not Shannon. He installed a chairlift.
One house separated mine from the ski hill. It belonged to John Trump,
another MIT prof who engineered the Van de Graaff generator into a
commercial product for generating million-volt x-rays and, yes, was uncle
of the Donald. John, as kind as he was bright, fortunately did not live
to see the apotheosis of his wayward nephew.


> We lost Claude Shannon on this day in 2001. He was a mathematician,
> electrical engineer, and cryptographer; he is regarded as the "father" of
> information theory, and he pioneered digital circuit design. Amongst
> other things he built a barbed-wire telegraph, the "Ultimate Machine" (it
> reached up and switched itself off), a Roman numeral computer ("THROBAC"),
> the Minivac 601 (a digital trainer), a Rubik's Cube solver, a mechanical
> mouse that learned how to solve mazes, and outlined a chess program
> (pre-Belle). He formulated the security mantra "The enemy knows the
> system", and did top-secret work in WW-2 on crypto and fire-control
> systems.

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