
How Mechanical Computers Worked - Kinnard
http://www.popularmechanics.com/technology/a19668/1953-video-how-mechanical-computers-work/
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dTal
I'm kind of stunned that nobody, ever, has built a "Turing-complete"
mechanical stored-program computer. The Analytical Engine would have been one,
but it was never built in its entirety. The Zuse Z1 was close, in that it was
an all mechanical, general purpose stored-program machine, but it lacked
Turing-completeness. People have built "Turing machines" out of Lego but they
don't really count as they generally lack the memory and speed to do anything
interesting at all.

I reckon it hasn't been done because people assume it already has been, and
it's a lot of work if you're not the first. I bet people picture huge clanking
contraptions like the Analytical Engine. But Zuse built the tabletop-sized Z1
in 2 years in his parent's living room, before Turing-completeness was known
to be a thing. It doesn't seem a stretch that with modern knowledge a
comparable amount of time and effort could yield an actual mechanical
computer. Doesn't seem like too high a price for a place in the history books.

