Schematics of Atanasoff-Berry Computer logic circuits?
Brian L. Stuart
blstuart at bellsouth.net
Thu Aug 21 16:10:07 CDT 2008
> Straying completely away from technical issues, and I'm somewhat loath to
> mention this, but the animosity engendered by the early-70s court battle
> continues decades later. The somewhat nasty inter-personal battle
> found it's way into the Amazon book reviews as recently as 2004.
> Another bizarre twist in the ENIAC patent saga on the legal/social side.
Indeed it does. Back when I was at Purdue, I knew Saul Rosen who
went WAY back. He referred to the push to prioritize Atanasoff
as the cult of Atanasoff. But it's so clear that this weird saga
really is about the legal/social and not the technical. Both
groups innovated in different ways and both are important to
study to get a good picture of history and of the evolution
in design. Everyone had to address the fundamental question
of memory. Eckert and Mauchley knew that it was an eventual
issue; Eckert wrote a paper (in 1944 IIRC) where he described
a magnetic disk (and even suggested a stored program on it).
But in the ENIAC, they largely punted on the question of memory.
But Atanasoff's rotating capacitor drum really does stand
out as an innovation in memory design. Even if it wouldn't
scale well, the rotating, regenerative memory structure is
very similar in concept to the recirculating, regenerative
delay line memories, like that used in the UNIVAC I.
> around with, but the implemention of tube logic can be problematic or
> unreliable, at least in the way the ABC tried to implement both NAND and NOR
> gates with resistive input circuitry.
This is the sort of thing that led Eckert to remark that the processing
part of the ABC would never have been particularly reliable. His
design for the ENIAC was radically different. It bore much similarity
to his earlier experience in tube-based counters. And his design
techniques were the only reason a machine with 18,000 tubes could
be expected to operate for any time at all.
Ultimately, we can see seeds of future technology in both machines,
but neither machine bore much resemblance to what came after either
in terms of architecture or the design of basic functional elements.
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