[Info-vax] OT: book from George Dyson.

[George Cornelius]

Neil Rieck wrote:
> Attention Computer Technologists. George Dyson (son of Freeman Dyson)
> just published a book titled "Turing's Cathedral: The Origins of the
> Digital Universe" which appears to be a must-own gem.

Spent an hour browsing through it at my Barnes 'n Noble
the other day - really quite good.

> book: http://www.amazon.com/Turings-Cathedral-Origins-Digital-Universe/dp/0375422773
> 
> video: http://ww3.tvo.org/video/173792/george-dyson-origins-digital-universe
> 
> I've been working in the computer industry since 1976 and had not
> heard the story about Williams Tube memory (1024 lighted areas of war-
> surplus oscilloscope cathode ray tubes). You connect 40 of these
> together to make 5 KB of memory. As the bits (screen phosphors) begin
> to fade they need to be refreshed. This is not much different than
> what goes on in modern DRAM where charges leak away from internal
> capacitors.

Just to clarify things, the book was discussing the Eniac
project, and this was the storage (RAM) technology.

The concept was borrowed from the Brits when RCA's superior
technology (tube based, but no CRT screen) was far behind
schedule.  They started out with 16 x 16 bits on the screen,
then expanded to 32 x 32.  I believe it required an external
optical device to sense whether a given bit was present or
not - sounded like one per CRT, where you sent the beam to
a given bit 'address' and the optical output would be high
or low depending on whether charge was present at that position.

The chief designer leter commented that given the various
issues with the technology they probably would have been
better off waiting for the RCA device.

George

P.S. Another bit of history: Iowa State University is
now considered to be the correct patent holder for some
of the key Eniac patents, per court rulings in the 80's,
I believe.  Atanasov et al had built a special purpose
digital computer to solve linear equations, the ABC
computer, and the much larger, general purpose, Eniac
used some of the same circuitry when it was devoloped
several years later.  The ABC used capacitive storage
on a drum, with refresh, so is an obvious precursor
to today's dynamic RAM.

> Neil Rieck
> Kitchener / Waterloo / Cambridge,
> Ontario, Canada.
> http://www3.sympatico.ca/n.rieck/