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

[Richard B. Gilbert]

On 4/6/2012 1:11 PM, George Cornelius wrote:
> 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/

ISTR that patents have a limited life; something like 17 years.  That
may be renewable, once only, for an additional 17 years.  A lot of those
early patents have expired or soon will expire.