[extropy-chat] Using Graphic controllers

Alan Eliasen eliasen at mindspring.com
Mon Apr 19 02:24:08 UTC 2004

David Lubkin wrote:
> The term "von Neumann design" refers to the design outlined in his paper
> "First Draft of a Report on the EDVAC."
> Nicholas Metropolis (who worked closely with von Neumann) wrote:
>> It is clear that the stored-program concept predates von Neumann's
>> participation in the EDVAC design. That von Neumann is often given
>> credit for this fundamental concept is likely due to the fact that he
>> wrote a preliminary report which summarized the earlier work on the
>> EDVAC design, including the stored-program concept. Von Neumann
>> contributed significantly to the development of this concept, but to
>> credit him with its invention is a historical error.
> Certainly Eckert and Mauchley ferociously disputed von Neumann's
> authorship.

   I just happened to be reading about this last night in _Alan Turing: The
Enigma_ by Andrew Hodges.  Recommended.  Here's his take:

   "The new machine was designed by the electronic engineers J.P. Eckert and
J. Mauchly, although von Neumann's first knowledge of it, apparently something
of an accident, came through talking on a railroad station with H.H.
Goldstine, a mathematician associated with the project." (p. 300)

   "But even when von Neumann joined the ENIAC team as 'adviser' in late 1944,
Eckert and Mauchly had perceived a quite different solution to their problem.
 This was to leave the hardware alone, and to make the instructions available
at electronic speeds by storing them /internally/, in electronic form."  (p. 302)

   "In March and April 1945, the ENIAC team had prepared a proposal, the
/Draft Report on the EDVAC./  The EDVAC--the Electronic Discrete Variable
Calculator--was the planned 'second electronic machine.'  The report was dated
30 June 1945, and signed by von Neumann.  It was not his design, but the
description of it bore the mark of his more mathematical mind rising above the
technicalities."  (p.302-303)

   This book places much of the credit on Alan Turing's idea of a "one tape"
Universal Turing Machine, defined in his famous "Computable Numbers" paper,
"on which everything--instructions, data, and working--was to be stored.  This
was the new idea, different from anything in Babbage's design, and one which
marked a turning point in proposals for digital machines.  For it threw all
the emphasis on to a new place -- the construction of a large, fast,
effective, all-purpose electronic 'memory'.  And in its way it made everything
much more simple, less cluttered in conception.  Von Neumann might well have
seen it as 'tempting', because it was almost too good an idea to be true.  But
it had been in /Computable Numbers/ all the time."  (p. 303)

   As a software and electronic engineer myself, I think there's a rather
significant qualitative difference in design between a one-tape Turing machine
and a practical machine architecture as found in EDVAC or ENIAC, and almost
all of the credit for this workable design should indeed to to the team led by
Eckert and Mauchly, and not von Neumann nor Turing.

  Alan Eliasen                 | "You cannot reason a person out of a
  eliasen at mindspring.com       |  position he did not reason himself
  http://futureboy.homeip.net/ |  into in the first place."
                               |     --Jonathan Swift

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