

Rediscovered EDSAC diagrams reveal secrets of first computers - ht_th
http://www.tnmoc.org/news/news-releases/lost-edsac-diagrams-reveal-secrets-one-earliest-computers

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userbinator
Would really like to see some scans of these...

I've looked at schematics of early computers, and although many of the
implementation details are quite different, it's often amazing how similar
they are to modern machine architectures. One of the biggest differences is
that these early machines were more like programmable calculators than
general-purpose computers, with really wide registers, support for floating-
point, and math-oriented instruction sets.

[http://en.wikipedia.org/wiki/Electronic_Delay_Storage_Automa...](http://en.wikipedia.org/wiki/Electronic_Delay_Storage_Automatic_Calculator)

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drdaeman
I think that was a necessity. The machines were built to do math, and at the
time they didn't have fancy modern compilers that could do pure magic
transforming human-convenient expressions into amazingly efficient machine
code. So they had to either design the machine to do the required operations
in hardware or make programmers do similar magic in their heads.

~~~
ht_th
You might be interested in reading _The preparation of programs for an
electronic digital computer_ (1951) By Maurice V. WIlkes, David J. Wheeler and
Stanley Gill. That's the textbook they used for the first programming course
(in Europe) using the EDSAC. The interesting thing to me about this book is
that the topics discussed can still be found in some way in "modern"
introduction texts to programming.

Part I

1\. The design or programs for electronic computing machines

2\. Input of orders

3\. Subroutines and parameters

4\. Library subroutines and their use in constructing programs

5\. Pitfalls

6\. Use of the EDSAC and its associated equipment

7\. Examples

Part II

8\. Specification of library subroutines

Part III: Appendices

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rootbear
I'm not old enough to have used a vacuum tube (or valve, the lovely British
word for them) computer, but I've developed an interest in these early
systems. I hope these circuit diagrams are scanned and become available some
day.

When reading about the EDSAC a while back, I realized that this was the
computer on which Fred Holye based the computer he describes in "The Black
Cloud", right down to it being housed in a former Anatomy School in Cambridge.
I've wondered if Hoyle actually used the EDSAC or was just familiar with it
enough to use it as a model for his fictional computer.

~~~
kps
Thomas Gold¹, who co-developed the Steady State hypothesis along with Hoyle
and Hermann Bondi, helped design EDSAC's mercury delay line memory, as he had
worked on delay lines for radar during the war.

¹[https://en.wikipedia.org/wiki/Thomas_Gold](https://en.wikipedia.org/wiki/Thomas_Gold)

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tempodox
Too bad we don't get to see the actual diagrams. I wonder if that's because
they are patented.

~~~
ht_th
Yes, I never understand these news articles referring to reports, digital
objects and whatnot, but not actually linking to the material.

Still, this EDSAC recovery project ([http://www.tnmoc.org/special-
projects/edsac](http://www.tnmoc.org/special-projects/edsac)) seems mighty
interesting. When I'm in the neighborhood of the museum, I'll plan paying them
a visit.

