Rediscovered EDSAC diagrams reveal secrets of first computers | Hacker News Reader

Rediscovered EDSAC diagrams reveal secrets of first computers

tnmoc.org

31 pointsht_th9 comments

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...

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.

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

I wonder if that was influenced by Feynman's pre-computer process of 'programming' ranks of operators on mechanical calculators to do series expansions for the Manhattan project? What he did there in space, was essentially what EDSAC did in time. Except he pipelined the process, which was a wrinkle that didn't happen in computers for decades?

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.

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.

¹https://en.wikipedia.org/wiki/Thomas_Gold

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

It's been 65 years. Considering patent lifespan is about 20 years in most jurisdictions, wouldn't any patents expire at least thrice?

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) seems mighty interesting. When I'm in the neighborhood of the museum, I'll plan paying them a visit.

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