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EDSAC Diagrams Rediscovered

timothy posted about 2 months ago | from the thought-they-were-wrong-but-were-mistaken dept.

United Kingdom 37

mikejuk (1801200) writes Due to its importance in the history of computing, the UK's Computer Conservation Society embarked on a 4-year project to build a replica of EDSAC. The main challenge facing the team of volunteers who are working on the rebuild is the lack of documentation. There are almost no original design documents remaining so the rebuild volunteers have to scrutinize photographs to puzzle out which bits go where. However, three years into the project, a set of 19 detailed circuit diagrams have come to light and been handed to the EDSAC team by John Loker, a former engineer in the University of Cambridge Mathematical Laboratory. "I started work as an engineer in the Maths Lab in 1959 just after EDSAC had been decommissioned. In a corridor there was a lot of stuff piled up ready to be thrown away, but amongst it I spotted a roll of circuit diagrams for EDSAC. I'm a collector, so I couldn't resist the urge to rescue them. " In the main, the documents confirm that the team has been correct in most of its re-engineering assumptions, but the drawings have thrown up a few surprises. The most significant discrepancy between the original and the reconstruction that the papers reveal is in the "initial orders" (boot ROM in modern terminology). In the absence of fuller information, the reconstruction team had considered and rejected one possibility which was in fact the one that was used by the original engineers. That will now be rectified in the reconstruction, which is due for completion in late 2015.

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Context: Pilfer vs Rescue? :-) (4, Interesting)

UnknownSoldier (67820) | about 2 months ago | (#47345763)

Always funny to read about a geek seeing the value in saving something for "historical sake" while a company / university just wants get rid of old "junk"

One man's treasure is another mans junk.

Will interesting to see if the completed project actually works.

Re:Context: Pilfer vs Rescue? :-) (1)

K. S. Kyosuke (729550) | about 2 months ago | (#47345785)

One man's treasure is another mans junk.

That's a tautology, isn't it?

Re:Context: Pilfer vs Rescue? :-) (0)

Anonymous Coward | about 2 months ago | (#47345845)

I'm not sure that you should be allowing your treasure to be treated in such a way.

Re:Context: Pilfer vs Rescue? :-) (0)

Anonymous Coward | about 2 months ago | (#47345849)

Either that or a rather florid way of coming out. Also

In the main, the documents confirm that the team has been correct in most of its re-engineering assumptions, but the drawings have thrown up a few surprises. The most significant discrepancy between the original and the reconstruction that the papers reveal is in the "initial orders" (boot ROM in modern terminology). In the absence of fuller information, the reconstruction team had considered and rejected one possibility which was in fact the one that was used by the original engineers.

- is a long way of saying not much. The final sentence is logically redundant, and could have been used to reveal something about the difference between re-engineered and original designs. Editors!

Re: Context: Pilfer vs Rescue? :-) (-1)

Anonymous Coward | about 2 months ago | (#47345853)

K s kyosuke is a fag, is one too

Just so everyone knows, he's talking about penises (-1)

Anonymous Coward | about 2 months ago | (#47345935)

It might not be clear to everyone, especially those not from America, but K. S. Kyosuke is talking about penises here. In America, "man treasure" and "family jewels" are slang for the penis and testes. "Junk" is also slang for the combination of the penis, scrotum and testes. So he's saying that the phrase the GP wrote can be translated as "One man's penis is another man's penis."

Just so everyone knows, he's talking about penises (0)

Anonymous Coward | about 2 months ago | (#47346065)

I would have thought that that interpretation was solely confined to America, and would be completely misunderstood by the entire rest of the World.

"Owning a half-finished spindle does not make you a tailor" as my countrymen say...

Re:Just so everyone knows, he's talking about peni (1)

K. S. Kyosuke (729550) | about 2 months ago | (#47346145)

Thanks to the two of you for confirming that I'm nothing but an innocent foreigner in this horrible joke!

Re:Just so everyone knows, he's talking about peni (2)

TeknoHog (164938) | about 2 months ago | (#47346591)

Interesting -- while I was aware of this meaning of "junk", it didn't occur to me to equate "treasure" with "family jewels". However, "One man's penis is another man's penis" is still a little weird, or at least Siamese.

Re:Context: Pilfer vs Rescue? :-) (1)

Jason Goatcher (3498937) | about 2 months ago | (#47347731)

How is that a tautology? I have a friend who is a liberal, while I'm a conservative, but the way he approaches problems is the same. So we get along because we agree on the "rules" of the game called life.

It's a similar thing with one man's trash being another man's treasure, people simply disagree on what is truly valuable.

Re:Context: Pilfer vs Rescue? :-) (1)

UnknownSoldier (67820) | about 2 months ago | (#47350041)

Maybe. Consider this:

Value is multi-dimensional and subjective.

Witness the price of vanity when people spend hundred of thousands of dollars on a watch. I don't wear a watch so they have zero value to me. Same item different costs.

To a collector, any rare item, has immense value. To the layman, anywhere from $0 up to some "reasonable" dollar amount.

And on the other hand, almost everyone considers the Mona Lisa to be a work of art. Now as to the actual price they would, or could, pay to own a copy of it varies but it is universally agreed that is is a treasure.

Putting this into more concrete terms. People who buy the same song off iTune for $0.99 all agree it is a "fair price." Is it junk? Only to the people who didn't buy it, or to the people who bought it and later regret it.

This is one reason I hate wikipedia and it's "No Trivia" rule. Some people find value in trivia ! Others don't. By including it the people who don't value it can simply skip it. But by not including it at all, the value of wikipedia is decreased because it could contain interesting information, but it doesn't.

Re:Context: Pilfer vs Rescue? :-) (1)

joh (27088) | about 2 months ago | (#47346037)

One man's treasure is another mans junk.

No, it's "my stuff, your shit": http://www.youtube.com/watch?v... [youtube.com]

Re:Context: Pilfer vs Rescue? :-) (3, Insightful)

AmiMoJo (196126) | about 2 months ago | (#47346263)

I'm sure it will be an excellent reproduction. The UK now has quite a few reconstructed classic machines, including various Babbage Engines and Colossus, the first computer. We really should make more of our computing history.

Re:Context: Pilfer vs Rescue? :-) (1)

K. S. Kyosuke (729550) | about 2 months ago | (#47346513)

What, even the Analytical Engine? Accept no imitations!

Re:Context: Pilfer vs Rescue? :-) (0)

Anonymous Coward | about 2 months ago | (#47347929)

Analytical Engine? How was this possible before putting a man into space?

Re:Context: Pilfer vs Rescue? :-) (1)

AmIAnAi (975049) | about 2 months ago | (#47349195)

Not yet ... but we're working on it [plan28.org]

Re:Context: Pilfer vs Rescue? :-) (0)

Anonymous Coward | about a month ago | (#47369673)

I'm stuck between 2 stools on this.

While I'd love to save the "old junk" for posterity, in 99.9% of cases it's impossible to find someone to step forward and collect it and nowhere to store it in the meantime. People don't usually think this stuff is worth saving until about a decade after it's been tossed.

Gus Gorman (-1)

Anonymous Coward | about 2 months ago | (#47345869)

Gus Gorman designed his Super computer on a napkin. Just sayin.

Re:Gus Gorman (0)

Anonymous Coward | about 2 months ago | (#47346737)

And precisely what is your point? That you have a keyboard and internet access?

Re:Gus Gorman (0)

Anonymous Coward | about 2 months ago | (#47347257)

That one should not use napkins as a flooring material on which to place your extremely high temperature machinery. Or something like that. Oh well, 42.

Can't some Africans help? (-1)

Anonymous Coward | about 2 months ago | (#47345981)

There are hundreds of millions of them, and apparently they're just as intelligent as white people. (You know, the 'evil', 'racist' whites who want to keep their own countries and live among their own kind - how awful of them!)

So why aren't Africans building computers? Anybody? Is it 'the legacy of slavery', or some other mythical reason?

Re:Can't some Africans help? (1)

joh (27088) | about 2 months ago | (#47346039)

Too many of them are preoccupied with surviving?

Re:Can't some Africans help? (0)

Anonymous Coward | about 2 months ago | (#47346353)

Patents put the kybosh on that even if they had the means otherwise. They could assemble them but to make them you need a chip fab; Those are expensive with most of the cost seeming to be due to intellectual restrictions.

Re:Can't some Africans help? (1)

K. S. Kyosuke (729550) | about 2 months ago | (#47346567)

There are hundreds of millions of them, and apparently they're just as intelligent as white people.

Unfortunately, white people aren't smart enough anymore. You need the Taiwanese or the Arabs to make your chips these days.

Slow news day? (-1)

Anonymous Coward | about 2 months ago | (#47346003)

I had time to go eat lunch, watch Wolverine which is two hours long, come back and there's only one more story on Slashdot?

What else have they gotten wrong? (2)

AbrasiveCat (999190) | about 2 months ago | (#47346221)

So the they get a few prints of part of the circuits, 9 pages of 150, and they see they made mistakes replicating the original. I wonder how many other mistakes they have made, and what happens if they are finishing and some more drawings surface showing they got stuff wrong? Will they throw it out the wrong and make it as designed or just say "hey good enough, we got most of it right"?

Re:What else have they gotten wrong? (1)

drinkypoo (153816) | about 2 months ago | (#47346239)

and what happens if they are finishing and some more drawings surface showing they got stuff wrong?

I imagine that they will revise anything that seems to explain a problem they've been having, or answers a question they couldn't otherwise answer. My question was along the avove lines, though. What if there have been changes since those drawings, for which there is no documentation? Heck, they might even undo something they did right. I imagine they're going to take that possibility into account, though. If they were idiots, this probably wouldn't seem interesting.

Re:What else have they gotten wrong? (1)

DerekLyons (302214) | about 2 months ago | (#47347883)

That was my thought too... Nineteen pages of the size shown in the pictures is pretty much nothing compared to a complete set of diagrams. It's like getting nineteen pages out of Game of Thrones (which is itself just one volume of a much larger series). If they found errors with so little new information, it does not give me much confidence that their recreation is accurate to any great degree. (Especially given that they tossed out an approach now known to be the one used.)

Not possible (-1)

Anonymous Coward | about 2 months ago | (#47346337)

We only have computers because of space. Computers have no use in themselves so we needed the Apollo project to get people interested in computers.

Therefore any reference to "computers" before 1962 is suspect, as it would invalidate the Holy Truth of the Space Spinoffs.

Re:Not possible (1)

K. S. Kyosuke (729550) | about 2 months ago | (#47346637)

No, we needed the Apollo project to ramp up SSI IC production, to make IBM develop first RTOSes, and to develop the first usable DBMSes.

Re:Not possible (0)

Anonymous Coward | about 2 months ago | (#47347281)

Weird, we were well on our way to inventing ICs anyways. Funny how we invented vacuum tubes and transistors all by ourselves but we needed SPAAAAAA-AAAAACE to make ICs.

Re:Not possible (0)

Anonymous Coward | about 2 months ago | (#47347269)

John von Neumann pushed for the modern stored program computer for the Manhattan project. We have the computers we have because of nuclear weapons.

Re:Not possible (0)

Anonymous Coward | about 2 months ago | (#47347315)

Well, and insurance companies, and banks, and industrial control, and math.... Space was just another customer by then, the world was already on its way to becoming all computerized by the 1960s...

Downloadable? (0)

Anonymous Coward | about 2 months ago | (#47346347)

So, did they post scans of these drawings we can download anywhere? Hopefully, after the were almost lost once, they'll see the merit of wide distribution now that they've been found again...

mod 0p (-1)

Anonymous Coward | about 2 months ago | (#47346569)

Documentation vs. Implementation (4, Interesting)

cstacy (534252) | about 2 months ago | (#47346865)

Since microelectronics, people don't re-wire CPUs anymore...well, they do if it's FPGAs and such. But even in the late 1960s computers were constructed with discrete electronic parts on PCBs. We got a lot of milage out of those vintage machines. I remember hooking up a primitive (by today's standards) logic analyzer to trace signals through the CPU, replacing components such as pulse amplifiers and flip-flops that comprised machine registers. In a research lab setting, it was not uncommon to modify the machines -- for example, new circuits to support dynamic paging (memory bus modifications, associative memory tables, etc.) So I am sure the working EDSAC machine must have had modifications that were not even recorded on these diagrams they have recovered. The story reminds me of a logbook entry that another hacker wrote when repairing the PDP-6 at the MIT AI Lab around 1982. It simply read, "Found wiring here not on schematic. Repaired circuit."

Donate them (1)

Peter Simpson (112887) | about 2 months ago | (#47349425)

Either to the National Museum of Computing (UK) or the Computer History Museum (US), and scan them so they can be put online.
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