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United Kingdom Hardware

EDSAC Computer To Be Rebuilt 97

Posted by timothy
from the ok-but-let's-only-rebuilt-the-allies dept.
nk497 writes with this bit from PCPro: "The first working stored-program computer is set to be rebuilt at Bletchley Park, home to the UK's National Museum of Computing. The Electronic Delay Storage Automatic Calculator ran its first programme in 1949, and was two metres high. Its 3,000 vacuum tubes took up four metres of floor space, and it could perform 650 instructions per second. All data input was via paper tape. The EDSAC used mercury-filled tubes for memory, but in the interests of safety, the replica will use an alternative non-toxic substance. Rebuilding it will take four years, and the public can visit to watch the work as it happens."
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EDSAC Computer To Be Rebuilt

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  • Or Linux for that matter...
    • by macraig (621737)

      Perhaps Windows CE instead? *ducks*

      • Actually the code that is run on the minimalistic instruction set reminds more to BrainFuck then to anything resembling a OS.

        • by mcgrew (92797) *

          Yet Grace Hopper managed to write compilers on not much better equipment. You can always mimic complex instruction set rith a reduced instruction set, but of course that will slow it down even more. PUT, GET, ADD, and SUB are theoretically the only instructions a CPU needs (did I miss one or two essential instructions?).

    • by mswhippingboy (754599) on Friday January 14, 2011 @08:45AM (#34876602)

      With 650 IPS and 512 18 bit words of memory I doubt much of any kind of monitor, much less OS could be implemented. Still, if anyone would like to give it a shot, there is an emulator available at

      http://www.dcs.warwick.ac.uk/~edsac/

      • by sznupi (719324)

        That's basically in the range of minimal ram requirements of Contiki (and not the only one for sure); IPS three orders of magnitude away from 8-bit machines, so nothing too dramatic.

        Question is how practical could it be considering probably quite "manual" I/O (nvm if there would be place left for any programs)

        Not bad, in half of a century - even "smartdust" beats such elders.

        • That's basically in the range of minimal ram requirements of Contiki (and not the only one for sure);

          While Contiki has a minimal RAM requirement of 2K, it also occupies 40K of ROM. The EDSAC had a total architectural maximum of 1024 words (albeit 18 bit words), but only 512 words were actually implemented. Still, I recall when I had a TRS-80 Model I that had a pretty functional version of BASIC implemented in only 4K of ROM and 4K of RAM. It's amazing what can be done in such constrained environments.

          • by sznupi (719324)

            Actually, it seems Contiki can go down even to tens of bytes (still some K's of flash of course) / it can be slimmed down from more typical installs.

            So there's probably some possibility (at least when it comes to memory), when targeting this one specific memory layout.

            (BTW, OS-9 looks like a totally jaw-dropping thing for TRS-80; and not available only way past the time of home computer it runs on, like Contiki or SymbOS)

  • 4 years to build? (Score:4, Insightful)

    by ciderbrew (1860166) on Friday January 14, 2011 @05:20AM (#34875466)
    The war will have been lost to Jerry by then!
    • by augustw (785088)

      EDSAC was built post WW2.

      • Pick either Seinfeld or Springer for me to back out of this one; but the war against them goes on.

        not too sure why you are talking about WW2.

        *looks are feet.
    • by pspahn (1175617)
      I'm at a loss for why it will take so long. I'm guessing it's because they'll have one guy working on it by himself during the weekends so he can avoid his nagging wife. When they asked him how long it would take him, he pulled "ahh! Four years!!" out of thin air.
      • I'm at a loss for why it will take so long.

        Not so bad now that we know what a computer is. Requirements slip was of course a big problem in the early days as a little bit of experience in construction gave you 1000 new ideas to try to implement.

        • by augustw (785088)

          Actually, EDSAC was originally built pretty quickly for the time (about 2 years) precisely because Wilkes, the project leader, decided to use only proven techniques and methods so as to supply a usable computing facility to Cambridge University, rather than extend the state of the art.

      • Re:4 years to build? (Score:5, Informative)

        by hcdejong (561314) <hobbes&xmsnet,nl> on Friday January 14, 2011 @06:42AM (#34875786)

        I think you're not far from the truth. The museum is run by volunteers, and depends on donations for income. They operate on a shoestring budget; this particular build will have dedicated funding, though.

      • Re:4 years to build? (Score:4, Informative)

        by jonbryce (703250) on Friday January 14, 2011 @07:05AM (#34875906) Homepage

        Probably. Also, elfin safety requires them to develop a new type of memory that simulates the mercury tubes used in the original.

      • At a guess, finding enough of the required types of valves (aka "tubes" in other languages) is a time consuming activity
        • by ae1294 (1547521)

          At a guess, finding enough of the required types of valves (aka "tubes" in other languages) is a time consuming activity

          Can't they just steal some from the Internet when nobody is looking?

  • Should have been enough for anybody. I bet it could calculate my tax return in the time it takes me to log in to gnome.

  • by Kupfernigk (1190345) on Friday January 14, 2011 @05:38AM (#34875538)
    In fact Alan Turing himself pointed out that a mixture of alcohol and water would do the job as well as mercury (he wanted to use gin.) Perhaps "Mercury delay line" just sounded more techie to the Civil Service.
    • You'd think a gin delay line would have no trouble getting finance.

      • "You'd think a gin delay line would have no trouble getting finance."

        A "gin delay line" sounds like a queue at the gentlemen's club, Sir Humphrey would never allow it.
      • Don't EVER delay my gin. (And why is mercury in a sealed tube 'dangerous'? Should I move away from the not-so-sealed barometer behind me? Is that why I need my gin?)
        • Mercury is nasty stuff [wikipedia.org], but barometers often contain alcohol anyway.

        • Mercury in a sealed tube is only as safe as the tube and the seal. There have to be arrangements to fill and empty the tube, and to allow for expansion. These are all potential weak points. I once had to condemn a piece of equipment built by an "electrician" which used 24 large mercury glass relays operated by rotary solenoids, in an open wooden box. The glass elements were rigidly attached and each time they switched the point of contact with the frame came under considerable pressure. One broken switch el
          • by Muad'Dave (255648)

            The whole abortion was replaced with a small PCB containing...

            PCBs!?!?! They're HORRIBLY dangerous! Oh, that's PCB [wikipedia.org], not PCB [wikipedia.org].

          • by mcgrew (92797) *

            One broken switch element and an entire factory would have had to be evacuated.

            That's insane. When I was a kid, there was mercury in a hell of a lot of places. Thermostats and thermometers in every home used mercury. If a thermometer broke, we kids would play with the mercury (fascinating metal).

            And these thermometers and switches had been in use for a couple of generations by then, yet I saw no evidence that anyone was harmed by it.

            Now, if you ingest it, from eating tuna fish or inhaling the dust from a br

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      In fact Alan Turing himself pointed out that a mixture of alcohol and water would do the job as well as mercury (he wanted to use gin.)

      I guess "non-toxic" depends on the amount you consume then.

      • It takes a lot of alcohol to poision and afaict it breaks down organically into harmless stuff so releases aren't a concern.

        Afaict liquid mercury isn't hugely dangerous simply because the body won't absorb much but vapours of mercury are worse and organic compounds of mercury are even worse. This gives a good reason for controlling it's use.

    • In fact Alan Turing himself pointed out that a mixture of alcohol and water would do the job as well as mercury (he wanted to use gin.) .

      Turing failed to include a dash of Angostura . . . with enough alcohol, the computer can shoot shit out, but everyone is too trashed to give a damn.

    • by lurcher (88082)

      As opposed to the entirly yummy and safe barium used in the valves getters.

    • by careysub (976506)

      Maybe they could use a gallium eutectic - you would preserve the ambience of a room-temperature liquid metal device* with more similar characteristics than water/alcohol (better acoustic impedance, non-corrosive, etc.). Although you see it for sale at prices of $15/g its current metal market price for high purity gallium is only $0.70/g. An alternative is Cerrolow 117, a reasonably inexpensive commercial alloy used for making mold prototypes, melts at 117 degrees F. Adding a small heating element would keep

  • by jareth-0205 (525594) on Friday January 14, 2011 @05:47AM (#34875572) Homepage

    The first stored program computer was the Manchester Baby

    http://en.wikipedia.org/wiki/Manchester_Small-Scale_Experimental_Machine [wikipedia.org]

    • The first stored program computer was the Manchester Baby

      http://en.wikipedia.org/wiki/Manchester_Small-Scale_Experimental_Machine [wikipedia.org]

      Surprising to see how involved Turing was during that time. Imagine how the computer industry would have developed if he had lived.

    • If you strech the definition of "working" to mean "practical", then the summary is correct. The Manchester Baby was technically first, but it was never meant to be a usefull computing device.

      • If you strech the definition of "working" to mean "practical",

        Clearly you're not a programmer... something doesn't need to be practical or usable to be considered "working"...

      • The method of storage in the Baby - a static charge used to represent 1 or 0 - proved to be the most effective form of storage for RAM (as static and dynamic CMOS) and is becoming more and more of a competitor for hard drives. Though CRT memory was short lived, in the long run Williams proved to be right. The Baby was prescient.
  • by hcdejong (561314) <hobbes&xmsnet,nl> on Friday January 14, 2011 @06:04AM (#34875634)

    I was at Bletchley Park a couple of months ago and by chance the National Museum of Computing [tnmoc.org] was open that day. They've got some interesting displays of old computers, and their goal is to get them all running again. They cover everything between EDSAC and modern computers. Their oldest computer is a Harwell WITCH from 1951 (a decimal computer), this is being restored at the moment. Other fun stuff includes a collection of calculators, and a BBC micro with a working BBC Domesday Project laserdisc installation.

    It's a separate museum on the Bletchley Park grounds, and its opening times are a bit limited (esp. in winter), so check before you go.

    • Also of interest is the 1949 CSIR Mark 1 (CSIRAC), which is held at the Museum of Victoria [museumvictoria.com.au] in Melbourne (unfortunately no longer on display). Because of its historical value, there is no intention to restore it to working order.

      I'd love to visit Bletchley Park one day though if I'm ever on that side of the world.

  • ... the rebuilding of the rebuilding of the Mark 1: http://www.computer50.org/mark1/index.html [computer50.org]

    There's a simulator here if you want to do some old-school coding http://www.davidsharp.com/baby/ [davidsharp.com] :)
  • by VortexCortex (1117377) <VortexCortex@Nos ... t-retrograde.com> on Friday January 14, 2011 @07:35AM (#34876076)

    I love the fact that there is a common desire to preserve our historic technological achievements.

    Working reproductions of dying / dead machines are a great learning tool -- We are all truly standing on the shoulders of giants today.

    I feel that efforts such as rebuilding the EDSAC are in the same vein as those that would create emulators [warwick.ac.uk] for our out of production computers and video game systems as a cheap way to preserve the past.

    What good is the EDSAC or an Emulator without a sampling of the programs the systems used to run? Surely different people would attribute different degrees of importance to different programs -- Thankfully digital storage is abundant and cheap enough that we are capable of preserving entire catalogs of programs.

    Notice however, that the more relevant, beneficial and useful a replica or emulator is, the more illegal it is to produce due to patents and copyrights.
    I fear that if the current copyright laws could be enforced absolutely, we stand to loose important parts of our history and culture for no other reason but greed. Given the long terms of copyright, it's a safe assumption that much of our digital heritage could decay and be lost before it's legal to reproduce it -- Even under good conditions CDs, Magnetic and Solid State Drives will all fail before 70 years after the author's life has elapsed.

    I'm very wary of DRM and the DMCA -- Today we can recreate past works to better understand the significance of the shoulders on which we stand; Tomorrow we may find ourselves searching for footing that has long since crumbled away.

    • You'll be happy to know that the DMCA exempts the Library of Congress then :) I believe portions have also been clarified such that archivers are not only allowed to store ditigal backups, but they can reverse the DRM if they can prove that it is for archival purposes.

      Of course, you'll probably also be happy to know that the DMCA doesn't mean a thing in most of the world, and that somewhere like Belarus will likely be the "digital Iona" of the future....

      • You'll be happy to know that the DMCA exempts the Library of Congress then :) I believe portions have also been clarified such that archivers are not only allowed to store ditigal backups, but they can reverse the DRM if they can prove that it is for archival purposes.

        Of course, you'll probably also be happy to know that the DMCA doesn't mean a thing in most of the world, and that somewhere like Belarus will likely be the "digital Iona" of the future....

        Sadly, just making it legal to break DRM doesn't mean the DRM will be broken. I.e. my brother's Zune will not sync with his Linux machine because of encryption -- He's now experiencing the Vendor lock-in that I warned him of.

        The point being: Once DRM is perfected it may not matter if it's legal for you to break it -- Encryption done right is very infeasible to break. E.g. DMCA does not require the DRMmers to jail-break your device for you -- What happens if you can't do it any other way?

  • by Anonymous Coward

    "The Electronic Delay Storage Automatic Calculator ran its first programme in 1949, and was two metres high"

    Which also happens to be the height of a killer robot. Coincidence? I don't think so.

  • by reboot246 (623534) on Friday January 14, 2011 @08:19AM (#34876360) Homepage
    they have an app for that.

    Barely.
  • by GodfatherofSoul (174979) on Friday January 14, 2011 @09:19AM (#34876950)

    We'd have the mind-numbing processing power to get my garage door open, and one less US state.

    • by magpie (3270)

      We'd have the mind-numbing processing power to get my garage door open, and one less US state.

      Seems a fair trade in some cases.

  • It's great to see that EDSAC will be rebuilt! I wonder if Maurice Wilkes, the project leader, was told before he passed away just this last November? He was probably the last of the "first generation" computer pioneers to pass away. Several slashdot stories of his passing were submitted, but I don't think it ever made the main page. At least he can get his props here now.

  • Can no one look up and confirm well-known facts? Heck, this stuff is still within living memory. The article claims that EDSAC was the "first working stored-program computer" and that is just wrong.

    The Manchester Small-Scale Experimental Machine [often known as "Baby"] was the first stored-program computer, not EDSAC. Baby was operational on June 1948; EDSAC didn't run anything until May 1949. Please don't play semantics with the word "working"; Baby worked, and in any case, all of these early compute

    • As mentioned elsewhere, the Baby was the testbed for EDSAC -- you could think of it as "EDSAC Lite". but it WAS a computer in its own right, so let's keep shaming the submitter and editors ;)

  • The EDSAC used mercury-filled tubes for memory, but in the interests of safety, the replica will use an alternative non-toxic substance.

    So.... hamsters?

  • I'm guessing the decision was not based on safety but practicality.

    A sealed tube of mercury is not a significant safety hazard in a one off application like this machine. There are an awful lot of wall thermostats out there with sealed glass bulbs of mercury in them.

    The EU has regulations on RoHs (Reduction of Hazardous substances) that apply to electronics. It's likely it just would have been too much paperwork hassle to get an exception.

    I'll bet for similar reasons the solder they use in connecting it wi

  • Edsac was not the first stored program digital computer.

    Konrad Zuse's Z3 was running in 1941... turing complete, vacuum tubes, and all.

  • The EDSAC used mercury-filled tubes for memory, but in the interests of safety, the replica will use an alternative non-toxic substance.

    Stupid safety theater. People all over the world sit RIGHT UNDERNEATH mercury-filled tubes. They're called fluorescent lighting.

    Do these tubes explode spontaneously or something? Maybe they should give everyone eye protection and breathing apparatuses.

We warn the reader in advance that the proof presented here depends on a clever but highly unmotivated trick. -- Howard Anton, "Elementary Linear Algebra"

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