back to article Bletchley Park boffins start trailblazer EDSAC computer rebuild

Physical production of a replica of EDSAC, aka the Electronic Delay Storage Automatic Calculator, has at last begun at The National Museum of Computing, located at World War II crypto centre Bletchley Park. EDSAC is an early computer originally put together at Cambridge University in the late 1940s. The initial work on the …

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  1. Anonymous Coward
    Anonymous Coward

    Video games

    EDSAC ran a version of noughts and crosses displayed on a cathode ray tube. It might well have been the world's first video game console.

    More seriously, the subroutine was also invented on EDSAC.

    1. melt

      Re: Video games

      The draughts game for the Manchester Baby had a graphical output on one of the CRTs; beating EDSAC by at least a year.

      See the latest edition of Resurrection: http://www.cs.man.ac.uk/CCS/res/res60.htm#f :D

      1. melt
        FAIL

        Re: Video games

        Whoops; i've just realised that Draughts was for the Ferranti Mark I, not the Baby. Carry on!

      2. JCitizen
        Coffee/keyboard

        Re: Video games

        That is fascinating melt! Bravo to you link! Very interesting! :D

  2. alain williams Silver badge

    Subroutines invented

    I thought that Ada Lovelace wrote about subroutines. OK: the analytical engine was not built, but she did talk about the idea.

    1. Yes Me Silver badge
      Holmes

      Re: Subroutines invented

      The modern inventor of the subroutine (recursive, to boot) was in fact Alan Turing in the original (1945-6) design of the ACE. The Cambridge crew never acknowledged this. All credit to EDSAC for being the first full scale stored-program machine, though.

      Alternativley, the modern inventor was Konrad Zuse in Plankalkül (1943-45), but that version was probably not known to the EDSAC designers.

  3. jason 7
    Joke

    Probably arrive before....

    ....my Nexus 4!

  4. Vladimir Plouzhnikov

    Delay lines

    Does that mean that they have figured out how to build the new delay lines (with all the health and safety bruhaha about using lots of Hg)?

    1. melt
      Happy

      Re: Delay lines

      "A long-standing question for the project has been the reconstruction of the mercury delay lines used by the original. These are problematic for several reasons: the precision engineering required to manufacture them is demanding, the operational, maintenance and durability aspects of mercury delay lines are challenging, especially for a museum rather than laboratory environment, and the cost of buying the mercury is significant. After investigations by Peter Linington into other storage technologies we have decide that the main store will be constructed using nickel delay lines. These were the immediate successor to mercury delay lines, follow similar physical principles, and are known to be reliable and long-lived in operation. That said, the techniques used in constructing them are essentially lost so Peter has mostly recently been investigating these and has been able to demonstrate a first proof of concept prototype.

      Given the importance of mercury delay lines in the history of early computers, the project has given itself the objective of, at a minimum, building a small stand-alone demonstration rig showing a mercury delay line in operation. One route to this might be to experimentally refill the surviving short delay line."

      http://www.cs.man.ac.uk/CCS/res/res60.htm#b (Was reading it in the bath last night)

      1. Vladimir Plouzhnikov

        Re: Delay lines

        Thanks!

      2. Graham Wilson

        @melt -- Re: Delay lines

        El Reg has been down this path before (which I'm sure you know):

        http://forums.theregister.co.uk/forum/1/2011/01/13/edsac_rebuild_bletchley_park/

        Many of us were pissed off then and our sentiment still hasn't changed--certainly not yours truly!

      3. JCitizen
        Coffee/keyboard

        Re: Delay lines

        I fondly remember working on certain reed mercury switches in automated machinery built in the late 50's and early 60's. The clunky part transistor - part electro-mechanical relay - part vacuum tube contraptions were a joy to work on. The parts lasted forever - you may not replace or repair a particular control box for a decade or more. However when I googled mercury delay lines, I was shocked at the sight of these gizmos! I hope they have good luck recreating them as close as possible, and KUDOs to the men/women involved in this project!

  5. Pet Peeve
    Pint

    Hats off guys

    Every time we turn around, the british are rebuilding another historical computer. Great job!

    1. Matt Piechota
      Flame

      Re: Hats off guys

      "Every time we turn around, the british are rebuilding another historical computer. Great job!"

      Well, you can't really expect the Brits to build a modern computer, right? :)

    2. JCitizen
      Coffee/keyboard

      Re: Hats off guys

      I am very thankful they are recreating history before everyone forgets how to do it. The future will be beholding to these historian builders. It is the fact that so much of this is being reproduced that actually makes me want to visit the UK very badly. I would just love to see them in operation!!!

  6. Anonymous Coward
    Anonymous Coward

    Is it done yet ?

    Carry on then......

  7. Anonymous Coward
    Linux

    I mean this is REALLY good.... but

    It's not very fucking useful.

    1. Jedit Silver badge
      Mushroom

      "It's not very fucking useful."

      And yet, still more useful than your post.

      There are a lot of good reasons for going back to first principles, not least of which is because it gives a better understanding of those principles. Considered in that light EDSAC-2015 is not a computer, it's a map. If the writing is in big letters and it only shows main roads, that's to help you read it better.

  8. ajm
    Thumb Up

    EDSAC web simulator

    As a student at Cambridge we were tasked with writing a web-based emulator of the EDSAC as part of the 50th anniversary celebrations. Our group got some original code to run - including the OXO game, as well as developing some latter day examples, such as Conway's life.

    Amazingly it still runs 13 years later . Our simulator is available here:

    http://this.isfluent.com/2013/1/edsac-simulator-63-years-on/

    1. JCitizen
      Coffee/keyboard

      Re: EDSAC web simulator

      This is SOOO cool! I can't emphasize it enough! I so thankful of the time taken by the readers who posted here today. To bad my java didn't work, I would have loved to play with the simulator!

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