Fable: The Machine That Was Late.

Calculating the trajectory of missiles during WWII to help gunnery officers with the settings for their artillery in changing conditions took so long that they could never be completed in time.

So a couple of academics were asked to build a vacuum tube-based calculating machine.

This they did.

The resulting machine used 18,000 tubes, weighed 30 tons, measured 100ft x 8ft x 3ft and cost $500,000 ($12.7m in today’s money).

Unfortunately for the war effort, the machine was completed in November 1945 – the same month that peace was declared.

Moral: Timing is important.



  1. Yes Sceppers, these old yarns show us how far we’ve moved on in 50 years.

  2. So are we all zeighost.

  3. That’s interesting zeitghost, and, judging by the progress at Culham, fusion still doesn’t work.

  4. It came in handy by proving that Teller’s first idea for the “Super” wouldn’t work.

  5. Yes ENIAC it was, Duncan, and, as you say, it was in use for at least a decade – still performing in 1955.

  6. I presume the computer was Eniac. I don’t think John von Neumann and the other peope who used it were too worried about it being a bit late. The fact that it was still being expanded in 1953 (with 100 words of core memory) shows how useful it was at the time.

  7. What a marvellous account Ian, thanks very much for it.

  8. The UK had its own equivalent after WW2 — it was called MOSAIC (Ministry Of Supply Automatic Integrating Computer) and was designed and built by Allen Coombs and Bill Chandler (my father-in-law) after they finished work on Colossus, and was used for “calculating trajectories”…


    Proper engineering — the memory store was a massive room-filling array of acoustic delay lines filled with 5 tons of mercury, with temperature kept stable to a fraction of a degree, which were kept dimensionally stable to a few thousandths of an inch with many tons of steel I-beams…

    • Thanks too – I was though amused (nay dismayed!) by this part of the article..

      ‘This is now ‘coded’ either by the programmer himself or by a girl specially trained for the job. This storage order code is passed to another girl who converts it all into punched cards.’



  9. Given the application – so is portability! 🙂

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