Nerd Heaven

Yesterday, Harry and I visited the National Museum of Computing, in Bletchley Park.

I was in nerd heaven, I tell you!

Firstly, we saw the Bombe: developed by Alan Turing and Gordon Welchman during WW2.  I did my best to explain to Harry, the principle behind its workings. I don’t think my explanation (with my limited knowledge) was much good, but he seemed to get the idea.

Then we saw Colossus: the world’s first programmable computer.  Built to decode messages from the Lorenz machine that was used to encode German High Command messages (named Tunny by the British codebreakers).


In the Mainframe room we were astonished at the size of the machines. Hard drives the size of refridgerators filled the room, each with a capacity smaller than today’s memory sticks! That big circular disk bottom right… I think that was 8K or something stupid like that.

A lot of it was made by ICL – International Computers Limited – a British computer company from way back, that I’d completely forgotten about.


This is a piece of memory – core memory, as it was known. Look at the size of it! And this wasn’t a prototype or anything, this was actually in use back in the day, plugged into mainframe computers.

Consisting of just 20K of memory: about 400,000 times less than the memory in a modern, cheap mobile phone. And each tiny little core was threaded onto the wires by hand. Jeez.

But then, as we wandered around, I started to see stuff that I recognised, like the Sinclair ZX81 – my very first computer; programmable calculators from the likes of Olivetti and Sharp and Texas Instruments; and the once ubiquitous BBC Micro, where I showed Harry what used to be everybody’s first attempt at programming in BASIC:

10 PRINT “Hello World”

20 GOTO 10


We then played the original version of Mario Kart on an old Atari. With it’s blocky 8-bit graphics and unusual controller, I thought I might be able to beat him. But, he thrashed me. As usual.

It was a great way to spend a few hours though and we both thoroughly enjoyed it.

Well, I know Harry enjoyed it, but for me, well, I was in nostalgic nirvana.


  1. Alan

    How things change in a week. Not one mention of food.
    A company I worked for many years ago in Harpenden had robot paint sprayers and in the office were a pair of very similar hard drives.
    If I lived more local to Bletchley it would be on my list of places to visit.
    The ZX81 was a must have black box just to punish yourself spending ages typing a program in just to find there was a misprint.

    • Masher

      Not only that, but I had the famous 16K wobbly RAM pack plugged into the back of mine. The slightest of knocks and the hours of typing on that crappy keyboard were lost in an instant!

      • Alan

        Yep. Many a time spent with rampack wobble. Those the days…….

        • Alan


  2. Brennig

    I didn’t do computing until I was 97 you know

    • Brennig

      Or perhaps I was 79. Anyway. I want to go. You’re going to have to take me. It sounds excellent and aces and also a place I’d like to visit. Please!!

      • Masher

        Well, you’re a grown man (I think), so you can probably take yourself, Bren. However, I’d be happy to meet up with you there sometime, if you want.

        • Alan

          Watch out Bren, Mr Masher is after a free cuppa.

  3. Brennig

    Just re-read this. I worked on an ICL computer in 500 BC. It was an ICL System 4 (actually the 4/72, to be precise), at RAF Hendon. We taught it to play Christmas Carols. Your tax £s hard at work there kids.

  4. Tony Kerrison

    The ICL 4/72 at the RAF’s Supply Control Centre at Hendon was the new, shiny, coming thing when I left SCC in 1974! It was, itself replaced by an Atlas 10 in due course, if memory (!) serves… The one I worked on from 1971-4 was the AEI 1010 Batch Processing machine, with three separate ‘complexes’. The memory was contained in a core store & on a fast-spinning bit of kit that lived under a metal dome. Input was from Punched paper Tape, Magnetic Tape & typed via a Friden Flexowriter. No screens anywhere! We ran 24/7 on a shift system, & were able to swap controls when maintenance or fault-finding took place. It used to get fairly hot in the hall in summer, & the rudimentary air-con didn’t work. Someone got ours to play a golf game using the keyboard. Happy days!

    • Masher

      All cutting-edge at the time, Tony, I’m sure.
      But there will always be some wag (a clever one), who will delight in getting millions of pounds worth of kit, to do something as banal as play noughts and crosses – WOPR springs to mind, though I can’t remember the name of the film.

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