Tommy Flowers Bletchley Park

[dave walsh]

Today's Guardian Magazine "Saturday" has an extremely good feature ["The Ghost In The Machine"] about Tommy Flowers and his vital but often unrecognised work constructing a machine for decoding Tunney Wheel Patterns, after a years delay when the Nazis changed the settings. This is an extremely informative article that pulls together all crucial technical and personal aspects of an amazing joint effort that saved so many lives.

Apparently it's only one of the stories in Andrew Smith's book "Devil in the Stack;A Coding Odyssey [Grove Press UK]

Dave W

[Craig Sawyers]

Flowers was responsible for the development of Colossus, necessary for regular breaking of the codes from the Lorenz SZ42 cipher machine. Flowers actually worked at the GPO at Dollis Hill.

The SZ42 sent at 80 Baud, and was a whole lot more complex than the manual Enigma machines. It was used by the German high command, so breaking the codes was of major strategic importance.

The interesting thing is that they never saw an SZ42 until after the war. They worked it out after two intercept were received. The SZ42 operator typed out a message, and a plain text response came back that it was garbled and to send it again. The operator then made the cardinal error of not changing the machine settings. He started to type again, but after a short while made a single typing shortcut.

Based on that single intercept, BP worked out the functional system of the SZ42.

It is all here https://www.codesandciphers.org.uk/lorenz/fish.htm

Colossus uses a 12 thyratron counting rings to mimic the wheels of the SZ42. The rest is more conventional WW2 valves, and bits from telephone exchanges (Dollis Hill - so easy to get the bits). When there was skepticism regarding the reliability of a machine with so many valves - because domestic radio receivers needed valves changed regularly, Flowers said "that is because of the thermal shock of turning the set off and on. Just don't ever turn Colossus off and it will be fine". He was right.

Colossus is not a general purpose computer. It was designed specifically to break SZ42 codes. In today's parlance it was a statistical maths co-processor.

Flowers was still alive when Tony Sale was rebuilding Colossus, pretty ancient in a wheelchair, but his recollections were critical to the project.

Craig

[Craig Sawyers]

The original German manuals, with some translated, for the SZ42 are here

https://cryptocellar.org/Lorenz/

Craig

[Vintage Engr]

Tommy Flowers was an interesting person to meet. He & my uncle had worked at Dollis Hill together, prior to Tommy being moved aside to concentrate on early computing, & ultimately Colossus.

I met him at one of our family occasions, he was a very unassuming character, modest.
Somewhere I have a video recording of him, which I must try to locate.


David.

[Trevor]

Yes Tommy a rather unsung hero of his era who even used his own money to complete his computer I have read about him
TRev

[McMurdo]

He was interviewed for local TV during the official opening of the colossus rebuild, it's on youtube somewhere.

Dollis Hill, including Flowers, had been asked to look at designing machinery for plotting incoming aircraft detected by the concrete sound mirrors, even though he was already working on automated reporting for the new top secret Chain Home system that he wasn't allowed to mention..quite a dilemma! (source: General Report on Tunny).

He was first involved in Bletchley Park on the Enigma problem when he was asked by his boss to go and meet Alan Turing, and the two got on well together, as Turing had long thought about machinery as a solution to mathematic problems and had taught himself electronics in order to experiment. Turing was one of the voices who later promoted Flowers' approach to code breaking machines as being the ideal one for the lorenz job. (source: Collossus, Paul Gannon)

[Craig Sawyers]

FWIW I restored BP/NMOC's Lorenz SZ42 to full functionality.

Craig

[Trevor]

FWIW I restored BP/NMOC's Lorenz SZ42 to full functionality.
Its worth a lot this Craig never undersell your work on restoring this vital piece of our history Tommy Flowers Alan Turing etc. Saved our way of life and all credit should go to them I have been to Bletchley park to pay homage to these people who did this .So from me many thanks and well done !

[Simon Gittins]

https://omnivorist.org/2012/11/tommy-flowers-would-be-wealth-creator/
This article ends with "In 1993, at the age of 87, Tommy Flowers bought himself a PC. Finding it difficult to get the hang of, he enrolled on a course in Basic Information Processing at Hendon College at the conclusion of which got a certificate with his name written on it by his tutor – who I imagine was entirely unaware of Tommy’s story."
The story, as I remember it from something published shortly afterwards, was that the tutor HAD heard of Tommy Flowers and was astonished to see him on this course.

[locknut]

Originally Posted by Craig Sawyers

FWIW I restored BP/NMOC's Lorenz SZ42 to full functionality.

I think if we had a "like" button, this would have collected quite a few. It's a great pleasure to see work like this, I take my hat off to you.

What an interesting thread.

[Craig Sawyers]

I attach a paper I wrote about the restoration. Working out the details was quite difficult at the time - the schematics, the wire colours and timing diagrams in particular. However the original schematics and timing diagrams are now here https://cryptocellar.org/Lorenz/ and would have made the restoration much easier!

There is a coda to this. The restoration work was when the machine was at the National Museum of Computing, and where everything to do with Colossus is located. At that time, you could buy one ticket and visit the main Bletchley Park site and TNMOC. However, following a falling out between Tony Sale and the main site, BP erected a fence between BP and TNMOC - so now you have to pay twice to see both sites.

Tony Sale (now alas dead) arranged a Cipher Challenge from the Heinz Nixdorf Museum in Paderborn. Two massive army grunts delivered the SZ42, and the team at the museum tried to power up the SZ42 before I arrived, and blew up the (new and replaced) mains transformer. They had a rapidly made replacement made, mounted externally to the SZ42, and we limped through the challenge. How they managed to blow up the mains transformer I have no idea.

Anyway, back in the UK, I had the correct mains transformer rewound (by Sowter, FOC)

But before I had a chance to fit it, BP main site appropriated the SZ42 from TNMOC.

And so it sits in a display case at BP, non functional. And I have the new mains transformer and original WW2 fixings on the top of a wardrobe.

Really daft, but there it is.

Craig

[Trevor]

Craig
What a wonderful body of work ! Thanks for your input and report here on he forum !
This has always been of great interest to me on many different levels electrical , political and social
Trev

[Boulevardier]

"BP main site appropriated the SZ42 from TNMOC."

Can you elaborate, Craig? Did BP just march in with guns and seize it, or was some sort of "diplomacy" involved?

Mike

[Craig Sawyers]

Originally Posted by Boulevardier

"BP main site appropriated the SZ42 from TNMOC."

Can you elaborate, Craig? Did BP just march in with guns and seize it, or was some sort of "diplomacy" involved?

Mike

Don't know - I wasn't there when it happened.

I suspect that it happened after Tony Sale shuffled off this mortal coil, because he would have fought to keep the SZ42 at TNMOC tooth and nail.

I think it is still formally owned by GCHQ, and TNMOC had to ask permission for me to restore it before I was let loose. Hence I suspect that before the main BP site/TNMOC split, who displayed and restored it was not in question. After the split, I think (but am not sure) BP argued that the GCHQ rights to the SZ42 vested in BP and not in TNMOC.

Last thing I was peripherally involved with was the Oslo machine, on loan to TNMOC. This is a partial SZ42. Why partial? Well it was a complex cipher machine and often went wrong. So some of the machines were used for spare bits.

So the Oslo machine is missing the motor, the current meter and a few bits and pieces. I was asked what would be necessary to get it working. Well, reproduction motor etc etc. All entirely possible.

The machine - like the one I restored - was gummed up with old grease. So I washed out the ball race bearings and repacked with grease when I restored the original complete SZ42.

We proposed a restoration scheme with Oslo museum and they refused. "The original grease is an historical artefact" - seriously. In point of fact the bearings in the SZ42 are standard even now. So you could take the original bearings out completely including the "historic grease", and install brand new ones.

All this palaver was to get a working SZ42 at TMOC. But the Oslo museum was not playing ball in the restoration game. Alas.

I think I mentioned the Oslo machine in the paper I attached earlier.

Craig

[Craig Sawyers]

Tony Sale was a real character. At one stage he asked me to pub lunch. Another of the elderly guys at BP/TNMOC was there.

They started reminiscing. "Do you remember the time we drilled through to the Soviet Embassy and installed bugs above the ceiling?", yes and we also did ...

I sat there gobsmacked. These two guys taking about all sorts of hairy security shenanigans.

Craig

[lesmw0sec]

I had the pleasure of a private tour with T. Sale - an interesting chap. On the subject of dodgy practice, does anyone recall Harry Spencer G6NA? He was also in the dirty tricks game and told me a few stories. Just prior to his death he apologised to me for not being more forthcoming and confessed that quite a few of their activities were against the law!

[wireman]

I was fortunate to be part of a trip to Bletchley Park in 2008...

https://edinburgh.bcs.org/events/2008-09/081004_photos.htm

[Ted Kendall]

Originally Posted by Craig Sawyers

"The original grease is an historical artefact" - seriously.

As if nobody knows the specification of the said grease. In any case, all that's left of the original after all this time would be soap...

[Craig Sawyers]

Originally Posted by wireman

I was fortunate to be part of a trip to Bletchley Park in 2008...

https://edinburgh.bcs.org/events/2008-09/081004_photos.htm

That looks like a great day! Well before the fence went up of course, so you saw the main site and Colossus, computer galleries etc.

Tony was quietly spoken, but was a massively talented technology polymath. His charming wife Margaret survived him for a number of years, and was herself a fascinating lady to chat to. She's now keeping Tony company somewhere...

Craig

[wireman]

Originally Posted by Craig Sawyers

That looks like a great day! Well before the fence went up of course, so you saw the main site and Colossus, computer galleries etc.

Craig

Yes, I think the park was closed and we had a special tour which started with lunch in the House. I should have some nice photos of the day and the exhibits, I'll have a look at the weekend.