• Audio
  • 5 mins
  • Level 1: Introductory

Colossus

Updated Tuesday 26th May 2009

At the heart of the code-breaking effort during WWII was an incredible piece of engineering - Colossus - the world's first programmable computing device.

So what was Colossus? On behalf of Digital Planet, Gareth Mitchell talks to Tony Sale about The Colossus Rebuild Project at The National Museum of Computing (based in Bletchley Park, UK).

Audio

Copyright Used with permission

Text

Tony Sale

Colossus was designed in World War II to break the German Lorenz cipher.  And the Lorenz SZ42 cipher machine was used literally by Hitler to his generals, so very important messages being sent enciphered on that, and it was absolutely top grade, top secret stuff and it needed Colossus to be able to find the settings the German operator had used on an intercept that we’d got, because they transmitted their cipher text by teleprinter, by radio, and we intercepted those signals but then we had to find the settings the German operator had used on his Lorenz machine before we could decipher the message. 

Then when you’d found those settings, you then plugged up those settings on our equivalent of the Lorenz SZ42 cipher machine.  Now we never had a Lorenz machine here in World War II, we never even saw one until right at the end of the war, but because of a horrendous German mistake, 30th August 1941, we managed to find out how the Lorenz machine worked and we were then able to build our equivalent, which was called Tunny. 

This is the intercepted message punched onto paper tape in the Baudot-Murray code and then loaded onto Colossus as an endless loop and being analysed over and over again by Colossus, because Colossus has got no memory, it’s a machine which is switched programme direct logic, very, very fast and very parallel.  It’s got no memory, so it has to read the cipher text over and over again, analysing it statistically and teasing out the wheel settings used to encipher it. 

You’ve got five different counters here, five sets of lights, and they show the counts of the match down the tape in thousands, hundreds, tens and units, for each of those five algorithms you're trying on there, and then the lower panel shows the actual wheel start positions that you're using at this moment to do that comparison.  And it’s those wheel start positions that you're changing, looking for the maximum scores, which tells you you’ve found the right positions. 

(2’16”).

And if that whetted your appetite about the Colossus, here's another way of looking at it. Once again, the Digital Planet team made use of Microsoft's experimental Photosynth service, and turned a bunch of snapshots into something much more than the sum of its parts. The original photos are all courtesy of Digital Planet's resident commentator, Bill Thompson.

Colossus photosynth Copyrighted image Icon Copyrighted image Copyright: Production team

Colossus photosynth

Want to try making your own Photosynths? You can do it with a pair of free programs. It only works on Windows XP and Vista, and you'll need to have a Windows Live ID. Download the Photosynth applications.

If you don't have a Windows PC, but do have an iPhone or an iPod Touch, you can create similar images with iSynth, which brings Photosynth to your mobile. Find out more about iSynth.

Find Out More

If digital photography is your thing, why not check out the Open University short course Digital photography: creating and sharing better images (delivered online and available worldwide).

 

For further information, take a look at our frequently asked questions which may give you the support you need.

Have a question?

Other content you may like

History & The Arts 

A visit to Ada Lovelace's memorial

Although her contribution to computing was far from being acknowledged at the time of her death, Ada Lovelace's family, and her inclusion in Byron's poetry, was enough to make her a subject of fascination. In 1853, The Leicester Chronicle sent a reporter to visit the memorial erected in her honour. This is his report.

Article

History & The Arts 

What Did Gutenberg Invent? - The printing process

Gutenberg is credited with inventing the printing process but what, exactly, did he invent? The details are somewhat sparse.

Article

History & The Arts 

Transistors and thermionic valves

Without the valve and the transistor there would be no radio, no television and no computers. How did these vital inventions come about?

Article

History & The Arts 

Unsung heroes

LCD ( Liquid Crystal Display) technology plays a vital role in today's electronic industry, not least in computers and mobile phones. But who developed it, and how?

Article

History & The Arts 

Benjamin Zephaniah's Personal Passion: Classic cars

Benjamin Zephaniah talks about his passion for classic cars

Article

History & The Arts 

Electric Dreams: Technology makeover

Let our interactive take you on an electric trip down memory lane.

Activity

History & The Arts 

Gutenberg The Man

Gutenberg was a goldsmith from Mainz who never signed his work. But what do we know about the man and his life?

Article

History & The Arts 

The Industrial Revolution and Time

Alun C Davies explains how developments in timekeeping and the way people viewed time played an important part in making the industrial revolution possible.

Article

History & The Arts 

Never trust a pirate: Christiaan Huygens’s Longitude Clocks

As a tribute to the historian Lisa Jardine, who died on October 25th, we're republishing her essay on the shady history of 17th Century timekeeping.

Article