Colossus, the world's first electronic computer, is up and running again.
A few miles outside London at Bletchley Park, the computer that cracked the German High Command's messages during the dying years of World War II is back at work.
It'll never run Windows - or any other of today's OSes either for that matter - but Colossus has been rebuilt from a single drawing and a handful of photographs by enthusiast Tony Sale, from the National Museum of Computing.
With so little available documentation, Colossus took 14 years to rebuild. Its data storage system consists of a paper tape loop running round a series of pulleys, and the processing element uses 2,400 valves - the whole computer resembles a Heath Robinson concoction.
The machine is now being used to crack messages transmitted by German radio hams using the same Lorenz SZ42 coding devices used by the German High Command in 1944, and it's being pitted against modern computers, to see which cracks codes fastest. You might expect this to be a one-horse race but Sale told the BBC that this was by no means the case, since Colossus was built for one purpose only, which makes it much faster than a general purpose machine.
The aim of the Cipher Challenge, as it's been dubbed, is to raise the profile of the museum and help fund the maintenance of Colossus and other exhibits.
Colossus was undeniably the world's first electronic computer, despite the alternative versions of history often promoted by dominant forces in today's computing industry, and pioneered many of the ideas embodied in the machine you're using to read this news story. It was invented and built by Post Office engineer Tommy Flowers at the behest of Alan Turing. Flowers spent all his working and spare time, along with much of his own money, developing the machine. It was the largest valve-based device ever built, and is credited with shortening the war by 18 months, as it allowed the British command to read the Germans' operational reports.
The original machine took 11 months to build and worked five times faster than the previous, relay-based model. Version 2 was hard on its heels, and was five times faster again. Ten Colossi were built for decoding purposes. However, as soon as the conflict was over, Winston Churchill ordered all but two destroyed, including all plans and drawings, for security reasons.
Britain's penchant for security overkill meant the massive efforts made both to build Colossus and Bletchley Park's decryption work were hidden from the public for 30 years, by which time the computer industry's centre of gravity had crossed the Atlantic, never to return. All those who worked at Bletchley Park were forbidden by the Official Secrets Act to speak of their experience, and Flowers died in 1998, a near-forgotten hero of the conflict. The government awarded him an OBE at the lowest level of MBE (member) and £1,000 for his efforts - payment that didn't begin to cover his personal outgoings on the project.
Colossus represents the oldest computer design still working - and it never crashed. How many of today's machines could boast that?