World's Oldest Digital Computer Still Works, Is Still Slow

Ever get kind of nostalgic when you head home for the holidays and decide to fire up the old Packard Bell to see if it’s still kicking? Maybe play a game or two of Skifree or load up Encarta ‘95 to learn some stuff about the world? Well, that’s more or less what the eggheads at Britain’s National Museum of Computing have been trying to do for the past three years with a 2.5-ton behemoth of a machine known as “the Witch” that nearly dates back to World War II. You can’t play SkiFree on Witch, nor can you browse through the annals of Microsoft’s encyclopedia. You can, however, multiply two numbers. It takes ten seconds to get an answer.

So the Witch—short for Wolverhampton Instrument for Teaching Computing from Harwell—isn’t the world’s most powerful digital computer, but it is the oldest. British scientists designed the machine in 1949 to help out at the UK’s Atomic Energy Research Establishment in Oxfordshire. Formally known as the Harwell Dekatron, the Witch took two years to build and has 10,000 moving parts. When it went into service in 1951, it saved the nuclear scientists some of the drudgery of crunching numbers and is said to have done as much work as a single staffer.

But the Witch’s heyday couldn’t last forever. By 1957, it had become obsolete as smaller, faster computers came to market. The Witch spent some time on the university circuit, helping professors teach the youngs how computers work, before being shipped off to the Birmingham Museum of Science in 1973. Eventually, that museum closed, and the Witch made its way to the National Museum of Computer, where it gathered dust until museum trustee Kevin Murrell spotted its control panel by chance while going through some photos of the museum’s storage holdings.

With a team of volunteers, Murrell used old photographs of the machine to figure out how to put the Witch back together. Three years later, they turned the Witch on for the first time in decades. “It’s important for us to have a machine like this back in working order as it gives us an understanding of the state of technology in the late 1940s in Britain,” Murrell told the BBC this week.

Let it be known that the state of technology in the late 1940s in Britain and elsewhere looks absolutely neolithic compared to today. To run programs on the Witch, you have to feed it ticker tape with instructions punched out by hand. Like Philadelphia’s 1946 EINAC computer, often though erroneously referred to as the world’s first digital computer, it works not in binary code but rather decimal. (The “Dekatron” bit of Harwell Dekatron refers to the valves used as memory storage.) To find the world’s first digital was actually built by John Vincent Atanasoff at Iowa State University in the 1930s, but you’ve probably never heard of it.

Aside from the fact that it still works, there’s nothing too extraordinary about the Witch in the greater arc of the history of computing. Its predecessor, the Colossus, sort of steals the thunder for that era of computing. The Colossus was the world’s first fully programmable digital compter and was designed to replace the Bombe, the famous (and colorful!) code-breaking machine that the British used to decipher encrypted messages produced by the "Germans’ Enigma machine. The Witch was also hardly the world’s largest computer when it was built, though it its pretty massive. That honor >SAGE, an American project begun in 1949 to give the United States a technological upper hand in the imminent Cold War.

All things considered, though, the Witch is a cool thing. It makes a funny clickety-clackety sound when it’s crunching numbers. It sort of looks like it belongs on a game show. And like Murrell said, it’s an invaluable artifact of computing history, a milestone that we now need a telescope to look back at. All else fails, the Witch would be a good Bond villain. Easy to defeat, but intimidatingly named.