Harwell Dekatron / WITCH Reboot tnmoc.org

TNMOC is awesome. Every geek in the UK should go. You can gift them old computing books for their growing library. Colossus is cool but seeing stuff I never knew about was more exciting e.g. The Dekatron with its decimal memory you can visually see the values, the awesome radar screens with trakker balls from the 40's or 50's, the cabinets full of early calculators (some are white spitting images of iDevices) or the early CAD system with a graphics card in a larger cabinet than the workstation. Early mainframes and minicomputers are just beautifully styled. 1 min video of the Dekatron running ▶ this video More info and 20 min video link

The Harwell WITCH used Dekatrons, which is a device that has 10 states and can therefore store one decimal digit each. ▶ this video

Last month I had the pleasure I of seeing a Dekatron[1] in action (for those that don't know, a dekatron is a decimal based computer, rather than binary). The machine in question is the oldest working computer in the world (older machines like the Colossus are actually reconstructions) and uses relays rather than valves. It was a true sight to see in action as the relays spin round with a hypnotic orange glow[2] [1] link [2] ▶ this video (the video doesn't really do it justice)