Greg Sadetsky Brings Back Claude Shannon's 1961 Minivac 601 Relay Computer — On the Web
Play around with the brainchild of the "father of information theory" in-browser — complete with simulated relay sounds.
Developer and vintage computing enthusiast Greg Sadetsky is making it possible to enjoy the rhythmic clack of Claude Shannon's Minivac 601 without having to scrounge up a bunch of relays and a hefty power supply — by putting the educational computing kit right in your web browser.
"Before microchips existed, computers were built with mechanical relays," Sadetsky explains of the project's background — or, more accurately, the technology which inspired it. "This is a working simulation of the Minivac 601, an educational computer designed by Claude Shannon. You can watch it think slowly enough to see every step."
Claude Shannon is, of course, best known as a pioneering mind in information theory responsible for popularizing the use of Boolean algebra in computation thanks to his 1937 thesis, laying the groundwork for artificial intelligence, and the 1948 paper A Mathematic Theory of Computation, which would in turn led to the development of the Internet, the Compact Disc, and commercial mobile telephones.
He was also the designer of an early educational computer, dubbed the Minivac 601 Digital Computer Kit — manufactured for sale by the Scientific Development Corporation. Launched on to the market in 1961 for $85 (around $923 accounting for inflation), the kit was based on double-pole double-throw electrical relays that acted as logic switches and memory. Jumper wires inserted in the front allowed the relays to be wired into a range of potential circuits, allowing the computer to perform basic calculations — or play a game of Tic-Tac-Toe.
Today, a working Minivac 601 is hard to find — both as a result of relatively weak sales and the electromechanical nature of its design, with moving parts that wore out over time. For those looking to play with one anyway, Sadetsky's simulation — built atop Willy McAllister's circuit-sandbox project — provides the means: a functional simulation running entirely in-browser, complete with the option to listen to the clack of the virtual relays as they switch.
"This site is a work in progress," Sadetsky says. "For now, [you can] peruse the original Minivac manuals (don't forget to check the erratas) and play around with the simulator. Drag wires, connect components, make a short circuit! (It's safe.)"
The simulator is available to use on Sadetsky's website; the source code is available on GitHub under an unspecified license.
Main article image courtesy of Autopilot, CC-BY-SA 4.0.