Redditor discovers legendary 1956 computer in grandparents’ basement

On Monday, German Reddit user c-wizz reported that they found a very rare 66-year-old Librascope LGP-30 computer (and several 1970 DEC PDP-8/e computers) in their grandparents’ basement. The LGP-30, first released in 1956, is one of 45 computers made in Europe and is perhaps best known as the computer used by Mel in the famous hacker piece.

Designed by Stan Frankel at Caltech in 1954, the LGP-30 (short for “Librascope General Purpose 30”) originally retailed for $47,000 (about $512,866 today inflation-adjusted) and weighed 800 pounds. Despite this, people considered it a small computer at the time due to its table-like size (about 44×33×26 inches). According to Masswerk.at, the LGP-30 included 113 vacuum tubes, 1,450 solid-state diodes, and a rotating magnetic memory drum —a tube 6.5 inches in diameter and 7 inches long, spinning at 3,700 rpm—that could store 4,069 31-bit data. words (equivalent to about 15.8 modern kilobytes).

Along with the LGP-30 main unit, c-wizz found a Flexowriter typewriter-style console (used for input and output with the machine) and something that looked like a paper tape reader for external data storage. Several PDP-8/e vehicles and some related equipment lurked nearby. “There seem to be other modules that belong to PDP/8E,” c-wizz wrote in a Reddit comment. “There is a whole 19-inch rack where all this is supposed to be mounted. Maybe I can find some guides and try to put it all together.”

Although PDP-8/e machines are rare and valuable in their own right, the LGP-30 perhaps stands out as the most interesting part of the basement discovery because it is part of the hacker legend. In the epic “History of Mel “, first published on a Usenet newsgroup in 1983, a Librascope programmer named Melvin Kay was tasked with porting the Blackjack program from an LGP-30 to another computer. The story’s author, Ed Nather, is later assigned to find a bug in the software, and along the way discovers Kay’s inventive and unconventional programming techniques. In addition, Edward Lorenz is said to have developed chaos theory (and the “butterfly effect”) as a result of weather experiments carried out on the LGP-30.

So what was this legendary car doing in grandparents’ basement? Ars reached out to c-wizz but didn’t get a response until this story was published. In a Reddit comment, c-wizz wrote: “The only thing I know is that my grandfather used it for some civil engineering calculations in the 60s and that he was one of the few people in the country who had such privately owned computer.

Whatever Grandpa uses the LGP-30 for, it looks like there might be some connection between it and the PDP-8/e found nearby. In another comment, c-wizz wrote “There seem to be some instructions on how to port code written for the LGP-30 to the PDP8\e.”

After lying in a basement for decades, the LGP-30 will likely need some serious work to get it up and running again. This is where a qualified computer museum can come in handy, and c-wizz seems to be doing just that. “It would be really cool if someone could get this thing up and running again,” wrote c-wizz. “I found a museum in Germany (where I’m from) that apparently has a working LGP-30. I think I’ll contact them.”