Only 45 were produced: LGP-30, the legendary 66-year-old computer found in the basement

A German Redditor named c-wizz recently announced that they had found a very rare 66-year-old Librascope LGP-30 computer (and several 1970 DEC PDP-8/e computers) in his grandparents’ basement. First released in 1956, the LGP-30 is one of only 45 examples produced in Europe and stands out as the computer used by “Mel” in a famous part of hacker history.

Developed by Stan Frankel at the California Institute of Technology in 1954, the LGP-30 (short for “Librascope General Purpose 30”) originally retailed for $47,000 (about $512,866 today, adjusted for inflation) and weighed about 365 pounds. However, at the time it was considered a small computer due to its table-like size. According to Masswerk.at, the LGP-30 has 113 vacuum tubes, 1,450 solid-state diodes, and a rotating magnetic drum memory (16.5cm in diameter and 18cm long, spinning at 3,700 RPM) that can store 4,069 31-bit words (equivalent to about 15.8 modern kilobytes). one tube).

Along with the main LGP-30 unit, c-wizz came up with what looks like a Flexowriter typewriter style console (used for input and output with the machine) and a paper tape reader for external data storage. Several PDP-8/e machines and some related equipment were also with him. “There seems to be more modules for PDP/8Es,” wrote c-wizz in a Reddit comment. I can try to put it together.”

Wikipedia

While the PDP-8/e machines are rare and valuable in their own right, the LGP-30 stands out as the most interesting part of the basement exploration, as it is a legendary piece of hacker history. In the epic “The Story of Mel”, which was first posted to a Usenet newsgroup in 1983, a Librascope programmer named Melvin Kaye was tasked with porting a Blackjack program from the LGP-30 to another computer. The story’s author, Ed Nather, is then tasked with finding a bug in the software, while discovering Kaye’s ingenious and unconventional programming tricks. Also, Edward Lorenz is said to have developed chaos theory (and the “butterfly effect”) as a result of aerial experiments on the LGP-30.

What this legendary machine is doing in that basement remains a mystery for now. In a Reddit comment, c-wizz says: “All I know is that my grandfather used it for some civil engineering calculations in the 60’s and he is one of the handful of people in the country who specifically owns such a computer”

For whatever purpose the grandparents used the LGP-30, there may be a relationship between it and nearby PDP-8/e units. In another comment c-wizz says “There seems to be some instructions on how to import the code written for the LGP-30 into the PDP8e”.

After decades of waiting in a basement, the LGP-30 will likely need significant attention to get it working again. A skilled computer museum might come into play here, and c-wizz seems to be investigating it. “It would be really cool if someone could get this thing working again,” says C-wizz. “I found a museum in Germany (where I live) that has a working LGP-30. I think I’ll get to them.”