Redditor Finds Ultra-Rare Refrigerator-Sized 1950s-Era Computer in Basement

It’s easy to forget just how far technology has come in a short time, but a Redditor’s vintage computer discovery will serve as a good reminder. When exploring their grandparent’s basement, the redditor found a pair of enormous computers from the mid-20th century. The computers are a PDP 8e, and more amazingly, an ultra-rare LGP-30.

The LGP-30, which is roughly the size of a chest freezer, was originally released in 1956 with a retail price of $47,000. That would buy you a spendy enterprise system even today, but adjusted for inflation, it was the equivalent of about half a million dollars in 1956. Only 45 were manufactured, due in large part to the high price. The fate of almost all these machines was already known, so the discovery of one in good condition is amazing.

Designer Stan Frankel, who worked on the iconic ENIAC computer, wanted to produce a reliable commercial system with minimal hardware requirements. It contains 113 vacuum tubes, but that number was kept low with the help of solid-state diode logic and a bit-serial architecture. It used a single instruction set with just 16 commands. This particular machine was apparently used for civil engineering calculations in Germany throughout the 1960s.

This computing relic used magnetic drum memory, which allowed for the machine to store up to 4,069 31-bit words — that’s about 15.8 kilobytes. Fellow redditors cautioned the discoverer, one c-wizz, not to turn on the machine until making sure the drum and associated motor are in perfect working order and at room temperature. Even a small misalignment brought on by decades of storage could ruin the hardware.

Even if the hardware is in perfect working order, starting this machine is no easy feat. The sequence is apparently one of the most complicated ever devised. The operator needs to load paper tape into the typewriter console, read an address field, transfer that to the computer register, read the data field, press some more buttons, read the result, and then do the whole thing six to eight more times, all the while listening to the machine’s distinctive ‘burrrp, clunk, clunk, clunk‘ rhythm.

On any other day in /r/vintagecomputing, the discovery of a PDP-8e would have been the big news. This machine was initially released in 1970 for $6,500. It’s more advanced than the LGP-30 with a 12-bit processor capable of 385,000 additions per second, and was designed to work with 60 types of peripherals, like a 2.5Mb hard drive and a modem.

As for the LGP-30, c-wizz has reached out to a local museum in Germany that has a working LGP-30 exhibit. Even if the newly discovered computer isn’t fixable, it’s still an incredible piece of computer history.