This 16KB memory module is larger than most laptops

The electronic contraption above isn’t some sort of high-tech server blade or insanely powerful graphics processor, it’s 16KB of memory circa 1970. More precisely, it’s a 16- by 11.5-inch core memory module. Core memory, in case you were wondering, is a technology from a bygone era where wires and metal rings stored bits of information in place of today’s semiconductors.

And where does one get such a wonderful piece of computer history? From a homebrewed PDP-11/05 minicomputer of course!

If you’re not familiar with it (and why would you be?) the PDP-11/05 was a minicomputer sold by DEC in the 1970s on into the 1990s. You can seen an image of one below, complete with tape drives. The module above is part of a computer the poster’s father constructed, complete with his own processor (not a microprocessor mind you, his is a giant board packed with perfectly placed wires). The system also packs a two-foot-long hard drive controller that can handle two 10MB disks. No wonder old computers were so large, all these components existed before discrete parts were shrunk down to the chips we know today.

About how large do you think a minicomputer was? Well, despite their name, minicomputers weren’t mini at all — they were multi-user systems that tended to take up full cabinets and/or racks. The name actually made sense because minicomputers were mid-sized systems classed between mainframes (which took up full rooms and were used by multiple people) and single-user personal computers/workstations (known as microcomputers). Minicomputers died off in the 1980s and 1990s as processors and networking improved. Some of the more famous minicomputers include the IBM System/3, the Data General Nova, the K-202, and the HP 3000.

Minicomputers don’t quite have the same incredible industrial design that we saw in the mainframes, but they have some impressive qualities in their own right and paved they way for both the servers and personal computers that replaced them. Plus, they have huge memory modules.