What do you do when you’ve bought some old Soviet core memory modules on eBay? If you are [CuriousMarc], you wire it up to some test connectors and use your test bench to see if the core memory still works. Spoiler alert: it does.

While it seems crude by today’s standard, there was a time when these memory modules would have been the amazing miniature tech of their day. Each little magnetic torus represents a bit and the modules have 1,024 and 4,096 tiny little donuts strung together in a grid.

Core memory did have several interesting benefits. First, it was non-volatile. The state of the bits did not depend on active power to the array. Second, core memory was notably radiation-resistant. That was a big reason the original Space Shuttles used core memory until tests indicated an upgrade to solid-state memory would be workable.

There were downsides, too, of course. The manual fabrication was costly, and reading a bit is destructive and requires rewriting. While the bit density seemed impressive at the time, we now look at these 1K bit and 4K bit devices then look at even the smallest SD card and you realize how times have changed.

Why do something like this? Why not? We liked the casings made for the modules which are both attractive and would protect against students or visitors poking the delicate little ferrite rings.

Think core memory was the strangest old memory around? Not by a long shot. Want core on your Arduino? No problem.