Here’s an article on a vintage core memory array, which was part of an IBM System/360 mainframe computer.
It’s written by Ken Shirriff.
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Thanks! A very informative article there. Coming from the land of chips, I’m used to the idea of 2D structures. One of the nice things about core memory is it’s very much a 3D structure.
The core memory consisted of 18 core planes stacked in horizontal layers. Connections to the edge of each plane are visible at the front.
128 KB core module assembly. Two core memory stacks are at the left, and the supporting circuitry is on the right. Fans (black) are at the bottom. Photo from IBM’s 360 and Early 370 Systems.
The 128 KB core memory unit contained two arrays and was almost three feet long.
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There’s a very interesting paper on how IBM manufactured core memories here (pdf). An interesting detail is that core planes were threaded and tested a line at a time: if there is a bad or missing core, it can be crushed and redone.
There’s also a good thread with lots of detail and images of core memories here. If this doesn’t look like a serious machine, what does:
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