Cores in space: The core memory module from a 1980 Spacelab computer

The Spacelab laboratory carried three Mitra 125 MS minicomputers, each equipped with 128 KB of magnetic core RAM built from tiny ferrite rings; the memory stack occupies about one-third of a computer and consists of seven boards linked by 160-pin connectors. Core memory stores each bit by magnetizing a toroidal core clockwise or counter-clockwise, and uses coincident current addressing—intersecting horizontal and vertical wires—to select individual bits without requiring a separate wire per core.