Memory Drum, 1970

Vermont Research Corporation used a gear shaper to cut extremely fine teeth into the edge of an aluminum disc.  (We have probably the only cutter still in existence.)  The “gear” teeth were filled with a magnetic substance and the tops of the teeth ground down so that the magnetic material had a little separation between the units.  A magnetic reader would take note of what was passing by.

This drum – inside the housing – is 18 inches in diameter, 117 Volts, 60HZ, 3527 RPM, and 32 tracks.

Canada’s museum of science and innovation, the Ingenium, has a later model that apparently stores 500 KB.  For reference, this desktop computer stores 237 GB, which is 237,000,000 KB. 

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