My favorite anecdote about magnetic core memory comes from the development of the Naval Tactical Data System.

https://ethw.org/First-Hand:The_Naval_Tactical_Data_System_i...

A paper bag of magnetic cores disappeared while the engineers were out to lunch:

> But shortly after, the engineer called and asked if the shipment was there. This did not sound too good. With a little detective work we found a cleaning crew had worked in the office while we were gone. A little more sleuthing revealed that the bag had been accidentally knocked into a waste basket, and that load of waste had already been dumped into the plant incinerator. The incinerator ashes were spread over a concrete floor, and sure enough there were small magnetic cores, about one sixteenth of an inch in outside diameter, mixed in with the ashes. The CP-642 B had 32,768 30-bit words in its memory, meaning, with spares, there were just about one million magnetic cores in the ashes. At ten cents per core, the ashes held about one hundred thousand dollars worth of cores.

We reasoned the cores were the result of a firing process, and the heat of the incinerator probably had not hurt them. Maybe it even made them better. A quick test of some of the cores picked from the ashes revealed the cores were as good as ever. We and a contingent of Univac engineers & technicians spent a fun filled day rescuing the cores from the ashes with long needles. The cores were strung into the machine’s memory planes, and it passed all performance and environmental tests with flying colors.

That entire history is worth a read if you are interested in computer history of the military variety.

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