Magnetic core module from HP 9101A Extended Memory Unit.
<p>Made by AMPEX for Hewlett Packard, 1970s;
</p>
“The 9101A was a 19-inch rack-mountable memory expander for the 9100A/B calculators. It provided an additional 20,832 bits of memory storage, or 248 fourteen-digit registers.”
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CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>