Can anyone identify what this board is/does?

Rick Bensene rickb at
Sat Dec 2 10:17:59 CST 2017

This is a wire rope ROM, but it is unpopulated, meaning that there are no wires strung through the cores to encode anything.
The little pegs located below the cores are for routing the wire.
The diodes are all for address selection, and the circuitry above the cores is the sense amplifiers to take the small current induced in the "secondary" winding around the core and amplify it to a level usable by the rest of the logic.  It is a 20-bit wide word.  I didn't take the time to try to figure out how many words that there are, but I'd suspect something on the order of 256 to 512 words could be stored.
To program it, thin magnet wire would be soldered to pads at the outputs of the address decoding (one pad for each "word"), and then threaded through (or not) each of the 20 cores to encode 1's and 0's, and then mass terminated on another pad.
The threading operation would be tedious.  Generally there would be a special needle-like tool that would be used to thread the wire for each word.
Definitely an interesting piece.

Rick Bensene, The Old Calculator Museum

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Tony Aiuto via cctalk
Sent: Friday, December 01, 2017 7:12 AM
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Subject: Can anyone identify what this board is/does?

EBay listing for a "Soviet Magnetic Ferrite Core Memory Board". It looks like 20 something gigantic cores and a lot of diodes. I am guessing it is some kind of ROM, but it doesn't look like a rope memory. And maybe the cores are not cores at all, but some sort of inductor. I've not seen this before.

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