What is this module?

That is very strange. It looks labor intensive.

This is more normal for core memory:

Yes, it is. This NASA note:

at page 4 says:

"There are many predictions that other technologies are to replace magnetic cores, but magnetic-core technology is so widespread and established that it is difficult for other technologies to replace it.

The core suffers, however, from the limitation of only DRO operation. unless more sophisticated geometries are used such as the multi- aperture devices (MAD) or Biax. The multi-aperture devices use the technique of two or more holes whose axes are parallel. can be set up to give NDRO operation, although a prime current cycle is required after every interrogate pulse. A memory of this type is very expensive, and requires relatively intricate wiring and has severe temperature limitations. Two devices (ref. 3) using this technique are the transfluxor and the Shmoo element. The currents re- quired for these devices are high, 900 mA for clear and 550 mA for set, with a minimum read-modify-write time of 4 to 5 usec."

So it appears that this Soviet module might indeed be an extremely rare form of RAM based on transfluxors. No idea why, as BIAXes were known back then.

If it is from a military device, as advertised, then the required effort would not be an issue. I can't find a photo right now, but once I saw a PCB with a number of toroids. Each toroid had a big hole in the PCB for the core and a a number of banana-shaped slots for the windings. The windings were wound through these PCB slots, making a flat and robust integrated structure. I think they did it manually, albeit the reason for going there is unclear to me.

Yes, a typical coincident current RAM from that era. The read-outs were destructive, as they currently are in FRAM.

Best regards, Piotr

The biax had orthogonal fields for the two holes, and the three-hole example has a thick wire making circumferential field, with the thin wire sensing radial field, also at right angles. I've mainly seen three-wire toroid core memories, the Soviet vintage item is certainly odd. Maybe it was easier to produce a cylinder with three axial holes, than a rectangular biax item?

They knew the biax technology:

which makes the engineering choices behind the first module it even stranger.

Best regards, Piotr

One of our instruments uses a FRAM to save the current front-panel setups, because the write endurance is huge, 1e14 cycles. So we can write to it often and not do a lot of thinking.

CYPRESS FM25L16B-G

If read is destructive, it's transparent to us. But we only read a saved setup once, at powerup.

It is transparent, but it consumes the write cycles the device should endure. It is worth to keep in mind not to be surprised one day.

So this is not an issue in this application.

Best regards, Piotr

That chip, at the maximum possible SPI data rate of read/write cycles, would last 85 years. We write about once per second, which should last about 3 million years. More actually, since we use rolling, checksummed buffers and only one has to work.