USSR Soviet Russian Military Ferrite Core Memory Stack Cube

[Alan]

Not something you see everyday.
eBay auction: #150928595047

[Vgkid]

If that date is to believed, this came out of a military computer dating drom 1983, only 7 years before I was born.
Other than that, this is really interesting, but the price is way to high.

[rastro]

It reminds me of the  Apollo Saturn V Launch Vehicle Digital Computer that Fran Blanche was reverse engineering.

[PaulAm]

I had a 16K core stack I sold back in the 80s.  I think I got $50 for it.  Should have held on to it, I guess.

I still have a Burroughs  7 bit x 45 word core I keep on my museum shelf.  It's about 4x4x2 inches.  Has 2 internal planes that had to  have been hand woven.

[rexxar]

Were these used as program memory or just RAM?

[SeanB]

Those were generally main memory, with only a few latches inside the CPU boards as registers. All operations were done on the core and generally output storage was paper tape, printed or displayed on a CRT. The main advantage of core is that it is non volatile, and if power is removed it can continue again on power up with the program.

[rexxar]

Those were generally main memory, with only a few latches inside the CPU boards as registers. All operations were done on the core and generally output storage was paper tape, printed or displayed on a CRT. The main advantage of core is that it is non volatile, and if power is removed it can continue again on power up with the program.

So some poor guy had to sit there and wind the cores in a particular pattern to "program" the device? 

I'd go insane!

[free_electron]

Those were generally main memory, with only a few latches inside the CPU boards as registers. All operations were done on the core and generally output storage was paper tape, printed or displayed on a CRT. The main advantage of core is that it is non volatile, and if power is removed it can continue again on power up with the program.

So some poor guy had to sit there and wind the cores in a particular pattern to "program" the device? 

I'd go insane!

oops, you change this instruction here in the middle of the program ...

[ElectroIrradiator]

Ferrite core memory is magnetic, non-volatile *and* electrically programmable. Think FRAM from the stone age, where each bit is a discrete toroid core.

[dfmischler]

So some poor guy had to sit there and wind the cores in a particular pattern to "program" the device? 

I'd go insane!

There were "ROM" core memories made that way, but normal "RAM" core was essentially non-volatile.  One of the properties of core memory was that read cycles are destructive and the original data had to be written back.  AFAIK every machine with core used a read followed by write memory cycle so it didn't take any longer to read a value, increment it, and write it back than it would to just read it (and write back the same data).

I assume that if the power failed at just the wrong time before the core write-back could be completed then a memory location could be damaged and you would have to reload core from scratch (e.g. paper tape, punch cards, tape, a disk if you were lucky).  Maybe designers took this into account and made sure the CPU would stop running memory cycles before that could happen.  I never got that deep into any of the designs to check.

[PaulAm]

No, that's not ROM.  It's nonvolatile memory.  A 1 or 0 is stored in each core depending on which way the core is magnetized.  To store a bit, the cores are on an X/Y grid.  You'd send a current pulse 1/2 that required to flip the state on the appropriate X and Y lines.  Only the core at the intersection would see enough current to be set.  To read it out, you would do the same thing and a sense wire would have an induced current from the magnetic field change.  A bit simplified, but that's it in a nutshell.  It's been a long time, but I think reading is destructive; you have to write the bit back after reading it.

There's a lot of support circuitry required: x and y drivers, sense amps plus logic to do something with it.

[nctnico]

That is right. Reading is destructive (just like FRAM and DRAM). You need to write the value back afterwards.
The price is much too high though. I recently sold a couple of core memory boards from 1973 (including the control circuitry) for $25 (or so) each.

[TerraHertz]

Throwing out a slab of core memory in my mid twenties still counts as one of the dumbest things I've ever done.

[c4757p]

Out of pure curiosity, just how nonvolatile is it? Can it be expected to hold data for a few hours, or a month, or a decade?

[dfmischler]

Easily months.  Maybe decades, I really don't know.  Essentially, the current used to flip the bits turns the cores into permanent magnets with a particular field orientation.  So it should have all the longevity of a permanent magnet, but all the things that can affect permanent magnets can affect the cores.  E.g. thermal and mechanical shock, strong magnetic fields, etc.

There was a rumor that a particular DEC PDP-15 I once knew wouldn't work right if you turned it 90 degrees because the aftermarket core memory was negatively affected by the earth's magnetic field.  That may have been bullshit, but I never found out because who wants to turn a computer that takes (3) 72" high 19" wide racks anyway?

I think this Wikipedia article on core memory is pretty good.

[zimzom]

Just seen one on ebay, Is there any more info on these devices like manuals, schematics?

http://www.ebay.ph/itm/VERY-RARE-Russian-Military-Ferrite-Core-Memory-Stack-Cube-Radiostation-USSR-/251475211996?pt=LH_DefaultDomain_0&hash=item3a8d1736dc

would be an interesting project for my calculator at some point.

[TheBorg]

And so the Borg came to earth.

[ErikTheNorwegian]

Aplollo guidence computer used solid core rope memory, they went to the moon, landed and came back based upon that tecnology.

I recomend Frank O`Brians book, The Apollo Guidance Computer, architecture and Operatin.  ISBN 978-1-4419-0876-6

The Apollo 64K solid core memory.



How to test it.. it was hell

[cimmo]

How to test it.. it was hell

For the uninitiated, this particular youtuber (Hunchbacked) is a bat sh!t crazy ApolloHoaxer.
So, enjoy his rather 'interesting' take on things technical which he really does not understand -  that he therefore declares are "delirious".

[SeanB]

Core rope has the advantage that a read is non destructive, and it can never suffer a SEU that flips a bit. Manufacture is a bit of an issue, but was the best available at the time. Was obsoleted when the first mask ROM came into production later, which in turn was obsoleted in all but ultra high volume when OTP EPROMS became cheap and available in cheap plastic DIP packages. I still remember in data books that they wanted the code for mask roms in INTEL HEX on a paper tape, or in an EPROM along with a printout of the code, and a minimum order for 10k of chips as a sample.

[GreyWoolfe]

theBorg, are they relatives?

[TheBorg]

theBorg, are they relatives?

It's rather a touchy subject for us actually. Very sad story. We sent our fellow members of the collective to assimilate the people of earth. We were hopeful about so many of these younglings, but alas most of these seem to have been held captive by the people of earth. We know these people only as "engineers". Many make it out to space and escape earth's gravity, but for unknown reasons turn around after a few days and reenter the atmosphere. Unfortunately, most are now trapped in earths gravity again, without hope of escape. The people of earth have seemed to realize that they are Borg vessels, and many are now displayed in something known as a "museum". Our only hope is that one day, our fellow collective members will once again join us, and escape from the captivity of the Earthlings. We are Borg. You will be assimilated.

[G7PSK]

Wonder if the memory is still readable, and if so what the target was.

[SeanB]

If it has not been near a really strong magnet you can read it out....... The original non volatile memory.

[amyk]

I've read an article about restoring a few-decades-old computer system, and they were able to recover most of the software from the core. It's definitely about as nonvolatile as other magnetic media.