USSR Soviet Russian Military Ferrite Core Memory Stack Cube - Page 1
Forum section: electronics / general

author: Alan
author_rank: Newbie
timestamp: August 28, 2013, 04:06:08 pm
content: Not something you see everyday.eBay auction: #150928595047

author: Vgkid
author_rank: Super Contributor
timestamp: August 28, 2013, 04:53:01 pm
content: 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.

author: rastro
author_rank: Frequent Contributor
timestamp: August 28, 2013, 05:01:04 pm
content: It reminds me of the Apollo Saturn V Launch Vehicle Digital Computer that Fran Blanche was reverse engineering.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 28, 2013, 05:17:40 pm
content: 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.

author: rexxar
author_rank: Frequent Contributor
timestamp: August 29, 2013, 03:39:16 am
content: Were these used as program memory or just RAM?

author: SeanB
author_rank: Super Contributor
timestamp: August 29, 2013, 04:08:24 am
content: 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.

author: rexxar
author_rank: Frequent Contributor
timestamp: August 29, 2013, 04:15:35 am
content: Quote from: SeanB on August 29, 2013, 04:08:24 amSo some poor guy had to sit there and wind the cores in a particular pattern to "program" the device?I'd go insane!

author: free_electron
author_rank: Super Contributor
timestamp: August 29, 2013, 03:53:34 pm
content: Quote from: rexxar on August 29, 2013, 04:15:35 amoops, you change this instruction here in the middle of the program ...

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 29, 2013, 03:59:43 pm
content: Ferrite core memory is magnetic, non-volatile *and* electrically programmable. Think FRAM from the stone age, where each bit is a discrete toroid core.

author: dfmischler
author_rank: Frequent Contributor
timestamp: August 29, 2013, 04:03:18 pm
content: Quote from: rexxar on August 29, 2013, 04:15:35 amThere 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.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 29, 2013, 04:04:11 pm
content: 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.

author: nctnico
author_rank: Super Contributor
timestamp: August 29, 2013, 05:44:14 pm
content: 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.

author: TerraHertz
author_rank: Super Contributor
timestamp: August 30, 2013, 12:23:00 pm
content: Throwing out a slab of core memory in my mid twenties still counts as one of the dumbest things I've ever done.

author: c4757p
author_rank: Super Contributor
timestamp: August 30, 2013, 12:35:51 pm
content: Out of pure curiosity, justhownonvolatile is it? Can it be expected to hold data for a few hours, or a month, or a decade?

author: dfmischler
author_rank: Frequent Contributor
timestamp: August 30, 2013, 12:47:06 pm
content: 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 thisWikipedia article on core memoryis pretty good.

author: zimzom
author_rank: Regular Contributor
timestamp: March 21, 2014, 01:52:25 pm
content: 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=item3a8d1736dcwould be an interesting project for my calculator at some point.

author: TheBorg
author_rank: Frequent Contributor
timestamp: March 21, 2014, 02:31:32 pm
content: And so the Borg came to earth.

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: March 21, 2014, 02:32:55 pm
content: 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 978-1-4419-0876-6The Apollo 64K solid core memory.How to test it.. it was hell

author: cimmo
author_rank: Frequent Contributor
timestamp: March 21, 2014, 05:02:38 pm
content: QuoteFor 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".

author: SeanB
author_rank: Super Contributor
timestamp: March 21, 2014, 05:23:21 pm
content: 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.

author: GreyWoolfe
author_rank: Unknown
timestamp: March 21, 2014, 08:44:21 pm
content: theBorg, are they relatives?

author: TheBorg
author_rank: Frequent Contributor
timestamp: March 22, 2014, 01:12:47 am
content: Quote from: GreyWoolfe on March 21, 2014, 08:44:21 pmIt'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.

author: G7PSK
author_rank: Super Contributor
timestamp: March 22, 2014, 08:48:28 am
content: Wonder if the memory is still readable, and if so what the target was.

author: SeanB
author_rank: Super Contributor
timestamp: March 22, 2014, 12:05:59 pm
content: If it has not been near a really strong magnet you can read it out....... The original non volatile memory.

author: amyk
author_rank: Super Contributor
timestamp: March 22, 2014, 01:36:20 pm
content: 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.