CDC 3000 Core Storage Unit | 1968 - Page 1
Forum section: electronics / general

author: pamperchu
author_rank: Contributor
timestamp: July 17, 2018, 02:45:04 am
content: I have a 1968, core memory stack from a CDC 3000, I think?,... that I would like to build an interface for, to connect it to a modern computer. I want to be able to read and write to the device, but I cant seem to find any data sheet/documents for it. I have read through many of CDC's manuals that have lots of information about the core storage unit, but so far I have not found any direct reference to what I have, or connector pin-outs.any help would be great, mostly want to know the pinouts of the few hundred connectionsPhotos of the device;https://imgur.com/a/uJjIg

author: Halcyon
author_rank: Unknown
timestamp: July 17, 2018, 09:41:00 am
content: Brilliant! Thanks for sharing. Sorry, I know nothing of these devices, so I can't help you on your quest. Hopefully someone here does.

author: pamperchu
author_rank: Contributor
timestamp: July 18, 2018, 06:05:19 am
content: found a picture of the device installed in the system, its a 3302, 16K word [262,144 bits]

author: edpalmer42
author_rank: Super Contributor
timestamp: July 18, 2018, 06:21:41 am
content: I have a small core plane (4K bits?). I've thought of trying to interface it by seeing if I could find data sheets for the interface chips. Can you remove a section so that you can see the interface chips?Ed

author: pamperchu
author_rank: Contributor
timestamp: July 18, 2018, 09:47:37 am
content: Quote from: edpalmer42 on July 18, 2018, 06:21:41 amhttp://www.bitsavers.org/pdf/cdc/3x00/24bit/3300/60158800A_3300_Training_Manual_Volume_2_Aug68.pdfhttp://www.bitsavers.org/pdf/cdc/3x00/24bit/3300/60157000H_3300_Computer_System_RefMan_Apr68.pdfThese manuals has some information on that, there are no chips inside.

author: Tom45
author_rank: Frequent Contributor
timestamp: July 18, 2018, 04:12:12 pm
content: Quote from: edpalmer42 on July 18, 2018, 06:21:41 amThe CDC 3300 predates ICs. Discrete components only. The CDC 3500 was the first to use integrated circuits. I worked with both back in the day, along with the CDC 6600 which was also all discrete components.I have the hardware manuals some place but better to check the manuals at Bitsavers.

author: @rt
author_rank: Super Contributor
timestamp: July 18, 2018, 08:47:32 pm
content: Those connectors at the bottom look like they are just connected straight to the address matrix.You can use H-Bridge drivers and current limiting resistors to drive those.

author: GregDunn
author_rank: Frequent Contributor
timestamp: July 18, 2018, 09:24:37 pm
content: Also, keep in mind that due to the way the current pulse detects the value in the core, the act of reading a core resets it to a 0, whether it was a 1 or a 0 before. So any hardware/software combination to use core memory for storage must be able to restore the value when it reads a 1.Some CDC memory was wired in a manner where it was capable of reading/writing multiple words in a cycle, which put some additional requirements on the memory controller.No idea whether there are any interface drivers in that module, or whether you'll have to build those too.

author: duak
author_rank: Super Contributor
timestamp: July 22, 2018, 02:14:00 am
content: I can't help you with the pinout but I do recall reading an article from the July '76 issue of Byte magazine on how to use core. Here's a link to some info on interfacing core and also has scans of the Byte article:http://www.aholme.co.uk/Core/Flipper.htmAt the time I had a plated wire memory array and was looking into interfacing it to an 8080. Back then I was younger and almost nothing was impossible.Cheers,

author: edpalmer42
author_rank: Super Contributor
timestamp: July 22, 2018, 02:54:53 am
content: Here's the original magazine. Archive.org has all issues of Byte and many other old electronics and computer magazines online. All fully OCR'd of course.https://archive.org/download/byte-magazine-1976-07/1976_07_BYTE_00-11_Core_Memories.pdf

author: @rt
author_rank: Super Contributor
timestamp: July 22, 2018, 09:19:02 am
content: A fellow by the name of Wayne Holder made a google page about using a Texas Instruments Quad Half H-Bridge driver to drive the "address matrix”.I think that better than six or so transistors, and it also is glitch free power up.https://sites.google.com/site/wayneholder/one-bit-ferrite-core-memoryWayne told me in email, around 2016, that he had trouble expanding it further into an address matrix.I didn’t though, and I used the same cores from eBay (from Bulgaria), and only a slightly different sense amplifier, which was made to accommodate a microcontroller input.Right now my 64 bit core memory is in a 12 month memory retention test, after having read correct data back after a six month retention test.I expect this to succeed too, but there’s really nothing left to do with it other than this.I covered mine quite extensively on YouTube.In the past, there was a Texas Instruments dedicated sense amplifier IC, but good luck finding that now!What is all that jazz on the top part of yours. From one angle in the B&W photo they look like selenium rectifiers, and in your original post pic, maybe valve (choob) heatsinks,but I really can’t tell.Either way, you’re in for a huge project to get it working. The entire array will have a sense amp for every 1024 bits or so, because you can’t snake one sense wire too far.Similarly if you have no drivers with that beast, you’ll be in for producing a lot of duplicated driver circuits.

author: dexters_lab
author_rank: Unknown
timestamp: July 25, 2018, 08:55:08 am
content: Quote from: pamperchu on July 17, 2018, 02:45:04 amsounds like an interesting but crazy project (i like crazy ideas!), hope you can make some sense of the connections and make some progress

author: precaud
author_rank: Frequent Contributor
timestamp: July 28, 2018, 05:55:03 pm
content: Ha! My dad hired on at CDC in 1968, as Int'l QC Manager. That was pretty much in their heyday.