December 2015 - vcf-midatlantic

Re: [vcf-midatlantic] Core Memory Purchase
by John Sully 03 Dec '15

03 Dec '15

Thanks for your help everyone. This is one of the stacks I was looking at: http://www.ebay.com/itm/USSR-Russian-Magnetic-Ferrite-Core-Memory-CUBE-from… I'm planning to build my own drive electronics so the less electronics on it the better in my opinion. Another goal is to have it big enough to "be interesting". Eventually I want to integrate it into a TTL CPU I'm planning to build. For now though I'd just be happy controlling it with a microcontroller.

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Re: [vcf-midatlantic] Core Memory Purchase
by Jonathan Gevaryahu 03 Dec '15

03 Dec '15

Here is a response about reviving old core memory boards, from Kevin 'kevtris' Horton, who has revived 3 of them in the past. -------- Forwarded Message -------- Subject: Re: Fwd: [vcf-midatlantic] Core Memory Purchase Date: Thu, 3 Dec 2015 01:15:52 -0500 From: K Horton <kevtris(a)comcast.net> To: Jonathan Gevaryahu <jgevaryahu(a)gmail.com> On 12/2/2015 22:17 , Jonathan Gevaryahu wrote: > kevtris, you have some experience resurrecting core memory. Do you > want to respond here? > > > -------- Forwarded Message -------- > Subject: [vcf-midatlantic] Core Memory Purchase > Date: Wed, 2 Dec 2015 16:56:35 -0800 > From: John Sully via vcf-midatlantic > <vcf-midatlantic(a)lists.vintagecomputerfederation.org> > Reply-To: vcf-midatlantic > <vcf-midatlantic(a)lists.vintagecomputerfederation.org> > To: vcf-midatlantic(a)lists.vintagecomputerfederation.org > CC: John Sully <john(a)csquare.ca> > > > > I'm planning to resurrect some old core memory as a hobby project. I was > wondering if anyone with experience on getting this memory working could > provide some insights on what I should look for. > > EBay seems to have a large number of expensive ones that don't appear to be > in working order - along with some much cheaper (relatively speaking) > russian made stacks. > yes, this is a big problem. if the core memory is shown "open" on ebay, don't buy it. there's a 99% chance it's going to be broken. The cores and wiring are extremely fragile, just blowing on it can destroy it (well not THAT bad, but it's still pretty insanely fragile). I have three fully working core memory boards: two 16K*18 and one 32K*18 boards. I had to fix all three of them, since they had bad parts here and there, but it wasn't TOO hard. All of them work similar; there's a hardware state machine that runs a little sequence for reads that do this: read the word, then write the same data back (since reading core is destructive). I successfully dumped the data that was sitting on all three of my core boards; the 16K boards were repaired and put in stock as spares apparently, and just had a 0101010101 pattern, while the 32K board contained actual NASA code! I dumped it but lost 256 words of data, unfortunately. That board had some problems with reading/writing because there was a bad transistor in the X driver, and there was a bad TTL chip. All of them had bad tantalum caps that I had to replace; the 32K board kept randomly drawing enough power to trip the current limit on my power supply every few hours, so I finally found it and replaced the cap which fixed that. The 32K board is extremely "advanced', compared to the 16K boards which are more traditional. The 32K board only has a single X and single Y driver instead of a bunch of each. All of them have a forest of transistor arrays, diodes, and pulse transformers to do selection because it saves a ton of hardware this way. I have a dir on my website with all the stuff I did on it and if there's interest I can make a video showing off my rig and how I tested the memory. I had schematics I drew for the boards but I think I might've lost them. there's some PDFs in there that give esoteric details on the care and feeding of core memory. http://blog.kevtris.org/blogfiles/corememory/

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Core Memory Purchase
by John Sully 02 Dec '15

02 Dec '15

I'm planning to resurrect some old core memory as a hobby project. I was wondering if anyone with experience on getting this memory working could provide some insights on what I should look for. EBay seems to have a large number of expensive ones that don't appear to be in working order - along with some much cheaper (relatively speaking) russian made stacks.

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Festivus - Who's going?
by Herb Johnson 02 Dec '15

02 Dec '15

Herb Johnson - sat late morning -- Herbert R. Johnson, New Jersey USA http://www.retrotechnology.com OR .net

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Re: [vcf-midatlantic] Festivus - Who's going?
by James Garland 02 Dec '15

02 Dec '15

> Put your name on the list and approximate arrival time. > > 1. Jeff Brace 10:30AM Saturday (Staying all weekend) > 2. Evan Koblentz > 3. Dean Notarnicola 11:00 Sat. only > 4. Bill Degnan TBD > 5. Bill Dudley and Xiulan Zhao (not sure of arrival time -- mid-afternoon > Sat?) > 6. Kelly L and Ann 11:00 Sat. only > 7. Steven Toth (mid morn Saturday, all weekend probably). > 8. Tom Hornberger - around 11 on Sun > 9. Dave Riley (noonish Saturday until noonish Sunday) > 10. Connor Krukosky > 11. Ian Primus > 12. Bob Murphy 11:30 Sat - (probably just a cameo to drop off gear) > 13. Chris Fala (both days, Sat. AM - time uncertain) > 14. Jonathan + Amy, 1100 SAT - SUN > 15. Neil Cherry around 3PM (Saturday only) > 16. Bill Dromgoole Saturday about 12:00 to 1:00 and Sunday > 17. James & Eric Garland ~11AM Sunday > 18. > 19. > 20.

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Re: [vcf-midatlantic] Vaxman
by VAXman＠tmesis.org 01 Dec '15

01 Dec '15

David Hoelzer via vcf-midatlantic writes: >Sorry to bother you listmates=E2=80=A6 > >Vaxman, I=E2=80=99d really appreciate it if you would reach out and = >explain to me why I suddenly have a PayPal payment dispute from you but >= no other emails to explain it. I tried to reach you directly but your >= listed email address bounces. Sorry, my wife and I were reviewing the PayPal for the yearly upcoming tax season when she asked me what cybersecurity was. I, for the life of me, didn't recall. Now that you've contacted me, I recall this. Sorry but I couldn't find any other email referneces to cyber-security. I'll remove the dispute immediately.

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Re: [vcf-midatlantic] New web site is live
by Evan Koblentz 01 Dec '15

01 Dec '15

> There's gonna be a VCF _West_ this year? Shh, don't tell anyone. :) It will not be this year (which ends in 30 days). I can't say more until some business things are settled.

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Vaxman
by David Hoelzer 01 Dec '15

01 Dec '15

Actually, the error is as follows: <vaxman(a)tmesis.com <mailto:vaxman@tmesis.com>>: host mail.tmesis.com <http://mail.tmesis.com/>[24.187.213.26] said: 554 5.7.1 Message rejected due to header contents. (in reply to end of DATA command) Reporting-MTA: dns; savfw21a.sans.org <http://savfw21a.sans.org/> X-Spam-Firewall-Queue-ID: D979713C0F8 X-Spam-Firewall-Sender: rfc822; dhoelzer(a)enclaveforensics.com <mailto:dhoelzer@enclaveforensics.com> Arrival-Date: Tue, 1 Dec 2015 20:19:42 +0000 (GMT) Final-Recipient: rfc822; vaxman(a)tmesis.com <mailto:vaxman@tmesis.com> Original-Recipient: rfc822;vaxman(a)tmesis.com <mailto:vaxman@tmesis.com> Action: failed Status: 5.7.1 Remote-MTA: dns; mail.tmesis.com <http://mail.tmesis.com/> Diagnostic-Code: smtp; 554 5.7.1 Message rejected due to header contents.

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Vaxman
by David Hoelzer 01 Dec '15

01 Dec '15

Sorry to bother you listmates… Vaxman, I’d really appreciate it if you would reach out and explain to me why I suddenly have a PayPal payment dispute from you but no other emails to explain it. I tried to reach you directly but your listed email address bounces. Thanks

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Festivus - Who's going?
by Chris Fala 01 Dec '15

01 Dec '15

Put your name on the list and approximate arrival time. 1. Jeff Brace 10:30AM Saturday (Staying all weekend) 2. Evan Koblentz 3. Dean Notarnicola 11:00 Sat. only 4. Drew Notarnicola 11:00 Sat. only 5. Bill Dudley and Xiulan Zhao (not sure of arrival time -- mid-afternoon Sat?) 6. Kelly L and Ann 11:00 Sat. only 7. Steven Toth (mid morn Saturday, all weekend probably). 8. Tom Hornberger - around 11 on Sun 9. Dave Riley (noonish Saturday) 10. Connor Krukosky 11. Ian Primus 12. Bob Murphy 11:30 Sat - (probably just a cameo to drop off gear) 13. Chris Fala (both days, Sat. AM - time uncertain) 14. 15. 16. 17. 18. 19. 20.

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