May 2026 - cctalk - classiccmp.org

by Jacob Ritorto

Hi all, I have this UD33 controller that works perfectly with another newer SMD disk (CDC 9720), but when I try it against my beautiful old Fuji 160 (M2284K), It gets through format okay but has intermittent errors on verify / reliability test. If I reduce the number of cylinders / heads, I can get it to pass, but not every time. I have a good thick ground and same cables that worked perfectly with the other disk, hoping that's enough of a sanity check on those. I have the UD33 configured thusly: type: 1 units: 1 sectors per track: 32 physical heads: 10 physical cylinders: 823 spare sectors per track: 1 spare cylinders: 2 configuration bits: 6 LOWER RPS: 3 UPPER RPS: 7 split into one drive with 1 head and the other with 9 heads to speed things along :) GAP 0: 259 GAP 1: 4112 GAP 2: 780 Spiral offset: 1 The drive's switches are set for soft sectoring and tag 4/5 enabled. I had tried hard sector setting on the drive with 32 sectors / 640 bytes. It's SO CLOSE to working I can taste it :). I have another Fuji 160 that is doing basically the identical same misbehaviour. And as usual, I am just not quite understanding the final clincher piece. Anyone know of better settings I should be using and most importantly Why? thx jake P.S. I was hoping that somewhere someone would have written down what controller settings work with the UD33 or QD32, etc, but no luck finding them. You'd think despite the 3 or so years gap in the disk vs controller that this would've been officially supported at some moment in the universe, no? I just wish I knew how to calculate it properly myself!

24 minutes

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Rainbow 100 and Univation Hard Disk

by Robert Armstrong

I have a Rainbow 100A with the Univation hard disk. Works (wow!), but the Univation HDD controller was not DEC compatible and you have to boot from a floppy to get the disk drivers loaded. And of course, the 100A ROMs didn't support any kind of hard disk, DEC or otherwise. Did anybody ever make an updated ROM image for the 100A that supported booting from the Univation directly? I think the 100A used 2716 EPROMs, and it'd be easy enough to burn some new ones. And is there any surviving documentation for the Univation? Bitsavers seems to have nothing. Thanks!

1 day, 14 hours

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xterminal

by cp

hi I have a tektronix xp217, with Tekxpress v7. Are you interested? let me know

1 day, 18 hours

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ID'ing a core module: Any Univac 1108/6 processors still existent?

by Brent Hilpert

I was asked to examine a large core module, it has a UNIVAC label and part no, manufactured in 1971 but probably a little older in design. No providence known. I suspect it is from an 1108 or perhaps an 1106, based on the reasoning presented in the web link below. I’m a little curious for a firmer confirmation though. 1108/6 documentation on bitsavers has been very useful, but what’s there doesn’t go deep enough into the hardware to provide a hard confirmation. Is there even an 1108 or 6 still in existence? The module, and what I’ve figured out: http://madrona.ca/e/coreUnivac/index.html <http://madrona.ca/e/coreUnivac/index.html>

2 days, 14 hours

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Did anyone here work on Burroughs A Series/Large Systems MCP back in the day?

by Alan Perry

Hi all, I worked on system software at Burroughs in the late 80s and a couple weeks ago gave a talk about Burroughs history in computers and the Large Systems/A Series/B5000 and B6500 architecture at VCF PNW. There was enough interest that I am putting together another talk or two. One of the topics is Large Systems MCP and I am looking for other people who worked with it to give their own perspective and confirm things I am trying to remember from 40 years ago. BTW, if you haven’t seen it, the trove of Burroughs documents in the bitsavers Burroughs collection on the Internet Archives is amazing. Unfortunately I still can’t find any documentation for most of the stuff that I worked on. I should have kept copies of those manuals when I left. alan

3 days, 22 hours

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Odd grounding issue with 19" Sun LCD

by Steve Lewis

Apologies for spamming this with a very specific hardware issue - but I felt this was so unusual, that it was worth sharing the kind-of solution. I have an old 386 running Solaris, works fine. I swapped the VGA monitor it, didn't think much of it. VGA is VGA right? (except old Compaq 286SLT have one of the VGA pins removed, but that's another story) The replacement monitor (19" Sun from c. 2001) worked fine. Booted system, logged in. But - I Couldn't ping. No networking. Checked the router. Check switch, all green lights. TV streaming still working. No one else in the house screaming about no internet. Hmm... But I couldn't ping out of that 386, nor FTP back into it, like I had been. I consulted GPT on its thoughts. I swapped NIC cables, VGA cables, long cables, short cables, moved the power brick of the 19" Dell. All same result. Finally, GPT made this comment, that I'll summarize like this: "If your NIC isn't working, try turning off your monitor." I figured another dumb AI hallucination. But holy smokes, that actually worked! It was a pure 1:1 correlation - whenever I turned that 19" Sun monitor off, I could ping out of the box and ftp into it. As soon as I powered it back on, all the network traffic stopped. It no fancy LCD - no speakers, no USB, just a typical VGA/DVI connector heavy LCD with a Sun Micro logo stamped on it. So the specific test was this: prep a ping command, like "ping 192.168.1.1" turn the monitor off, press ENTER. Wait 2 seconds, power the monitor back on. And yea, consistently, that worked. But when trying to ping while the monitor was left on, I couldn't ping from the NIC in this 386. GPT's only suggestion was some sort of grounding interference by this particular 19" Sun monitor, and some blah-blah about how old 386's are more impacted about EMI. Just curious what other think on this - any particular known issue about 2001-ish period Sun 19 flat-panel LCDs? This one uses a 19V DC power brick (and I tried using different outlets). I never would have considered trying to solve the NIC issue by powering off the monitor. So I have to put back on the widescreen for now - which everything works fine with that. So not a real solution, but I gotta admit that GPT did help uncover what was causing the issue. Cheers, Steve

5 days, 7 hours

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MIMIC microcomputer information

by wrcooke＠wrcooke.net

I ran across an ad in the March 1979 Popular Electronics. It is for a small computer board called "MIMIC" from Real Time Intelligence Corporation of Rochester, NY. From the picture and small amount of information in the ad I am guessing it is a minimal 6802 processor system. I am interested in knowing more about it, but so far my searches have turned up nothing on the computer or the company. Does anyone know anything about it? Links to info? The magazine can be found here https://www.worldradiohistory.com/Popular-Electronics-Guide.htm and the ad is on page 6 (8 of the PDF.) Thanks, Will You just can't beat the person who never gives up. Babe Ruth

6 days, 22 hours

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VCF West 2026 Call for speakers! Aug. 1 & 2, Mountain View, CA

by Jeffrey Brace

VCF WEST 2026 CALL FOR SPEAKERS! We have a new exhibit registration system: https://em.vcfed.org/events/vcf-west-2026/speaker-signup DATES: Aug 1st and 2nd at the Computer History Museum in Mountain View, CA. INFO:https://vcfed.org/vcf-west

1 week

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FTGH Old Issues of IEEE SigSoft Software Engineering Notes

by Rob Jarratt

I have a ton of these covering the period from around 2000-2005. I may have more. Are they of interest to anyone? They are in the UK. Would prefer local collection, I could post them in the UK if needed. They are going to be heavy, but if anyone *really* wants them then I might be prepared to ship them internationally. Obviously shipping will be for the recipient to pay, but the journals are free. Thanks Rob

1 week, 1 day

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Charles Simonyi on his flying experience with Howard

by Paul McJones

This is a very poor machine transcription of a Zoom conversation I had with Charles about 5 years ago. I went flying with him once a month. 00:15:04 Charles Simonyi Yeah the yeah this uh this kind of third hand plane and then flying with him and. 00:15:15 Charles Simonyi We were flying at night and we had a complete electrical failure. 00:15:21 Paul McJones Oh, really. 00:15:22 Charles Simonyi Yeah, in the San Jose airspace. 00:15:27 Charles Simonyi And dum dum. 00:15:31 Charles Simonyi There are actual procedures to come to. 00:15:37 Charles Simonyi Do. 00:15:40 Charles Simonyi You approach an airport with radio failure. 00:15:43 Charles Simonyi He was supposed to fly by the You know lookout. 00:15:47 Charles Simonyi Of course it was. 00:15:48 Charles Simonyi It was completely beautiful weather, you know, zillion visibility and and you were supposed to fly by the. 00:15:57 Charles Simonyi Uhm, he knew all the procedure. 00:16:00 Charles Simonyi We fly by the the control tower and then they guide you down with this thing called the light gun. 00:16:07 Charles Simonyi Which is a colored oh colored thing that actually you can see even in the movies. 00:16:13 Charles Simonyi You can see it kind of hanging from the from the ceiling. 00:16:16 Charles Simonyi There's this big flashlights, you know that you you can direct at planes and and and the weird thing is that that. 00:16:27 Charles Simonyi I was learning to fly at the time, so I'm doing a little bit of knowledge and and the when you clear to land, it's a it's steady green. 00:16:38 Charles Simonyi And flashing green means standby. 00:16:40 Charles Simonyi OK, wait for the client and and we saw this. 00:16:45 Charles Simonyi I saw flashing green. 00:16:47 Charles Simonyi And I said, wait, wait, it's we are not clear. 00:16:50 Charles Simonyi Yeah. 00:16:51 Charles Simonyi And and how it said no, no, no. 00:16:53 Charles Simonyi That's a steady light, except that they are not hitting us, right? 00:16:58 Charles Simonyi Oh Oh yeah, yeah. 00:16:58 Charles Simonyi Oh yeah. 00:16:58 Charles Simonyi 00:16:59 Charles Simonyi So I've just realized and and he said just look very close to the source and you can see a little bit of of the beam and see that it's steady. 00:17:10 Paul McJones OK. 00:17:10 Paul McJones OK. 00:17:11 Charles Simonyi And and I realized. 00:17:13 Charles Simonyi I mean, I still remember how. 00:17:15 Charles Simonyi You know, and then you would have to see this in a simulator or something. 00:17:19 Charles Simonyi Otherwise you know if I had been alone, I would have never landed because they they can't take you straight. 00:17:26 Paul McJones Yeah, yeah. 00:17:26 Charles Simonyi And I was thinking about this silly, silly distinction. 00:17:31 Charles Simonyi Because, operationally, it's it's very difficult to tell the difference, But anyway.

1 week, 2 days

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