- vcf-midatlantic - lists.vcfed.org

Re: [vcf-midatlantic] restoring PDP-8/L
by Bill Degnan 02 Sep '24

02 Sep '24

If possible, bring to a workshop? BIll On Mon, Sep 2, 2024 at 1:45 PM Mike Rieker via vcf-midatlantic < vcf-midatlantic(a)lists.vcfed.org> wrote: > Hi All, > > I'm restoring a PDP-8/L. I got it mostly working, had to replace a couple > chips. > > Anyway so of course, the memory isn't reliable. I can deposit to some > locations and they read back ok, but other locations do not. And which > locations are good seems change from day to day though I'm not sure about > that yet. > > It is able to run a small loop (IAC / JMP .-1) seemingly for hours on end > after hunting for some good memory locations, so the memory isn't a > complete basket case. After all it is doing read/write cycles just to > fetch instructions. > > I have checked the supply voltages and there is a timing diagram in the > PDP-8/L maint volume 1 book that seems ok. This one seems a little slow > (like 600nS instead of 500nS), but the stuff seems to be in place, > relative to each other. The manual shows some current waveforms to check > but I don't have a current probe (one is on order). Anyone have > experience getting this stuff to work? > > Thanks, > Mike Rieker > > >

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restoring PDP-8/L
by wmrieker＠nii.net 02 Sep '24

02 Sep '24

Hi All, I'm restoring a PDP-8/L. I got it mostly working, had to replace a couple chips. Anyway so of course, the memory isn't reliable. I can deposit to some locations and they read back ok, but other locations do not. And which locations are good seems change from day to day though I'm not sure about that yet. It is able to run a small loop (IAC / JMP .-1) seemingly for hours on end after hunting for some good memory locations, so the memory isn't a complete basket case. After all it is doing read/write cycles just to fetch instructions. I have checked the supply voltages and there is a timing diagram in the PDP-8/L maint volume 1 book that seems ok. This one seems a little slow (like 600nS instead of 500nS), but the stuff seems to be in place, relative to each other. The manual shows some current waveforms to check but I don't have a current probe (one is on order). Anyone have experience getting this stuff to work? Thanks, Mike Rieker

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Receive only Teletype 33 in Marlboro NJ for $75
by Joseph Giliberti 01 Sep '24

01 Sep '24

Not exactly common to see https://www.facebook.com/share/EG9y1gDnxQDQPAKY/?mibextid=kL3p88

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Re: [vcf-midatlantic] slightly OT: Collector vs. Hoarder
by Michael Thompson 29 Aug '24

29 Aug '24

We have an executor and an alternate executor. I made a list of the major parts of my hoard collection and where the items should go. My wife, executor, and an alternate executor know my wishes. Hopefully everything won't go for gold scrap. -- Michael Thompson

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Corvus Omninet , curious 'fact'
by Herbert Johnson 28 Aug '24

28 Aug '24

> I have no idea what qualifies as the first commercially successful network. Well, telegraph lines? that's electrical transmission along wires among many-to-many nodes. The trouble with chasing "firsts" is defining the "first what?". Because, there's always a prior case, that's almost but not quite like the "first-of". It's a judgement call. I gave up the practice of calling out firsts. Early personal-computer networking has many origins. Generally, it's about sharing a precious at-the-time resource (say, a database, a hard drive, a cable or transciever to a remote location, and so on). Current loop allowed sharing of Teletypes and use over distance. Where to start? But most of your post, was about Corvus technology, and then about ThickNet Ethernet falling down and hurting people. I can't speak to Corvus stuff, Web search will work that for you, library research if you need period pre-Internet magazines. Even with ThickNet, thick coax had/has prior use in high frequency radio communications. The point about properly mounting heavy cables and taps, is that later networking used *lighter* cabling and taps, so installation safety wasn't an issue. Thus it *seems* to be an issue in uninformed retrospect - who uses big cables today? At the time, mounting heavy cables and associated equipment was part of normal practices, unremarkable. In 1980 or so I ran a network of a hundred plus terminals to a DecSystem-20. Directly at first, later via a terminal server. The terminals were wired on wired-telephone twisted pairs, 50-pair cables of size, between punch-down terminal blocks. We had also ThickNet orange coax cable among several PDP-11 computers between various buildings and the DEC-20 system. Buildings of the era has all kinds of cabling runs, for AC power and phone-lines, pipes for plumbing, etc. Cables were installed following best-practices, other than the fact we ran RS-232 / EIA voltage levels for over 100 feet on twisted pair telephone cables. That's when I learned that bandwidth was related to signal/noise. Baud rates at 9600 baud worked, except for the very longest runs, failing due to distributed capacitance. Local lightning strikes, tended to take out our DEC terminal interface boards when they were directly connected. The later intervening terminal server resolved that. Regards, Herb -- Herbert R. Johnson, New Jersey USA https://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing email: hjohnson AT retrotechnology DOT com or try later herbjohnson AT comcast DOT net

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Corvus Omninet , curious 'fact'
by Neil Cherry 28 Aug '24

28 Aug '24

Came across this while poking around ebay: Corvus Concept Systems Computer Didn't know anything about to off to the wiki and: https://en.wikipedia.org/wiki/Corvus_Systems In 1980 Corvus came out with the first commercially successful local area network (LAN), called Omninet.[17] Most Ethernet deployments of the time ran at 3 Mbit/s and cost one or two thousand dollars per computer. Ethernet also used a thick and heavy cable that felt like a lead pipe when bent,[citation needed] which was run in proximity to each computer, often in the ceiling plenum. The weight of the cable was such that injury to workers from ceiling failure and falling cables was a real danger. A transceiver unit was spliced or tapped into the cable for each computer, with an additional AUI cable running from the transceiver to the computer itself. I had actually heard about the Corvus network stuff in the 80 but as a noob wasn't going to dig into it with the cost. I do like the injury claim. I don't recall ever hearing about that but I do recall the bends like a lead pipe part. I have no idea what qualifies as the first commercially successful network. -- Linux Home Automation Neil Cherry kd2zrq(a)linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies KD2ZRQ

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Next Volunteer Day October 4, 2024 at InfoAge
by Jeffrey Brace 28 Aug '24

28 Aug '24

Hello everyone, We need volunteers from 1PM to 5PM in the warehouse to help Thomas and crew. Please let me know if you can make it! Take care! Jeff Brace VCF National Board Member Chairman & Vice President Vintage Computer Festival East Showrunner VCF Mid-Atlantic Event Manager Vintage Computer Federation is a 501c3 charity https://vcfed.org/ <http://www.vcfed.org/> jeffrey(a)vcfed.org

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Re: [vcf-midatlantic] slightly OT: Collector vs. Hoarder
by Bob Shuster 28 Aug '24

28 Aug '24

My bad, Dave! It was Mike Rosen (Sentrytv) responding to your message who pointed this out, and I mixed up who said what! - Bob > From: Dave McGuire <mcguire(a)neurotica.com> > Subject: Re: [vcf-midatlantic] slightly OT: Collector vs. Hoarder > On 8/27/24 10:32, Bob Shuster via vcf-midatlantic wrote: >> This is precisely why I started to sell off my collection, and as >> Dave McGuire pointed out it?s the people who come after we?re gone >> that will have to deal with it! As I stated on the front page of my >> sales page: "There comes a time when one's collection overwhelms the >> ability to store or maintain it ... I imagine the pain of my family >> in having to do this after I'm gone!" > > I certainly wasn't the one who pointed that out. I was the one > advocating for finding a compatible spouse to begin with. > > If fat, funny-looking, high-maintenance "me" can do it, any guy can. > > -Dave

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Re: [vcf-midatlantic] slightly OT: Collector vs. Hoarder
by Dave McGuire 27 Aug '24

27 Aug '24

On 8/27/24 10:32, Bob Shuster via vcf-midatlantic wrote: > This is precisely why I started to sell off my collection, and as > Dave McGuire pointed out it’s the people who come after we’re gone > that will have to deal with it! As I stated on the front page of my > sales page: "There comes a time when one's collection overwhelms the > ability to store or maintain it ... I imagine the pain of my family > in having to do this after I'm gone!" I certainly wasn't the one who pointed that out. I was the one advocating for finding a compatible spouse to begin with. If fat, funny-looking, high-maintenance "me" can do it, any guy can. -Dave -- Dave McGuire, AK4HZ New Kensington, PA

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slightly OT: Collector vs. Hoarder
by Bart Hirst 27 Aug '24

27 Aug '24

This part of the last post caught my eye: *>Clearly, this was a collector, not just a hoarder.* This is worrying! Is there some test that can be taken to determine ‘collectorness’ vs ‘hoarderness’?? p.s. for myself I may need professional help and/or medication to understand why I keep "collecting" floppy drives :( -- Bart Hirst "This signature will now be eaten up and spit out by Velociraptors."

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