Post ASzWv4hLZdNuygxtp2 by danak6jq@mastodon.social
(DIR) More posts by danak6jq@mastodon.social
(DIR) Post #ASxpzieWTYJErjeVu4 by danak6jq@mastodon.social
2023-02-20T19:55:53Z
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Makers of supermini- and mainframe computers were just bonkers about ECL in the mid-1980s, and CMOS wholesale replaced ECL by 1990.
(DIR) Post #ASxpzj8efWPcNBkZs0 by carlsonj@mastodon.social
2023-02-21T04:45:52Z
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@danak6jq I was studying EE at CMU from 1983-1987. The professors were deeply into NMOS and CMOS at the time; TTL and ECL were dead. I remember being skeptical at the time, and surprised that they were right in the end.
(DIR) Post #ASxpzk0tPrnV5P7tPU by rwwh@mastodon.social
2023-02-21T06:16:11Z
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@carlsonj @danak6jq This must have been TTL? 1974 vintage….
(DIR) Post #ASxpzkmkXw4vTpW70K by danak6jq@mastodon.social
2023-02-21T06:33:21Z
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@rwwh @carlsonj looks a bit like a RAM board in the way it is organized
(DIR) Post #ASxpzlJiZMRx84wROK by rwwh@mastodon.social
2023-02-21T07:24:31Z
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@danak6jq @carlsonj yup. Next to the paper “repaired by” label in the SW corner, the board is marked “Memory”. This must be one of the first chip memories, because as far as I remember it was from the same machine that also had the (slightly older) core memory card. Check out the 2 W resistors…
(DIR) Post #ASxpzlnqlKYKdX2VMG by carlsonj@mastodon.social
2023-02-21T13:54:57Z
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@rwwh @danak6jq Real memory doesn't forget just because you turn off the power!I remember pulling the breaker at the rear of a W2500 just for fun, and then turning it back on. It kept going as if nothing at all had happened. The power-fail interrupt copied the first 256 words of SRAM to the last reserved 256 words of core, and the restart copied it back.
(DIR) Post #ASxq9PiXjNd32F9i6q by brouhaha@mastodon.social
2023-02-21T04:36:59Z
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@danak6jq Bob Supnik, who was in charge of microprocessor design at DEC, tells about how the VAX 9000 (giant ECL machine) development team literally could not comprehend that the CMOS NVAX chip under simultaneous development was going to have comparable performance. Guess which of the two was successful.
(DIR) Post #ASxq9QegFE8JwYM8jA by danak6jq@mastodon.social
2023-02-21T04:38:42Z
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@brouhaha Oh, this is the example I use of the rapid switch-up in the late 1980s. VAX 9000 is a story unto itself, starting with the remnants of the glorious calamity that was Trilogy Systems. NVAX really changed things.
(DIR) Post #ASxq9R7OWT6NNbn4U4 by rwwh@mastodon.social
2023-02-21T05:32:36Z
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@danak6jq @brouhaha I worked for an organisation with a VAX 9000 in 1993. While that machine was in the machine room, I had a 200 MHz DEC Alpha under my desk that blew away everything else in the building. When the 9000 was taken apart, I took one module of the four that made up a CPU home; I brought that to a museum last year (together with some DG Nova stuff I had lying around)
(DIR) Post #ASxq9RcaeU3UwMNz6m by danak6jq@mastodon.social
2023-02-21T05:38:34Z
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@rwwh @brouhaha that VAX 9000 module has to be quite neat! Alpha really should have been victorious, but DEC had arguably lost their corporate mojo. DEC Microelectronics was smokin' in the '90s
(DIR) Post #ASxq9RicI4sNF3CnVA by brouhaha@mastodon.social
2023-02-21T04:53:43Z
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@danak6jq Even more problematic was that corporate management, all the way up to Ken Olsen, also did not believe it. It's estimated that the VAX 9000 effort cost several billion dollars, of which only a tiny fraction was recouped by system sales.
(DIR) Post #ASxq9SDSRPXumhdQZc by rwwh@mastodon.social
2023-02-21T05:50:34Z
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@danak6jq @brouhaha This was the VAX9000 module. I guess it measures about 12 cm on a side, weight approximately 2 kg? I remember there were four of these on each of the two CPU boards.
(DIR) Post #ASxqPx9bBPJ9MyhI5Q by azonenberg@ioc.exchange
2023-02-21T07:22:23Z
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@danak6jq Tell that to my professor who was still pushing a 40 GHz ECL based CPU design circa 2014.Wonder if he's still working on it?
(DIR) Post #ASxqPxk6zeVzCDmS00 by danak6jq@mastodon.social
2023-02-21T07:24:37Z
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@azonenberg I have so. many. questions. (not the least of which is "what RAM do you use with a 40GHz CPU?". I bet the answer is 40GHz ECL RAM)
(DIR) Post #ASxqPyM2icr95rWk7c by azonenberg@ioc.exchange
2023-02-21T07:32:13Z
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@danak6jq Well I guess that answers that question... https://hr.rpi.edu/faculty-staff-memory/remembrance-john-jack-mcdonaldBut if you search his publications you'll probably find details? He was on my PhD committee but my thesis wasn't related to this particular project.
(DIR) Post #ASxqPz2aASsrDnQiQa by azonenberg@ioc.exchange
2023-02-21T07:37:33Z
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@danak6jq Here's an 18.4 GHz SiGe BiCMOS register file https://ieeexplore.ieee.org/document/6740804And a SiGe HBT CPU testbed https://www.researchgate.net/publication/2997897_SiGe_HBT_microprocessor_core_test_vehicle
(DIR) Post #ASzWv2jOt1q4sTuVkG by stuartmarks@mastodon.social
2023-02-21T01:33:26Z
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@danak6jq Crays were ECL, right? I remember in the early 1980s one of my EE profs talked about some news that a semiconductor manufacturer (not sure, maybe NatSemi) was going all in on CMOS. This was a big deal. What drove the switch? Power consumption and heat dissipation I guess?
(DIR) Post #ASzWv3KydJtel1UWJc by danak6jq@mastodon.social
2023-02-21T02:22:15Z
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@stuartmarks ECL was king of speed from primordial days (early 1960s) until the late 1980s. Power/heat were the huge reasons, the density of integration is higher for CMOS. You know the story of DEC VAX 9000 vs NVAX?
(DIR) Post #ASzWv42vzt3gxM3cpc by bsmaalders@mas.to
2023-02-21T03:49:10Z
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@danak6jq @stuartmarks When I worked at FMC's Central Engineering Labs in the mid 1980s, the IT group loved their Vax. Everyone used it from the admins to the finite element design folks... but there was no chargeback; computer time was free. So the head of IT had FMC buy a V9000 (8600), but it was expensive, so computer time was no longer free - it was $$$ to recover costs. Everyone started buying PCs, Sun workstations, ... Chaos ensued, rogue compute resources made "against policy"...
(DIR) Post #ASzWv4hLZdNuygxtp2 by danak6jq@mastodon.social
2023-02-21T03:54:18Z
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@bsmaalders @stuartmarks "expensive" seems like such an understatement for the VAX 9000.
(DIR) Post #ASzWv4pV5JuHNymPWy by danak6jq@mastodon.social
2023-02-21T02:31:10Z
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@stuartmarks Bonus points: the VAX 9000 bought the packaging IP from Trilogy Systems - the Gene Amdahl venture that spectacularly imploded in the early-mid 1980s. That's worth a read, too.
(DIR) Post #ASzWv5AloEv8RwjOgS by bsmaalders@mas.to
2023-02-21T03:58:35Z
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@danak6jq @stuartmarks That was an 8600; I checked Wikipedia and the timeline of the new vaxen. It was nearly 40 years ago...
(DIR) Post #ASzWv5ZELIUDfoAvoG by danmcd@hostux.social
2023-02-21T05:33:42Z
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@bsmaalders @danak6jq @stuartmarks I used an 8600 in 1989, it was the successor to the still online 11/780. Both ran VMS.
(DIR) Post #ASzWv6CZyzxhdqaM8u by danak6jq@mastodon.social
2023-02-21T05:50:36Z
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@danmcd @bsmaalders @stuartmarks In maybe 1994, I had the chance to buy an apparently complete VAX-11/780 just taken out of service, with disk(s), tape drive, etc., for $700 - because that was the gold salvage value at the time. Didn't go for it.
(DIR) Post #ASzWv6hm70upCbBGlc by bsmaalders@mas.to
2023-02-22T02:41:48Z
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@danak6jq @danmcd @stuartmarks The rate of technical change in those years was just wrenching; hardware aged really fast, and if a company didn't ship product on time - or missed a transition - it really hurt the bottom line. This happened because there was so much competition - lots of different vendors, trying lots of new ideas. DEC's attempt to protect their larger VAXen from smaller machines led to their MicroVaxs not competing with anyone else's machines.
(DIR) Post #ASzWv7VP8Uc9gWOu7k by kentborg@social.tchncs.de
2023-02-22T03:26:21Z
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@bsmaalders @danak6jq @danmcd @stuartmarks The term I knew was "window". If the product is too far ahead it misses the window because it doesn't work, or work well enough, the window wasn't open yet.Too late? And the window is closedI worked in the semiconductor equipment biz, on "direct write e-beam lithography". We missed any window that might have been.I ended up working on a computerized electron microscope. (It worked! Very cool…)
(DIR) Post #ASzWv821BEhbJfewxU by publius@mastodon.sdf.org
2023-02-24T03:07:46Z
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@kentborg @bsmaalders @danak6jq @danmcd @stuartmarks I admit, I've long thought of direct-write e-beam lithography as a key technique for the kind of highly flexible low-volume fabs which might be needed to support space colonies.
(DIR) Post #ASzXNp1quWcWmKGRBg by danak6jq@mastodon.social
2023-02-22T03:34:41Z
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@bsmaalders @danmcd @stuartmarks the 80s were pretty wild, just thinking of single-chip CPUs, the i860, i960, Am29k, WE32x00, M68k, M88k all came and went (i960, AM29k, M68k lived longer as embedded processors). MIPS, SPARC, Alpha came and lasted for a while (though MIPS becmes embedded and recently re-focused on RISC-V). PPC emerged as the decade ended. Never mind the CCI Power6/32, or the holdouts from the 70s like AM100
(DIR) Post #ASzXNprxmmIvNwe3Pc by stuartmarks@mastodon.social
2023-02-22T05:38:48Z
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@danak6jq @bsmaalders @danmcd Even before all the micros were the VAX killer “minisupercomputers” from Pyramid, Convex, Sequent, Encore, and others.
(DIR) Post #ASzXNqPzkFWh5UZESO by danmcd@hostux.social
2023-02-22T05:41:55Z
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@stuartmarks @danak6jq @bsmaalders I used a sequent symmetry in grad school. It served as the place students compiled and ran their assignments. Lots of panics the night before a project was due!
(DIR) Post #ASzXNr1DVrIgwvyxTU by danak6jq@mastodon.social
2023-02-22T05:44:12Z
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@danmcd @stuartmarks @bsmaalders Encore started-out with NS32032, another one of the 80s CPUs I forgot
(DIR) Post #ASzXNrqyPQhVXSCI9A by carlsonj@mastodon.social
2023-02-23T13:39:10Z
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@danak6jq @danmcd @stuartmarks @bsmaalders Happy to send to a good home. https://www.workingcode.com/forsale/computer-parts/1002.html
(DIR) Post #ASzXNsVNzB1jYn6Z8a by publius@mastodon.sdf.org
2023-02-24T03:13:01Z
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@carlsonj @danak6jq @danmcd @stuartmarks @bsmaalders Oh my goodness, that's amazing!
(DIR) Post #AT0b1Urpmgjequ9FMu by kentborg@social.tchncs.de
2023-02-24T15:07:25Z
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@publius @bsmaalders @danak6jq @danmcd @stuartmarks Fabs in space? That sounds extensive. FGAs might help push off the need…
(DIR) Post #AT0iTgnNjE4FdOSJsW by publius@mastodon.sdf.org
2023-02-24T16:52:04Z
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@kentborg @bsmaalders @danak6jq @danmcd @stuartmarks It's a definite tradeoff. Chips can be brought from Earth very cheaply, chips in packaging still quite cheaply… but the need for various electronic devices argues for manufacturing them locally to avoid supply-chain disruptions.High-purity silicon should be much easier to prepare than on Earth (free vacuum!), but the subsequent processing is a much bigger challenge. Are ICs really that much worse than rectifiers and power transistors?