One additional benefit was that an MG enables one to "coast" a bit through transient power glitches. That is, you'd see the lights flicker, but the machine stays up. Power failures in the bad old days could be very expensive. Old computers did not like being stopped suddenly and then restarted. On the CDC mainframes, you could be down for much of a shift. --Chuck

I recall we had a motor generator and fluid cooling for the 3033 we had. We also had 2 smaller ones as well ( forget the numbers ). They all ran 360 code.. It is astounding how far things have come from that time. Dwight ________________________________ From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Brent Hilpert via cctalk <cctalk at classiccmp.org> Sent: Tuesday, May 4, 2021 4:32 PM To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Subject: Re: Motor generator On 2021-May-04, at 4:06 PM, Donald via cctalk wrote: I dont know about the 360, but a motor/gen can provide several benefits: - isolate the load side from mains noise - provide a degree of regulation from mains fluctuation thanks to the inertia of the rotating mass - raise the frequency so subsequent power supply transformers and caps can be smaller (ala 400Hz operation in aircraft) - convert to 3-phase as Chuck mentioned, although I would have thought that by the time a 360 is running from a motor-gen it's probably already being supplied with incoming 3-phase mains

On 5/4/21 7:54 PM, Paul Koning via cctalk wrote: And the Univac 1100... bill

The IBM 7090 used a motor generator, IBM model 7618 apparently http://ed-thelen.org/comp-hist/7090-PowerSupplyControl&Distribution-223… Marc

"massive" 2- We had a Motor/Generator for our Honeywell L66. Not sure it was because it wanted US voltages or just for a clean supply Dave

On 5/5/2021 7:18 PM, Jules Richardson via cctalk wrote: While I was in grad school at U.W. (the one in Wisconsin) we had obtained via surplus an IBM 7094 II from military surplus - I seem to recall WSMR (White Sands Missle Range). Of course, it had an MG. We got it put together and with a replaced transistor here and there (one of which was modern silicon) we got it running. We had NO peripherals, but my friend Paul came up with the idea to use a sense switch to talk RS-232 at 9600bps, and using that he got the Purdue University Fast FORTRAN Translator (PUFFT)loaded and up and running, and I wrote some support code on a Datacraft 6024 to send it card images and receive print lines. One evening after supper I convinced my wife to let me head down to the CS building and play. I stepped into the CS building and man, there was a lot of smokey smell and obvious evidence of smoke - but no alarms. It got worse as I headed down towards the basement where we had the gear set up. It turned out one of the bearings in the MG had welded itself to the shaft (and not for lack of proper lubrication). Thing was about 5" in diameter. That put us out of commission for a while, until many months later the UW Machine shop fixed it up. Not too long after that machine, and an IBM 1410 that had been donated by Oscar Mayer were sold off to a place in Ohio where they actually were still using that second hand gear in 1977 - and it was that very same outfit that we visited decades later and recovered the IBM 1410 PR155 operating system tape and diagnostics, a copy of OS/360, and other interesting stuff. JRJ

On 5/6/2021 12:14 AM, Chuck Guzis via cctalk wrote: Apparently, yes: https://dl.acm.org/doi/10.1145/365660.365671 https://docs.lib.purdue.edu/dissertations/AAI7003878/ https://minds.wisconsin.edu/bitstream/handle/1793/57766/TR160.pdf?sequence=… The last two papers involved Edouard Desautels, who was at UW when I was there - I really like the guy. He coordinated the "systems lab" and I think was central to acquiring the 7094 II from surplus. The last paper (which you can actually download unlike Purdue who seems to have locked their papers up) hints at why that might have been done. UW had a Univac 1108 and two B5500's when I started (the second loaned because Burroughs was late delivering the B8500 - and then lied to UW when the faculty paid a visit - by lashing up a pair of B6500's, according to one prof. I had who was there.) The 1108 and B5500's were replaced by a Univac 1110 before I graduated in 1975. There was also a CDC 3600 and a CDC 1604. The CDC 3600 was damaged in the infamous Sterling Hall bombing, but I think the 1604 came out fine. I expect those were both gone by 1975. The system lab had a PDP-11/20 and a Datacraft 6024, then after UNIX showed up (V6 and then V7) got a PDP-11/45 and a PDP-11/40 that was not used for UNIX, and then a PDP-11/70 for UNIX for the CS department shortly after I graduated and left. The 7094 II and the Oscar Mayer 1410 were not used for anything serious and only lasted a couple of years - there were not even any peripherals for them. I think Prof. Desautels intended they be used for entry level instructional classes in FORTRAN and COBOL, maybe (see above). Engineering had a couple of IBM 1620's (one with a disk) that became disused when they obtained a Datacraft 6024 around 1970, I think. The electrical engineering department had a PDP-11/20 almost identical to the one the the CS dept. had that I did some independent study on. The School of Business, where I worked as student help / grad project assistant had an IBM 1410 that had been used by the UW Registrar. When the administration consolidated, they obtained some model of IBM S/360. There was an old old IBM 7094 with oil core (or maybe even a 7090, I don't recall) on the 9th floor of the Chemistry building used by one particular researcher. It had Potter peripherals. At one point it failed pretty badly, and three of us went over to see if we could figure out the problem. They ended up calling in a couple of guys from Purdue to help figure it out. The Social Science Research Institute had a S/360 (a model 30 or 50, I think), as well, right across the street from the School of Business. To try and get their arms around instructional computing, the UW computing committee (which somehow ended up with an acronym something like acc-acc) commissioned a DEC PDP-11/70 for students to use, replacing the Business School 1410 and some other smaller systems. It was a disaster - it just couldn't keep up. We were able to play with it because it was core-resident - didn't need any peripherals to run once it got loaded (see the above third paper.)

On Thu, 6 May 2021 at 02:19, Jules Richardson via cctalk <cctalk at classiccmp.org> wrote: Oh yes indeed. Sophie Wilson did a talk at the last ROUGOL meeting, last month. Not sure if the video is online yet. I can share it here when it's up if folk are interested. There are a few stories of bring-up of the first ARM chips that were remarkable. * The unanticipatedly low power draw; * Simulating the instruction set in BBC BASIC on a BBC Micro during the design phase, instead of some vastly-expensive bigger system; * The fact that the very first silicon worked very nearly perfectly first time; * Embedding a `MANDEL` instruction into the BASIC for demos, because people expected it so often that it was worth implementing someone's algorithm in ARM code and putting it directly into the interpreter. She's really quite pessimistic about the future of microprocessor manufacture. She gleefully made fun of Intel quite a bit, but pointed out the [cough] _inaccuracies_ and shall we say _over-enthusiastic_ claims of their marketing materials concerning die size. She's quite impressed with AMD's recent designs, which partition parts of multicore processors into separate dies, so that only the bits that really need it can be made on the very expensive tiny feature size processes, and other bits on cheaper, larger feature sizes. Oddly she barely mentioned Apple Silicon, merely that they were extremely aggressive with wide superscalar designs and so on. Her overall point being that although it _is_ possible for transistor sizes etc to get a _little_ smaller than is mainstream now, the industry is now at the point where smaller-feature-size, faster chips are actually getting _more_ expensive to make, not less. We are very nearly at the end of the line of high-end chips getting faster at all. Part of this is due to language design. I noticed myself that in recent decades, chips seem to be designed to run C fast, to put it simply. Wilson feels that the instruction model of C is now a limiting factor, and that one of the only ways to go is something akin to her own FirePath processor design for Broadcom. Firepath is more or less the "Son of ARM". Not much is public about Firepath and this is one of the best references I know: https://everything2.com/title/FirePath It can do things like load 8 different bytes of data into a set of registers, perform arithmetic on them, and depending on the result, put the results back somewhere else or not, in a single assembler opcode in a single cycle... and she feels that no contemporary high-level language can usefully express such operations. I suppose APL might come closest, but it's hardly mainstream. I find it an interesting thought that once the only way to get more performance will soon be to switch to radically different processor architectures that always work in ways very loosely comparable to MMX or Altivec (and their descendants), and write new programs in new languages on new OSes that can exploit deep hardware parallelism. The flipside of the coin may be that current, "traditional" designs will get smaller and cheaper and use less power, and the only way to squeeze better performance out of them will be to use smaller, simpler OSes. There's a chance here for what the mainstream sees as obsolete or irrelevant OSes and languages to enjoy a revival. The vanguard could be VMS. I'd love to see this. I found it amusing after my FOSDEM talk in February, which talked about this. I was talking about some of the ideas on the Squeak Smalltalk mailing list. I listed a set of criteria I'd been using to narrow down my selection of criteria: ? a clean, simple OS, with SMP support, that supported pre-emption, memory management etc. ? in a type-safe language, with a native-object-code compiler ? not JITTed, not using a VM or runtime ? and a readable language, not something far outside the Algol family of imperative HLLs ? that was portable across different architectures ? that was FOSS and could be forked ? that was documented and had a user community who knew it ? that can be built with FOSS tools (which RISC OS fails, for instance) ? which is or was used by non-specialists for general purpose computing ? which can usefully access the Internet ? which runs on commodity hardware ? which does not have a strongly filesystem-centric design that would not fit a PMEM-only computer (i.e. not an xNix) ... and several people went "no, that is impossible. Match all of those at once and you have the null set. And I said, no, this is why I picked Oberon and A2. The result seemed to be a number of people who hadn't been paying much attention sitting up and asking what language/OS this was. It was similar to trying to summarise what I'd learned about Lisp to a Unix community in Another Place a few years ago. It all washed over them until I quoted observations such as Alan Kay's "Lisp is the Maxwell's Equations of programming languages", which made a few people suddenly wake up and go read the links I was providing. Some stuff may yet come back from obscurity. I hope. :-) -- Liam Proven ? Profile: https://about.me/liamproven Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com Twitter/Facebook/LinkedIn/Flickr: lproven ? Skype: liamproven UK: +44 7939-087884 ? ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053

On Thu, 6 May 2021 at 16:13, Paul Koning <paulkoning at comcast.net> wrote: I think because for lesser minds, such as mine, it's line noise. A friend of mine, a Perl guru, studied A-Plus for a while. (Morgan Stanley's in-house APL dialect.) He said to me that "when I came back to Perl, I found it irritatingly verbose..." and then was immediately deeply shocked at the thought. I seriously think this is why Lisp didn't go mainstream. For a certain type of human mind, it's wonderful and clear and expressive, but for most of us, it's just a step too far. Ditto Forth, ditto Postscript, etc. Plain old algebraic infix notation has thrived for half a millennium because it's easily assimilated and comprehended, and many arguably better notations just are not. The importance of being easy, as opposed to being clear, or unambiguous, or expressive, etc., is widely underestimated. Ooh, great. Thank you, I will read up on these. -- Liam Proven ? Profile: https://about.me/liamproven Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com Twitter/Facebook/LinkedIn/Flickr: lproven ? Skype: liamproven UK: +44 7939-087884 ? ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053

On 5/5/21 5:18 AM, Paul Koning wrote: It was the "white noise" from the vacuum pumps in the tape drive banks that drove me nuts after a few hours. After 8 hours or so, I sometimes found my hands shaking. Of course this facility had a very large machine floor with several full-sized installations. Eventually, management provided ear protection. As far as any "whine"--I vaguely recall hearing a high-pitched whine if I put my ear close to the power adjustment panel in a CDC Cyber--but it was barely audible. As far as the MG sets themselves, I never went there--any noise at SVLOPE was drowned out by the fans in the cooling tower. I don't recall where the power equipment at ARHOPS was located. --Chuck

We had a room on the ground floor at ETA that housed an MG set that ran the CY205 (and maybe the 835 and 875 too) in the basement. They had isolated the MG from the mounting pretty well in addition to sound proofing the room because with door closed, you couldn?t really tell it was in there? which was nice because the room was right off the main entry hallway :-) Chris

On Thursday (05/06/2021 at 08:37PM -0700), Chuck Guzis wrote: The HQ building (nee BTC) was built just a year before ETA started, so 1982 or so. But somehow it ended up with very 70s-ish decor, even if it was all new 70s-ish decor. It's possible they wanted all the guys that moved down from ARHOPS and ADL to still feel at home... cje -- Chris Elmquist

On Friday (05/07/2021 at 09:03AM -0700), Chuck Guzis wrote: Yup. There were a fair number of the gun-metal grey desks that looked like they had come back from the Korean war or something that some of the guys brought from ADL to ETA. Wanted to keep their own desk! Ha. That really was a CDC trademark in all of their documentation. I must have grown up on the wrong side of the tracks because I remember thinking it was kind of cool. I even went so far as to seek out an OCR type wheel for my Diablo printer so that I could print listings at home that looked like the ones I did at work :-) What can I say? I was young and impressionable then... LOL. cje -- Chris Elmquist