test-drb January 2008

test-drb@ccmp.vtda.org

221 participants
430 discussions

Big Iron (was VLSI of classic architectures)

by roger.holmes＠microspot.co.uk

>> Current custodian of the University of London machine, having >> bought the >> 200,000 pound machine for 150 pounds in 1976. > > Still a 200,000 pound machine, regardless of the price. > That was big iron back then. :) How hard is to keep and get spares > for that system? I bought a machine which I stripped for spares and also the previous owners had got most of the parts from the factory when they had cleared their parts store. Some SES light bulbs are still available from classic car parts stores, and wedge lamps were used in old telephone exchanges which sometimes come up on eBay, I even got some 17volt ones a while back, and some are still available new from RS components and they even make LED equivalents at a price, though they're the wrong shade of white. The rarer transistors sometimes come up on eBay too. The commonest (Mullard GET871/GET872/A/B/C) are difficult to get, though I passed on a half dozen on eBay where the blue plastic had turned brown - looked like they had blown up or got hot when de-soldered. Fortunately I have enough for the foreseeable future. Diodes (mainly OA5 and OA10) did have sky high prices and now are unavailable but I've got thousands. Of course resistors, capacitors and inductors are still available, though they do not look the same, and I still have to find out why the resistors have double green bands where there should be a gold band for the tolerance. I have been lucky so far with the electrolytics, not one has blown up, despite being 46 years old. They bought the best components available back then, and hand built them and tested every soldered joint and marked it with lacquer to show it had been tested. The biggest electrolytics are bigger than a hand grenade, so I hope they never fail! There two types of valves in the tape drives. I got about a hundred of one type with the machine, and not used one, the other type I've picked up in the States on eBay, they are used in old CNC spark eroders apparently. I am rapidly getting though my stock of 'rubber' pinch rollers for the mag tape drives, which go hard and crack up. The same thing happens with the rubber-like roller in the punch card reader, but that is about 4 inch diameter, so it is currently wrapped in four layers of motorcycle inner tube, though its not very effective and I may have to mould a new one in synthetic rubber. Most of the mechanical parts are simply unavailable, but I have a lathe and a milling machine. I bought some flat belts for driving the tape capstan rollers, they are commonly used as knitting machine drive belts apparently. V belts for the drums and line printer are fortunately standard car parts. Line printer ribbons will be a problem (when I get the printer working again). I have a box of a dozen or more but if they have now dried up by now I will be amazed. There used to be re-inking firms around, or maybe I could just buy the ink and get my hands dirty. Should not be unsurmountable, even if the fabric has failed, its just (nylon?) cloth, should be able to get something to do the job. I've a good stock of blank punched cards and paper tape (5 and 8 track) and enough mag tapes to keep me going for a long time. Fan fold paper is probably still available new and when I see any cheap locally on eBay I buy it up. The logic indicator tubes (DM170 or something like that) never seem to fail. The microswitches (particularly the start switch which takes a hammering when single stepping a program) are in short supply, though I don't see too much of a problem in fitting modern sub-micro versions and extending the actuating arms. Multi-segment rotary switches just need a squirt of switch cleaner/lubricant from time to time. One problem, and it sounds stupid, is the rotary switch knobs. They are made of plastic and they fit on a 1/4 inch shaft with a flat section, nothing unusual there. There is a boss on the back which fits into a recess in the formica covered blockboard (yes the computer has wood in it) front panel. These bosses break off. The shafts are not long enough for most modern knobs, and anyway I want to keep it looking original. Because of the recess, it is not possible to use knobs with a screw. I am thinking about making some aluminium knobs which I can glue or screw into the original front parts of the knobs. The problem is making the flat part which fits the flat of the shaft. I suppose I could make them of brass and then put sufficient soft solder in the hole so that I can shove it onto the shaft so that it won't come off easily. I guess there must be a tool for making D-shaped holes somewhere, or maybe there should be some spring steel in there somehow. The relay contacts need cleaning sometimes, though they are platinum so are pretty reliable. There are no edge connectors in the computer itself, every one of the 4000 PCBs is wire wrapped in, which means there are about 50,000 test points. The racks in the computer are also wire wrapped together, no plugs and sockets. This all improves reliability and I think accounts for the machine's survival (well that and my eccentricity). The tape drives have some plugs and sockets and edge connectors, but have so far been reasonably reliable as well. Castors were a nightmare. The tyres on the ones on the (800 lb) tape drives crack up. The ones on the computer have a flat top with a stud poking out. The stud has a washer and a nut and fit into an open ended slot with another nut on top. Any jolt and the stud bends. If I have to move anything heavy now, I remove the washer and first nut and make up a three inch piece of wood the equivalent thickness to take their place, which spreads the load over a larger area instead of concentrating it on the stud. Fuses: small ones still available from Maplin for peanuts, large ones are NATO standard and cost silly money, so I drill the ends, empty out the sand and solder 10,15 or 20 amp domestic fuse wire into the old cartridges. Meters, so far very reliable apart from one where the needle would not go above a certain point, so I had to dismantle it and glue the glass back in which was what the needle was jamming on. I think that just about covers all the parts which go wrong. Roger Holmes

16 years, 11 months

VLSI of classic architectures (was Re: 11/70 board set on e-bay. . .)

by roger.holmes＠microspot.co.uk

On 16 Jan, 2008, at 18:00, cctalk-request at classiccmp.org wrote: > > Message: 11 > Date: Tue, 15 Jan 2008 22:13:44 -0800 (PST) > From: "James A. Markevitch" <jam at magic.com> > Subject: Re: VLSI of classic architectures (was Re: 11/70 board set on > e-bay. . .) > To: cctalk at classiccmp.org > Message-ID: <200801160613.WAA26599 at magellan.magic.com> > >> On 15/01/2008 17:37, James A. Markevitch wrote: >>>> Chuckles at the typo.Is the PDP-8 the only classic architecure >>>> from the mid >>>> 1960's that was made with VLSI components. >>> >>> IBM 360 (still being made today) >> >> Is it? > > The 360 itself is not, but the architecture is, and in multi-GHz > parts. > >>> PDP-11 (LSI-11) >> >> Definitely not mid 1960s. The first PDP-11 appeared in 1970, and >> LSI-11 >> came out in 1975! > > Well, the architecture was conceived in April 1969, I believe :-). > Guess > that's not quite mid 1960's. It is not normal to consider conception dates, neither with computers nor babies. I don't go calling my ICT 1301 a late '50s computer just because it was conceived in 1959, nor because thats when some of the technical drawings date from. Its an early '60s machine because the first one shipped in 1962, and you could even argue about that as it was actually an extra prototype which the University of London pressed ICT into supplying because otherwise there would be no undergraduate intake in 1962 as they were committed to it, having had the computer on order for a LONG time. As the factory prototypes were refined, engineers would be sent out to also modify the university's machine. At a meeting of the Computer Conservation Society, the chap in charge of the software said it was the only computer which ICT/ICT ever shipped where the system software and libraries were ready before the first machine shipped. Most of it had been hand executed to verify it apart from the real time aspects, which had been the big hold up, particularly the routine which punched one card whilst reading six cards and printing one line. For months they had been travelling from London to Coventry every night to test the next amendment of version one and failing whilst some of the programmers had been putting together a version two in their spare time. One night they rang their manager, waking him in the early hours. They said they were not getting anywhere with version one, and asked for permission to try version two. This was grudgingly given as a sop to frustration. It worked first time, and version one was abandoned and at last all the software was ready. Roger Holmes. Current custodian of the University of London machine, having bought the 200,000 pound machine for 150 pounds in 1976.

16 years, 11 months

Craigslist- MicroVAX, DECstation, etc.

by compoobah＠valleyimplants.com

On Jan 17, 2008, at 2:11 AM, Doc Shipley wrote: > There can't be too many people named Chris in Buffalo who > collect old > Unix gear and have an amazing array of install media and software for > them. If this is who I think it is, he's legit and very easy to deal > with. I've bought both equipment and media from him. Yes, it is him. He's also the one who sells PS/2->SGI {Indigo|Crimson| Onyx|Personal IRIS|Professional IRIS} keyboard adaptors.

16 years, 11 months

IBM PS/2 Model 25

by filippo.santolin＠flyinformatica.it

Dear Sir, i would like to ask you the price for IBM 8530-021 and cost for shipping to italy. IBM 8530-021 computer still working?? Best Regards Filippo Fly Informatica snc tel. 0572 445340 fax 0572 448378 Le informazioni contenute nella presente comunicazione ed i relativi allegati possono essere riservati e sono comunque, destinati esclusivamente alle persone e agli Enti sopraindicati. La diffusione, distribuzione e/o copiatura del documento trasmesso da parte di qualsiasi soggetto diverso dal destinatario ? proibita, sia ai sensi dell'art. 616 c.p. che ai sensi del D.Lgs.n.196/2003. Se avete ricevuto questo messaggio per errore, vi preghiamo di distruggerlo e di informarci immediatamente per telefono allo 0572 445340 o inviando un messaggio di posta elettronica all'indirizzo: info at flyinformatica.it. In caso di ricezione mancata o incompleta, telefonare al numero 0572 445340.

16 years, 11 months

Went down to the ETH today...

by jos.mar＠bluewin.ch

... and was rewarded with a gift of 3 very rare Honewell Bull diskcartidges, which will go a long way in keeping my Lilith running for a few more years. And even more importantly, I got loaned all technical infomation on the Lilith : circuit decription, schematics, microcode listings, you name it, it is there ! Expect scans shortly ! ( and they have a nice Cray on display in their basement ) However I do feel somewhat stupid now, having spend quite a bit of time reversing engineering my own Lilith.... Jos Dreesen

16 years, 11 months

Vol 53, Issue 32 - "gummy" pinch roller problem

by mike＠brickfieldspark.org

One thing that has worked for mee in the past is to replace the "gummy" rubber with black adhesive lined heatshrink tubing. Measure the old roller diameter, remove old rubber down to metal part, carefuly shrink on a piece of new heatshrink. Oversize heatshring builds up thickness quickely, sizes close to the diameter do so more slowly. With *care* it can be turned to the correct diameter although not by much, you need to be close to finished size. I used adhesive lined for the first layer on the metal core, susequent layers stick to each other quite well. Mike > > Message: 19 > Date: Wed, 16 Jan 2008 22:03:35 +0900 > From: "David Vohs" <netsurfer_x1 at fastmailbox.net> > Subject: Ye old HP-85 "gummy" pinch roller problem. > To: cctalk at classiccmp.org > Message-ID: <1200488615.10086.1231544527 at webmail.messagingengine.com> > Content-Type: text/plain; charset="ISO-8859-1" > > Just wanted to pose the question to the group in regards to the gummy > pinch roller problem in the HP-85. > > Anyone know where I can find a commpatible, hard plasic pinch roller? > >

16 years, 11 months

contemplating selling my Canon Cat

by chrism3667＠yahoo.com

very much strapped for cash. If you're interested, e-mail an offer off-list. I have to admit it's not going to go cheaply...snifful ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs

16 years, 11 months

FREE: Compaq Contura 4/25cx laptop

by silent700＠gmail.com

It powers on, doesn't see the internal hard drive (or there isn't on there,) 12mb, modem installed, floppy drive works, serial port works. Don't have the A/C adaptor but works off the Toshiba adaptor I had lying around. Not particularly classic, but it kills me to throw even this one out. So if anyone needs yet another serial terminal.... Free + shipping from 60074. -- j

16 years, 11 months

VLSI of classic architectures (was Re: 11/70 board set on e-bay. . .)

by jam＠magic.com

> Chuckles at the typo.Is the PDP-8 the only classic architecure from the mid > 1960's that was made with VLSI components. IBM 360 (still being made today) Data General Nova (MicroNOVA) PDP-11 (LSI-11) Maybe HP 21xx (A series?) Just to name a few. James Markevitch

16 years, 11 months

FOR SALE: TI-99/4A EXPANSION SYSTEM w/ SPEECH, RS232, TRIPLETECH

by mikedg63＠mybluelight.com

FOR SALE: TI-99/4A EXPANSION SYSTEM w/ SPEECH, RS232, TRIPLETECH Is this still for sale? Thanks _____________________________________________________________ Print your own high quality pictures with great photo paper! Click here! http://thirdpartyoffers.mybluelight.com/TGL2321/fc/Ioyw6i51vQRQR4EqfExwqG15…

16 years, 11 months

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test-drb January 2008