test-drb October 1999

test-drb@ccmp.vtda.org

216 participants
748 discussions

by spc＠armigeron.com

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25 years, 1 month

Available sale/trade: OSI Challenger 1P

by jimw＠agora.rdrop.com

Another step in my ongoing attempts to bring some focus (and room) to my collection. (and help finance a possible upcoming major restoration project) Ohio Scientific Challenger 1P microcomputer Includes 5.25 diskette drive, manuals, software (original disks plus extras). Unit is in overall good shape, some paint wear around the keyboard (no wrist rests back in those days). Pictures available on my web site. Have not fired it up in some time so it exact condition is unknown but it is complete. I'm thinking $250.00 (plus shipping) unless someone convinces me that I'm totally out of the park on that. Interesting trades (see the 'Most Wanted' list on my web site for ideas) always entertained. -jim --- jimw(a)computergarage.org The Computer Garage - http://www.computergarage.org Computer Garage Fax - (503) 646-0174

25 years, 1 month

gauging interest in VAX 6000-530

by allisonp＠world.std.com

<> VAX 7000's in a brand new computer room. Said corporation has numerous <> computer rooms with VAXen, and these systems are heavily used. < <Maybe I should have said "Nobody -sane- is going to....". Try managing that, nice all in one place system. Sanity is restored. <How fast is a Vax 7000? http://www.digital.com/timeline/1992-3.htm <describes a little about the VAX 7000, but no hard speed data. Far to brief for you spec's experts to appreciate. <Incidentally, the vax 7000 was introduced 7 years ago; have there been any <upgrades since then? Yes, disks and network peripherals. Lower cost. and it's scaleable for multiple cpus and clustering. <The paradigm today is client on Ethernet, server cluster in the back room. <Scalable, cheap, reliable. Scalable, buy a bigger server? Run out of net bandwith? Multiple servers that are NT based add one more? Been there doing that. HAve they figured out how to cluster PCs (I know Linux Beuwolf... and right out of a box too). Gee and I thought adding another VAX to a cluster was a powerful scaleable solution. That failover capability from the 80s is pass`e too I'd bet. <One Big Box In The Back Room is what people did in the 40s, 50s and 60s.... And 70s, 80s and even the 90s. The big box in the back room is called a server now (likely several servers). <You're right, speed isn't everything; it's the -only- thing! ;-) Yes, rebooting faster is better when you have to. ;) <My PCs are damn reliable; are you buying junk? They are -waaaaaaaaaaay- mo <reliable than the VAX-11/780s, VAX-11/750s and VAX-11/785s that I have I'd hopes so, those are 20 years old. Will your PCs even run after 20 years? 10 years? How about 5? Then again why not run that super fast VAX beater 486dx2/66 still? <used in the past. (I run BSDI unix on a Pentium Pro, as well as NetBSD on <other machines, and they have -never- crashed.) Good for you. Run NT for a while and get to appreciate the rest of the real industry. Do you serve 6 different databases? How about thin windows clients from them? FTP and web pages are nice can they serve out disk space for W95 workgroups and legacy dos programs? Whats the backups like? Do the 40 clientshave a back up schedule to the server(s)? What fun it is when the user changes their setting and locks up their workgroup? How system security management for PCs, servers? Well, thats a sample of the Intranet I run and maintain. Can't say I like all the MS stuff but I'd realy hate to train users for unix/linux that barely want to deal with PCs at all. For a small business a common system based on big iron is really cheaper and easier to maintain. Allison

25 years, 1 month

PDP-8/e PSU questions

by ethan_dicks＠yahoo.com

I moved my PDP-8/e this weekend and have been inventorying and testing various components. At the moment, the PSU isn't cooperating. ISTR there were some molex connector jumpers at various points, but I may be missing one or two. Up on the front, I have an empty 3-pin molex shell on, IIRC, P5. On the back, there is one 3-pin jumper in place and an empty 3-pin connector next to it. I get no lights, no sound, no nothing out of this. The fuses are good. Any suggestions? -ethan ===== Infinet has been sold. The domain is going away in February. Please send all replies to erd(a)iname.com __________________________________________________ Do You Yahoo!? Bid and sell for free at http://auctions.yahoo.com

25 years, 1 month

OT: how big would it be? - PCBs at home

by allisonp＠world.std.com

<Has any of you ever encountered an approach to this that could be managed i <the home environment with equipment costing, nominally, less that a k-buck Being close to doing this I can speak about it some. The key to doing plated through hole is a process called electroless copper plating. I don't do that for one reason, it's a nasty process and the materials are poison and its wastes are poison to the max. I farm it out. the films for high res stuff are gerber photoplots you can farm that work out. laser printer plots are not adaquate for anything less than 25mil features and even then... At work we pay 87$ to get B size plots from Acad-13. This is not cheap and is likely the upper end as I get them elsewhere for ~20 for A size. the drilling, it's possible to build a threeaxis drill press that is NC controlled with better than 0.005 accuracy with relative ease. that will drill for you. With patience and a simple jig in a drillpress you can do this by hand. Sensitizing, exposure and development are trivial. the photoresist can be very expensive though. They run from 300 to 800 USD a gallon (that a lot) and getting a pint quanity can be hard. The easy way is to pour on the resist (under safelight) and spin the board at 3000rpm for 20 sec. The coat is very uniform then and quite thin. Exposure is a light box with two UV lamps of adaquate size(20w, 2ft, shortwave). Development is generally whatever the resist requries and takes a few minutes. htere are positive resists and also negative, pick the right one to match your photoplots (or pick the photoplots to match the resist)! Etching the board is simple and can be handled by most hobbiests. <or two and achieving nominally 10-mil traces with 8-10 mil separation or <anything close to that? How about a dry-film solder mask? Dry film mask may be part of the resist used or a seperate operation. It's not essential but it helps. A z280 board under devlopment using 10 mil features, two sided with PTH is what I'm basing my experince on. Also the company I work for does foil heaters and temperature sensors so the have a minimal PCB operation (no drilling, single sided, no PTH). Allison

25 years, 1 month

OT: how big would it be? - PCBs at home

by pete＠dunnington.u-net.com

On Oct 22, 15:20, daniel wrote: > Making PCBs at home is a rediculous waste of time. I have a vacuum lightbox > here as well as a commercial processing system, a silkscreening set up, even > a wave solder machine in my home and nothing compares to what the big guys > can do and charge for the same thing. If you're trying to emulate the way a professional PCB house will make them, or if you need moderate to large quantities, I suppose I agree. But for two or three boards, I strongly disagree. I've made dozens, possibly hundreds of PCBs at home or at work, and it doesn't take that long, nor is it very difficult. I certainly prefer it to wire-wrap. Of course, you typically won't be able to get such fine lines, and putting two tracks between the pins of a 0.1" pitch DIP isn't something I'd do. I wouldn't consider using a professional PCB company for a one- or two-off unless it truly was very special, or a prototype for something that later would be made by the hundred. I make same-size artwork on a decent laser printer, and expose that onto sensitized boards. With a little care, registration is easily good enough for double sided PCBs. It's even possible to do plated-through holes, though I don't -- I use track pins, because the through hole stuff is relatively expensive. > My last *production* company use to > make its own prototype doublesided PCBs in house and it wasn't worth it. I > have a company I use now that will make me a double sided PCB, GOLD PLATED > contacts, solder mask both sides (pre-drilled of course), and silk screened, > and cut for less than a $1 a board in quantities of 500. OK, but do they also charge $490 for a one-off prototype? Most companies here charge according to the number of layers and amount of setup -- and that's mostly related to the number of plated holes, not board area. > Pre-sensitised boards are useless as they usually come flawed and the > coating thickness is not consitant. The company I use now for PCBs used a > "roll" of sentised film that was "ironed" onto a 3' X 3' board. Far better > process. Maybe, but I've never had a problem with pre-sensitised board. Sensitising it myself with an aerosol turned out to be a less-than-clever idea, though :-) > Don't forget a good GERBER and NC drill file is needed and most PCB > manufacturers find little problems with the files that you may not uncover > in Most PCB houses here are perfectly happy with 2x size artwork, and many will accept same-size, possibly with a small surcharge. Marvin mentioned a number of ways to produce artwork. I've seen most of them used. Dot matrix printers aren't usually very good in terms of black/white contrast, nor sharpness (but often OK for x2 camera-ready artwork). I once discussed using an offset litho press to print directly onto flexible PCBs, but I don't know if the person I spoke to actually did that -- it should certainly have much higher resolution than a silkscreen. And people really do use tape on mylar film (well, maybe not much nowadays, but it used to be common). Lots of hobbyists over here print onto acetate or drafting film with a laser printer, and that works pretty well -- it goes straight into my light box. Daniel wrote "He drills the boards first, then photosensitizes them. They get UV, then he develops them in water (I think it was). Then he electroforms copper to create plate through holes, then tins, then gold plates, I think then he did the solder mask on both sides (I am sure that was silk screened) and finally the boards were silk-screened (layout), then cut." That's a fairly typical commercial method, except it wouldn't be water development. At home, it would be a weak solution of caustic soda, but that "goes off" very quickly, so a more esoteric substance is used commercially. -- Pete Peter Turnbull Dept. of Computer Science University of York

25 years, 1 month

Benchmark Wars (was Re: gauging interest in VAX 6000-530)

by cmcmanis＠mcmanis.com

Several people have gone after this topic many different times. It can't be "won." It can't be won because computers are tools and one can always find an application that makes less efficient use of the tool to "prove" their point. If you're doing ray tracing, get a fast PC. If you're timesharing dozens of people, a VAX is not a bad choice. Its all about "balance" and truly good designers can get good balance for the task at hand without being stuck in some rut. My favorite example was the HP2000 with BASIC supporting 40 users. In our lab at school we had one of the "fast" ones (it had some addon from a floating point company (FPS?)) and it was considered too pokey for anything compared to the 11/55. But over in the business school the very same model (sans FP, but same group of machines donated by HP) was comfortably running what seemed like zillions of HP terminals in HPBASIC. Balance. --Chuck (For Mike, have you ever actually run a 486 based PC architecture machine with a dozen actual serial interfaces connected to terminals? It is instructive because the damn things saturate the ISA bus and no disk traffic happens at all! On a PCI equipped bus with the users coming over the network via telnet its workable, but for terminal based I/O the DEC timeshare systems were (and probably still are) the best that you can buy.)

25 years, 1 month

Anderson Digital Computer

by jolminkh＠nsw.bigpond.net.au

A junk dealer I stay in touch with tells me he has an ancient computer he insists is labelled "Anderson Digital Computer". He says it is a metal box containing a screen and a separate keyboard. I'm to go to see it this week some time. Can anyone shed some light on what this might be? He knows nothing about computers so it might be an XT clone for all I know. Hans

25 years, 1 month

gauging interest in VAX 6000-530

by allisonp＠world.std.com

<No confusion; there are simply different metrics for performance and she's <using a different one than you. You are both, in fact, correct. The 486 <will outperform the VAX in integer performance, but the VAX has bundles <more bandwidth to disk than the 486 ever dreamed of. Rodger that but also to memory and IO as well. It's pretty difficult to interface more than a handful of serial lines to a PC. My MicrovaxII comfortably has 32lines (all running at 9600 as that was the fasest modem in 1989!). <> Fact is, these old machines were slow, noisy, hot, power-guzzling behemou <> compared with what we have today. < <No argument there ;-) No facts!. By 1990 vaxen and other vendors (sun, Appllo, IBM...) had pizza boxes and made PCs look like they were running in reverse at no higher power, often higher res video and better IO. VAXen were amoung the first to run busses like FDDI and broadband as well when PCs didn't have interfaces for that yet. Allison

25 years, 1 month

Last chance before they hit SCRAP...

by kyrrin＠bluefeathertech.com

This is going to the CLASSICCMP and NetBSD port-VAX lists, and to the two PDP-11 newsgroups. RE-PC in Tukwila, WA (south of Seattle) has a whole palletful (at least six) Seagate 'Sabre' series SMD drives NEW in their original packaging. These are already in their carrier tray with a power supply. I don't know capacity or model number -- was rushed, didn't have time to dig -- but I do know that this is the last chance to get them before they're scrapped. I did look at one, briefly. They appear to be the earlier series of Sabre, the ones that sat vertically in their mounting tray, as opposed to the later series that sat flat and were physically smaller. I also confirmed that they're SMD interface by direct viewing of the connectors: One 60-pin and one 26-pin Berg male header, standard .050 pitch. Initial asking price is $20.00 per unit, with definite discounts possible if you get more than one. To put it another way, the store would rather sell them than scrap them, and the manager of the place does recognize that there are those of us who do use the older hardware. Contact Maurice from 10:00 - 19:00 PDT at 206-575-8737 (press 0 during the voice announcement to bypass said announcement and start the phones ringing). They're closed on Sunday, but they'll be open tomorrow (Saturday). I hope this is of interest to at least some of you. Thanks for reading. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner and head honcho, Blue Feather Technologies http://www.bluefeathertech.com // E-mail: kyrrin(a)bluefeathertech.com Amateur Radio: WD6EOS since Dec. '77 "Our science can only describe an object, event, or living thing in our own human terms. It cannot, in any way, define any of them..."

25 years, 1 month

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test-drb October 1999