December 2001 - test-drb@ccmp.vtda.org

by brian＠quarterbyte.com

Sridhar wrote... > S/390 does NOT run on microprocessors of any kind, let alone > one as slow as PPC. Don't tell that to the folks at http://www.conmicro.cx/hercules/ (Of course, it depends on what your definition of "on" is). Brian =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- _| _| _| Brian Knittel / Quarterbyte Systems, Inc. _| _| _| Tel: 1-510-559-7930 Fax: 1-510-525-6889 _| _| _| Email: brian(a)quarterbyte.com _| _| _| http://www.quarterbyte.com

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 16, Innfogra(a)aol.com wrote: > Found it. A very interesting issue. There are several other stories I would > be interested in also. Thank you. You're very welcome. Unfortunately these scans aren't from *my* bytes...my collection doesn't go back that far, as I was 7 years old in 1976...so I can't go scan more of 'em. :-( Eventually I'll beef up my BYTE collection, probably via eBay. There are a LOT of great articles in there. Of course I do have all of the wonderful Ciarcia books, so my BYTE collecting motivation has been partially satisfied. :-) -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 16, ajp166 wrote: > > I wonder if it would be possible (and practical) to use a > >microcontroller, perhaps a PIC, to act as a core controller. Use the > >A/D and D/A hardware to handle the drive and sense stuff, and do all > >the timing in firmware...making it easily tweakable. > > Not likely as the sense voltages are quite small and the slice time > has to just right. Well I wouldn't expect to connect it *directly* to the PIC...some analog jellybeans would seem appropriate. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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Is there no end

by mcguire＠neurotica.com

On December 16, Ben Franchuk wrote: > > > Remember the (iirc) Compaq ad. Thier 286 had a meg of static ram onboard. > > > The ad depicted an empty desk with two tire tracks burt into it and a > > > surprised user behind. > > > > Static RAM? Are you sure? I've never heard of static RAM in a > > PeeCee. That's neat. > > Yes there is some -- it is called cache.:) I suspect a sever type > PC is more likely to have static than dynamic. I never did like PC > marketing -- clock speed -- not memory speed used as a benchmark. Nonono, I mean *main* memory, not cache. I sincerely doubt there are any PeeCees in the 486-or-newer arena with static RAM for main memory. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

>> I have some scans of an old BYTE Magazine article (July 1976 I think) >> that details how to build a common interface for an arbitrary chunk of >> core. I haven't really read it in-depth but I plan to someday. I can >> put it online if anyone would like to see it. I'd love to see scans of this one too. I remember the article but somehow lost it. Allison

23 years, 7 months

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Ampro Little Board questions...

by ajp166＠bellatlantic.net

From: Don Maslin <donm(a)cts.com> >It should not have a twist like a PC cable, and can be a length of >34-conductor ribbon cable, Gene, with a 50-pin female header on each >end. What ever length is needed. Ah, dont you mean 34 pin? 50 pin would be the SCSI. Allison

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

The older large ferrite core is easier to work with though much slower. The bigger cores produce a larger output when they switch but the cycle times are in the 3-5uS range. The later is helpful for demos as nothing is too fast. Allison -----Original Message----- From: Loboyko Steve <sloboyko(a)yahoo.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Saturday, December 15, 2001 11:36 PM Subject: Re: [PDP8-Lovers] how to clean a PDP8/A, dishwasher? >I've looked into this too. Problems are many. It's >definitely not a trivial project, lots of analog and >electromagnetic voodoo, and the chips that made it >easier are very hard to find. I've got a small >capacity large doughnut ca. 1960 core plane from an >IBM machine and a 4K by 16 plane from the 70's with >very tiny doughnuts, both unused, and I'd love to >demonstrate how it worked. > > >--- ajp166 <ajp166(a)bellatlantic.net> wrote: >> From: John Allain <allain(a)panix.com> >> >I have a Question for the other core users out >> there: >> >How would I test-signal a board, for demos, that is >> >just a core frame, IE one sacrificed from its stack >> >> >and sold at the e- flea market? >> >> >> It's a non trivial thing to do. Core by definition >> is destructive >> read out memory. So to demo a core you need to >> provide >> the coincident current (x,y) and the >> inhibit/write/read signals >> with the associated timing. Both the currents and >> the >> timing are critical. takes a lot of stuff to do >> that. >> >> Allison >> >> > > >__________________________________________________ >Do You Yahoo!? >Check out Yahoo! Shopping and Yahoo! Auctions for all of >your unique holiday gifts! Buy at http://shopping.yahoo.com >or bid at http://auctions.yahoo.com

23 years, 7 months

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Ampro Little Board questions...

by ajp166＠bellatlantic.net

From: Gene Buckle <geneb(a)deltasoft.com> >I know I can use any length of ribbon I want. What I'd like to know is >what it was when it was new. (and it's 34 pin card-edge connectors that >are needed :) ) I take them off old PC floppy cables. >The drive is a Miniscribe 8425S and AFAIK, it's set to ID 0 with the >terminating resistors installed. Seagate or Maxtor is not listed as a >_controller_ choice when HFORMAT is run. Yep! It's possible to use that drive but the Ampro provided tools only recognized drives from the era, there were many good choices in later years. Allison

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 15, Ben Franchuk wrote: > > I have some scans of an old BYTE Magazine article (July 1976 I think) > > that details how to build a common interface for an arbitrary chunk of > > core. I haven't really read it in-depth but I plan to someday. I can > > put it online if anyone would like to see it. > > I think that was a design for the 8080 and the S100 bus. > It was a really nice design too if I remember right. I remember > somebody doing a core-demo on the web. I think it used a iron washer > as the core. Since this is not high speed only the current is critical > here. It should be pretty easy to interface to other processors, then... > (Boy do I miss the early Bytes -- ordinary people designing and using > computers > -- not multi-billion $$$ bloatware companies -- ) Yup. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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On Sequent Symmetry S81 and PC Jr.

by csmith＠amdocs.com

> -----Original Message----- > From: Jochen Kunz [mailto:jkunz@unixag-kl.fh-kl.de] > On 2001.12.14 18:08 Christopher Smith wrote: > > [Sequent Symmetry S81] > > Drives, but I can probably handle that... > What interface SMD? Possibly, it's hard to tell since I'm not sure what an SMD interface looks like. I could turn it over and check but I don't know what to look for. ;) > > I believe that the system was board-for-board compatible > with the S27, > The Unix-AG once owned a S27 with 8 CPUs, 80MB RAM, 7 SMD disks, > Exabyte, ... I know where the machine is now, including a complete set > of OS software. If you get the machine working, ask me for software. I certainly will. > Don't expect much of that machine. I could get only 200kB/s via the > Ethernet, the SMD disk controller could not handle more then 700kB/s. > (The same disks can deliver more than 2MB/s on a Sun 3/260.) That is > real poor for such a high end beast. I was really > disapointed. But it is Did you get the chance to find out how performance faired when you add more CPU? > nice to see an old 4.2BSD UNIX derivate with AT&T universe > running on 8 > CPUs in a SMP config. It is amusing for me to see _any_ intel cpu running in an SMP config, and the fact that from what I've heard, Sequent made them do it fairly well, intrigues me. Regards, Chris Christopher Smith, Perl Developer Amdocs - Champaign, IL /usr/bin/perl -e ' print((~"\x95\xc4\xe3"^"Just Another Perl Hacker.")."\x08!\n"); '

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by Innfogra＠aol.com

In a message dated 12/15/01 10:54:50 PM Pacific Standard Time, mcguire(a)neurotica.com writes: > > > The scans are up at http://ti.neurotica.com/core. They're a bunch > of jpegs. No, that wasn't my idea, I didn't do the scanning. :) I > might try to turn them into a pdf one of these days. > > Found it. A very interesting issue. There are several other stories I would be interested in also. Thank you. Paxton Astoria, OR

23 years, 7 months

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Morrow MD3 Documentation.

by geoffr＠zipcon.net

Anyone have any of the docs for this beastie? I have one but no docs. I have been having trouble figuring out which terminal emulation to use when connected to it, also If someone has the docs I would be will ing to get my scanner hooked up again to my computer and see about making a PDF of them for posterity....

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by Innfogra＠aol.com

In a message dated 12/15/01 9:15:47 PM Pacific Standard Time, mcguire(a)neurotica.com writes: > I have some scans of an old BYTE Magazine article (July 1976 I think) > that details how to build a common interface for an arbitrary chunk of > core. I haven't really read it in-depth but I plan to someday. I can > put it online if anyone would like to see it. > I would like to see it. I have several pieces of core. Paxton Astoria, OR

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 16, Pat Finnegan wrote: > > I have some scans of an old BYTE Magazine article (July 1976 I think) > > that details how to build a common interface for an arbitrary chunk of > > core. I haven't really read it in-depth but I plan to someday. I can > > put it online if anyone would like to see it. > > I'd definately be interested. The scans are up at http://ti.neurotica.com/core. They're a bunch of jpegs. No, that wasn't my idea, I didn't do the scanning. :) I might try to turn them into a pdf one of these days. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 16, John Allain wrote: > > I have some scans of an old BYTE Magazine article (July 1976 I think) > > that details how to build a common interface for an arbitrary chunk of > > core. I haven't really read it in-depth but I plan to someday. I can > > put it online if anyone would like to see it. > > It Would help lots more Dave if you dug out that disk drive. > The mv3500 is still pretty useless w/o swap space. I've gotten to the bottom of the "staging area"...I think that pile of drives is in my storage locker up in Maryland. I will know for sure soon. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 15, ajp166 wrote: > >I have a Question for the other core users out there: > >How would I test-signal a board, for demos, that is > >just a core frame, IE one sacrificed from its stack > >and sold at the e- flea market? > > It's a non trivial thing to do. Core by definition is destructive > read out memory. So to demo a core you need to provide > the coincident current (x,y) and the inhibit/write/read signals > with the associated timing. Both the currents and the > timing are critical. takes a lot of stuff to do that. I have some scans of an old BYTE Magazine article (July 1976 I think) that details how to build a common interface for an arbitrary chunk of core. I haven't really read it in-depth but I plan to someday. I can put it online if anyone would like to see it. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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Is there no end

by mcguire＠neurotica.com

On December 15, Ben Franchuk wrote: > > > > I have little doubt about the appropriateness... of your response. > > > > Care to say when its appropriate to own three S/390's? > > > > > It's wholly inappropriate. He should give one to me. > > > > And one to me. Then he has one, and that's somewhat less inappropriate. ;-) > > Why collect 390's? 360's are more impressive! :) I suspect Sridhar doesn't have the S/390s for "historic" purposes...Ordinarily I'd just shut up and let him say that, but I just talked with him on the phone, he's outside of Richmond on his way down here. I'm going to make him eat some beef while he's here. :-) > BTW does the 390 architecture still emulate the 360's? I believe so, yes. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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ANNOUNCE--Altair32 version 2.1 released!

by ajp166＠bellatlantic.net

From: Richard A. Cini, Jr. <rcini(a)msn.com> > On the negative side, a small regression error has crept in and 4k BASIC >will no longer run. This is not so bad because if you could run 8k BASIC >there's no reason to run 4k BASIC. This is broken. Since 4kbasic and 8kbasic ran on the same altairs it suggests something in the emulator is broken. FYI: much of MITS and Altair compatable software used input Port 0FFh as a 8bit input (usually to configure IO). Allison

23 years, 7 months

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Ampro Little Board questions...

by ajp166＠bellatlantic.net

I only needed one floppy and with the twisted end cut off it was perfect. Allison -----Original Message----- From: Richard Erlacher <edick(a)idcomm.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Saturday, December 15, 2001 11:00 PM Subject: Re: Ampro Little Board questions... >A PC floppy cable certainly wouldn't work with the Little Boards I have, since >they use the standard floppy disk cable, which has no twists or cuts. > >Dick > >----- Original Message ----- >From: "ajp166" <ajp166(a)bellatlantic.net> >To: <classiccmp(a)classiccmp.org> >Sent: Saturday, December 15, 2001 2:44 PM >Subject: Re: Ampro Little Board questions... > > >> From: Gene Buckle <geneb(a)deltasoft.com> >> >belongs with it. Does anyone have a Series 100 box that could give me >> >the measurements and connector orientation & location of the floppy >> >cable? >> >> >> Nothing magic. the last one I had used was from a PC. >> >> >Secondly, I don't know what "brand" SCSI controller is built into the >> >board. The SCSI chip seems to be an NCR 5830, but that leads me nowhere >> >in relation to whether or not it's an Adaptec or other model controller. >> >I need to know the brand because the hd formatting software needs to >> >know it. >> >> >> Your applying PC logic to it. It's is not Adaptec, i'ts just SCSI >> (SCS1 or II) host and the NCR5380 is one of the early and common >> chips used for that. >> >> The brand applies to the "other" board, what is known as a SCSI >> bridge board. Adaptec, Xybec, WD and other made them. You >> need to know what board and what drive to do the formatting. If >> you dont mind hacking Z80 code you can go frm an AMPRO LB >> with SCSI to a smaller SCSI drive (64mb or less, or the rest will >> be unused). >> >> Allison >> >> >> >> > >

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: John Allain <allain(a)panix.com> >I have a Question for the other core users out there: >How would I test-signal a board, for demos, that is >just a core frame, IE one sacrificed from its stack >and sold at the e- flea market? It's a non trivial thing to do. Core by definition is destructive read out memory. So to demo a core you need to provide the coincident current (x,y) and the inhibit/write/read signals with the associated timing. Both the currents and the timing are critical. takes a lot of stuff to do that. Allison

23 years, 7 months

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ANNOUNCE--Altair32 version 2.1 released!

by rcini＠msn.com

Hello, all: Just a quick announcement. Today was the official release of version 2.1 of the Altair32 Emulator. Yeah! It's been about four months since the 2.0 release and a lot has happened since then. Floppy disk images for CP/M, Altair DOS and Disk BASIC are fully functional and the Altair32 now has an integrated debugger, courtesy of Jim Battle's Sol-20 emulation project. These two items alone took over half of the time between releases and integrating the debugger required a major overhaul of the 8080 emulation code. On the negative side, a small regression error has crept in and 4k BASIC will no longer run. This is not so bad because if you could run 8k BASIC there's no reason to run 4k BASIC. The next phase of the project will hopefully include some or all of the following: Continued code cleanup; minor fixes to IMSAI conditional Further testing of the debugger (it's been only lightly tested with the Altair32) A set of Windows-based tools to manipulate diskette images (to enable people to download programs from http://www.retroarchive.org and get them onto diskettes) Support for BBS software Support for different floppy controllers/disk formats and maybe a pseudo-floppy hard drive. That's it for now. As always, you can check out the project at: http://highgate.comm.sfu.ca/~rcini/classiccmp/Altair32.htm Rich Rich Cini Collector of classic computers Build Master for the Altair32 Emulation Project Web site: http://highgate.comm.sfu.ca/~rcini/classiccmp/ /************************************************************/

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 12:28, Matthew Sell wrote: > Typically, the time spent "in the water" isn't long enough to damage. Even > items made of steel and iron won't rust if the water is removed after the > cycle is complete. If they sit overnight, well, that's a different story. > > The only production problem I saw with untreated water was with an > electronic test instrument that had a lot of high-impedance signal > interconnects throughout. Many signal lines ran for long distances next to > each other. While the design of this piece of test equipment was > questionable, it was our duty to get it to work. > > The two biggest problems were contaminants from the water supply used in > the washing process (city water - switched to using a commercial filtration > system), and humidity (had to paint a sealant on all of the boards). That's a well-known problem. Some of the residues from a domestic water supply -- especially in hard water areas -- are mildly hygroscopic, and as a result, the boards would acquire very small amounts of moisture on the surface, especially when exposed to a humid atmosphere. In combination with the salts in the residue, this makes for leakage across the board, which could easily upset very high impedance circuits. I heard of someone who had the opposite problem. He designed a CMOS circuit which worked fine when forst contructed, but stopped when given anti-environment protection or was potted. He'd inadvertantly relied on the normal leakage across a PCB to hold the unused inputs of a CMOS gate at a particular level. Remove the leakage current and the gate stops working properly. Solution: add the pullup resistor that should have been there in the first place. -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 1:32, Matthew Sell wrote: > Here's the secrets to doing this right: > > 1) Do not use any detergents. NONE. Why not? Commercially, detergents are used to remove flux. I use laboratory detergent to clean PCBs I've made or modified. I don't use washing-up liquid, though, and I don't use the harsher detergents sometimes found in dishwasher detergent. -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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"Geeks" and licensing

by mcguire＠neurotica.com

On December 15, Jim Davis wrote: > IMHO: All software development should be performed as such: > > 1) Requirements - what should it do, and not do. Spin this till > everybody > signs off. > 2) Prelim design - Ok, a rough outline of the design, data structures > and control/data flow defined here. > 3) Detailed design - Define all the modules and their function, break it > down. > 4) Test plan - integrate testing into detailed design, make it unit > testable. > a unit is somthing that has input and output and side effects, like a > function. > 5) Finally, coding - build modules in parallel with test code. > 6) Unit testing - verify that modules comply with detailed design. > 7) Integration testing - hook it all together, make sure it works, apply > test plan developed in step 4 for fully integrated aplication. > > Do 1-3 until marketing decides what they want,4-7 until you find no > errors. > > For safety critical, you should /have to perform statement and decision > coverage in > step 6 and 7 and the detailed design should have a one-to-one > corespondence > with the detailed design document. Hmm, that procedure "reads" nice, but it sounds like more meetings than actual work. But then I've been a software developer for about twelve years, and nobody that I've worked with can figure out how I can blow off all the meetings and not get fired...it's because I end up writing all the code that the rest of the developers are talking about in their meetings, WHILE they're in their meetings, and by the time they're doing screwing around, the code is running. Procedures are nice, but they can be taken too far. Goal-orientation is better. (While I'll freely admit that this approach simply doesn't work for multi-million line applications, I should state that I generally work on applications of less than one million lines, but generally more than 100,000. I further state that my methods should probably NOT be used in life-critical applications...more than two eyes need to look at that stuff, no matter what.) -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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Should engineers be licensed (Was "Geeks")

by CLeyson＠aol.com

On Sat 15 Dec 2001, Jeffrey S. Sharp wrote: > There's a big difference between writing code to solve problems and being > a software engineer. Designing, coding, and compiling is only 40% of the > battle. Hopefully you're also spending some time planning and testing. The company I work for seem to have forgotten the planning and testing part of the software design process. We had a lot of embedded software written by outside contractors for a 486 running QNX real time OS. Over the years the software has evolved into the hardware equivalent of a rats nest and it's been left to our customers to find the bugs - most being "show stoppers". I sometimes wonder just how many customers we've lost because of this. Also, dont get me wrong, the same should be applied to hardware design. We recently interviewed an electronics engineering graduate who didn't know the difference between NPN and PNP transistors !! What do they teach kids these days ?? Should engineers be licensed ? - It's not a bad idea. Chris Leyson

23 years, 7 months

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Couple of items available - more info . . .

by cfandt＠netsync.net

>X-Authentication-Warning: ns2.ezwind.net: majordom set sender to >owner-classiccmp(a)classiccmp.org using -f >X-Sender: cfandt(a)206.231.8.2 >X-Mailer: QUALCOMM Windows Eudora Pro Version 4.1 >Date: Thu, 13 Dec 2001 21:54:36 -0500 >To: <classiccmp(a)classiccmp.org> >From: Christian Fandt <cfandt(a)netsync.net> >Subject: Couple of items available . . . >Sender: owner-classiccmp(a)classiccmp.org >Reply-To: classiccmp(a)classiccmp.org > >I've got four Iomega Bournoulli Boxes, model A210H, if anybody wants them. >I can maybe think of a few bits to swap for them but that doesn't matter. I >just need the room (as several list members who've visited us can attest) >and want them to go to a new home. > >I can ship but just reimburse me for the shipping cost and maybe purchase >of a proper shipping carton or two as needed. Seem to weigh 15 to 20 lbs. >each. Zip code 14701. > >Also, any interest in several IBM 3287 printers? Dot matrix 132 column page >printers which use SNA network interface. I have had a few questions asking (basically) what those Bournoulli Boxes are. Please forgive me as I thought they were somewhat well known - but that's probably because we used them all over the plant where I once worked and I kinda got used to them. Plus, it's been a relatively long time since they fell out use and younger folks of course wouldn't know much of them. At any rate, they are a removeable media mass storage device which uses what are essentially disk cartridges. Vintage '82-'85, I think. The media inside its case, IIRC, is similar to an 8" floppy disk except encased in a rigid plastic case. The cart is something like 8" wide, about 12" long and about 5/8" or so thick. These model A210H units have two 10 megabyte drives within a single enclosure. It measures approximately 5 inches high, about 12 inches wide and about 13-14 inches front-to-back. The PC XT, AT and compatible host machines had installed within themselves a proprietary ISA card with a cable from it to the Bournoulli Box. I know I've got at least two of these cards tucked away somewhere but I need to dig and hunt for them. They're packed away in one of the boxes from our move to this house several years ago. I've got a software driver disk or two around too. Same thing: where the h*** are they at the moment? But I can find them with diligent hunting. We live on a 66' x 210' lot and they can be eventually found :-) Iomega's Bournoulli Boxes were great for use as backup of the contemporary 20-to-80 mb hard disks of that era. That is what these units had been used for at my ex-employer along with their use as local data storage for daily Customer Service and Field Service records. I rescued them when we cleaned out an off site warehouse back in the mid 90's. I've also got maybe a dozen or more of the cartridges, too, which I just found. Yours for the taking too. Same conditions as previously stated (pay shipping, help towards a shipping box if actually needed, etc., yadda-yadda-yadda). Come and get 'em. Thanks. -Chris -- -- NNNN Christian Fandt, Electronic/Electrical Historian Jamestown, NY USA cfandt(a)netsync.net Member of Antique Wireless Association URL: http://www.antiquewireless.org/

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 15:47, Chad Fernandez wrote: > So it's almost like cloth, but made of wire? Yup, though the ferrite core rings mean the spacing between strands is larger than in cloth woven from thread. And it's knitted. I was told the other day that there are still two old ladies in the Midlands who can repair some types of core by re-knitting it. -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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if you hadn't already known this about the PDP-8

by mcguire＠neurotica.com

On December 13, Doc wrote: > > Remember Linux too needs lots of memory. With >16 meg on a video card > > your OS needs about 16x that. It is the video display that is the > > killer. > > BZZZT!! Wrong. > > Linux *likes* lots of memory. I can show you X running on a 386SX with > 12M and a 1M video card. Not just a demo; that's my friend's firewall. A firewall with a video card? Gotta love them PCs. ;) But yes, I agree...Linux can be made to work well on machines with small quantities of memory. It's actually pretty good at it. -Dave -- Dave McGuire St. Petersburg, FL

23 years, 7 months

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Is there no end

by SUPRDAVE＠aol.com

In a message dated 12/15/2001 7:18:46 PM Eastern Standard Time, jhellige(a)earthlink.net writes: << >That is just right. Airc, IBM would'nt buy Intel's processor for the IBM >PC unless Intel had multiple sources. This was to ensure supply to IBM if >Intel's plants were overridden by bugs, damages by an infusion of dust (or >aluminum powder.....;-)). AMD at least (and I think Seimens and NEC as >well) was contracted to produce the 8088 cpu. AMD was given all info >needed to clone the chips. > >This relationship continued through the 80286 and 80386 processors, but >became very strained as AMD was making 386's cheaper and imho better than >the intel products by modifying the Intel designs. Intel and AMD ended up >in court over the 80486 chip ; intel claiming that the contract between it >and AMD did not include information or production of this CPU. AMD was >eventually forced to produce a 'clean room' 80486 design but because of >the delays caused by the litigation they had plenty of time to do it. AMD's faster coprocessors also caused quite a problem if I remember correctly. Harris also pushed the 286 faster than any of the other sources. I remember PC Magazine running an article comparing various 286 machines with a headline that mimicked the Corvair's 'Unsafe at any speed' headline. >> I've always liked AMD stuff. My first PC I got myself was an AMD 386 dx40. I couldnt decide whether to get a 486-25 and didnt quite understand the sx/dx issue. Ran OS/2 great on 8 meg. Later, I found that the AMD 486 dx2/80 was cheaper than Intel's 66 so I got that and never any problems with it. -- Kwanzaa is NOT a real holiday.

23 years, 7 months

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Burroughs - any information?

by mhstein＠usa.net

Where were you a few years ago when I was looking for a home for my Burroughs software & manuals (didn't run across this list at the time though). After 10 years or so programming these babies (L/TC/B80&90) I'd accumulated pretty well every piece of firmware, utility & app software there was, but then (as now) there wasn't much interest in what most people (unfairly, in my biased opinion) derided as "just" an accounting machine (you haven't lived 'till you've played Lunar Lander with a golfball printer...) Unlike the mainframes, these machines were generally sold outright & therefore scrapped outside of Burroughs, so there were lots of them around. Finally sold the hard disk carts to a rebuilder, recycled the floppies & tossed the mylar tapes & manuals. HOWEVER, I do still have an electrical parts catalogue from 1972, a little early for the B80, but might have some of those chips from the TC listed; if you're interested, send me a couple of part numbers off list & I'll see if they're listed and it's worth while scanning it for ya. If size vs computing power were a criterion, there wouldn't be very many old mainframes in Sridhar's collection... And yes, rugged indeed; extremely reliable, aside >from the occasional head crash. Alas, many of them were disembowelled & ended up as desks or workbenches. As mentioned elsewhere, I also still have a digital cassette drive & tapes with who knows what on them (for the L/TC's), as well as a TD700 flat- screen display unit & controller for the B80, if anybody's interested. mike ----------------Original Message----------------- Date: Fri, 14 Dec 2001 17:44:21 +0100 From: "Sipke de Wal" <sipke(a)wxs.nl> Subject: Re: Burroughs - any information? I did obtain about 5 TC5500 consoles and a B80 back in the '80. They were rather large for their computing power and no software was obtainable so I scrapped them. I still have a couple of kilo's TTL-chips from them, with their own Burroughs legacy partnumbers. Very rugged design though! Maybe you could get some old "B" hardeware but software was out of the question. Sipke de Wal

23 years, 7 months

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Is there no end

by mythtech＠Mac.com

Ugh... this takes the cake. I was pulling apart a 486 logic board, and I pulled the heat sink off the chip... to be greated with an AMD 486 chip with "Made for Microsoft Windows" and the Windows logo stamped on it. What... no other OS is supposed to use an intel compatible processor?!? I am sure anyone that bought this chip to use with any other OS probably paid an MS tax because of that stamp! Just for that, I think I might see if I can get my Intel build of Rhapsody to install on it. Ok, so it isn't 10 years or older, but at least you people can understand the pain. -c

23 years, 7 months

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Hardest to Find Classic Computers (Was: RE: Way OT: Just

by mcguire＠neurotica.com

On December 16, Huw Davies wrote: > The problem with the Alphabook was that it's not exactly fast and > the battery life is short. They are also hard to find and expensive > should you find one. I suspect that a 1GHz laptop will run a VAX > emulation faster than the Alphabook with better battery life too. Yes but then you'd have the embarrassment of being seen carrying a PeeCee around. That's a hangin' offense around here! ;) -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by mcguire＠neurotica.com

On December 15, Pete Turnbull wrote: > No normal detergent will attack ordinary plastics or epoxies. Some > industrial detergent powders include caustic ingedients, and (mainly for > that reason, and because they can harm skin) are banned from domestic sale > in the UK, and also, I beieve, in the USA. In general, any home-use > detergent safe to use on your skin, clothes, etc, is safe on PCBs and > electronics. Alconox Inc. makes a few different cleaning compounds specifically for PCBs and electronic components. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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Flashing Light Indicators un Simple Front Panels

by mcguire＠neurotica.com

On December 15, Pete Turnbull wrote: > Actually, I think that's a good suggestion, if you can find someone with > the same ROMs. In my experience, most programmers actually do use the same > algorithm -- one of the common CRCs. At least, all three programmers I > regularly use do, and the checksums match the ones printed on SGI ROMs and > a few other ROMs I have that have printed checksums. Hmm..lucky. ;) My Data-I/O 2900, Heath 4801, and printed checksums on my SGI I2's ROMs don't match. -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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Flashing Light Indicators un Simple Front Panels

by pete＠dunnington.u-net.com

On Dec 15, 14:29, Dave McGuire wrote: > What kind of ROMs does it use? Another possibility might be to find > someone with the same model of PR1ME (how rare are they?) and checksum > the ROMs & compare them...most PROM burners will generate checksums, > but now that I think of it, PROM burner manufacturers have yet to > standardize on a checksumming algorithm so it'd probably be useless > unless they're summed with the same make/model of burner. :-( Actually, I think that's a good suggestion, if you can find someone with the same ROMs. In my experience, most programmers actually do use the same algorithm -- one of the common CRCs. At least, all three programmers I regularly use do, and the checksums match the ones printed on SGI ROMs and a few other ROMs I have that have printed checksums. -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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Flashing Light Indicators un Simple Front Panels

by pete＠dunnington.u-net.com

On Dec 15, 14:09, Douglas Quebbeman wrote: > > On Dec 14, 16:16, Douglas Quebbeman wrote: > > > > > In particular, do any of you have familiarity with > > > systems that flash the on or power light as an > > > indicattor, sopecifiecally, of a power supply > > > problem? > > > > The only thing I can think of that's *designed* to do something like that > > is an SGI Indy; if you power one up and it can't even run the the code in > > the PROM, it flashes the power light (which is a two-colour LED). The > > usual cause id that there's no (recognisable) RAM at all in it. Probably > > not relevant to a PR1ME. > > No, I'm afraid you may have hit it on the head, and it's been the > direction I've been leaning, that the microcode ROMs may have > fried, but that just blows my mind. Possible, of course, but in the case of an Indy, the processor and PSU are working, and it gets only as far as the "I think, therefore I am a processor; I wonder if I have any memory" test in the PROM, and then executes a loop which controls the LED in the PSU if there's no RAM. At least, that's what I believe; I've not seen a detailed description of the PROM startup. I suppose your problem may be something similar, in that the CPU is running but can't do anyting useful because either it's crippled or some other part of the system is disfuntional. Does the CPU control the power supply LED(s), like it does in an Indy? -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: Jeffrey S. Sharp <jss(a)subatomix.com> >I asked and was told not to clean the core, that whatever junk gets stuck >in there wou't hurt the core's operation. Maybe it's time for round 2 of >the discussion. > >What if something in that dust is conductive? I'd rise in clean water maybe Isopropanol(91% or better) by dipping in a pan with a large quanitiy. Agitate minimally, no brushing or high pressure air near the mat. dry with warm (NOT HOT) hairdryer. >What if something in that dust has wierd magnetic properties? >What if that dust interferes with the core's cooling? See above. >What if I slowly dipped the core board into a pan of IPA or distilled >water, then slowly lifted it out, and repeated until the core board was >clean? IPA may not be the best bet for the muck. Use a lage quanity so that you don't saturate the solution with the muck. Rinse again with fresh solution to further remove the muck. You might try water with a small (1%) amount of detergent too. Risnse water out with IPA and blow dry with hair dryer on warm, not hot. Remember IPA is flammable and to do a PDP-8 core I'd use about 2 quarts (2L for those on the otherside) for first rine and about the same for the second. So use care and DO IT OUTSIDE. Allison

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 10:34, Chad Fernandez wrote: > I've never seen core in real life...... how small are the wires? Depends on the core, but thinner than hair, usually. There's a picture of an H214 core board on EBay at the moment; you'll see 12 large and 8 small dark rectangles on it. http://cgi.ebay.co.uk/aw-cgi/eBayISAPI.dll?ViewItem&item=1309747460 The larger rectangles measure approximately 5/8" x 2 1/4". Those rectangles are the core mat; it's an 8K x 16 bit core mat. Each of those 131072 ferrite cores has three wires going through it. -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: Chad Fernandez <fernande(a)internet1.net> >I use the dishwasher to clean computers too, but what about core >memory? I've never handled it myself, but I understand it is quite >delicate.... any special handling needed? I did a pdp-8/f, washed everything save for the PS and the Core plane. The acutal core plane was fairly clean but everything else was a mess and needed a bath serious. Allison

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 12:20, Matthew Sell wrote: > I don't know enough about the effects of using certain chemicals on the > various plastics and expoxies used in the manufacture of the boards, so I > steer clear of using a detergent unless I know that it would be perfectly fine. No normal detergent will attack ordinary plastics or epoxies. Some industrial detergent powders include caustic ingedients, and (mainly for that reason, and because they can harm skin) are banned from domestic sale in the UK, and also, I beieve, in the USA. In general, any home-use detergent safe to use on your skin, clothes, etc, is safe on PCBs and electronics. I'd be wary of some organic solvents, including alcohols, however. Some attack plastics such as Perspex (Lucite), polystyrene, ABS, etc; some will attack some types of enamel insulation on wire; some affect PVC insulation, making it swell or become brittle. > My experience has been that with certain devices that spend entire lives > inside, that usually a rinse with hot water makes them look new. I've been > satisfied with just using hot water, and everything looks nearly new when > complete. Unfortunately that doesn't apply to computers that have been in places where they may accumulate sticky substances from the air (tobacco film, brewing residue, oily film + dust, etc). In that case, warm water and a moderate amount of detergent is the kindest thing you could use. Ever tried to clean an old TV set with plain water? -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: Mark Crispin <mrc(a)CAC.Washington.EDU> >I am appalled that anyone would seriously consider putting any electronic >equipment, much less antiques, in a dishwasher. You never seen how they were made then. >It may be alright to (gently!) vaccuum away dust and deteriorated foam >rubber, although a feather duster may be more appropriate. I would not Believe it or not vacuuming can create damaging ESD for sensitive boards like core drivers and even TTL! >risk anything else, and certainly not insert anything (including water or >alcohol) under the plexiglass shield protecting the core. Correct there. The core plane is fragile. >A damp cloth with perhaps a bit of soap to the exterior surfaces of the >case is probably all you really need, but be sure not to let any liquid >seep into the inerior. A lot of the PDP-8s have lived in industrial enviornments and offices where clean air is unheard of. Many really are filthy. Allison

23 years, 7 months

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how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: Gunther Schadow <gunther(a)aurora.regenstrief.org> >I have that itching to start up my new PDP8/A even without >disks attached. Have a programmers console, so that's enough >to enter a few programs. It's intriguing to see a machine Congrats! >But first I need to give this thing a good cleaning. A friend >has assured me that there's nothing better than the dishwasher, >with the exception of big capacitors and, what about magnetic >core memory? So, how should I clean the RAM cards? How the >DC power supply units? The PS do by hand and CORE planes never goes in the dishwasher. The core IO boards can be dishwashed. >If I put the other stuff in the dishwasher, I know there should >be no detergent and no heat dry. But what about the rinsing >aid, do I have to pump this out of the reservoir? No problem. I use minimal detergent as most of the dreg on the boards is water soluable. >I heard of another method using hand-washing first, then drying >and finally a bath in Isopropanol. Is that what I should do >with the core memory cards? Core planes are very fragile and usually covered enough to prevent much muck inside. the driver boards usually get nasty dirty. >Finally, finally, I noticed that the cards are all slightly >bent from being kept in a horizontal position. They are sagging >a little, like a hammock. Would that be a cause of concern >in the long run? Should I mount the chassis in an upright >position in the future? Not an issue, dont try to straighten. >PS: I am probably going to make one "portable" PDP-8, where >the console is mounted on the chassis and the rest of the >opening covered plus a handle on the top. That would be neat >for bringing into the classroom to teach fundamentals of >computer programming, wouldn't it? yes it would PDP-8 is still a good minimalist model to work from. Allison

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 9:27, Ben Franchuk wrote: > I also would consider the qaulity of the water. I would wash in > distilled > water. The last thing you want is clorine or other acids and junk from > the > water slower eating your PCB. For the time it takes to wash a PCB, nothing dissolved in normal water is going to matter. Make sure it's free of paticulate matter that might get stuck somwhere, don't use the raw undiluted waste from someone else's chemical process, but there's no need to go over the top. The chlorine added to tap water, for example, will do no harm. -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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Flashing Light Indicators un Simple Front Panels

by mcguire＠neurotica.com

On December 15, Douglas Quebbeman wrote: > No, I'm afraid you may have hit it on the head, and it's been the > direction I've been leaning, that the microcode ROMs may have > fried, but that just blows my mind. Tonight, I'll set up the No, Doug...the microcode ROMs being fried should blow the PR1ME's mind, not yours. ;) (Sorry, I couldn't resist!) > PC that's got my ROM burner/reader, and read each one (if the > ROMs aren't too large a size for my Needham unit). I'm assuming > I'll see all 00s or all FFs (or maybe something like FEs) if > they're blown; been a long time since I've looked at popped > ROMs... What kind of ROMs does it use? Another possibility might be to find someone with the same model of PR1ME (how rare are they?) and checksum the ROMs & compare them...most PROM burners will generate checksums, but now that I think of it, PROM burner manufacturers have yet to standardize on a checksumming algorithm so it'd probably be useless unless they're summed with the same make/model of burner. :-( -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years, 7 months

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Flashing Light Indicators un Simple Front Panels

by dhquebbeman＠theestopinalgroup.com

> On Dec 14, 16:16, Douglas Quebbeman wrote: > > > In particular, do any of you have familiarity with > > systems that flash the on or power light as an > > indicattor, sopecifiecally, of a power supply > > problem? > > The only thing I can think of that's *designed* to do something like that > is an SGI Indy; if you power one up and it can't even run the the code in > the PROM, it flashes the power light (which is a two-colour LED). The > usual cause id that there's no (recognisable) RAM at all in it. Probably > not relevant to a PR1ME. No, I'm afraid you may have hit it on the head, and it's been the direction I've been leaning, that the microcode ROMs may have fried, but that just blows my mind. Tonight, I'll set up the PC that's got my ROM burner/reader, and read each one (if the ROMs aren't too large a size for my Needham unit). I'm assuming I'll see all 00s or all FFs (or maybe something like FEs) if they're blown; been a long time since I've looked at popped ROMs... About the only other possibility is that the backplane got cooked, but it looks fine... -dq

23 years, 7 months

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[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by msell＠ontimesupport.com

Guys, This argument always comes up every few months on the video game collecting newsgroups that I'm a member of. Here we go.... How do you think the boards were cleaned by the manufacturer? Boardwashers!!!!! (big versions of dishwashers - usually with conveyors for constant operation) I've been employed by two different electronic test equipment manufacturers, and have consulted a bunch more regarding quality control and calibration of electronic test equipment. EVERY SINGLE ONE OF THEM USES WATER TO CLEAN THE BOARDS. No shit. Depending on the type of equipment that is being produced, some may use distilled water, others filtered water, some use "deionized" water. But it's still water. Hot water. I clean all of my computers, upright video games, and all of the boards >from my two 11/780's and one PDP-11/34A in the dishwasher. No damage yet, after several YEARS of doing this. I've put high-voltage power supplies, low voltage power supplies, floppy disk drives, CPU boards and everything else in the wash. What doesn't fit in the dishwasher gets blasted with 409 and hot water in the tub. Here's the secrets to doing this right: 1) Do not use any detergents. NONE. 2) Turn off the plate warming and drying cycles. The heating elements in the washer can distort or damage plastics. 3) Remove soon after cycle is complete. Do not let items sit overnight. Shake off water. 4) Stand up or hang to dry. 5) Let items dry inside the house for several days. I usually don't touch washed items for at least 3-4 days. 6) Don't plug the item in to power of any form until step #5 has completed. For delicate items, I use water from the sink at a low flow rate, and spray a mixture of 409 and water onto the item and allow it to soak for a few minutes before rinsing. I may use a soft paintbrush to clean stubborn dirt if necessary. Rinse and repeat. I know that a good percentage of you are skeptical. Every one of my games in my arcade collection had at least the CPU boardset in the dishwasher. Several others had every single board through the wash. All of them work, and did so before going into the dishwasher and immediately after drying. Others had the monitors powerwashed. I took an entire 11/780 out into my driveway and I powerwashed the chassis AND backplane! Don't take my word for it; take a board that you know is operational, of little value to you, test it out, and run it through the dishwasher using the steps outlined above. After a few days of drying, test it out. It'll work. And - I severely doubt that you get it any cleaner using any other method. Of course, don't wash the boards with your regular load of plates and pots..... : ) - Matt At 10:25 PM 12/14/2001 -0800, you wrote: >On Fri, 14 Dec 2001, Gunther Schadow wrote: > > But first I need to give this thing a good cleaning. > >Why? > > > A friend > > has assured me that there's nothing better than the dishwasher, > > with the exception of big capacitors and, what about magnetic > > core memory? > >I am appalled that anyone would seriously consider putting any electronic >equipment, much less antiques, in a dishwasher. > >It may be alright to (gently!) vaccuum away dust and deteriorated foam >rubber, although a feather duster may be more appropriate. I would not >risk anything else, and certainly not insert anything (including water or >alcohol) under the plexiglass shield protecting the core. > >A damp cloth with perhaps a bit of soap to the exterior surfaces of the >case is probably all you really need, but be sure not to let any liquid >seep into the inerior. > >-- Mark -- > >http://staff.washington.edu/mrc >Science does not emerge from voting, party politics, or public debate. Matthew Sell Programmer On Time Support, Inc. www.ontimesupport.com (281) 296-6066 Join the Metrology Software discussion group METLIST! http://www.ontimesupport.com/cgi-bin/mojo/mojo.cgi "One World, One Web, One Program" - Microsoft Promotional Ad "Ein Volk, Ein Reich, Ein Fuhrer" - Adolf Hitler Many thanks for this tagline to a fellow RGVAC'er...

23 years, 7 months

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Color Coding, A/C (Mains) Leads, USA ONLY, Redux

by dhquebbeman＠theestopinalgroup.com

> Two parallel blades is 120V 15A. One perpendicular to the other is > (usually!) 120V 20A, but it could be a 250V plug, too. The 120V 20A plug > can be adjusted to fit a 15A recep by the judicious(sp?) application of a > pair of pliers... No, I've never done such a dangerous thing! -_^ Just > remember, too close to the body of the plug and it'll shear off, too far out > and it won't insert fully into the plug. Sorry I wasn't clear- plug matches the outlet it goes into, no need to "re-engineer"... -dq

23 years, 7 months

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Hardest to Find Classic Computers

by dhquebbeman＠theestopinalgroup.com

> The Lilith & the Tektronix Magnolia. These I regret not > hanging on to. I have never seen another. I still have > a Lilith mouse. Did the Magnolia really Smalltalk-80 in reverse-video mode? The only ones I've seen were in photos, and one showed white text on black background in Smalltalk... -dq

23 years, 7 months

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how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 14, 23:47, Gunther Schadow wrote: > But first I need to give this thing a good cleaning. A friend > has assured me that there's nothing better than the dishwasher, > with the exception of big capacitors and, what about magnetic > core memory? So, how should I clean the RAM cards? How the > DC power supply units? NOT the core! If you need to clean the core, my suggestion would be to immerse it in a washing-up basin with tepid water and a little soap or washing-up detergent, and *gently* swish it about a little. Then rinse twice, let it drain, and dry off gently. Don't use compressed air or solvents. > If I put the other stuff in the dishwasher, I know there should > be no detergent and no heat dry. But what about the rinsing > aid, do I have to pump this out of the reservoir? I don't think the detergent will do any harm, providing it's not too caustic, but avoid excessively hot water and high-temperature drying. Before you use the dishwasher, check for switches etc that might not take kindly to being immersed in soapy water, and either carefully remove them (taking careful note of where they go) and relays (don't wash relays). Also check for any labels that will be damaged or which might come off and end up where you don't want them. The rinse aid won't do any harm at all, in fact it wil help the water drain off (it's just a wetting agent). > I heard of another method using hand-washing first, then drying > and finally a bath in Isopropanol. Is that what I should do > with the core memory cards? Yes, see above, but omit the IPA. When I cleaned my PDP-8/E recently, I put all the boards except the core in the dishwasher, along with the front panel circuit board (I removed the LEDs first, since they were in bi-pin sockets), over-the-top connectors, and the two backplanes. I ran it on the usual cycle, with detergent and rinse aid. When I took the boards out, I blew off the remaining water (some tends to stay under ICs) with compressed air, and gave anything that might harbour water (DIP switches, panel switches) a good dose of iso-propyl alcohol, which I then drained/blew off. The IPA mixes with the remaining water and helps to remove it; the air removes the last traces of IPA. Finally I treated all the switches to a small dose of low-residue switch cleaner/lubricant. Similar treatment for the backplanes and connectors, except it's hard to get the last of the water/IPA out so I let them stand upright in front of a hair drier on a low heat setting for a couple of hours while I got on with other things. The PSU was too big for the dishwasher, and I wouldn't have wanted the transformer in there anyway. The 8/E has a linear supply with a big transformer; the 8/A has a switcher, I think. Anyway, I took off the side panel, removed the fans, relay, and fuse carriers (carefully noting how they were wired). I sprayed it with enzymatic cleaner (it was smelly) and detergent mixed with water in a spray bottle to dissolve the muck, left it to sit for a few minutes, and then rinsed it out with the garden hose (low pressure!) trying to avoid getting too much water into the transformer. Then I drained it out, and used most of a 500g aerosol of IPA to flush out the water, and compressed air to remove the residue, especially in the connectors. I let it stand in a warm dry room overnight before powering it up; I figured there might still be dampness in nooks and crannies in the transformer, and I didn't want to take chances. If you have small parts that need washed, then they can go in the cutlery basket in the dishwasher providing they're heavy enough not to jump out (metal brackets for example) or in a strong mesh bag in the dishwasher. For more delicate things you can tie them in a pillowcase and put them in the washing machine. I use the pillowcase/washing machine for keytops, cartridge cases, etc. Most of the foam in my 8/E was past redemption, so I stripped it off with a wallpaper stripping knife and replaced it with "high-density" upholstery foam about 3/8" thick -- not the really high density stuff that seems to be made of lumps of recylcled stuff, just the stuff used to pad seats. I cleaned off the old glue and stuck the new foam on with spray glue, after masking off the area to spray (like you would for spray paint). The foam under the backplanes was OK, so it went in the (clothes) washing machine on a hot wash. > Finally, finally, I noticed that the cards are all slightly > bent from being kept in a horizontal position. They are sagging > a little, like a hammock. Would that be a cause of concern > in the long run? Should I mount the chassis in an upright > position in the future? Not unless they're so badly warped that things might short between cards. Some of mine were warped when I got them, and don't seem to have suffered. > any other things I should know? Use a pen torch to look in the backplane slots for any rubbish the dishwasher might not remove (paperclips, cruddy foam, etc). Do make sure everything is dry before you power them up (or even reassemble them). Do make a note of where and how everything you remove goes back. I thought all the LEDs in my panel were the same way up; they weren't and it took me half an hour (without the circuit diagrams) to get them all the right way round. I find it helpful to put the screws from each section or panel or whatever into a separate ziplock bag or a dish; there are always some missing and it helps figure out what goes where, how many are needed, and what lengths they should be when you come to reassemble it all. Check the fans rotate freely; I always relubricate bronze bearing types with light machine oil. I have a few toggle-in programs I've collected or modified for first-time confidence testing, like the inchworm program and a couple of serial port testers (continuously write character to console; echo console, etc). -- Pete Peter Turnbull Network Manager University of York

23 years, 7 months

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Co-routines was Re: [PDP8-Lovers] if you hadn't already known this about the PDP-8

by mranalog＠attbi.com

"Sean 'Captain Napalm' Conner" <spc(a)conman.org> wrote: > So what, exactly is a co-routine? I've heard the term before, but I'm not > entirely sure what they are, or how they would work. > -spc (I may have used them in assembly, but not knew the proper term ... ) The only time I remember using a coroutine was a time when I had no interrupts to use. The Sega Genesis has a 68000 with main program memory, plus a sound system controlled by a Z80 with it's own sound memory. Sound memory is loaded with a sound driver written in Z80 assembly. Now the sound system has a free running timer but no interrupts, so most games had a sound driver that played FM sounds or a sound driver that played digitized sound. My job was to take an FM sound driver and make it play digitized sound at the same time. So I wrote a routine that quickly checked if a digitized sound was playing and if it was, then check if it was time to stuff the next value of the digitized sound. The hard part was then to pepper the existing sound driver with calls to this coroutine such that the existing sound driver would not be slowed down and that the digitized sound would be played at a constant rate. It worked great. Oh! "what, exactly is a co-routine?" A coroutine is a procedure that executes from the point it last suspended execution up to the next instruction that suspends its execution. That is, it preserves state between invocations. Regards, --Doug ========================================= Doug Coward @ home in Poulsbo, WA Analog Computer Online Museum and History Center http://www.best.com/~dcoward/analog =========================================

23 years, 7 months

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test-drb December 2001