test-drb August 2004

test-drb@ccmp.vtda.org

283 participants
661 discussions

by evan947＠yahoo.com

Many things went to Boston's Science Museum as well. > What became of the Boston Computer Museum, anyway? And what happened to > their collection, such as it was? It moved to the west coast and became the Computer History Museum. --

19 years, 11 months

Trying to remember a machine

by jcwren＠jcwren.com

I'm trying to recall the name of a machine made back in the 80's, I think. I'm pretty sure it was 68000 based, had 2 1/2 or 1/3 height 8" floppies stacked, was as wide as the floppy drives, about 8" tall (guessing), and maybe 6" to 8" deeper than the floppy drives. I was thinking it was a Sage II or Sage IV, but those all had side-by-side 5.25" drives. I'm not positive, but I think this was a Pascal P-machine, or at least was in it's native configuration, if it was 68000. Anyone remember what I'm trying to think of? --jc

19 years, 11 months

MITS Teletype Interface Board

by dwight.elvey＠amd.com

Hi It doesn't look like it has enough on it to be a RS-232 converter but it could be a 20 to 60 mil converter. You might look at the circuit layout around the thansistors labeled Q1 to Q4. Tracing this part out will most likely figure out what the intent is. It looks like it does replace some of the power supply sections of a ASR33 so that would explain the look of a power supply. You can power the unit up and look at the voltages on the DB25. I tend to agree that missing both pin 1 and pin 7 would indicate that it wasn't a RS232. Dwight >From: "Brian Knittel" <brian(a)quarterbyte.com> > >Hi, > >For those of you who asked to see the MITS >Teletype Interface board I mentioned a couple >of days ago, I've put a picture at >http://www.ibm1130.org/misc/mits-tty-interface.jpg > >The molex connector at the bottom left below the relay >is where the data cable connects. The other end is >a DB25 connector, and the wires go to pins 2-6. Since >there is no connection to pin 7 (signal ground) it must >be current loop. > >Brian >

19 years, 11 months

KA630 guru/tests?

by mouse＠Rodents.Montreal.QC.CA

Now that I'm back on the list, by dint of unsub + resub (which I really should have thought to do earlier, rather than waiting against the time Jay finally emerges from the aftermath of VCF East).... I'm trying to build a KA630 emulator, more because I think it'll be fun and will teach me stuff than because I actually have a use for such a thing (there are plenty of good open-source VAX emulators out there already). I picked the KA630 because it's the only VAX implementation I have enough information on to even really attempt to build a simulator for. I dumped the ROMs from one of my KA630s (e/l/p/n:3fff 20040000, plus some postprocessing of the capture file) to get firmware. But the emulated VAX hangs at selftest step B. The manual I have (EK-KA630-UG-001) says this means that the IPCR is not working properly (probably broken Qbus electronics, on a real KA630), but it doesn't go into any significant detail. Furthermore, if I break to the simulator and manually advance it past the "blbc r0,." that it's hanging at, it continues, but ends up with an error at step 7 - apparently it can't find any working memory(!). Now, the manual could be simply wrong. I've found it lying (or, let me be charitable, "not matching the machine I have") at once already; it claims certain bits are write-only, but the ROM code depends on being able to read them. Or I could be mis-emulating the Qbus stuff. Or I could have a bug in the emulation of an instruction somewhere. So, I'm looking for either or both of (a) someone who's enough of a KA630 guru to help or (b) some kind of VAX instruction-set test suite, to help verify that I have the instruction emulations right. (I caught one instruction emulation bug already, quite by chance; there is surely at least one more.) Thoughts? /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse(a)rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

19 years, 11 months

Hardware/doc preservatoion, was Re: rarest computers.

by dwight.elvey＠amd.com

>From: "Paul Koning" <pkoning(a)equallogic.com> > >>>>>> "Paul" == Paul Koning <pkoning(a)equallogic.com> writes: > >>>>>> "Steven" == Steven N Hirsch <shirsch(a)adelphia.net> writes: > Steven> On Wed, 4 Aug 2004, ben franchuk wrote: > >>> PS. Years ago in BYTE ( early 1990's? ) they had spoke up of a > >>> CPU designed for reliable operation for real time control of > >>> things like power plants or subways or aircraft. They claimed it > >>> was so simple that programs could be proven to be bug free. I was > >>> wondering if they manufactured or sold any the devices. > > Steven> That would be the British "Viper" CPU. Computational theory > Steven> suggests (proves, perhaps? - it's been a few years) that use > Steven> of hardware or software stacks renders behavior > Steven> indeterminate. > > Paul> Baloney. Anyone who has paid any attention to Dijkstra knows > Paul> that such a statement would have to be complete and utter > Paul> nonsense. > >PS. It is certainly true that programs can be proven to match their >specification. That's not quite the same as proving them bug free -- >it now requires the specification to be bug free. > >But such proofs in no way require the absence of a stack. That's >actually rather obvious, because any program that uses a stack can be >rewritten into a program that does not use one. But in fact such a >rewrite does not help readability at all. > >It probably is not a coincidence that the scientist who did much early >work on stacks is also the scientist who spent a lifetime working on >program correctness (E.W.Dijkstra). > > paul > Hi I think that it is interesting that there is a programmer in the UK that produces one of the few provable program products for correctness ( to specification ) that meet some standard ( I forget which ) and his programs are all done in Forth ( that uses two stacks ). My understanding is that most of the reason he can produce this is that the language it self is built and verified by him and that even though there are stacks, use is usually more controlled and maximum depths can be calculated. Most Forth processes are done with cooperative tasking rather than the more random effects of preemptive. This also means better predictability. The other part is that Forth programs tend to be highly factored. This means that hierarchical verification is more practical. It is easier to understand the range of valid inputs for each piece and how those effect the next level up. He writes program for such things as subway control systems. His products need to meet tight controls that need to be absolutely correct or people die. Strange that he would use a language that not only uses a stack but uses two stacks and still produces verifiable results. He considers that choice to be a most important one. Dwight

19 years, 11 months

old stuff found

by waltje＠pdp11.nl

Hi all, I found three interesting bits of stuff today: 1. HeathkitH-8 2. Tandy Color Computer 3 3. Instructigraph code/teletype practice set with practice tapes, keys and (tube) amp There's also a cute Tandy 200-in-one Electronics Lab kit, thats way cool :) I am cleaning out someone's garage for them, and would probably want to sell the above items to get them some money. Any interest here, or should I go ePay ? Cheers, Fred

19 years, 11 months

Article on data rot on CD's

by cb＠mythtech.net

>Some of the CD longevity articles talk about this... those safes >are rated to preserve paper. The char or combustion temperature for >paper is far higher than the highest temperature that a CD-R >will survive. True, I hadn't thought about that angle of it. I suppose a CD or disk will warp enough to ruin it long before paper starts to show signs of heat damage. Its still going to be better then keeping important media in a cardboard box. -chris <http://www.mythtech.net>

19 years, 11 months

OT: Simple electronics question...

by woyciesjes＠sbcglobal.net

I do realize that this doesn't really apply here, but I know some of the electronic geniuses here can help me out... I have a little Timex clock radio. Works great, except when I want to fall asleep to the radio, I need to turn it down so as not to disturb my wife. Problem is, that the volume control isn't sensitive enough at the low volume I want. So, my thought is to put a resistor on the positive lead of the speaker, which (I think) would lower the overall volume output, and give me a wider range to adjust the volume to a quiet level. I'm just not sure what size resistor to use, or if that is even the right way to go. I haven't cracked it open yet, but I'm fairly certain it's only a single speaker in there, and it's probably a 16 ohm one at that. Am I on the right track? -- --- Dave Woyciesjes --- ICQ# 905818

19 years, 11 months

Fw: OT stupid Welsh and Americans (was Re: Cirris 1000)

by geoffreythomas＠onetel.com

This one got lost too . What's going on ? ----- Original Message ----- From: "Geoffrey Thomas" <geoffreythomas(a)onetel.com> To: "Joe R." <rigdonj(a)cfl.rr.com> Sent: Wednesday, August 04, 2004 12:59 AM Subject: Re: OT stupid Welsh and Americans (was Re: Cirris 1000) > > >But our comrade Joe is using a purely perjorative term from the English > > >colonial past. > > > > I might be classified as a lot of things but Comrade is definitely not > > one of them! Where the hell did that come from anyway? > > It's meant to be irony.

19 years, 11 months

Fw: OT stupid Welsh and Americans (was Re: Cirris 1000)

by geoffreythomas＠onetel.com

This message got lost , here it is again. It wasn't censored was it ? ----- Original Message ----- From: "Geoffrey Thomas" <geoffreythomas(a)onetel.com> To: "Joe R." <rigdonj(a)cfl.rr.com> Sent: Tuesday, August 03, 2004 12:42 PM Subject: Re: OT stupid Welsh and Americans (was Re: Cirris 1000) > > ----- Original Message ----- > From: "Joe R." <rigdonj(a)cfl.rr.com> > To: "Geoffrey Thomas" <geoffreythomas(a)onetel.com>; "General Discussion: > On-Topic and Off-Topic Posts" <cctalk(a)classiccmp.org> > Sent: Tuesday, August 03, 2004 12:01 AM > Subject: Re: OT stupid Welsh and Americans (was Re: Cirris 1000) > > > > Considering the English colonial past, the English don't have the right > > to complain about anything! Not only see Opium wars, see black slavery > > (who do you think shipped the slaves to America and the Caribeaan in > > exchange for sugar and rum?), Irish potato famine, Endentured Servitude > > (another word for slavery), debitor's prison, scalp bounties (both in > North > > American and for Australian Aborigines), press gangs (ship's crews). Then > > go see American Revolution! > > > > Now do you REALLY want to get into a debate about English colonial > past???? > > > > My 2 cents worth, > > Joe > > I'm not English , I'm Welsh - hence my objection to your use of the term in > an offensive (to me ) manner. > You don't need to tell me about the English colonial past - the Welsh have > been on the wrong end of it - hence the large migration to the USA to get > away from them . Hence also the large no. of signatories on the declaration > of independence who are of Welsh descent. > > Geoff. >

19 years, 11 months

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test-drb August 2004