test-drb March 2013

test-drb@ccmp.vtda.org

200 participants
326 discussions

by enrico.lazzerini＠email.it

Hi at all, I'm sorry I'm not very prepared and my English is basic. I have a mainboard with CPU Z80 derived from the famous Ferguson Big Board 1 (that i have working fine). It has a CPU Z80A running at 4MHz, 64KByte DRAM, FDC 1797 with external data separator FDC9228BT. It equipped with its own BIOS that is loaded into memory at address F800H but it not has the operating system CP/M. If instead of his eprom i insert the firmware coming from Ferguson Bigboard 1 (which is loaded into memory at address F000H) that has FDC 1771 it run properly loading the operating system CP/M 2.2. I looked in my experience and modified the CP/M loader and CBIOS to point at the entry points of the bios at F800H, so the loader loads into memory correctly ALL the CCP, the BDOS and CBIOS, but it not complete the boot CP/M with the prompt (the error that comes to me is: track 2 sector 1 not found. it is an area where normally there is no CP/M code and that it is regularly read with a simple read command available from the firmware). I ASK FOR: Anybody has any idea? Is there a Z80 emulator where I can load the BIOS and i can try to load the operating system CP/M to see what type of problem? Regards Enri

11 years, 9 months

PDP 11/23 advice

by charlesmorris800＠centurytel.net

I have a H9273-A backplane gathering dust that I'll sell cheap. -Charles

11 years, 9 months

Slide Rules (was: Calculators)

by mtapley＠swri.edu

James (and Chris), I graduated in 1980, McCallum High School, Austin, Texas. We had a slide rule team, with a coach. In addition, my Biology and physics teachers all let me use slide rule for all homework and tests, giving me credit if my answer was within about 0.5% or so. Dunno whether that counts, but if so would push the date out to 1980. I did get a TI-59 (still have it, sticky keyboard and I'll bet the card reader doesn't work) middle of my senior year. That was a pleasant culture shock... I don't know that I ever saw one of the six-foot-long "supercomputers" :-) . At 20:07 -0600 3/2/13, <James> wrote: >This leads me to my belief that I was the last slide rule teacher.? >In 1975, in Ghana, .... -- - Mark 210-379-4635 ----------------------------------------------------------------------- Large Asteroids headed toward planets inhabited by beings that don't have technology adequate to stop them: Think of it as Evolution in Fast-Forward.

11 years, 9 months

PDP 11/23 advice

by ian.finder＠gmail.com

Hi everyone, I recently obtained a box of stuff. The box appears to contain a complete 11/23 boardset! I've wanted a PDP 11 for some time, so needless to say, it would be great to make an actual PDP 11/23 out of the boards. My options appear to be purchasing a complete chassis with a backplane, power supply, and IO-- or alternatively building my own replacements for these parts. I'd also need a disk at some point, but for now that's out of scope. Can anyone comment on the feasibility of either of these options? Are chassis something that pop up from time to time? Are there multiple models that will take this board set? Alternatively, is the backplane something fancy I'd be unable to roll my own of? Cheers, - Ian Sent via mobile.

11 years, 9 months

Available retro-computing PCBs

by LYNCHAJ＠YAHOO.COM

Hi There are many N8VEM PCBs remaining for the ECB systems http://n8vem-sbc.pbworks.com/w/page/35044530/PCB%20Inventory There are about three S-100 Regular Prototyping boards (non-buffered) and about seven S-100 LAVA board PCBs http://s100computers.com/My%20System%20Pages/Lava-10%20Board/LAVA-10%20Board .htm For planning purposes, I've ordered another batch of the XT-IDE V2 PCBs which should be here in late Mar 2013 http://www.vintage-computer.com/vcforum/showwiki.php?title=XTIDE+Rev2 The initial batch of twenty XT-FDC V1 PCBs will be here for the initial builders in late Mar 2013 http://www.vintage-computer.com/vcforum/showwiki.php?title=XT-FDC+Rev1 Finally, I am planning on ordering the second prototype board for the SCSI to IDE/SD (aka S2I) bridge board as soon as the PCB gets updated with all the builder feedback. Hopefully this will be in the next few days. http://n8vem-sbc.pbworks.com/w/page/62549548/S2I%20Firmware%20Status If you are interested in any of the above projects please contact me at LYNCHAJ at YAHOO.COM Thanks and have a nice day! Andrew Lynch

11 years, 9 months

Imaging a Tape

by steve＠stephenmerrony.co.uk

What is the current best practice for creating an image of a SCSI tape in such a way that it can later be used to reliably make a replica of that tape? I have a fully functioning SCSI tape drive (via Linux at the moment) and want to image various sorts of Data General (and other) tapes safely and also duplicate a couple of them. They are in various odd formats. I can use the non-rewinding device (/dev/nrst0 etc) to get individual files off the tapes but that is tedious and writing a tape like that seems like a nightmare. I found tcopy and built it - but it expects two drives and does not deal with the drive-and-file case. Steve DG Info and Restoration Blog - http://stephen.homedns.org/dg/

11 years, 9 months

Natsemi MM5736 pinout

by jules.richardson99＠gmail.com

Does anyone happen to have the pinout handy for a Natsemi MM5736 IC (mid-'70s)? In particular, I want to know which pin is GND. I came home with a little Novus 650 calculator yesterday, but the power switch (which switches the ground line) is dead - of course the keypad's heat-staked so before I waste time having to do surgery in order to clean switch contacts, I'd like to see if the calc looks like it might be otherwise functional. cheers Jules

11 years, 9 months

Slide Rules

by feldman.r＠comcast.net

>Message: 6 >Date: Thu, 7 Mar 2013 09:43:21 -0800 (PST) >From: Fred Cisin <cisin at xenosoft.com> > >So, is it a flat spiral or a helix? >Either one at 10" diameter is an impressively long scale, for a LOT of >accuracy! It seems like it would be physically impossible to make a flat spiral _SLIDE_ rule (where one scale can be repositioned against another scale). The Computer History Museum has a spiral slide rule (http://www.computerhistory.org/collections/accession/102633252), but it is not clear from the picture if the scales _SLIDE_ against each other. In a spiral, the area of a segment that as one degree wide by one spiral line to the next decreases as one goes toward the center, so a slide would bind if you tried to turn it toward the center or would be loose and not evenly contact the next band if you turned it away from the center. In an earlier post in this thread, someone said that they had not used their slide rule in anger. As a kid, I made something that would have been useful if they had wanted to. I took a cheap wooden slide rule, lightly sanded the groves, waxed the slide, and wrapped four big rubber bands along the length, so one end was on the outer part at one end and the other end was on the slide. Worked sort of like a cross bow or spear gun. I could send the slider through 6 layers of corrugated card board at about 20 feet! Bob

11 years, 9 months

Burroughs adding machine

by jules.richardson99＠gmail.com

Any early Burroughs experts here? Yesterday I discovered a Burroughs "Style no. 3" adding machine in a junk/antiques store (the kind of wonderful store where you have to dig through stuff to get to more stuff, and when you get to that there's even more stuff underneath/inside it :-) Anyway, it's got the pedestal, side-desk and printing mechanism (at least I assume that the gubbins at the back is a printer, although I couldn't immediately see how it transfers to the paper - poss. just not visible with the platen in the way). It seems to be basically the same as this one: http://www.fi.edu/learn/sci-tech/adding-machine/adding-machine.php ... except: 1) it doesn't have the row of red/white keys across the top, 2) the desk on this one is much larger/nicer, 3) there's no ornate Burroughs script at the base of the keyboard area; instead it says "Burroughs" and "center of type" above the keyboard, 4) the backing to the keyboard seems to be black (not green) 5) the keytop for the lower-left key on the keyboard is red (and a little larger), not metal. The mechanism seems free and cosmetically it's in pretty good shape, considering that it's probably pushing 100 years in age - the main drawback is that it's missing one of the '2' keys (the R/H side glass is cracked and the rubber pads at the top of the pedestal have disintegrated, but both of those problems should be solvable). Immediate questions: 1) Any idea of age? s/n is 27434. I'm leaning toward 1906 as that seems to be when the no. 3 showed up, and by October of that year there had been some 40,000 of them built - but that's assuming that the serial numbers don't carry across all models. I'm surprised if they built that many of them before they were rendered obsolete by a newer model, though. 2) The lack of '2' key is really the main thing stopping me from bringing this thing home. I expect they're common to many early Burroughs machines; is anyone known to carry parts from junk machines, or has anyone succeeded in creating a reproduction key using modern materials? cheers Jules

11 years, 9 months

MPX-16 (Was: BS about "changes in cost of cheapest machines"

by rampaginggreenhulk＠yahoo.com

------------------------------ On Fri, Mar 8, 2013 11:59 AM PST Chuck Guzis wrote: >On 03/07/2013 11:34 PM, Chris Tofu wrote: > >> Okay, I've got the schematics for the Explorer 88/PC (Netronics R&D, New >> LItchfield, Conn), which uses an 8250 for async, has a separate keyboard >> and cassette interface. No video as far as I can tell. >> >> Would you consider sharing these with your down trodden brothers in the community who've had to go without? > >Google Is Your Friend. Look at the ad on page 4 of this PDF: > >http://www.thecomputerarchive.com/archive/Magazines/Kilobaud%20Microcomputi… > >Netronics marketed a variety of kits--the original Explorer, which I believe was a Z80 box, the Explorer 85, which was an 8085 box and the Explorer 88/PC. Looking at the prices is somewhat germane to the original topic. Can you imagine spending $250 for a floppy controller card or $300 for a keyboard? > >Marcus has some "Blue Seed" stuff on his site: > >http://maben.homeip.net/static/S100/IBM/5150%20PC/blue%20seed%20IBM%20Mothe… > >--Chuck I'll check it out. Thanks for getting back. So many find my "condition" offensive. A lot of people indeed do have a problem with people's problems. I'm doing my best to address the logorreah (and my poor spelling). But Hashem it's not like it's halitosis! I feel so isolated. As long as Top Gunner doesn't consign me to the iggy bin I feel I'm making progress. I have a lot of interest in sbc's. I wish I knew how to better research them, in particular the quasi mythical millions of 80186/80188 based embedded controllers. I walked into a place in Bohemia Long Island many years ago and they were manufacturing just that. Apparently a great many small companies were doing just that -

11 years, 9 months

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test-drb March 2013