test-drb August 2015

test-drb@ccmp.vtda.org

206 participants
257 discussions

by jnc＠mercury.lcs.mit.edu

> From: Mark G. Thomas > 4x M8192 - KDJ11 (AA or AB?) -- two work, two fail POST And alas, we don't seem to have any prints for that card (although we do have what amounts to a tech manual, so maybe we can create a set, with a certain amount of tracing with an ohmmeter), so at the moment, at least, fixing them isn't so easy. > I was hoping I could boot XXDP or RT11 from an RX33/RQDX3. The > RX33/RQDX3 works in my 11/53 Well, that's a very good sign... > Since none of this has a bootstrap, I run the bootstrap from ROM > provided by a Dilog SCSI card here, but typing "DU" or "DU0" at the > prompt spins the floppy ever-so-briefly, then kicks out an error about > no boot media found. Suggestions? Maybe I should try other bootstrap? Definitely; the code on the Dilog card might not support that controller properly (even though it seems to recognize "DU"). > I'm a little confused about what should work and what should not work, > with just the 18 bit qbus. If you have less than 256KB of memory (so Q22 processors won't wrap around, when trying to size memory, and think there's memory there above 256K - although Q18 memory probably will stop responding at 248KB, anyway), pretty much everything _should_ work, I would think. The high address lines being put out by the processor, DMA devices, etc should just have no effect. Although the details get tricky... E.g. if you don't have BDAL18-21 for a Q22 memory card, what will its bus interface do when faced with those lines, which aren't driven in any way - _especially_ not pulled up by terminators? Some DEC memory cards (e.g. MSV11-L, M8059) have jumpers to run in either Q18 or Q22 mode, to work around this. > Do I need to wire wrap the additional address lines to be able to do > anything with these KDJ11 CPUs? No, if you have less than 256KB of memory, the high bits should just be ignored (I think - I haven't actually tried this, to be absolutely sure). > Does anyone have good instructions for this modification -- I'll > probably want to do it. Do I just add the additional address lines, or > are there other considerations? I have modified an H9273 backplane (Q18) to H9276 (Q22), and it works fine; all I did was bus all the BDAL18-21 pins together: pretty easy, as it's a Q/CD backplane, not a Q/Q - just run a wire down, and solder it to each pin as it goes (those backplanes don't have the pins stick out far enough for wire wrap). Q/Q will be only slightly more complicated (since you have to bus down one side, then run the signals up and across to the top of the other side, and then bus them in turn - do it this way, to avoid creating a branch in the bus which will encourage reflections); I have done this mod on a Q18/Q18 backplane (a Sigma Q18/Q18), but have yet to actually try it. The only complication might come with termination/pull-ups. Not all backplanes have these built in (e.g. the DEC H9273/H9276 don't). But you might not need them - IIRC both the 11/23 and 11/73 have on-board termination which will pull the lines up. But if you _do_ need them... best bet, unless you want to start soldering resistors to the backplane, is a terminator board with Q22 pullups. That's a whole separate discussion which I will leave for the moment... :-) Noel

9 years, 2 months

New post take longer to appear then replies?

by cctalk＠fahimi.net

Just wondering if new posts are moderated vs. replies? I posted a new message to the list a few hours ago and it still has not shown up. However, a reply to a preexisting message I sent out a few minutes ago has already appeared. Thanks.

9 years, 2 months

Where to get a Vax or microvax

by lyokoboy0＠gmail.com

I have had an interest in the DEC VAX line of computers for some time now and am trying to find a good place to get a system to start out with. The main pourpose being to have a machine to use VMS on. I have been running VMS on emulated hardware via SIMH, however i would like to move to running on real hardware. What would be the best machine for a beginner to VAX Hardware to start out with? My main place for looking for hardware has been ebay, although most of what im seeing is untested and expensive. Is there a better place to find older machines like this?

9 years, 2 months

maybe OT: Powerbook 5300 OS upgrade

by starbase89＠gmail.com

Greetings! I know that many of my posts to this list tend to be on the fringes of what is normally discussed here. I apologize in advance if this is too new for the group. I am trying to get my Powerbook 5300 up and running as a usable word processor (with portable printer) for school and for email. It is currently running System 7.5.2. The machine is capable of supporting MacOS 9.1, but my goal is 8.6. I see them talking on lowendmac that upgrading the OS makes the machine more solid, but it doesn't explain how to do it. The machine only has a floppy drive and no networking. Were there any system 8.6 install floppies? I can't think of another way to get it on there. TIA Joe

9 years, 2 months

Cheap board guy

by jwsmail＠jwsss.com

I have the following from the gold scrapper guy so far... Great tip. Wonder if anyone else partook of the tipoff. Thanks Jim http://jimsoldtoys.blogspot.com/2015/08/dec-boards-kdj11-2-kdf11-and-motoro…

9 years, 2 months

R: DECdatasystem 534 (11/34) and VT52 for sale at VCF Midwest 10

by supervinx＠libero.it

Location? -------- Messaggio originale -------- Da: Julian Wolfe <julian at twinax.org> Data:20/08/2015 15:44 (GMT+01:00) A: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Oggetto: DECdatasystem 534 (11/34) and VT52 for sale at VCF Midwest 10 I will be selling my DECdatasystem 534 and VT52 at the show. Cabinet rack, 72x24x26".11/34a, 32kW of core and A/D+D/A cards. System runs fine and drops to a console prompt, and passes all the diags I've been able to throw at it. I've restored all the foam filters and the cabinet was pressure washed a couple of years ago so no funny smells or mold. I have no peripherals for it. The VT52 does not power on. I'm entertaining pre-show offers, so let me know privately if you are interested in either of these items. Julian

9 years, 2 months

8-inch alignment floppy wanted

by spacewar＠gmail.com

Does anyone have a spare 8-inch alignment floppy they'd be willing to sell? I'd prefer a double-sided one, but even a single-sided would be better than nothing.

9 years, 2 months

5.25 floppies that read but don't write

by marc.verdiell＠gmail.com

Thanks Chuck. Looks like you are on to something, I'll search in this direction. Unlikely it has anything to do with the disks themselves, which were blank. The 500 kHz write signal present on the connector just doesn't make it to the head, whereas the 300 kHz does. On the other handm something along what Chuck suggests could create this exact problem. I'll let you know how it goes. I am aware of the narrow track problem of 360k written by HD drives, so I have other native 360k DD drives for that purpose. For now I just want my HD drive to behave as one ;-) >At high density, have you taken a good look at pin 2 of the floppy >interface? Have you checked to see if pin 2 is configured (via jumpers) >as "density select"? Various drives have different jumperings for >pins 2 and 34 (and sometimes 4). For example, I deal with some Japanese >CNC gear that uses pin 2 for disk change and pin 34 for read (and pin 4 >for "in use". >--Chuck >> So I tried to force formatting in DOS at 360k, and sure enough it >> worked! I can then read the diskette back, write on it, etc... And of >> course it failed formatting at 1.2 Mb. But the drive (Chinon FR-506) >> is a 1.2M one, and reads fine at 1.2M! Any clue? Is there a drive >> setting that would prevent it to write at high density but let it do >> at low density?

9 years, 2 months

MIPS systems available...

by lbickley＠bickleywest.com

Weirdstuff recently received the following: (2) Magnum 4000SC-50 mips systems (2) RS 2030 mips systems Look clean (from the outside)... Contact Jim if you're interested in them. Usual disclaimer: I have no relationship with Weirdstuff other than as a client. I receive no remuneration for posting this. I do a weekly "tour" of their facilities to find vintage gear. Cheers, Lyle -- 73 AF6WS Bickley Consulting West Inc. http://bickleywest.com "Black holes are where God is dividing by zero"

9 years, 2 months

5.25 floppies that read but don't write

by marc.verdiell＠gmail.com

Following Chuck's advice, I scoped out the pin 22 and 24 (write data and write gate) on the floppy, and they looked fine. Then being curious, I managed to figure out what the write wire for Head 0 was. And I discovered I got nice matching writing pulses at 300 kHz (formatting at 360k density), but none at 500 kHz (1.2 Mb density). Results posted here: http://www.vintage-computer.com/vcforum/showthread.php?43874-5-1-4-quot-Flop py-Drive-Not-Reading/page9 So I tried to force formatting in DOS at 360k, and sure enough it worked! I can then read the diskette back, write on it, etc... And of course it failed formatting at 1.2 Mb. But the drive (Chinon FR-506) is a 1.2M one, and reads fine at 1.2M! Any clue? Is there a drive setting that would prevent it to write at high density but let it do at low density? Marc > Date: Tue, 18 Aug 2015 21:30:31 -0700 > From: cclist at sydex.com > To: cctalk at classiccmp.org > Subject: Re: 5.25 floppies that read but don't write > > On 08/18/2015 09:05 PM, Marc Verdiell wrote: > > > > > > I have connected a 1.2M 5.25" floppy to my computer. After a bit of > > jumper learning and setting, it's recognized and reads my old DD and > > HD floppies fine. But for the life of me I cannot write to it. Not > > under DOS, Win98, or WindowsXP. Which all read fine. > > Make sure that "WRITE GATE" goes low (use a logic probe) on pin 24 of > the drive while you do your write. If so, your floppy write circuitry > has a problem. I.e., it's not the cable. > > --Chuck >

9 years, 2 months

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test-drb August 2015