test-drb

test-drb@ccmp.vtda.org

101090 discussions

by jnc＠mercury.lcs.mit.edu

> From: Ben Sinclair > I don't believe I have any discontinuity, but how would I tell? Well, usually, it's caused by leaving a card or grant jumper out. I don't think I've ever seen anything else cause it, although I suppose an electronics failure on a card (failure to pass the grant) could also cause it. But neither of those sounds like it's happening here (since you have only one card that can interrupt...) > I think with my backplane (H9273) I'm supposed to put everything down > the left side, with the BVD11 at the bottom. Right. The 9273 is a so-called Q/CD backplane, which means the QBUS (which only takes one dual slot) runs down the left side (when looking at it from the side the boards plug into); all the RHS slots are wired for C-D interconnect. > Currently I have starting from the top left and going down the left > side: M8186, M8044, M8043, then the BVD at the very bottom. That sounds right. And the chances of the 8044 not passing the grant are zilch, since it has very substantial grant jumpers. So unless your backplane is damaged (again, very unlikely), or the grant drive on the CPU card is bad (possible, I suppose), the grant should be getting to the DLV11-J (I'm assuming that test uses the console DL11 to test interrupts - can't think what else it could possibly be using :-). So, if the CPU checks OK, maybe the DLV11-J has a problem with interrupts? Is there a DL11 diag you can run on it? (If not, I can whip up a simple test to check it out.) > I have another memory board, but I know it's bad, so I can't try that! Probably the one you have passes the memory diag, though, right? If it's not an issue with the DL11 interrupting, it sounds like we may have to dig into that diag to find out what it thinks it's doing when it blows up. If I can get my tool-chain working (currently downloading the abs-loader isn't working right somehow), I'll see if I can figure out how to load it, and DDT along with it, and poke into it. Locating the fiche would be another way to go... Noel

11 years, 8 months

Reading a CD that has no reflective layer

by spacewar＠gmail.com

John Foust wrote: > Apart from the card and the drive, there's the question of > the DOS driver software disks. I imagine it was just an API > and there weren't any tools at the DOS level. I'm pretty sure they provided the API used by MSCDEX, though I don't know where that API (MSCDEX bottom side) is documented. > You mentioned you'd never seen the SCSI CM110. This fellow > seems to have one. It looks like he had connections to Eindhoven. Cool! I'd like to get one someday, but it's not a high priority. Same with DEC KRQ50 (M7552) controller for RRD50.

11 years, 8 months

Reading a CD that has no reflective layer

by jfoust＠threedee.com

At 06:03 PM 11/18/2014, Eric Smith wrote: > I do not have a CM153 interface card. The interface >consists of three or four RS-422 pairs. At one time I >reverse-engineered the 8051 firmware in the drive and understood the >details of the interface quite well, but I've forgotten them and >cannot currently locate my old notes or the service manual. Yes, googling turned up a number of your messages from a decade or more ago. You still have a pile of them, but you never had an interface card? As I said, there's a fellow on eBay selling them cheap and new-in-box for $10. Apart from the card and the drive, there's the question of the DOS driver software disks. I imagine it was just an API and there weren't any tools at the DOS level. You mentioned you'd never seen the SCSI CM110. This fellow seems to have one. It looks like he had connections to Eindhoven. http://home.claranet.nl/users/pb0aia/cm/sroom.html - John

11 years, 8 months

Big VAX shipping in Europe

by wdonzelli＠gmail.com

> I would *love* to get my hands on the larger VAXen. It would be such > a pity if they'd to to the scrapper... I do even have space and > three-phase power for thembut I see no straight-forward way to ship > them over here... OK, I am curious. No, I am not interested in the machines (unless it was a VAX 9000). How much could one reasonable expect to pay for getting a big VAX, lets say a 350 kg in the typical DEC cabinet, from mainland Europe to Britain? Or from Britain to mainland Europe? Or even to and from Scandinavia? Sure, one could hire movers and riggers - pay them enough and they will deliver a locomotive - but what about typical on-the-cheap hobbyist methods? -- Will

11 years, 8 months

Looking for a Linux-usable EPROM programmer

by cruff＠ruffspot.net

If anyone is looking for a USB attached programmer, I picked up a Batronix BX40 Bagero II programmer recently, which is supported under Linux, OS X and Windows. This specific model doesn't handle PAL, GAL, MCU or NAND flash, but they have another model that does. It doesn't even require an external power supply.

11 years, 8 months

VAXen in Hawai

by stephane.tsacas＠gmail.com

Civil Bytes: Our New Governor Should Upgrade State?s Sorry Technology http://www.civilbeat.com/2014/11/civil-bytes-our-new-governor-should-upgrad… -- Stephane

11 years, 8 months

PDP-11/23 Debugging

by jnc＠mercury.lcs.mit.edu

> From: John Wallace > Perhaps not so obviously,11/23 boards were available in variants with > or without floating point, and (iirc) with or without memory management > unit (MMU) (correction welcome). No, you're right on target. (Although one couldn't have FP without the MMU; the FP registers were actually in the MMU chip, see MicroComputers+Memories '82 pp. 350-351. > is it vaguely conceivable that the diagnostic in question needs a piece > of hardware that isn't on the board in question Hmm. Possible, but from what I know, unlikely. That test claims to test: Part 1 - the CPU checks out the basic PDP11 instructions in every addressing mode with various data patterns. Part 2 - tests all trap instructions, trap overflow conditions R6, interrupts, the reset and wait instruction. Part 3 - tests the EXTENDED INSTRUCTION SET, the ASH, ASHC, MUL and DIV instruction all of which are, AFAIK, part of the basic chip. (Unlike the 11/03 and 11/40, where MUL et al are part of the optional EIS.) Although I see 'interrupts' listed there - I wonder what they are using to generate the interrupt? The console serial line? Must be, I can't think of any other device in the config he was testing. Ben, you didn't have a discontinuity in the grant jumpering, did you? What kind of backplane do you have, and in what order/slots were the boards plugged in? > or is seriously broken on the board in question? That is the other possibiliy. Ben, do you get the same error with both CPU cards? Do you have spare memory/serial line cards you can swap in? Noel

11 years, 8 months

Looking for: Parts keyboard for chicklet PET (or just a "-" keycap)

by derschjo＠gmail.com

Made good progress with the PET; after fixing the video I got the reset circuit humming again (a bad ceramic cap on the 555 trigger circuit) and it fired right up after that, much to my surprise. And only 4 of the 18 6550 RAMs are bad :). Replaced a few terrible sockets and it's running reliably, albeit with only 6K of RAM. The keyboard on this thing has suffered some abuse; the "-" keycap on the numeric keypad has been broken off. I figure it's a long shot, but does anyone happen to have a spare "parts" quality keyboard they'd be willing to sacrifice a "-" key from? Thanks, Josh

11 years, 8 months

Reading a CD that has no reflective layer

by tothwolf＠concentric.net

On Tue, 18 Nov 2014, John Foust wrote: > At 09:30 AM 11/18/2014, Mouse wrote: > >> I was speculating that, on the scales of interest here, it's >> easier/cheaper to produce a non-smooth surface of a uniform material >> (how pressed CDs are actually made) than to produce a smooth surface of >> a nonuniform material (the alternative). > > I see... you're asking why CDs couldn't be made with a printing process > (ink on paper being effectively smooth) as opposed to the non-smooth > method of pits and lands. On one hand, it almost sounds like you've > re-invented CD-R, where a dye gets zapped and changes its reflectivity - > but I was surprised to read that even CD-Rs have a single spiral > "pre-groove" pressed into the polycarbonate. You'd need a rather precise > printing process to make tiny spots. > >> Yes, but I think the light normally used for CD reading is outside the >> visible range. This raises the possibility that the disc might be >> clear in the visible range but not in the range used for reading. Your >> experience trying to read it argues against that, though. Oh well, it >> was a nice theory while it lasted. > > At this point, I only hold out hope for finding an existing reader that > can see the pits, and the best candidate seems to be the oldest readers, > not the newest. > > I can't help but think this is an important topic for data recovery. A > peeled reflective layer is a common failure mode for discs. If there > was a way to dissolve everything above the pits (the label and aluminum) > and recoat with acrylic for protection, and read a clear CD, you could > rescue failed CDs. Couldn't one also apply a layer of aluminum? This is commonly done with mirrors for optics in telescopes and such, by hobbyists. I'm not 100% familiar with the process, but I understand it is done in a small vacuum chamber with some sort of electrical process to vaporize the aluminum. I think I actually have a /very/ early Philips cd-writer drive in storage, but it is behind a couple of large stacks of gear. It has a SCSI interface and is about the size of a home stereo component. I /might/ also have a Philips CM-100 on another more accessible shelf, but it may be a few days or a week before I can have a look and see what I have. I seem to remember the drive I have has an unusual data connector. Does the CM-100 require a special interface card?

11 years, 8 months

PDP-11/23 Debugging

by johnwallace4＠yahoo.co.uk

Apologies if this is obvious/already covered, but along the same lines as Noel's "it's probably 'JKDBD0', not "JKDBDO" it's almost certainly "JKDBD0 DCF11 AA CPU DIAGNOSTIC" or maybe even "JKDBD0 DCF11-AA CPU DIAGNOSTIC" not "JKDBDO DCFlI AA CPU DIAGNOSTIC". Of itself, that may not matter much. However, it may lead elsewhere. The F11 was [obviously] the 11/23 (and /24) chipset. Perhaps not so obviously,11/23 boards were available in variants with or without floating point, and (iirc) with or without memory management unit (MMU) (correction welcome). Also, the relevant bits were socketed, hence a particular board today may not match the board (and part number) as originally manufactured. Relevant handbooks etc will contain further details. I can't remember what's been previously written in this thread, but is it vaguely conceivable that the diagnostic in question needs a piece of hardware that isn't on the board in question, or is seriously broken on the board in question? A search for DCF11-AA CPU Diagnostic gets a few hits, including http://www.pdp-11.nl/pdp11-24/cpu/diags/jkdb.html which contains the delightful line "For more infromation refer to your microfiche library." and some rather more useful stuff too - sounds like you've found this or an equivalent already? Hope this helps, best of luck. John Wallace

11 years, 8 months

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test-drb