test-drb

test-drb@ccmp.vtda.org

101090 discussions

by jnc＠mercury.lcs.mit.edu

Hi, a heads-up on sending expensive items via FedEx. They appear to have a new policy, limiting honouring insurance coverage; so, in my opinion, they are now unsuitable for shipping valuable items. Data point 1: a couple of months back, I bought a PDP-11/40 on eBait. It was shipped via FedEx in two separate packages: one with boards, and one holding the chassis/front-panel. They somehow managed to lose the second box - and then refused to fully pay out the insurance coverage on that box. We provided them with data on an open eBay auction for an identical item, to prove that our valuation was not inflated, but it didn't help - they only paid out a reduced amout, not what the thing was worth, and _what we had insured it for_ (even though _they_ lost it). Data point 2: I collect Japanese woodblock prints; a large dealer I do business with used to do all their shipping via FedEx - dozens of shipments per week - but as of yesterday I as informed that they are now switching. Why? FedEx lost a valuable, insured, package - and would only pay out US1K on it, not the full insured value, leaving the dealer to absorb most of the loss (several US$K). There's a clear pattern here; FedEx is refusing to honour the full insurance coverage when an item is lost. So I wouldn't ship anythihg valuable via FedEx unless you can find an outside insurer to cover it - since Fedex's own insurance coverage now often cannot be relied upon. Noel

5 years, 12 months

DX.sys for RT11 5.5

by cz＠alembic.crystel.com

Quick question: Does anyone have a copy of dx.sys for RT11 version 5.5? I'm getting my RX01 disk running but don't seem to have this driver and the 5.1 driver does. not. work. under 5.5 Thanks! Chris

5 years, 12 months

Ok, got the Perq tapes

by cz＠alembic.crystel.com

Ok, so this evening I went back to the house to do a quick evacuation of the most critical stuff and take some better pictures. This time I brought a massive xeon flashlight which helps to get quicker pictures with less shake. I also picked up a pile of Perq boards, and all the DC600 tapes and floppies I could take out. The car was loaded with them, someone is going to have to curate these. But since I know that the most important thing is the software and not the hardware I decided this is what to get as the top priority. There appears to be a third Perq in there as well on the other side of the basement. No big drives (14 inch or 8 inch) but a lot of MFM and SCSI disks. Couldn't grab those, too heavy. I'm going to put together a list of people and see if I can figure out a way to get things out. The garage is blocked by an old car, and this stuff will not go up the steps. Too narrow. Never dull. Latest pictures are at https://www.crystel.com/bob (I moved the old ones to a subfolder). I also took a better set of pictures of the VME boards, look like Sun boards. C

5 years, 12 months

Wake-on-LAN, teletype style

by steven＠malikoff.com

I've started scanning a few more of the BHP docs I recovered a while back, and thought this one was interesting. A 1973 gizmo that buffers just enough received data for a relay to close and power up a teleprinter's motor to operating speed before printing, apparently half a second was sufficient it reckons. The buffering is through a pair of 64 x 4-bit Fairchild 3341 FIFO memory chips. https://archive.org/details/utec-bmc-6092-buffered-idle-line-motor-control-… One of the other docs mentions they had an ASR33 with this buffered motor control installed connected to PDP-11/10. Steve.

5 years, 12 months

Bob Davis and old computer stuff

by jnc＠mercury.lcs.mit.edu

> From: Chris Zach > We have to move fast though, this needs to be cleaned out. How can > people help me on this? I'm sure there must be institutions that would love to have the PERQs; they were very important machines, historically, and are quite rare. Alas, although I'd normally be up for helping in such a recovery operation (I'm in Virginia), I'm recovering from a moderate case of Covid19 (didn't have to go to hospital, luckily, but I had a bad fever), and am still pretty weak, so it's probably beyond me at this point. Noel

5 years, 12 months

Cybernetics Data Products scrolling LED sign

by charlesmorris800＠centurytel.net

I'm trying to repair a partially functioning Cybernetics Data Products ADT-2002 scrolling LED sign from the early 80's. Previous owner said there was a power failure or lightning strike, don't remember which, and gave it to me. The brief version of the instructions are taped to the keyboard, and that is the only manual I can find. Power supply is functional and delivering 5 volts where it should. On boot it's supposed to say "UNIT OPERATIONAL" on the display before plugging in the keyboard ribbon cable. There is garbage displayed instead. When the keyboard is plugged in, the display responds to start/stop scroll (green and red keys), and messages can be input. The memory (yellow key) and control (blue key) functions don't seem to work. There actually is a microprocessor (8048 or 8051), but inside the keyboard only. Another observation: The display only scrolls a couple of characters, jumps back to the beginning and repeats forever. But the actual display board has a 24-pin Harris PROM (fuse link), seven 2102's 1K memory for the 7 rows of LEDs and many 7400 TTL including? 4-bit counters, comparators and adders. No CPU at all, so it must be a state machine, and a fairly complex one at that unless some of the "smarts" are actually in the keyboard microprocessor. The cable from the keyboard connects directly to the PROM without any buffering. I have found that only the lowest 4 bits of the memory address lines have activity on them, which explains why two characters scroll before it repeats (16 columns). I can't find anything strange looking (e.g. non-TTL levels) on the middle and upper nibbles except that they don't move. There does not seem to be any information on this unit online. I'd like to find a repair manual (probably too long a long shot), but even a schematic would save a lot of hair pulling! Thanks for any help.

5 years, 12 months

Fixed my pdt11/150

by cz＠alembic.crystel.com

So I've had a boat anchor pdt11/150 here for awhile. It's probably one of the weirdest pdp11s ever built: An 11/03 CPU ish, six serial ports, ish, and a pair of RX01 drives. Ish. The trick is the system is very closed in: There are 4 boards inside with a lot of early microprocessors to do the IO instead of a real Q bus. The bottom board is a controller that is sort of like an RX01 but instead of using the DX: driver it uses a special PD: driver. The CPU connects to this with a 14 pin DIP ribbon cable, and on the back of the CPU module is a 64kb memory module and a serial module that has a console, printer, modem and three additional serial ports that are their own thing. Problem with this one was that it would not come up. Serial tests seemed to fail using an error code of waiting for input which didn't make a lot of sense. So today I decided to pull the serial board and see if I could swap the UARTs. I quickly figured out the problem: The serial board "connects" to the main board by two sets of bars with three screws each that hold the board to an interconnecting header that sends the signals. As soon as I loosened the screws I realized that the header isn't connecting to pins on either board, it literally presses against pads on the boards that complete the circuit. Nothing but pressure and springiness holds it together. No screw, pin and socket, anything. With that I cleaned off the headers and wiped down the pads on the boards till they shined like the top of the chrystler building. I then reassembled and torqued the screws down evenly, finishing with the center screw first followed by the outside screws. It is to note that the hinges that hold the CPU and memory/serial boards to the body of this thing attach to the bottom of those screws so when you open it up you are flexing the assembly and probably stretching the screws a bit. Which results in bad contact... Plugged it in and all is well. RT-11SJ (S) V05.01C .DIR SY: SPCINV.SAV 10 21-Mar-1989 OTHELO.SAV 45 21-Mar-1989 SPCINV.DAT 1 21-Mar-1989 TODAY .SAV 20 22-Feb-1988 DECMAN.SAV 14 21-Mar-1989 SPACWR.SAV 13 21-Mar-1989 STRTRK.SAV 54 21-Mar-1989 SWAP .SYS 26P 27-Jul-1984 RT11SJ.SYS 64P 19-Jun-1988 TT .SYS 2P 19-Jun-1988 PD .SYS 3P 19-Jun-1988 DX .SYS 4P 21-Jan-2000 PIP .SAV 30P 21-Jan-2000 DUP .SAV 52P 21-Jan-2000 DIR .SAV 20P 21-Jan-2000 15 Files, 358 Blocks 128 Free blocks Another little DEC mystery solved. One odd thing about these: There are only four chip slots for the CPU and microcode, but one of the carriers has two dies on it so the system *does* have EIS and FIS instructions. Why not... Chris

5 years, 12 months

LINC-8

by jnc＠mercury.lcs.mit.edu

Wow: https://www.ebay.com/itm/353062352448 I've read manuals for these, but I've never even seen a picture of one before. Noel

5 years, 12 months

No subject

by couryhouse＠aol.com

5 years, 12 months

Bob Davis and old computer stuff

by cz＠alembic.crystel.com

Hi! Does anyone here remember Bob Davis? C

5 years, 12 months

Bob pictures from 2005, it's like the titanic....

by cz＠alembic.crystel.com

The outpouring of messages and help has been quite inspirational. It seems that the Perq data is really important, so I will be going back today for a bit to try and get the boxes of data tapes out of there. DC600's, I'm sure they will need to be restored somehow but I'll try to get them. In the meantime here are 4 pictures from 2005 of the stash. To be honest almost nothing has changed between then and now, it was like looking at pictures of the titanic from 1912 and today. https://www.crystel.com/bob/bob%201.jpg https://www.crystel.com/bob/bob%202.jpg https://www.crystel.com/bob/bob%203.jpg https://www.crystel.com/bob/bob%204.jpg Chris

5 years, 12 months

pdp11/84 PMI memory: What is the problem with Q bus?

by mark＠matlockfamily.com

> I actually have -B/-C boards, I should plug one in in QBUS mode, and get my > QSIC prototype working again (it somehow random failed during the last year, > and I've been too lazy to debug it), and write a little program to DMA blocks > in and out, and see what happens to the data. If I get really energetic I > could throw a 'scope on the bus and look at bus cycles and see if they look > OK. > > It would be interesting to have some more detail on the failure. > > Noel Noel, The experiments you describe above would be very interesting! In the accidental tests I did using -C boards in an 11/83, RSX booted ok and ran for a good bit but I think errors Started to accumulate due to bad DMA writes that either were written to the wrong logical block Or the data written was scrambled. When this happened on my BA23 11/83 I scratched my head Took the boards to a BA123 11/83 and repeated the mistake. Fortunately I use two SCSI2SD devices In each system and leave one identical unit unmounted except during disk to disk backups. With good memory boards I was able to do a disk to disk restore and recover everything up to My last backup. > And that might make sense: PMI memory responds to the Q bus just like > normal memory. So from a Q bus device perspective it's just boring old > memory and thus no speed improvement. What might speed up is if I did > memory to memory (VM0:) copies, but with only 2mb running at the moment > there's not a lot of time to check for performance differences. Chris, I think the way that you see the biggest performance improvements in PMI over Q22 memory Is when you have heavy asynchronous I/O happening at the same time the CPU is compute bound And the memory access is not well cached due to the type of programs being run. This is more Likely to happen in a busy multi-user environment. RSX has a tool IOX that was developed to load a RSX system and simulate multiple users. The CPU can get at memory via the PMI and not be delayed Waiting on the Q22 bus. This is particularly helpful with larger block mode Q22 transfers that don?t cause CPU memory access delays. Mark

6 years

Dixie Canner CPT 8000?

by anders.k.nelson＠gmail.com

https://www.ebay.com/itm/143536589578 What in the world is this?

6 years

pdp11/84 PMI memory: What is the problem with Q bus?

by jnc＠mercury.lcs.mit.edu

> From: Mark Matlock > Are you able to use a Qbus MTI controller in the 11/84's Qbus section > of the backplane? This is something I've often wondered about but never > tried. I looked into this in some detail, but I don't know: https://gunkies.org/wiki/KTJ11-B_UNIBUS_adapter#QBUS_slots Amswering it definitively would probably require looking at DMA and interrupt cycles with a logic analyzer on the bus, to see what the CPU does with them. And the KDJ11-B and KDJ11-E (the 11/94 uses the same bacplane with a different CPU card) might act differently. > For anyone who is curious about what Happens when a M8637-C version > board is used as PMI memory in an 11/83 I can speak From experience. > ... > After this the disk is corrupted and you will need to restore the > system disk from backups Ah, very informative; thanks for reporting. So whatever the fault is (perhaps the QBUS block transfer issue reported up-thread), it must _seem_ to work, but fail in actuality. It would be interesting to appply a logic analyzer, and see what the bus transaction looks like, if it looks OK on the bus (in which case it's an internal failure). Noel

6 years

pdp11/84 PMI memory: What is the problem with Q bus?

by jnc＠mercury.lcs.mit.edu

> From: Jerry Weiss > Sorry about the uNOTE confusion.. No problem, it only took me about a minute to find the right one; my note was to warn other people who didn't know about the number duplication. > If you look at the Memory Comparison table in this OEM uNOTE, it only > lists Block Mode for "JD/JE ONLY". Oh, right. Still, it sounds from reports here like regular DMA doesn't work in QBUS mode either - and technically that table entry might mean than since it doesn't work for the QBUS _at all_, that includes no block mode. I actually have -B/-C boards, I should plug one in in QBUS mode, and get my QSIC prototype working again (it somehow random failed during the last year, and I've been too lazy to debug it), and write a little program to DMA blocks in and out, and see what happens to the data. If I get really energetic I could throw a 'scope on the bus and look at bus cycles and see if they look OK. It would be interesting to have some more detail on the failure. Noel

6 years

pdp11/84 PMI memory: What is the problem with Q bus?

by jnc＠mercury.lcs.mit.edu

> From: Jerry Weiss > uNOTE # 028 indicates that MSV-11 JB/JC (M8637-B/C) doesn't do block > mode. I went and looked at uNOTE #28, after I found it (it's not in the initial set of uNOTEs, but in the second set - the so-called 'OEM uNOTEs"; note that the numbers were re-used between the two sets, so there are _two different_ uNOTE #28's). I couldn't find anything there about the JB/JC not doing block mode? All it says is they "can not be used in a Q-BUS system due to gate array incompatibilities". Noel

6 years

pdp11/84 PMI memory: What is the problem with Q bus?

by jnc＠mercury.lcs.mit.edu

> From: Chris Zach > Just checked the configuration and block mode DMA *is* off. Interesting. So it's not bklock-mode on the QBUS which is screwed up, but normal QBUS transfers. That jibes with the comment abour "gate array incompatibilities" (which I take to mean "errors" :-). > was the 11/70's MASSBUS channels nothing more than RH11-C's attached to > the old FASTBUS on the 11/45 cpu core (which is what an 11/70 really > is, with cache) or did they port right to the memory box? RH70's are totally different from RH11's - a hex card, and a couple of quads - and the interface to the /70's memory system is totally different from the RH11's (which goes to the UNIBUS): https://gunkies.org/wiki/RH70_MASSBUS_controller It has interfaces to both the cache, and the memory bus (although the diagram in the 11/70 CPU handbook shows it as only connected to the cache). I didn't follow the "the old FASTBUS on the 11/45 cpu core (which is what an 11/70 really is, with cache)"; the 70's cache is what's connected to what used to be the FASTBUS, the memory bus connects to the cache, IIRC. Noel

6 years

Kennedy 9800 - Power-up tips?

by anders.k.nelson＠gmail.com

Hi friends, Now that I have enough hobby time having quit my job two weeks before the apocalypse, I'm interested in poking at my Kennedy 9800 tape controller project. I bought the tape unit in Q3 2017 and the seller said they had powered it up and nothing seemed awry. I have not powered it up and reading about old electrolytic cap issues I'm curious if I should do anything beyond replace any obviously leaking/ruptured capacitors. IIRC people have used a variac to gradually bring the power supply up to operating voltage and somewhat refresh the capacitors - is this a thing? Is this advisable? Any help is appreciated! -- Anders Nelson www.erogear.com

6 years

pdp11/84 PMI memory: What is the problem with Q bus?

by mark＠matlockfamily.com

> Date: Tue, 21 Apr 2020 16:17:07 -0400 > From: Chris Zach <cz at alembic.crystel.com> > To: cctalk at classiccmp.org > Subject: Re: pdp11/84 PMI memory: What is the problem with Q bus? > Message-ID: <27647f0e-19d4-b484-d288-e9f3bb715363 at alembic.crystel.com> > Content-Type: text/plain; charset=utf-8; format=flowed > > Thanks Mark! Actually this was just the boards from the 11/84 (no idea > what happened to the chassis, drat) so it's an 11/84 CPU (18mhz, FPP > chip installed), 2 PMI boards (one old 2mb, one new 1mb) a console board > of some sort and the Unibus map. > > I popped this into my BA23 to speed things up a bit in place of my quad > height 11/73 CPU with 2mb memory. So far it seems to work, and with the > CA memory in the PMI slot managed to boot RSX11M 4.2 and compile up EMPIRE. Chris, I understand now. I also have a PDP-11/83 in a BA123 box and the CPU and PMI memory (M8637-E) can move from the Qbus box to the 11/84 box and work fine In either. I spent a good bit of time tinkering with the 11/84 power supply which did not Work until I put a M7556 minimum load module in it. Basically the +/- 12 Volts needs a Load or you get a hung bus error. Also, with the Unibus you have to pay attention to The NPR/NPG grant jumpers. For disks on the QBus systems I used the UC07 and SCSI2SD. The UC07 can be can be configured for block mode transfers and I think it is doing it. I guess I?d need to hook up a logic analyzer to know for sure. The 11/84 uses a UniBone and when it is emulating a MSCP disk, it can do 150 I/Os a second (using IOX on RSX11M+) The 11/83 using the UC07 and a SCSI2SD Does about 60 I/Os per second. I think the UC07 could go faster but is limited by the SDcard interface. I need to put a fast real SCSI disk on it sometime and see what it can do. > > My guess is the 11/84's Unibus talks directly to the PMI bus and > orchestrates the data transfers, but there is something wrong when the > PMI memory is accessed on the true Q bus. That would not happen on an > 11/84 (CPU and Map use PMI only) but when you have a Q bus DMA device it > probably manifests at random. It's possible the MTI card is throttling > the DMA to single mode instead of hog mode, wonder if I want to screw up > my disk to verify this?. What is the model # for your MTI disk controller? > > Drat. On the positive side it's chock full of 256k chips, which I could > pull off and put on the EA board to bring it up to 2mb memory. I have > air heat tools and a pre-heater so getting the chips off should be > pretty basic. Getting them on the new board though could be a pain since > all the holes are soldered over?. Moving the RAM chips sounds a bit tedious but would certainly be possible. > > No way to reprogram or fix it I assume? Are you asking about making the M8637-B or -C into the -D or -E? If so I?ve never seen any reference to doing that. I was very fortunate that the person Who sold me the M8637-C was willing to trade it for a -E. Mark

6 years

Odd punched cards

by peter＠vanpeborgh.eu

Guys, I got a positive response about the Port-A-Punch cards so no longer any need to respond to this one. Very encouraging. Still looking for Jacquard cards and original Hollerith cards. Hope springs eternal. peter || | | | | | | | | Peter Van Peborgh 62 St Mary's Rise Writhlington Radstock Somerset BA3 3PD UK 01761 439 234 "Our times are in God's wise and loving hands" || | | | | | | | |

6 years

Grinnell Systems

by emu＠e-bbes.com

Hi all, was just fishing in old memories & graphics systems. We had in the 1980's a big fridge from Grinnell Systems as a frame buffer on a 11/34. Anybody remember those? Links to any documentation? Cheers!

6 years

Looking for new punched card type

by cctalk＠emailtoilet.com

Peter, I have several Port-A-Punch cards. Would you like 1 of each? Do a search at www.ibmjunkman.com and check Holders 162, 568 and 1856. Donald

6 years

[ancient thread] HP 1820-1584 IC replacement?

by spacewar＠gmail.com

Back in 2013, Bob Rosenbloom asked: > I have an HP 9872 plotter that just died. According to the internal self > test (very nice!) > one of the bib (MOS to TTL) drivers has failed. Tony Duell wrote: > the devie is very simple (it's simialr to the 74LS245) but the problem is that one side of it does not work with TTL levels. It's a level shifter too. Although the BIB functioned as a level shifter, in later devices using the 1818-2500 standalone 40-pin BPC Binary Processor Chip, including the 9872C and 9872T, HP actually used the 74LS245 instead of the BIB. The only thing they did to meet the MOS level input requirements of the BPC was to put a 10Kohm pullup resistor to +5V on each data line on the MOS side of the buffer. As noted elsewhere, the 74LS245 isn't pin compatible with the BIB, so an adapter would be needed to substitute it. The 9872A, which uses the BPC with the BIB chip, does not have pullups on the MOS side. It also uses the HP 16-bit NMOS ROM directly on the MOS side, and it's remotely possible that adding 10K pullups could be a problem with the ROM.

6 years

MicroVAX 3100/95 PSU Weirdness

by robert.jarratt＠ntlworld.com

I am on a mission to fix a bunch of power supplies and now I am looking at my MicroVAX 3100/95. A few days ago I mentioned that the big smoothing capacitors on the primary side might need replacing. I have done that now. However, in doing so, I have discovered that *one* of the capacitors does not get discharged after the power has gone off (this applies both to the original ones and the brand-new replacements). Furthermore, after discharging them with a resistor and checking that the charge had gone, several hours later, the one that does not discharge, has some charge again, that was not there before! Does anyone know if these PSUs have a bleed resistor to discharge the smoothing capacitors? Why would only one be discharged, is there normally one bleed resistor per capacitor? Why would the capacitor acquire charge again when it hasn't been powered on? Thanks Rob

6 years

Unix Kermit (aka C-Kermit) version 4 spelunking

by imp＠bsdimp.com

Greetings I went looking for a specific version of C-Kermit to reconstruct sources for an old system (The Boston Software Works Venix for Rainbow that I have). I didn't find the 4C(052) I was looking for, but did find many previous 'presumed lost' versions. https://bsdimp.blogspot.com/2020/04/finding-kermit-4x.html has the details. Of particular note: I got almost all the lost versions off DECUS tapes hosted in various places because they were copies of the KERMIT tape, pruned down to just be the DEC stuff. Maybe people here care, maybe not... Warner

6 years

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