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Troubleshooting DEC Pro 350 w/ Ultrix-11

A

AndrewZ

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Apr 13, 2023
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I scored a DEC Pro 350 from a salvage facility last week. First boot showed random lines. After swapping in a known good
001002 video card the system attempted to boot intoUltrix-11.jpg Ultrix-11 (see attached screen shot) but ended with a panic.
The large disk whining. I reseated the cards but the second boot resulted only in display of random lines. The third boot attempt resulted in no display at all.

Any recommendations for the troubleshooting process? I suppose I will swap out the floppy controller card, and swap in a known good disk controller card and RAM card.
 
Chapter 8 doesn't say Ultrix-11 is not compatible with the Pro. And since Ultrix derives from system 7, as does Venix, which was known to be compatible, it could just be that Ultrix-11 was released after that manual went to press.

I do have another Pro running P/OS. Could I swap in that disk and thus run the diagnostics of P/OS?
 
Bitly said:
Based on Handbook page 8-1, Ultrix isn't (wasn't?) supported on the Pro 300 series. I'd probably start with RT-11 to make sure the hardware works.

CW
Click to expand...
Pro 300 "series" is comprised of the 350 (with F11 CPU) and the 380 (with J11). The earlier F series CPU did not have separate I & D spaces and may very well not support Ultrix. I've never tried to install it on mine.
 
The driver code from Venix or BSD could have been used. Those run on Pro. I get errors when I try to image the disk with the Decromancer MFM emulator, which is pretty slick. Recovery of this disk is not looking good.
 
Wait a minute..... That is a very unusual and unique disk and brings up a lot of questions:
1) How did someone get the display to work for Ultrix 11? Normally you have to run a graphics driver for the display as it doesn't respond to 177560/60
2) How did someone get the hard drive working? That's a custom interface and not at all like the RQDX3
3) Wut?
4) It's possible the OS was built on a Pro/380 which does have split I/D. That would cause some interesting failures on a 350.

Would it be possible to send the drive either to me or DDG to let us image that thing and see what the heck it is? That may be a unique disk from someone in DEC development. The important thing is when it's gone, it's gone.

Edit: Even if you get errors on an initial dump, there is probably enough interesting stuff to help reconstruct what they did and how. Where did this system come from? Is it an RD53?

C
 
It's a Seagate ST-412. When I put the disk into a known-good Pro 350 it hangs when booting into multi-user. When I try to boot the image, same thing. I have heard there were Pro graphics demos on UNIX. So someone must have written a graphics driver. I agree this is rare and pretty cool. I would like to see it restored. Send me your address on PM.
 
Agree. This disk need to be properly dumped. Involve David Gesswein to get help! @djg

There is another possibilty to try the image in the Xhomer Pro 350 simulator and see what happens. You can instrument the simulator with tracing functionality to see what happens.
 
Here is a link to the Ultrix-11 extract file, emulation parameters, and log file. It comes up in single user mode and then hangs. Ultrix-11 Pro 350 Image - fails

I used: mfm_read --sectors 16,0 --heads 4 --cylinders 306 --header_crc 0xffff,0x1021,16,0 -data_crc 0xffff,0x1021,16,0 -sector_length 256 --retries 60,4 --drive 1

It is a ST-412 RD51-A.
 
Interesting. Did you get any errors when you imaged the disk?

(*hmmmmm. How can we read a Pro/350 disk image in say SIMH?)
 
czunit said:
Interesting. Did you get any errors when you imaged the disk?

(*hmmmmm. How can we read a Pro/350 disk image in say SIMH?)
Click to expand...
Depends upon how you imaged the original diskette. If you use IMD or Applesauce it won't be directly useful until run through a utility like my dsk2simh.py program.

UPDATE: Do not listen to me (ETOOLITTLECOFFEE). I thought you were discussing diskette images.
 
Sure, but what format would it appear as? The RQDX3 is a different disk geometry and format than say a RK05, correct? Or can you mount a POS disk as a RSX11M+ file system in SIMH using the DU: driver?
 
czunit said:
Interesting. Did you get any errors when you imaged the disk?

(*hmmmmm. How can we read a Pro/350 disk image in say SIMH?)
Click to expand...
I did get errors, which is probably why it won't boot. Hopefully they are listed in the log file.
 
ultrix is aware of disk geometries but i think you should be able to mount any properly formatted ultrix disk on any properly working ultrix install, unless i'm misunderstanding the question? i.e. an image of a formatted rd53 should still be usable in simh as an rd53, i would think
 
Almost any disk driver in any OS will have information about the device geometry. But all the FS for PDP-11 that I know of do not use disk geometry.
So if the device driver does not use software interleaving (DX1-2, RX50, etc.) - the captured image can be connected to the RQ device in SIMH and see the FS without problems.
Also, without problems with an image without interleaving without specifying the device, but only the FS, my program ImageUtils works.
There are exceptions for ImageUtils - for XXDP disk images, a device must be specified - because the service information is located in different places and has a different size for different disks, but the disk geometry is also not used.
 
Last edited:
AndrewZ said:
I did get errors, which is probably why it won't boot. Hopefully they are listed in the log file.
Click to expand...
The last cylinder is in a different format. Can be decoded with
mfm_util --emu Ultrix_a --format WD_1006 --sectors 16,1 --heads 4 --cylinders 306 --header_crc 0xffff,0x1021,16,0 --data_crc 0xffff,0x1021,16,0 --sector_length 512 --ext /tmp/t
The rest of the disk will not decode with this format.
Expected 19584 sectors got 64 good sectors, 1220 bad header, 18300 bad data


The last cylinder the sector numbering starts with 1 instead of 0 of the rest of the disk which is this error
Logical sector 16 out of range 0-15 sector 16 cyl 305 head 0 phys sector 16

The rest of the disk has 16 extra bytes after the data before the CRC that is part of the PRO disk format. The last cylinder doesn't.

Looks to me like you have a good read. The most likely cause for the funny last cylinder is the PRO didn't reformat the last cylinder and it has format from previous data.

Even if that funny last cylinder is needed by the PRO the emulator file does have it. I don't think the read is why the boot is failing.
 
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