Help with dump QNX 1.2

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robbo007
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Re: Help with dump QNX 1.2

Post by robbo007 »

Thanks for all your comments chaps.
SomeGuy wrote: Mon Apr 26, 2021 7:28 pm Copy protection type is a mis-numbered sector on the last track (Track 39 head 1). Can be duplicated by ImageDisk.
Are you using HxC to convert to IMD or the psi tools?
SomeGuy
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Re: Help with dump QNX 1.2

Post by SomeGuy »

I used the tools included with the PCE emulator (PRI.EXE, PSI.EXE, and PFI.EXE)

Here is an example of decoding a low density 360k image read with a 1.2mb drive:

pfi track00.0.raw disk1.pfi
pfi disk1.pfi -p double-step -R 1 -r 600000 -p decode pri disk1.pri
pri disk1.pri -p decode mfm disk1.psi -f -v
psi disk1.psi disk1.img
psi disk1.psi -L > disk1.txt

You can use "psi disk1.psi disk1.imd" to output to an Imagedisk file instead.
The output text file shows you where errors are. The output may also show "postion" issues but those are just warnings.
Also, since kryoflux images store multiple revolutions, sometimes specifying a different -R value may give different results when there are errors.
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robbo007
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Re: Help with dump QNX 1.2

Post by robbo007 »

SomeGuy wrote: Tue Apr 27, 2021 4:12 pm I used the tools included with the PCE emulator (PRI.EXE, PSI.EXE, and PFI.EXE)

Here is an example of decoding a low density 360k image read with a 1.2mb drive:

pfi track00.0.raw disk1.pfi
pfi disk1.pfi -p double-step -R 1 -r 600000 -p decode pri disk1.pri
pri disk1.pri -p decode mfm disk1.psi -f -v
psi disk1.psi disk1.img
psi disk1.psi -L > disk1.txt

You can use "psi disk1.psi disk1.imd" to output to an Imagedisk file instead.
That seem to work. The disk now writes in IMD to a floppy disk and boots on my IBM 5160. I'm not sure to what extent the data loss is? Am I right in saying if the KF RAW images are damaged as the others were saying due to the USB problems then also this IMD image would also contain the same damaged/missing data? As I am still using a "damaged" source to make a backup to floppy.
SomeGuy
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Re: Help with dump QNX 1.2

Post by SomeGuy »

So with the PCE tools, you can inspect the output log to see what sectors and tracks it found in the specified revolution as well as where it found them. So what we look for is that, in this case, sectors 1-9 on both heads are present, and there is no CRC error.

As I mentioned, when I ran it on my machine, I got good sector dumps (all sectors, no CRC errors) on all disks except the second DOSFSYS disk which had the errors only in empty space. Since everything looked complete in the log, that leads me to think the dumps converted this way are "OK".

Apparently these tools don't really care about the integrity of the RAW file, only that it can seek through them and try to decode something.

Keep in mind that that decoding flux is literally listening to "noise" and trying to write down what is heard. HxC, DTC, PCE, and real floppy controllers all use slightly different algorithms so one may have better or worse luck than another.

Since it was mentioned above, I took another look at track 62 on the boot disk, it only seems to have captured the first revolution OK, but not the ones after it. The PCE tools seem happy decoding that, but obviously DTC barfs.

Anyway, I compared conversions using the SCP files as well, and it matches up enough to confirm it converted properly. So in my opinion, it is complete.

All that said, the flux dumps are a mess, Ideally I'd try and clean and dump such a disk again. Clearly these had some physical damage. I have no idea if there was a problem with the drive that read it. It sort of smells like it may have been mastered on a low quality drive, and given the timeframe, that is likely.

BTW, anyone get that to run in PCE? When I tried it I just get a debugger error: "undefined operation [FE a0]"
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robbo007
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Re: Help with dump QNX 1.2

Post by robbo007 »

SomeGuy wrote: Thu Apr 29, 2021 8:31 pm S

Anyway, I compared conversions using the SCP files as well, and it matches up enough to confirm it converted properly. So in my opinion, it is complete.

BTW, anyone get that to run in PCE? When I tried it I just get a debugger error: "undefined operation [FE a0]"
Thanks for that. I've seen it works under x86Box but using the cracked version.
ZrX
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Re: Help with dump QNX 1.2

Post by ZrX »

Was able to decode all the raw dumps with my tool.

Some bad tracks/sectors on dosfsys_ but they were unused.

But some of the disks show really bad issues of not spinning properly.
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robbo007
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Re: Help with dump QNX 1.2

Post by robbo007 »

ZrX wrote: Sat May 01, 2021 2:11 pm Was able to decode all the raw dumps with my tool.

Some bad tracks/sectors on dosfsys_ but they were unused.

But some of the disks show really bad issues of not spinning properly.
What tool would that be? 😱
ZrX
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Re: Help with dump QNX 1.2

Post by ZrX »

Try if writing these shows any improvement.

http://oms.wmhost.com/clean-qnx12-kryoflux-raw.zip
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robbo007
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Re: Help with dump QNX 1.2

Post by robbo007 »

That worked well, thanks :) It would be interesting to see the differences between this and the PCE converted images. Are your tool available to us mere mortals?

BTW: If anyone is interested. Here are QNX version 0.4 and other versions of 2.x even on 360k. Unfortunately dumped by the same person / computer so they seem (at least QNX 0.4) have the same corruption problem in the raw files. SomeGuy's trick to convert to ImageDisk seems to work for write back. Would be good to see these on WinWorldPC and Archive.org for preservation purposes.

https://www.mediafire.com/file/m9e0m0fz ... 0.zip/file
https://www.mediafire.com/file/28he5zth ... 2.zip/file
ZrX
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Re: Help with dump QNX 1.2

Post by ZrX »

Main issue is that the tool has no user control over any of the functions other than a compiler.

Look into some MFM disk sector layout? Change things in the source and compile.
Extract the raw bitstream from a GCR coded track? Change things in the source and compile.
Try some error recovery techniques on a disk? Change things in the source and compile.
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