DOM Corrupted?

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DOM Corrupted?

Postby Tempest » Sat Feb 13, 2016 11:46 am

As some of you know I've been having troubles with my jrIDE lately. I think I've narrowed the problem down to my DOM. It displays garbage as a name in the jrIDE menu, BUT DOS 3.3 recognizes it and will allow me to format it. If I format it I can write and read files from it just fine. However the problem comes when I try to FDISK it. Even though FDISK says it's making a primary DOS partition on it and will display that such a partition exists, I can't boot from it or write files to it. When I try to write files to it it gives me a file creation error (only after I've made it a primary dos partition, just formatting it and writing files works just fine) and when I try to boot from it it says that there's no operating system.

The fact that the name is all corrupted in the jrIDE menu worries me. However Windows 10 and Linux seem to see the DOM, but they see it as a 32MB drive. It's actually a 2GB DOM. Is there a way to totally reformat and fix the DOM? I don't believe the problem is the jrIDE as it sees my old IDE hard drive just fine and that works great.
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Re: DOM Corrupted?

Postby Brutman » Sat Feb 13, 2016 11:53 am

Start from scratch ... wipe out any partitions that are on the DOM and start over. You should be able to do this from Windows. Delete all of the partitions.

I would start back on the PCjr with DOS 3.3 since it doesn't need any patches to work.

  • Boot from a clean DOS 3.3 floppy
  • Run fdisk. Make sure it sees the DOM as an empty drive
  • Create one partition for DOS. Make sure it gets set to active. Since this is DOS 3.3 it will be a FAT16 partition.
  • Fdisk will want you to reboot after it writes the changes
  • Reboot from the DOS 3.3 floppy and then format the C drive using the /s parameter to transfer the system

After this you should have a minimal bootable DOS system.

If the jrIDE is not identifying the DOM correctly then I doubt it will work. What does the corruption look like? ie: What is the exact string that Windows or some other system reports and what does the jrIDE report?
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Re: DOM Corrupted?

Postby Tempest » Sat Feb 13, 2016 12:26 pm

It should say something like PQI DiskOnModule but it keeps saying weird things like PQH HDD DirkNmlodul. Sometimes it will be PQH'HDD'DirkNmlodul.

I tried the steps you laid out but the command.com file that got copied over was displaying as something like commad!.CO and was obviously corrupt. Sounds like my DOM just went bad somehow. The weird thing is that Windows and Linux (using GPARTED) seem to see it just fine and report the real name with no corruption.
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Re: DOM Corrupted?

Postby Brutman » Sat Feb 13, 2016 12:31 pm

Does any drive work on the jrIDE?

You can't say whether it is the DOM or the jrIDE based on what you have told us. Especially since the DOM works on other systems.
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Re: DOM Corrupted?

Postby Tempest » Sat Feb 13, 2016 12:40 pm

Yes my regular old IDE hard drive works just fine on the jrIDE
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Re: DOM Corrupted?

Postby Brutman » Sat Feb 13, 2016 12:42 pm

The PQI DOMs are pretty good - I use one on my L40SX. We might just have a timing problem between the jrIDE and the PQI.

Other people are using DOMs though, so I'm kind of skeptical. How many other systems have you tried the PQI on? Are you using an 80 conductor IDE cable or is it plugging directly into the jrIDE? (Dont' use a 40 wire IDE cable.)
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Re: DOM Corrupted?

Postby Tempest » Sat Feb 13, 2016 1:09 pm

What do you know, that was it. I was using an IDE cable to connect the DOM so I didn't have to reach into the sidecar case each time I wanted to remove it. I plugged it in directly to the jrIDE and it works just fine.

I have another problem however. It appears that if I put the top of the case on the jr (especially if I put the monitor on top of it) the disk drive reading arm will jam. I think the top of the case is somehow touching it and the disk drive it too high up. I think the disk drive is in the tray correctly, is there a way to check this?
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Re: DOM Corrupted?

Postby Brutman » Sat Feb 13, 2016 1:19 pm

Are the friction tabs ("feet") of the drive tray pushed all the way through the case? They'll either make a satisfying "snap" sound, or they'll crack and just go in nicely. Old plastic is a pain to deal with ...

Never use the older style 40 wire IDE cables. They should be fine, but I've had nothing but problems with them and the jrIDE.
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Re: DOM Corrupted?

Postby Tempest » Sat Feb 13, 2016 1:41 pm

Yes, looks like they must have broken off a long time ago. Still having that problem though.
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Re: DOM Corrupted?

Postby Tempest » Sat Feb 13, 2016 3:31 pm

I solved the disk drive problem (I think) but putting some foam weather stripping on the tabs of the tray that go up against the top of the case. It only adds a millimeter or so of clearance but that appears to be enough. So far so good.

The DOM however seems to want to go back to being corrupted. It works alright for a bit but then it will suddenly go all wonky on me. If I play with it a bit (unplug it or wiggle the jrIDE) it will usually go back to normal, but then it will corrupt again with me touching anything from time to time. Either the DOM is flaky or the jrIDE has a loose solder joint or something of that nature (I looked but didn't see anything with the naked eye). I'd test it again with my regular IDE drive but the external power supply I was using with it decided to go snap, crackle, pop (they're REALLY susceptible to power surges) so I need to get a new one. This is the whole reason I went with a DOM in the first place. :)

Does anyone do jrIDE repair?
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