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AT&T PC 6300 Customer Diagnostic Disk image format??

dkedrowitsch

Experienced Member
Joined
Dec 27, 2006
Messages
102
Location
Boyertown, PA USA
I've tried writing both the DOS 3.2 and 3.3 versions of this diagnostic disk using the images available at the PC 6300 Shrine and on http://olivettim24.hadesnet.org/download.html without success.

All the other system disk images on these sites are no problem, but for some reason the Diagnostic disk images are 8-bytes too short and if forced onto a floppy have the directory listing skewed one byte too far with corrupted data. WinImage won't even attempt to open it.

I've tried adding 8-bytes of empty data into various parts of the boot sector or simply appended to the end of the file, but no dice.

Obviously others have no issues creating a usable floppy with these images so... whats your secret??
 
Nope I'm using dskimage.com, a popular tool by Mike Brutman, and also an old shareware tool I've been fond of since the 90s called Disk Copy Fast that handles raw images as well. Both of these are being run on my DOS 5 powered V20 clone. Because this is a 5-1/4" disk I'm trying to create I've been copying the 360K image files via 720K floppy from my USB floppy drive, then using the XT with 3-1/2 and 5-1/4 drives to write the images to new 5-1/4 diskettes.

I've created all the other AT&T PC 6300 system disks using this method without fail. But in this one particular case the image is 8K shorter than all the others, and does not work.

I suspect the image file itself, not the tools or the method. Unless of course for some reason this diagnostic disk image was created using a completely different method from the rest of the PC 6300 system disk catalog.
 
That image is borked. Someone ran it through something that converted all CRLF bytes to CR, as if it were a text file. Can't undo that.
 
Dang it. Both versions? One version was included with the AT&T DOS v3.20 disk set, and another with the AT&T DOS v3.30.

I don't suppose anyone has a valid image to share? There are a number of M24/PC 6300 collectors out there who refer to using this diagnostic disk so surely there's a valid image in circulation somewhere....
 
WikipediA says:

DCF format is not compatible with Rawrite (.ima) or .IMG file format.

That's for finding that, but my own experience contradicts what the Wikipedia article says.

Perhaps when DCF is used to create images in its own native format that is different, but it writes generic raw images just fine.

In any event, the self extracting executable SomeGuy referenced worked perfectly! I've completed my set of PC 6300 system and diagnostic disks, and can now use the video test patterns it generates to finish aligning the monitor I recently repaired.

Thanks!
 
I have no idea what the underlying format is, and how much compatibility there is in each direction, but I can create an image with DCF on my AT, ftp it to my modern computer, and open it in winimage. I just did this yesterday.
 
I've had a quick look; the format written by DCF 5.1 is a raw disc image with an extra 512 bytes at the end containing geometry information.
Code:
00168000   00 A0 05 F6  F6 F6 F6 F6  F6 F6 F6 00  02 01 F6 F6  ................
00168010   02 E0 00 40  0B F0 09 00  12 00 02 00  F6 F6 F6 F6  ...@............
00168020   F6 F6 F6 F6  F6 F6 F6 F6  F6 F6 F6 C4  C3 C6 B5 B1  ................
00168030   F6 F6 F6 F6  F6 F6 F6 F6  F6 F6 F6 F6  F6 F6 F6 F6  ................
...
001681F0   F6 F6 F6 F6  F6 F6 F6 F6  F6 F6 F6 F6  F6 F6 F6 F6  ................
So it should be possible to read it with WinImage or mtools, or loopback-mount it under Linux. Writing it with rawrite would probably write the data but give an error when it tried to write the extra sector to track 81.
 
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