Determine 8" Disk Format

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nauseous
Posts: 3
Joined: Thu May 27, 2021 10:47 pm

Determine 8" Disk Format

Post by nauseous »

Hi All,

I have an old S100 machine with lots of 5" and 8" media to be dumped. The drive I am using for 8" media is a Mitsubishi M2896. Again I am unsure on the current status of this drive and if it is operational.

Successful in getting a dump from the drive, but not able to make any sense of the raw image file. Can't find any FM or MFM encoding being used so far.

From the manual I'm using the below command. I have tried changing value for Sector Size with no luck yet.
dtc -p -f<dumpdir/<dumpfile> -i0 -f<dumpdir/dumpfile>.img -v360 -z0 -g0 -i3 -e76 -l8

Output file can be found here (first 2 tracks): https://www.dropbox.com/s/5qquqnb0wwgn0 ... s.zip?dl=0

Do the attached tracks show signs of data?

Thanks again,
Nauseous
brightcaster
Posts: 405
Joined: Fri Nov 08, 2013 10:48 pm

Re: Determine 8" Disk Format

Post by brightcaster »

It's only noise on the tracks you submitted....

David
SomeGuy
Posts: 319
Joined: Wed Feb 18, 2015 8:18 pm

Re: Determine 8" Disk Format

Post by SomeGuy »

I've also got an M2896, it has worked well for me.

At a glance, that dump looks like 100% noise. Check that the drive heads are clean, and that the head is engaging when the drive is activated. Hopefully your disks have not been degaussed.

Until the issue is resolved, I'd recommend using the GUI tool to make preservation stream dumps, and watching the histogram. That will visually show you if you are getting "something" or just noise.
nauseous
Posts: 3
Joined: Thu May 27, 2021 10:47 pm

Re: Determine 8" Disk Format

Post by nauseous »

Hi Someguy,

I have 2 of these 8" drives. One is reading maxtrack = 79, the other maxtrack = 41. Would you mind confirming what you are seeing with your drive? I suspect the unit with lower value is at fault.
SomeGuy
Posts: 319
Joined: Wed Feb 18, 2015 8:18 pm

Re: Determine 8" Disk Format

Post by SomeGuy »

I don't have mine hooked up at the moment. As I recall it would step to 79 or 80.

But 8" drives are all officially 77 track drives. Anything past that is just extra because the drive's microcontroller or physical stop hasn't stopped the head from moving. If I recall correctly, the Kryoflux calibration tool is only designed to detect 40 and 80 track drives, so it does not always work right on 8" drives. Instead you have to feed the max track value 77 in to the DTC GUI. If you are concerned about the head moving correctly, you will have to physically watch it as it steps over all tracks. (If it starts banging the head when the software says it is only on track 39 or so then double stepping is incorrectly turned on).

This model of drive has enough jumper options, you WILL need to consult the tecnical manual to make sure they are set appropriately.
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