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Weak Disk Imaging

NeXT

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Oct 22, 2008
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Kamloops, BC, Canada
As a (somewhat expensive) side project from the Sun MCA-3000 thread about two months ago I purchased a stack of floppy disks for the vehicle diagnostic system as an attempt to deal with the problem where Sun was stupid and decided using somewhat fragile and dirt sensitive floppy disk media in an automotive maintenance environment was an awesome idea (I mean there WAS a hard disk option but that's another can of worms) and it seems nobody else has at least in a public space made images of these required floppies available for when you do eventually trash a disk. The Internet is scattered with people begging for copies of the disks and Snap-On, who acquired Sun EOL'd these analyzers many years ago.

Well I finally got the disks onto my bench and I'm starting the process of imaging them into a fairly straightforward disk image format that doesn't require fancy tools, adapters or software. Rawread is refusing to work under 64-bit Windows 7 but Winimage seems happy to make uncompressed .IMA images. No the Disk-o-Matic is currently not operating so I don't really have a means to get access to tools like ImageDisk.
The disks themselves are nothing special. 720kb 3.5" media formatted to MS-DOS with no copy protection. Aside from one Acura disk with a cookie separated from the hub (that will require something more advanced to recover the data) the rest of the various vehicle test disks have been good with the only faults been reading the last few sectors on the disk where hopefully nothing was written. Most of the disks are only about 40-60% full. My problem is the three floppies that make up the main booting and diagnostic application disks. These get used the most and as a result are in the worst condition. One disk gets about halfway through Winimage and then gets stuck reading a sector. The second sounds like the cookie is dirty and likewise has more than one spot where Winimage can't seem to read the disk in. The last disk sounds like garbage and repeatedly you have to tell it to ignore read errors but eventually it reads most of the disk in.
For the first disk under Windows I can drag and drop all the files off the disk, so I can just append the disk image with those and it should be okay. The second disk is the same but there's two files even Windows can't seem to read. Should be okay there as in the stack was a copy of that floppy. That disk too sounds dirty but the two files in question read fine, so again I can probably append the image and it will be okay. The last disk is pretty much a write-off.

I know there are much better imaging utilities than Windows Explorer and WinImage out there, but I don't have them. Likewise I need to keep the images in a somewhat idiot-proof format. Are there any suggestions for dealing with these disks where they are starting to get a bit weak?
 
Disk magnetics are pretty stiff; the majority of problems I have are with shedding or contaminated media. IMD is pretty good, but I guess you can't boot MSDOS?
 
I mean, I can. There's a Compaq Portable 386 sitting beside the table that has IMD AND Rawread already on it because I use the system mainly for WRITING out images, but I've tried to avoid feeding it disks to image because the floppy drive is a PITA to clean if you foul the heads.
 
I assume you have already cleaned your drive heads.

When I have a disk that won't read some sectors in a standard drive (but isn't shedding/moldy), I will try it in my LS-120 drive. Around 25% of the time it will be able to read everything.
 
Yeah I cleaned the drive before starting and got consistently good reads on other disks, then ran into these three, cleaned the disks/drives, tried again, same result, moved onto other disks and had no issues again.
I can dig around and I think I got a spare PC Card LS-120 drive somewhere.
 
Next,
It would be interesting if you could would boot a Debian computer and give gddrescue V1.23 a try.
It should allow you to read as much of the floppy as possible, and recover the missing data
from other duplicate floppy's. You can also read in reverse order to retrieve more of the missing data.

gddrescue:


Debian 11 supports the following floppy formats as described in the /etc/mediaprm file.

If you could make some duplicate images of the different floppy's (Disk3) with a Greaseweazle or Kryoflux, I could test
with gddrescue to see how well it rebuilds the floppy data.

In fact you can make several images of floppy 1, 2, and 3 (marking the original's) and I can try processing all three.

Larry
 

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