Successfully fixed a damaged block on an AmigaDOS disk

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frame
Posts: 1
Joined: Tue Nov 13, 2018 8:31 pm

Successfully fixed a damaged block on an AmigaDOS disk

Post by frame » Fri Nov 16, 2018 11:57 pm

This isn't a support issue, but I wanted to share successful disk (not data) recovery story. I hope this type of post is accepted here.

I've recently obtained a physical copy of AmigaOS, provided on six 3½" MF2DD floppies. One of the disks had one (or more) broken blocks.

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I tried to format the disk with an Amiga 1200, but AmigaOS 3.1.4 couldn't to finish the job.

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So I downloaded the original ADF-image and connected the built in floppy (Chinon, FZ-354, CM: maxtrack=83, salvaged from an Amiga 600) to the Kryoflux.

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I used `DTC -fDisk.adf -w` to write to the same defective floppy disk and the task successfully completed. I used `DTC -fDiskClone -i0 -fDiskClone.adf -i5` to read it back: The SHA-256 checksums of Disk.adf and DiskCloned.adf matched. :D

The disk now works. I can copy data from it without any issues or strange floppy drive sounds. As a final test, I formatted the disk and it successfully completed.

Here's the full log in case this means anything to someone: https://gist.github.com/frame/434e4ebe5 ... 2ead44f08e

SomeGuy
Posts: 179
Joined: Wed Feb 18, 2015 8:18 pm

Re: Successfully fixed a damaged block on an AmigaDOS disk

Post by SomeGuy » Sat Nov 17, 2018 3:20 am

Keep in mind that the Kryoflux can't fix physically damaged disks. You probably got lucky and it put the data at a slightly different index offset than a genuine machine would. Also, sometimes good quality disks will increase their readability after multiple read or write passes due to scraping residue or gunk off. (but never assume a disk is good quality)

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