[Coco] Recovering Data from Bad Disks

[Jayeson Lee-Steere]

I have a lot of old Coco disks and now that I have my Coco set up, I'm in
the process of extracting the data off them. I am running Drivewire 4 in
HBDOS mode and BACKUP 0 TO n creates a .DSK per physical disk which is
exactly what I want.

However, many of them are bad, including everything that has any of my work
on them. I do however have a backup disk for everything, but those two have
a lot of bad disks too. I was thinking that if I extracted what I could
from both versions and hex-diff the .dsk images, I should be able to
recover a lot. I vaguely recall back in the day that there was software
that would allow ignoring (checksum?) errors during copy and often you'd
end up with only one bad byte. I have no idea what that was though. Does
anyone know what I'm talking about?

Another option would be to write something myself that uses DSKCON as it
would allow me to log out additional info such as which sectors were bad. I
have a vague recollection though that the DSKCON routines don't give any of
the sector data on error?

- Jayeson Lee-Steere