Re: Help with bad disk

[dalloff@freenet.columbus.oh.us (Dave Althoff)]

Michael A. Naud (manaud@naz.edu) wrote:
: I have a DOS 3.3 disk that copy II plus keeps reading with an IO error on 
: sector 11. Is there some way to fix this? Is there some work around to 
: bypass this sector (or the boot sector) to be able to recover the files. 
: Please email an answer if you know of a way. We have a very distraught 
: person with a bad Apple II disk.

Do you mean Track $11?  If so, then you've got a big problem because that
is where the directory is located.  Can I assume that this disk is just
DOS programs and files, not some wild copy-protected or direct-access
stuff?  Good.  In that case, I have a program called Dark II (have no idea
where I got it lo so many years ago)  which will search a disk for
anything that looks like a track/sector list, and build a directory from
scratch.  Or you could do it by hand.  In any case, there are several
things you could try:

1.  Find a copy of BAG OF TRICKS, and use it to re-format Track $11; ask
it to preserve data if possible.  Then try copying the disk.  Still no good?

2.  Find out if you can read ANY sector of Track $11.  If, for example,
Sector 00 is bad but the other $0E sectors are okay, then you are okay. 
Using a program such as FID or the Copy II Plus file copier, copy the
files one-by-one to another disk.  If Sector 0 of Track $11 is trashed, it
means the track bitmap is probably no good, which is very dangerous.

3.  If you can't get anything out of that track, you may have to build a
new directory from scratch.  I would INIT a fresh disk, then use a
track-copy program to copy all of the tracks EXCEPT Track $11.  In this
case, you will end up with a copy of the disk that has all of the files on
it, but only garbage data in an otherwise valid directory track.  Then
using a program such as Dark II or Bag of Tricks - FIXCAT to search for
files, you can re-build the directory.  Or you can do it by hand, but it
isn't fun.

Please contact me directly for clarification, further info, etc.
--Dave Althoff, Jr.  (dalloff@freenet.columbus.oh.us)
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