Also look at deana.{txt,com} for more information.

From: crow@coos.dartmouth.edu (Preston F. Crow)
Newsgroups: comp.sys.atari.8bit
Subject: Re: Transferring Atari disks to PC
Date: 18 Jan 1995 09:20:05 GMT

Back before Christmas, there was quite a bit of discussion about
reading Atari formatted disks (single and enhanced density--double has
been solved for some time) on a PC.  I don't think we ever came to a
complete conclusion, unfortunately.  Here's what I think we figured
out:

The program "Anadisk" claims to read almost any disk format, and will
dump the contents into a raw disk file.  For enhanced density disks,
it correctly figures out the format, but generally fails to read
entire sectors correctly.  It usually gets the first "half" of each
sector or so correct, but that's all.  For single density disks, it
either fails entirely, or succeeds perfectly, depending on the
hardware that you're using.  (I've never seen it work for me, so I'm
not sure what hardware is required.)

From a technical standpoint, this is what we know:

Atari formatted disks encode the data with all the bits inverted, so a
raw dump of the disk will require a bit flipping program to make it
usable.

Enhanced density disks are technically double density in that they use
MFM encoding, whereas single density uses FM encoding.  Most(?) PC's
aren't capable of reading FM formatted disks, due to hardware
constraints (is it the controller card or the drive???).

If you use both sides of your disks by flipping them over to use the
back side on the Atari, you won't be able to read the back side unless
you punch another timing hole in the jacket, as PC drives use the
timing hole.


So the main questions that remain are:
 * What do you need to get your PC to read FM disks?
 * How do we overcome the problems reading enhanced density disks?

--PC