On 7/19/22 6:53 AM, Alan Rat wrote:
> Also, I might ask, is there a substantive difference between a .DSK file and a .DO file? Someone converted some actual disks for me, and I was expecting .DSK files, but instead he gave me .DO files; but when simply changing the extension from .DO to .DSK the "disk" could still be CATALOGged, LOADed from, SAVEd to, etc. by AppleWin either way. But these .DO files are the ones from disks which booted on my Apple IIe that won't boot in AppleWin.
Apple II disks have something called sector skew, or "order" - physical
sectors on a 5-1/4" disk don't follow in 1,2,3 order. And the specific
order that is used by DOS (i.e. 3.3) is different than that followed by
ProDOS. So if a person is extracting sectors from a disk and copying
them out to the outside world, they have the ability to record them in
an image file in either "order" - not necessarily following what the
operating system actually used, either.
Historically, a .DO suffix meant that a disk was recorded in DOS sector
order (regardless of what the original OS was/is). A .PO suffix meant
that a disk was recorded in ProDOS order (again, regardless of reality).
Most image transfer tools always use DOS order for 5-1/4" disks no
matter what. The suffix of .DSK is ambiguous, and offers no clues as to
which order the image is in.
Most tools can apply some fairly standard heuristics to figure out what
the actual order, and underlying OS, actually is. It is *possible* that
those heuristics are failing to correctly identify what your disk image
is trying to represent, so that's why it would be very interesting to
actually look at it. It's also possible that the disk image is
mislabeled and is actually in ProDOS order even though it says .DO,
which can confuse some tools (AppleWin included). So you might even try
renaming your file with a .PO suffix to see if that changes anything.