Re: Zip Drive Question

["Peter Watson" <paw77@NOhotmailSPAM.com>]

"Dave Althoff Jr" <dalloff@gcfn.org> wrote in message
news:8umhjg$sfi$1@acme.gcfn.org...
> It turns out that my system (which DOES use the Apple High Speed SCSI
> card) isn't as unusual as I once thought...a "pure" MS-DOS ZIP disk will
> set off the Finder's "The disk in SCSIHD02 is unrecognizable" error.  So
> it most certainly has something to do with the fact that the one disk I
> had been using, though now an MS-DOS disk, began its life as a Macintosh
disk.

How do you connect the Zip drive on the PC? Via the parallel port or using a
SCSI card?
I wouldn't expect a parallel port connected Zip drive to recognise a
SCSI-partitioned Zip
disk. Hmmm, although having said that, maybe I'm wrong. The parallel port
Zip drive
seems to be trying to act like a SCSI device (it uses a SCSI driver!), so
maybe it can handle
the SCSI (ie. Apple-like) partition scheme. If so, this makes more sense of
why this disk
is working everywhere, and NOT being complained about on the GS.

A "normal" MS-DOS Zip disk does not have a SCSI partition map, just an
MS-DOS
partition map, which the IIgs certainly doesn't like!

> I don't remember for certain whether I formatted that disk on the GS or
> not, but I thought I did, and the only thing I have on the GS that can
> handle an MS-DOS ZIP disk is MUG!.  I experimentally stuck a PC-format ZIP
> into the drive and hit the format button, and I got a format dialog, but
> the largest volume size it would permit was 21 Mb.  Since I didn't want to
> format the disk, I didn't go any further.  But I wonder about that, too...

That's pretty much what I would expect. Until such times as someone can show
me
a generic format process, I pretty much have to hard code the appropriate
values
for different disk sizes. So you certainly could have formatted the Zip disk
as a
21Mb "Floptical", and it may well even have worked (if you didn't mind
losing
around 75Mb of your Zip disk!).

I eventually got around to supporting the 100Mb drives (and I'm hoping to
support
the 250Mb drives too). The only catch has been that (using Apple's SCSI
card, anyway)
if the disk has previously been "Apple"-formatted (Mac or GS), then GS/OS
makes it
*extremely* difficult to erase the partition map. I can do it with Chinook
Utilities, but
I haven't worked out how to program it yet. And if I can't zap the partition
map, then I
can't do a low-level format, and I can't create an MS-DOS partition like the
"standard"
MS-DOS Zip disks.

> It was a year ago that I created the 'mystery disk'.  I wonder if the fact
> that it was already formatted in a standard format made a difference,
> allowing MUG! to identify it as a 100Mb disk.  After all, the SCSI device
> just gets a 'Format' command...MUG! just has to figure out how to make it
> DOS-compliant.  Or something like that; I still know a whole lot more
> about DOS 3.3 than I know about GS/OS... 8-)

See my comments above about how (in)effective the GS/OS "format" command
can be when it doesn't want to play.  :-(

Anyway, it sounds like it's highly unlikely that you used MUG! to format the
disk.
Even if you did, you would have ended up with a "small" Zip disk.
--
Peter Watson
-- Write to MSDOS disks on the Apple IIgs?
-- Impossible!  ;-)