Re: Revisiting the GS/Mac SCSI formatting problem

[David.Empson@bbs.actrix.gen.nz]

In article <1ldrvuINNjha@aludra.usc.edu> erictayl@aludra.usc.edu (Eric Taylor) writes:
> 
> 	Ok, I have been sort of following the discussion about formatting
> a HD on the GS for use on a Mac.  I know that you must get GenericMacSCSI 
> onto the HFS partition somehow and I know that the only GS program in
> existance to do it is ADU.
> 
> 	My question is, when does ADU give the prompt asking if
> the drive is to be used on a Mac?  

Under the Partition command.  You can only put a Mac driver onto the
disk if it has a partition map, since the driver resides in its own
partition.

>  	My problem...  I have recently bought an Insite floptical
> mechanism for my GS.  I love it!!  I am using the RamFast 3.0L ROMS
> to support it.  I have formatted the VHD disks and I am using them
> regularly.  I have a friend with a Mac and I want to be able to 
> format the VHDs on the GS and then use them on the Mac.  Whenever I
> simply format one in the HFS format, and then I insert it into the
> Mac Insite floptical, I get a dialog stating that the disk is not
> formatted.  I know this is because I never put a driver on it.

Ick!  Partitioning a floppy disk?  :-(

How could you access existing 720k and 1.44 MB floppies on a Mac with
a floptical?  The IIgs doesn't need a partition map to be present - it
can just use the entire volume.

You could of course format the disks on the Mac, which would add the
device driver, then access them from the IIgs.

> 	Perhaps some kind person could go over the exact manner in which
> to use ADU to format a disk for use on a Mac.  Show us the steps to
> use and when important dialogs show up.  I do not believe I have ever
> seen ADU ask me if I am going to use the disk on a Mac.  If the person
> is really nice, they would explain where GenericMacSCSI should be
> located and a manner in which to get the driver off of a pre-formatted
> disk for use in MacGenericSCSI.

I tried this with my SyQuest drive, so the principle should be the same.

In ADU, click the Disk button until the appropriate disk is highlighted.

Click the Partition button, and the OK button in the warning dialog.

Adjust the partition sizes as required, and name the partitions.  You
only need one partition.

Click the Partition button.  If you only created one partition, ADU
will ask if you want to hard format the drive.

ADU will then probably bring up a dialog saying "Unable to load the
Macintosh driver.  HFS partitions will not be usable on Macintosh
computers." 

The problem is that there is no GenericMacSCSI file.  This file has to
be in the *:SYSTEM:DRIVERS directory.  The file type isn't specified
by the ADU documentation.  The file must contain two resources.  The
first contains the driver code, and the second contains some
information about the driver.

I don't know of any easy method to extract this information from a
disk.  It may be possible to bypass the drive's partitioning scheme to
directly read physical blocks (using the GS/OS SCSI drivers), but the
process wouldn't be easy.
-- 
David Empson

Internet: David.Empson@bbs.actrix.gen.nz    EMPSON_D@kosmos.wcc.govt.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand