Re: Help: ADU and sharing a hard drive between a mac and 2gs

[supertimer@aol.com (Supertimer)]

goble@kin.on.net (David. E. Goble) wrote:

>Hi All;
>
>I have an external 105Meg Quantum (LP105S 910109405) Ver 3.1 according
>to SCSI Probe 4.3 and a IBM Seagate program.
>
>It was partitioned (4, 32, 32, 32), formatted and intialised for my
>Apple 2gs (running sys 5.0.2) with Apple II High Speed SCSI card
>Utilities ver 2.0.

32MB should not be used for all partitions.  The IIGS recognizes
HFS formatted partitions using the HFS FST, so it is best to
have one 32MB ProDOS partition to boot from and one ~70MB
HFS partition.

>This has worked fawlessly. I have upgraded to system 6 and it has
>still worked perfectly and the old ADU can still partition,
>format/initialise the drive.
>
>I recently got my hands on a MacSE/30 and wanted to partition and
>format the drive so I can connect it to either computer as a boot
>drive, by having one partition as a mac boot volume.
>
>This is when I found a problem. I tried to repartition the drive using
>the new ADU (ver1.2), after setting up the partitions and pressing the
>partition button, it said; it can not partition the drive. It can
>however format/initialise and zero it...

The problem is that ADU can only properly partition Mac
readable HFS partitions IF the drive is an Apple brand
SCSI drive.  The reason?  Apple wrote ADU to scan for
an Apple ROM on the hard drive before it installs the
Mac SCSI drive built into ADU's resource fork.  Without
it, it cannot partition HFS partitions that are readable on
Macs.  In fact, without this power, it is possible that
ADU will have problems dealing with previously Mac
partitioned hard disk drives such as this one.

The solution is a program called GenEx.  Look for on
the ground ftp server:

     ftp://ground.ecn.uiowa.edu/apple2/apple16/

This program extracts the GenericMacSCSI driver from
ADU's resource fork and puts it into the IIGS' drivers
folder.  ADU will look in this folder for a generic driver
if it cannot find an Apple brand hard drive but no third
party drive maker ever made a Mac driver to install on
the IIGS to do this.  However, in all cases, Apple's own
driver has worked on third party SCSI drives.

So...get GenEx, extract the GenericMacSCSI driver
from ADU and place it in the IIGS' System:Drivers
folder.  Run ADU and partition the drive first partition
32MB and second partition the rest of the drive
(~70MB).  Check your System:FST folder to make
sure the HFS.FST is there.  Then format the two
partitions from the Finder.  Format the 32MB one
ProDOS and the ~70MB one HFS.

BOTH ProDOS and HFS partitions will now show up
in the IIGS Finder.  The IIGS behaves just like
MacOS with regards to the HFS partition, so all
things like max file size, number of files, file naming
conventions, etc., are Mac style.  Spaces and
symbols are now legal file name characters.

Install GS/OS on the ProDOS partition.  Now when
you take the drive over to your Mac, the HFS
partition shows up.

Congratulations, you have formatted a dual platform
drive.

>Yes, I booted from the system 6 3.5 inch boot disk and run ADU from
>the system 6 tools disk. I can partition, format and intialise the
>drive on my 486 and on my MacSE/30

In this case, format with ADU is required but ADU's
GenericMacSCSI driver must first be extracted with
the GenEx program.

>(The drive will not boot on the apple 2gs after being partitioned and
>formatted on the MacSE/30 and having partitioned and formatted it on
>the MacSE/30, I tried booting from floopies with the drive connected,
>but it has a 16k partition that the 2gs wants to either eject or
>initialise. I assume this is why the 2gs will not boot from the drive)

Of course.  The IIGS does not recognize the way
current Mac software names the driver partition
(the 16k thing).  However, ADU creates a differently
named partition that both the Mac and IIGS will
recognize so BOTH Mac and IIGS will hide that
partition (needed by the Mac) IF the drive was
formatted on ADU, not the Mac.  THEREFORE, it
is important to get GenEx as soon as possible to
enable your ADU to do this.

>So why does the new ADU have a problem with partitioning?

It is not an Apple brand drive.  It has already been
formatted on a Mac with newer Mac partition
software.  ADU needs GenEx to get around the
problem.

>Is there a way for the 2gs to ignore the 16k partition created by the
>MacSE/30, so the drive can be a boot disk for the 2gs?

Yes.  ADU+GenEx.

>Also can both systems (Mac system 6/7.5.3 and 2gs system 6 be on the
>drive, so that both systems will boot when the drive is connect to the
>right computer?

Possible provided ADU+GenEx is used.  In such
a case, the IIGS will see both ProDOS and HFS
partitions but the Mac will see ONLY the HFS one.