Re: Mac/GS dual boot hard drive?

[dempson@actrix.gen.nz (David Empson)]

arekusu <eddy@cs.ucdavis.edu> wrote:

> Since I just picked up a new drive, I'm wondering what the general
> concensus was on partitioning it to also be Mac-bootable.

There shouldn't be a problem doing this, as long as you have a Macintosh
device driver available for it, and the partitioning software used can
set everything up properly.  This is easier said than done.

First, a warning: do NOT attempt to connect the drive to a Mac and IIgs
at the same time.  Turn everything off, and move the drive over to the
other SCSI bus when required.

The specific requirements for having a drive that can boot on either
system are:

1. The first non-driver partition on the drive must be ProDOS.  (This
may not be strictly necessary, but it avoids confusion.)

2. The Mac driver must be installed.  This means you have to use the
appropriate Mac software to partition the drive.  If you have an Apple
SCSI card, you may be able to use Advanced Disk Utility, with some work
required to set up a Mac device driver to be installed on the disk.

This is all much easier with Apple-branded drives, because Advanced Disk
Utilitiy includes the Mac device driver for Apple drives.  This driver
should work with most third-party drives, and a program has been
distributed which extracts the driver and sets it up for use with
third-party drives.

For non-Apple drives and an Apple SCSI card on the Apple II, the easiest
solution would be:

(a) Use the Mac partitioning software to set up the drive.  Create at
least two HFS partitions: the first one must be 32MB or less, and the
remaining ones can be any size you like.  Don't install any software
yet.

(b) Move the drive to the Apple II and boot from floppy (or an existing
hard drive) with the HFS FST installed.  Once you reach Finder, erase
the first partition on the new drive, and change the file system to
ProDOS.

(c) Install all software required (on both machines).  The Mac should be
able to boot from the second or any subsequent HFS partition.

The Mac driver may be confused by the ProDOS partition.  Some
third-party drivers will mount ProDOS partitions on the Mac desktop,
others ignore them completely.

I'm not sure how easy this will be with a RamFast.  In particular, the
RamFast probably won't change the partition owner in the partition map
when you do the erase operation.  This means that the Mac will still see
the partition as an HFS one, with a corrupted file system.

> It's a 200 meg disk, I was thinking one 32 meg prodos, one 32 meg
> (Mac bootable) HFS, and the rest a big HFS partition.

There is no particular reason to have two HFS partitions, except for
personal reasons such as helping to organise data.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand