Re: can a Mac read an Apple II SCSI drive?

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

In article <1994Jul30.154919.1@csc.canterbury.ac.nz>,
 <misc176@csc.canterbury.ac.nz> wrote:
> I not so long ago obtained a SCSI card for my Apple IIE (Apple II HS
> SCSI card) and picked up a 20MB hard drive. The idea I had was that I
> would be able to use this drive to store my heaps of II stuff on, and
> to use it also with the Macintoshs I have access to, including a
> friends one with an Apple IIE card in it.

This is possible, but is a little tricky to set up.

The Macintosh is the main problem area.  The Mac requires a device
driver on the hard drive, which is normally installed by the software
included with the drive (if you bought it with Macintosh support
software).

If it was an "Apple" branded drive, the necessary software is included
with the Macintosh System Software: I think it is called "Apple HDSC
Setup", or something like that.  It can initialize the drive, install a
device driver, and create one or more partitions.

If it isn't an Apple brand drive, you may need a third-party set of
utilities for the Mac.

There is no software for an Apple IIe which will allow you to
partition a drive and install a Macintosh device driver.  For the
IIgs, the "Advanced Disk Utility" program included with System 6.0 and
later can install a Mac driver on an Apple hard drive, and if you have
a third-party driver (as I do) it can also install it on other drives.

The second problem is partitioning the drive.

The Macintosh and Apple IIe have different native file systems (HFS on
the Macintosh, ProDOS on the IIe).  The Macintosh is not normally able
to read a hard drive partition using the ProDOS file system, but there
is a "ProDOS File System Extension" included with the software for the
Apple IIe card for the Macintosh LC, which allows the Mac to read and
write ProDOS hard drive partitions.

You have to be a little careful with this extension, especially if you
try to write general Macintosh files to a ProDOS volume: if the file
has a resource fork, the IIe will not be able to read the file (or
delete it!)  I've heard that using it from Mac programs other than
Finder will result in a resource fork being created on all files saved
on the ProDOS volume.


There are a couple of freeware programs for the IIe, which allow files
to be copied from an HFS 3.5" disk, but I don't think they support a
hard drive partition.

You need to consider whether you want to set up a single ProDOS
partition on the drive, or two partitions: one HFS and one ProDOS.

>     So I have a problem: I considered updating the drivers on the drive with
> the Silverlining drivers, but I don't know whether that would make the drive
> unreadable by the Apple II HS SCSI card/ProDOS.

I think SilverLining can do almost everything you need.  If you
initialize and partition the drive using SilverLining, it should
install the necessary Mac driver.  (This will erase everything that is
currently on the drive, so make sure you have a backup first.)

The difficult part is getting a ProDOS partition on there.  Assuming
you create a single HFS partition using SilverLining, the Apple HS
SCSI card should recognise the drive as having a single partition in a
foreign file system (if there are any PrODOS partitions on the drive,
it will ignore any HFS partitions that may be there, but if there are
no ProDOS partitions, it will give you access to the first non-ProDOS
partition).

You can then use any ProDOS-based utility program which can initialize
arbitrary sized disks (e.g Copy II+) to do a soft reformat of the
partition and it will be changed into ProDOS format.

Another option is to use SilverLining to create two HFS partitions,
then use a ProDOS-based utility to reformat the first one (the second
one will never be available).

> The Apple II SCSI partition program

(which is the bare minimum needed to use the card and offers no useful
features)

>     Any help/advice pointers would be appreciated, as would any
> software that would achieve the above aims.

Unfortunately, the ideal program for this is no longer available:
Chinook SCSI Utilities (for use with Apple SCSI cards on the IIe and
IIgs).  It lets you set partition sizes down to the block level, and
can reformat individual partitions without affecting others.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand