Re: Can you boot a IIGS from a Mac w/ IIe card?

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

In article <3ijdsm$bc6@cleese.apana.org.au>,
Jonathan Pratt <ntt@cleese.apana.org.au> wrote:
> 
> I had a friend with a powerbook who had his GS on one end of the SCSI
> chain, and the powerbook on the other, and both could 'see' the hard
> drives inbetween, including the internal one on the powerbook.  Therefore
> I suppose you could use the one hard disk from both computers, but you
> couldn't boot them both (because they would both want to boot the root
> partition)

Actually, you should be able to boot both machines from the drive, as
long as the IIgs's ProDOS partition is the first one.  The Mac should
be able to boot from the HFS partition even if another partition comes
first.

There are a few very important points to keep in mind when trying this:

1. It will only work with an Apple SCSI card.  The RamFAST doesn't
   support SCSI arbitration, so it and the Mac could step on each others
   transmissions, causing data corruption.

2. The computers must be set to different SCSI IDs.  Most Macs are
   fixed at SCSI ID 7, so the IIgs must be set to a different ID.

3. Be VERY careful if both computers are using the drive at the same time.
   Ideally, the computers should have independent partitions which
   only they can access.  It may be safe to read files from the other
   computer's partition (but with HFS, who knows...) but it is
   definitely not safe to write to a partition from both computers.
   You are asking for directory and file corruption.

   It is much safer to have only one computer powered on at a time.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand