8500 won't boot if unused drive disconnected
The short story: My 8500 won't boot if I remove a drive that should not
be accessed during boot. I would like to see if I can get the Mac to
boot without it.
The long story:
I have a Mac 8500 (this is an Old World PCI Mac) that boots into Mac OS
from an external drive. It then loads BootX to go into Linux. My linux
drive is mounted internally.
There are two SCSI buses in the 8500, the internal uses the MESH
controller and is a SCSI-2 bus, and the external uses some other
controller and is a SCSI-1 bus.
I don't really use the disk drive that originally came with the machine
much anymore. It is on the internal bus at SCSI id 0. The Linux drive
is at SCSI ID 1. I'm preparing to replace all my drives with a single
40 GB Ultra160 drive that will run off an Adaptec 29160 that I added to
the machine today.
There is room for only two drives internally, so I would like to take
out the original drive, the one at ID 0, and mount my Linux drive (ID 1)
and the new Ultra160 drive internally. Then I will install Mac OS on
one partition, and transfer my Linux installation to some other
partitions, and then stop using all the drives but the new one.
This should cut down on noise and heat, and my two current internal
drives are very old and at least one of them has gotten flaky.
The problem is, if the drive at ID 0 is disconnected, the Mac won't
boot. I get a gray screen, and the mouse pointer appears and I can move
it around, but it just sits there. I don't get the floppy disk icon
that would indicate it's searching for a boot drive.
I have two theories about this:
- The ID 0 drive holds the internal bus terminator. Maybe if I got a
terminator I can mount on my ribbon cable, then things would work. Do
such terminators exist (this would mount on the internal ribbon cable,
not like the external terminators that have Centronics connectors on
them). Where could I find one?
- The Mac is loading the SCSI disk driver off my ID 0 drive, and that
allows the Mac to continue to boot. If that's the case, there wouldn't
be any way around leaving this drive installed, which would be
unfortunate, but workable. I'd have to mount my Linux disk in an
external case to do my file transfer.
Any ideas what is going on?
--
Michael D. Crawford
GoingWare Inc. - Expert Software Development and Consulting
crawford@goingware.com
http://www.goingware.com/
Tilting at Windmills for a Better Tomorrow.
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