Re: HELP:Trouble With //GS SCSI Card

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

Supertimer <supertimer@aol.com> wrote:

> mmcginley@STOPSPAMkscable.com (Michael W. McGinley) wrote:
> 
> >sw#2,3,4 Closed
> 
> Your SCSI ID is 7.
> 
> Here's the table:
> 
> For each SCSI ID, Switches 2, 3, and 4 must be set to:
> 
> SCSI ID=7  closed,closed,closed
> SCSI ID=6  closed,closed,open
> SCSI ID=5  closed,open,closed
> SCSI ID=4  closed,open,open
> SCSI ID=3  open,closed,closed
> SCSI ID=2  open,closed,open
> SCSI ID=1  open,open,open
> 
> I recommend setting SCSI ID to 2.

Are you talking about the SCSI ID of the card or of the drive?  I'd
recommend leaving the SCSI ID of the card always set to 7, unless you
have to change it because a device has a fixed ID of 7.

The higher the ID, the higher the priority of the device (in bus
contention situations).  The computer should be the highest, so it
always gets the first crack at the SCSI bus.

> SCSI ID of 2 is special to the Apple High Speed SCSI card.  It makes the
> computer pause on startup to let the drive spin up.

I think this is just Apple's rather poor documentation of a feature.

The Apple High-speed SCSI card polls each possible SCSI ID (apart from
its own), starting at 7 and going down to 0.  It takes about half a
second to poll each ID, so the lower you set the drive's SCSI ID, the
longer it will take the computer to poll it.

(I'm not sure about the "half second" figure - that is from memory, and
my IIgs has been dismantled so I can't check it.  It might be as much as
one second per SCSI ID.)

Setting the drive's SCSI ID to 2 gives you something like two seconds
after the computer starts searching before it will find the drive.  You
get another second if you set the SCSI ID to 0.

I've always set my SCSI drive to ID 6 (or thereabouts).  I just make
sure the drive is switched on and spun up (about five seconds) before I
turn on the computer.

> Also, Apple does not set up its System 6.0.1 boot disk to
> include the Apple High Speed SCSI drivers.  These drivers
> are in the System/Drivers folder on one of the System Tools
> disks or the Install disk (I forget which one).

The Install disk.  (They have to be there, so you can install the system
software onto a hard drive.)

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