Subject: Re: SCSI wiring
To: Steven M. Bellovin <smb@cs.columbia.edu>
From: Brett Lymn <blymn@baesystems.com.au>
List: tech-kern
Date: 08/10/2005 13:37:45
On Tue, Aug 09, 2005 at 03:49:32PM -0400, Steven M. Bellovin wrote:
> 
> That's right -- there's no magic about the ID, and I don't think I've 
> ever seen a host adapter where changing that was hard.
> 

Well taking that statement as read it is not correct.  There is
_no_reason_ the bus controller _must_ be scsi id 7 but there is a
reason why it is set to 7, in an arbitration the highest number device
will win the race and take control of the bus.  This is the reason why
Sun used to set their tape drives to id's 4 and 5, so the tape had
higher priority over the disk reads during a backup.  If I recall
correctly on a wide bus devices 8 - 15 arbitrate below id 0.

-- 
Brett Lymn