Subject: Re: SCSI wiring
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Bill Studenmund <>
List: tech-kern
Date: 08/09/2005 17:14:00
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On Tue, Aug 09, 2005 at 03:37:01PM -0400, der Mouse wrote:
> What I was looking for was a way to connect two devices, each of which
> thinks it's at ID 7, without producing a conflict.  It appears there
> more or less is no such way (since swapping the wires produces an
> arbitration conflict by breaking the assumption that any given device
> is at the same ID as seen by all devices); the best suggestion seems to
> be mycroft's, to have at least one of the hosts change its SCSI
> interface's ID.

You probably want both of them to change their ID. The problem is that=20
initial chip bringup may set a device's ID to 7 and driver config later=20
sets it to the correct ID. Like a motherboard SCSI firmware may set to ID=
7 and it's the OS later that sets the right ID.

So if one device uses ID 7 normally, you can get conflicts while the other=
box is (re)booting.

The joys of how you do this are one of the reasons folks came up with=20
SANs. :-)

Take care,


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