Subject: Re: SCSI wiring
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Steven M. Bellovin <>
List: tech-kern
Date: 08/09/2005 15:49:32
In message <200508091940.PAA20684@Sparkle.Rodents.Montreal.QC.CA>, der Mouse wr
>>> Ah, there's the difference, then: the reason the swapped-wires case
>>> doesn't work is that they disagree over the ordering between their
>>> IDs.
>> I don't even think you need to swap wires -- it's a bus; all devices,
>> including the host adapter, are equal, as I understand it.
>Yes, but.
>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.

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.

		--Steven M. Bellovin,