[5299] in linux-scsi channel archive
Re: PATCH: Different SCSI ordering for WIDE SCSI chains.
daemon@ATHENA.MIT.EDU (Mark Garlanger)
Sat Dec 5 12:44:31 1998
Date: Fri, 04 Dec 1998 21:30:35 -0600
From: Mark Garlanger <garlangr@cyberramp.net>
To: lancer@airways.com
CC: Rolf Fokkens <rolf@flits102-126.flits.rug.nl>, linux-scsi@vger.rutgers.edu
D. Lance Robinson wrote:
>
> When mixing narrow and wide devices you must only use the first eight
> scsi ids. If you don't, scsi arbitration will not work correctly. The
> scsi bus uses the data bits to arbitrate for the bus. A narrow device
> does not see the upper eight arbitration bits and can fowl things up.
> Your wide devices can still work in wide mode, but their addresses
> should be set between 0 and 7 where the narrow devices can see them for
> arbitration.
>
Is this true?? I have never heard this mentioned before, I just looked
through my Adaptec 2940UW Manual, in the SCSI ID Numbers section it
says NOTHING like this... This would be a big hole in the SCSI standard
if you can't have more than 7 devices if you use ANY narrow devices. My
current system in which I have had no problems:
IDs
============
0,8 - Wide
1,2,3,4,5 - Narrow
Mark
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