Re: PATCH: Different SCSI ordering for WIDE SCSI chains.

Rik van Riel (H.H.vanRiel@phys.uu.nl)
Thu, 26 Nov 1998 07:44:22 +0100 (CET)


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On Wed, 25 Nov 1998, Rolf Fokkens wrote:

> Furhermore I heard that non-wide take actually two ID's when
> connected on a WIDE chain: the configured ID and that ID+8. They can
> be addressed by their own ID, but the other ID is lost.

They don't. SCSI uses a separate piece of wiring (actually
just the data wires) for each ID.

> Now comes the catch: when I DO connect an external non-wide device,
> it's ID is between the ID's of the internal wide devices (unless it
> hat ID 0). This causes problems during boot when I have connected an
> external device: what used to be /dev/sdb has become /dev/sdc. Now
> /etc/fstab is no longer accurate!
>
> To avoid this problem, I changed the scanning order for wide scsi
> devices in the kernel. I changed it to:
> 0,8,1,9,2,10,3,11,4,12,5,13,6,14,7,15.

A better, and more appropriate, fix would be to use something
like scsidev (userland) or devfs.

> I attached a patch to take care of this in kernel 2.1.129. it should
> be applied to drivers/scsi/scsi.c

No it shouldn't. You have created a solution for your specific
problem. It would completely mess up other people's systems!

regards,

Rik -- slowly getting used to dvorak kbd layout...
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