Subject: Re: Shared scsi??
To: Andrew Sporner <>
From: Aaro J Koskinen <>
List: tech-kern
Date: 06/20/2000 21:32:53
On Tue, 20 Jun 2000, Andrew Sporner wrote:

> What level of shared scsi is currently supported in the kernel.  What
> I mean here is the ability to have multiple hosts on a scsi bus with
> different initiators.

Not really supported, but you should get it working (that's because the
multihost support doesn't actually require much support from kernel).
Last time I checked there couple things that were sloppily

- SCSI ID was hardcoded to 7 in some drivers (compile time constant).
It would be nice to use same kernel image in all hosts on the same SCSI
bus. Perhaps it could be assumed that user has configured a correct ID
to SCSI BIOS and use that value... Or use SCAM negotiation, but I think
it requires target-mode and it's not possible to implement for all

- Some drivers reset the SCSI bus on attach(). Not very polite if the
other host is transferring data while the other one boots. Also, the
device reset in the scsipi interface (none seems to use it, tough) is
implemented using a bus reset while the correct way to do it is to send
a reset message, which affects only a single device on the bus.

Aaro Koskinen,,