On 22 Mar 2000, Florian Weimer wrote:
> Jens Axboe <[EMAIL PROTECTED]> writes:
>
> > On Wed, Mar 22 2000, Florian Weimer wrote:
> > > Is it possible to use a standard SCSI host adapter to fake other SCSI
> > > devices on the same bus (for example, an additional hard disk with a
> > > SCSI ID different from that of the host adapter)? If the answer is yes,
> > > can I use the current "generic" user-space SCSI interface for that?
> > >
> > > (This sounds crazy, I know, but I think I'd have an interesting
> > > application for this stuff...)
If you want the SCSI host adapter show up on the bus in addition to itself
(with SCSI-id 7 and someother), I doubt that you have a chance to find
some hardware that does that. You could emulate a faked scsi device on the
bus in the kernel drivers though...
However, I understand you want this host adapter show up as a device on
a bus of another host adapter (in the same or another machine): That can
be done. Your host adapter must allow to set an id different from 7
and it must be able to accept commands from another device.
I know adapters which can do that (like my old AHA1742) and I assume there
are many, but not all, which will do that.
The point, however, is that then linux must be prepared to get interrupted
from the adapter, fetch some command from it and react somehow (by sending
or receiving some data). AFAIK, the linux SCSI layer is not prepared to
deal with such things. By far not, no chance. It could probably be done
all in the lower scsi layer (host adapter), but then you had no general
API to it.
The generic scsi interface which is far above those layers has no chance
at all to do it.
However, there is/was an IP-over-SCSI project (URL) which would work like
this: one host shows up as a device to the other. They would have dealt
with that.
Michael.
--
Michael Weller: [EMAIL PROTECTED], [EMAIL PROTECTED],
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