Re: PATCH: ide-scsi.c to allow claiming of Onstream drives

From: Matthew Dharm (mdharm-kernel@one-eyed-alien.net)
Date: Wed Sep 13 2000 - 18:25:18 EST

On Wed, Sep 13, 2000 at 03:53:13PM -0700, Andre Hedrick wrote:
>
> On Wed, 13 Sep 2000, Matthew Dharm wrote:
>
> > Attached is a patch to ide-scsi.c against 2.4.0-test8. Please consider
> > applying it.
> >
> > This patch removes the logic which causes ide-scsi to refuse to attach
> > itself to an IDE OnStream drive. While these drives are not supported by
> > the standard st.c driver, there is userspace support (using the sg
> > interface) which works with the ATAPI drive with ide-scsi patched with this
> > patch.
> >
> > So there really is no reason for ide-scsi to reject this device.
>
> Yes,
>
> There is a reason that it was put there, DI-30's require special IO that
> st.o does not know how to do.
>
> Look at all the hoops that it took to get ide-tape to work.
> If ide-scsi would have done the trick, it would have saved headaches.
>
> Unless OnStream has changed the firmware it will fail, but please try.

I am well aware of the fact that st.c is unable to suppor this drive. It's
also unable to support the OnStream SC-30 and SC-50 units. Realistically,
st should reject these drives -- work is being done on a patch to st do
accomplish this.

However, the userspace solution (which uses the scsi generic interface)
_will_ work with the ATAPI drive under ide-scsi emulation. There is also
an (experimental) kernel driver (called osst) which will do the work of st
-- this driver works with the SC-30, SC-50, and DI-30 (ATAPI) units. Of
course, the only way either the osst or sg driver will work with my ATAPI
drive is if ide-scsi will do the emulation.

I should point out that I've tested this configuration, and it works well.

Unfortunately, ide-tape and these other drivers (both sg and osst) use
different logical formats on the tape. Tapes made on my ATAPI drive with
osst + ide-scsi are unreadble by ide-tape. However, they are readable on
SCSI units (and should be readble with USB units as soon as I'm done with
that driver).

The point is, there is no reason for ide-scsi to refuse to do the
emulation. I personally find that emulation useful to do backups with.
There _is_ a reason for st.c to reject these OnStream drives, but that
logic belongs in st.c, not in ide-scsi.c

Matt 

-- 
Matthew Dharm                              Home: mdharm-usb@one-eyed-alien.net 
Maintainer, Linux USB Mass Storage Driver

You should try to see the techs say "three piece suit".
					-- The Chief
User Friendly, 11/23/1997
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