FC-TAPE Command Reference Numbers

Binford, Charles charles.binford at symbios.com
Tue Nov 3 10:54:36 PST 1998

* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* "Binford, Charles" <charles.binford at symbios.com>
In general I agree with Dave.  FC drivers don't do mode sense and don't
want to.  However, I can also see Bob's point of not wanting to mix a
SCSI thing-a-ma-jig into PRLI if it is not needed.  So, I thought I'd
through out possible compromise.

Parallel SCSI has several transport specific bits in the standard
Inquiry page (bytes 6 and 7).  It seems reasonable to me to define one
of these bits as the indication of whether or not the precise ordering
is enabled or not.  I don't think that will break Bob's intent.  The
question is, Dave, do you find doing an Inquiry from your adapter as
repugnant as a Mode Sense?

Charles Binford
LSI Logic Storage Systems
(316) 636-8566

> -----Original Message-----
> From:	Baldwin, Dave [SMTP:Dave.Baldwin at emulex.com]
> Sent:	Thursday, October 29, 1998 5:23 PM
> To:	'Bob Snively'
> Cc:	fc at nsco.network.com; t10 at symbios.com
> Subject:	RE: FC-TAPE Command Reference Numbers
> * From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
> * "Baldwin, Dave" <Dave.Baldwin at emulex.com>
> *
> Bob,
> PLEASE put the PRLI CRNS bit back in to the FCP-2 document. We have
> discussed this issue previously in the FC-TAPE working group, and the
> decision was to provide this feature.
> Some companies have control over all pieces of the operating systems
> they have to deal with, so your proposal would make sense in these
> environments.
> Other companies, like mine, need to provide HBA device drivers that
> run on several different operating systems. We do not have a lot of
> influence over operating system vendors, and can't get them to put the
> necessary changes in required by your implementation. Some still can't
> support more than 16 targets per adapter board, or more than 8 LUNs
> per target, which for us would be a higher priority than implementing
> the ECRN functionality. We don't have several years before we need
> this behavior, we need it now.
> HBA drivers are not supposed to be doing MODE SENSE/SELECT commands,
> and doing so would be very distasteful. Using the CRNS bit to
> determine whether the HBA driver provides a CRN in the FCP_CMD is a
> very simple and very useful mechanism. Please reconsider your
> decision.
> Best regards,
> Dave Baldwin
> Emulex Network Systems
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