CA Questions

peterson_gary at emc.com peterson_gary at emc.com
Mon Dec 3 10:35:35 PST 2001


* From the T10 Reflector (t10 at t10.org), posted by:
* peterson_gary at emc.com
*
Two follow-up questions:

#1: Can an ACA-tagged task be cleared by a Clear Task command?

#2: If yes, and the tag supplied in a Clear Task command matches the tag in
a ACA-tagged command, how do you know that the ACA command's tag is valid
since the field that specifies whether a command is tagged or not contains a
value indicating the command is an ACA command?


-----Original Message-----
From: Gerry.Houlder at seagate.com [mailto:Gerry.Houlder at seagate.com]
Sent: Monday, December 03, 2001 10:03 AM
To: t10 at t10.org
Subject: Re: CA Questions


* From the T10 Reflector (t10 at t10.org), posted by:
* Gerry.Houlder at seagate.com
*

These are my answers to the two questions.

ANS-1: In CA mode the initiator doesn't send ACA tag commands, only in ACA
mode.
I presume your question refers to ACA mode. The initiator can send one ACA
task
at a time but can send several ACA tasks before clearing ACA condition. Yes
the
normal tag validation rules are in effect but note that targets are not
required
to check for duplicate tags. Most parallel SCSI devices still do check but
most
FC devices do not (they have much larger tag space).

ANS-2: The new ACA or CA (depending on state of NACA bit in CDB) affects
the task
set according to its regular rules and mode page settings (e.g., QErr
field).
The task set could be suspended or aborted.






peterson_gary at emc.com@t10.org on 12/01/2001 03:15:38 PM

Sent by:  owner-t10 at t10.org


To:   t10 at t10.org, ralphoweber at compuserve.com
cc:   peterson_gary at emc.com

Subject:  CA Questions


* From the T10 Reflector (t10 at t10.org), posted by:
* peterson_gary at emc.com
*
Two more Contingent Allegiance Questions, if I may...

1. When in CA mode, the initiator will send a single ACA Task for
execution.
     Is the QTag value valid for this Task, and are normal Tag validation
rules (e.g. no duplicates) still in effect?


2. In Sam-2 rev 21 section 5.8.1.8, clause (d), it states that a ACA Task
that reports a Check Condition clears the ACA Condition.
     The footnote also states that a new ACA may be entered if the NACA
bit was set in the CDB of the ATA Task.

     Does the establishment of a 'new' CA condition modify the Task Set
in any way, or do all tasks remain in the suspended state?


     (I think the answer is no [they remain suspended], but it has been
suggested to me that this issue could be clarified in the spec).

Thanks for your support ant patience...
------------------------------------------------------------------
Gary S. Peterson
CLARiiON Storage Systems, a Division of EMC Corp.
Phone:  508/382-7150
FAX:     508/382-7913
Cell:     508/472-4001
Email:   peterson_gary at emc.com

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