ZBC - FINISH ZONE on a closed zone (late LB comment)

Curtis Stevens curtis.stevens at wdc.com
Tue Mar 3 14:31:12 PST 2015


* From the T10 Reflector (t10 at t10.org), posted by:
* Curtis Stevens <curtis.stevens at wdc.com>
*
David, if you check the zone condition statement machine ZC4: Closed to ZC2:
Implicit open (4.3.3.2.5.3), you will see that there is a transition for
FINISH ZONE in the closed state.  The transition to implicit open is
important...  FINISH ZONE may cause writing to occur in these devices.	As a
result, open zone resources are required to perform a finish zone operation. 
It is possible that the FINISH ZONE command fails on a drive with too many
explicitly open zones.
-------------------------------------------------
Curtis E. Stevens
Director, Standards & Features Technology
3355 Michelson Dr. #100
Office: 1-1041
Irvine, Ca. 92612
Phone: 949-672-7933
Cell: 949-307-5050
E-Mail: Curtis.Stevens at WDC.com
Remember, you may only be blamed for something if you are actually doing
something.
-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Black, David
Sent: Tuesday, March 03, 2015 11:17 AM
To: T10 Reflector
Subject: ZBC - FINISH ZONE on a closed zone (late LB comment)
* From the T10 Reflector (t10 at t10.org), posted by:
* "Black, David" <david.black at emc.com>
*
In a review with some of our engineers, we found a missing case in the FINISH
ZONE command that looks like it'll involve state machine changes.  Please
consider the following to be a late letter ballot comment from EMC (caveat -
I haven't checked this for overlap with other letter ballot comments):
-------------
The effect of a FINISH ZONE command effect on a closed zone is unspecified. 
This should not be an error, and it should cause a closed zone to transition
to full (even though no such transition is in the current state machine)
because ...
... if a zone is implicitly opened, the application client expects to be able
to issue a FINISH ZONE command to make that zone full.	If an implicitly
opened zone is implicitly closed by a zone management operation, the
application client is unaware of that zone state change, and hence still
expects to be able to issue a FINISH ZONE command.  The result should not be
an error (e.g., ILLEGAL REQUEST is definitely the wrong answer), and the
application client still expects the result to be a full zone.
-------------
Thanks,
--David
----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
david.black at emc.com        Mobile: +1 (978) 394-7754
----------------------------------------------------
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