Question about CLEAR TASK SET and ABORT TASK SET

Gerry Houlder gerry.houlder at seagate.com
Tue Jan 15 12:10:41 PST 2013


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1301150_f.htm">HTML-formatted message</a>

I have a question about the effects of the ABORT TASK SET and CLEAR TASK
SET functions.
The scope of these functions is affected by the TST setting (i.e., whether
the device server maintains a separate task set for each I_T nexus
(TST=001b) or puts all commands from all I_T nexes in the same task set
(TST=000b).
My historical understanding of these functions is:
   - ABORT TASK SET is supposed to abort all commands within the defined
   task set. If TST=000b, this would be all commands from all I_T nexes; if
   TST=001b, this would be all commands from a particular I_T nexus.
   - CLEAR TASK SET is supposed to clear all commands in all task sets,
   regardless of TST bit setting.
The SAM-5 wording regarding these functions seem to describe these
functions differently.
   -  The ABORT TASK SET wording seems to require aborting command for a
   single I_T nexus, which is part of the task set (assuming the device
server
   has outstanding commands from several I_T nexes) if TST=000b and an entire
   task set if TST=001b.
   - SAM-5 wording for CLEAR TASK SET says it only affects one task set, so
   if TST=000b then it affects all commands and if TST=001b then only the
   commands in a single task set (i.e., from one I_T nexus) are affected.
   - With the current SAM-5 definitions, neither ABORT TASK SET or CLEAR
   TASK SET will abort all commands in all task sets if TST=0001b. This seems
   wrong.
I think the current SAM-5 wording of these functions is not the best. Where
do we go from here?



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