Concerning CLEAR TASK SET and TST=001b

Tue Apr 7 06:34:44 PDT 1998

* From the T10 (formerly SCSI) Reflector (t10 at, posted by:
I think we owe a debt of gratitude to Charles Monia, who has asked the
question leading to closure of this debate.

Since the definition of TST=001b is not incorporated in any draft of
SAM-2, looking to drafts of SAM-2 is not sufficient to understand the
existing circumstances.  One must read the TST=001b proposal (97-225r2)
before one considers the fate of CLEAR TASK SET.  Therefore, I quote
the approved proposal document:

  "In addition based upon the decision for CLEAR TASK SET to be
  the mechanism for clearing all task sets, the CLEAR ALL TASK SETS
  definition has been removed."

This statement reflects the desire of the working group that CLEAR TASK SET
produce identical results regardless of the value of TST.  I think the 
desired behavior is reflected in the following quote from SAM-2.

  "The target shall perform an action equivalent to receiving a series of 
  ABORT TASK requests from each initiator."

The above SAM-2 quote is not altered by the text changes in 97-225r2, and I
believe it is not brief to the point of misrepresenting the content of the 

In my mind, the question of making CLEAR TASK SET obsolete for TST=001b
is closed.  The working group and T10 have spoken clearly on this point.
ABORT TASK SET and CLEAR TASK SET are different.  The meaning of ABORT
TASK SET is affected by the Task Set Type (TST) field, the meaning of
CLEAR TASK SET is not.  Both have valid, T10 approved, definitions when
TST=001b (and incidentally the definitions are different).  Changing this
will require approval by T10 of a proposal that changes the effect of
approved proposal 97-225r2, not to mention the effect of a conscieous,
recorded decision of the working group.


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