Unit Attention and queued commands

Les Record ljr at austin.ibm.com
Thu May 15 15:31:24 PDT 1997

* From the SCSI Reflector (scsi at symbios.com), posted by:
* ljr at austin.ibm.com (Les Record)
Assume we have a SCSI-2 target with QERR=0 (Mode page 0A), and we get the
following sequence:

2   TAG 1 - COMMAND - disconnect
3   TAG 2 - COMMAND - disconnect
4   TAG 3 - COMMAND - disconnect
6   UNTAG - COMMAND=Request Sense - DATA=Sense Data - STATUS=Good - COMPLETE
7   ????

What should happen to the commands queued prior to the CAC generation at line
5, since they were received while a Unit Attention exists (due to the reset)
but prior to the generation of the CAC?  The standard says (section 7.9,
paragraph 7):

"If an initiator issues a command other than INQUIRY or REQUEST SENSE while a
unit attention condition exists for that initiator (prior to generating the
contingent allegiance condition for the unit attention condition), the target
shall not perform the command and shall report CHECK CONDITION status..."

	Les Record  +
"Computers in the future may weigh no more than 1.5 tons."
 -- Popular Mechanics, 1949
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