SPC-4 Control mode page TAS bit

Kevin D Butt kdbutt at us.ibm.com
Fri Nov 6 09:11:23 PST 2009

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SPC-4r22 Control mode page has the following definition for TAS
A task aborted status (TAS) bit set to zero specifies that aborted tasks 
shall be terminated by the device server without any response to the 
application client. A TAS bit set to one specifies that tasks aborted by 
the actions of an I_T nexus other than the I_T nexus on which the command 
was received shall be completed with TASK ABORTED status (see SAM-4).
This doesn't seem to be a precise definition.  The "set to zero" sense 
refers to the application client (by default that means on the I_T nexus 
over which the task was issued).  The "set to one" specifies multiple I_T 
nexuses.  I am not sure, but I think the intent is:
A task from an I_T nexus that gets aborted by the actions of another I_T 
nexus shall be reported to the I_T nexus on which the command was received 
if the TAS bit is set to one, but shall not be if the TAS bit is set to 
zero.  I don't think this should attempt to say anything about what is 
reported for actions taken by the I_T nexus through which the command was 
Do I understand the intent of this bit?
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at us.ibm.com

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