SPC-4 Control mode page TAS bit

Ralph Weber roweber at ieee.org
Mon Nov 16 20:24:10 PST 2009

Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r0911164_f.htm">HTML-formatted message</a>

SAM-5 r02 subclause 5.6 provides a much more complete
discussion of the effects of the TAS bit.
In the event that you find the Control Mode page
description lacking after reading SAM-5, please
feel free to bring a clarifying proposal to the
next CAP meeting.
All the best,
Kevin D Butt wrote:
> 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 received.
> Do I understand the intent of this bit?
> Thanks,
> 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
> http://www-03.ibm.com/servers/storage/ 

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