SCSI-2 Contingent Allegiance handling

Binford, Charles cbinford at
Wed Sep 27 14:48:00 PDT 1995

>From: Chuck Gibson
>To: SCSI Reflector
>Subject: SCSI-2 Contingent Allegiance handling
>Date: Wednesday, September 27, 1995 1:49PM
>What is the proper behavior for a SCSI-2 target when the first command
>(from the same initiator) after entering the Contingent Allegiance 
>is a
>tagged command?
...... stuff deleted
>After checking a few implementations, there doesn't seem to be a standard
>way to
>respond.  In the past, I have cleared CA on the next command from the
>regardless of whether it was tagged or untagged.
>Any thoughts??

We asked the same question a few years back.  The answer we received was
 - Clear the CA

This is a bit of a hybrid, read between the lines kind of solution.  The 
QUEUE FULL matches the behaviour specified for the same condition under 
Extended CA.  The Clear the CA matches the  "... The contingent allegiance 
condition shall be cleared upon .... ANY SUBSEQUENT COMMAND for the I_T_x 
nexus",  statement you quoted.

I also think a
 - Send BUSY
 - Clear the CA
solution is acceptable.

Just my opinion :-)

Charles.Binford at

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