UA interlock & multiple initiators

Edward A. Gardner eag at
Thu Feb 20 09:47:59 PST 2003

* From the T10 Reflector (t10 at, posted by:
* "Edward A. Gardner" <eag at>
The intent was that a UA interlock would only be for the individual I_T_L 
nexus that had a failed command.  That is, your "latter" case.

Please check SAM-3.  SPC-3 only states the mechanism for enabling / 
disabling UA interlock.  SPC-3 is not supposed to describe how it 
works.  That is in SAM-3 (and under the principle of specifying things in 
one place, should not be redundantly specified in SPC-3).  If you think 
SAM-3 is ambiguous or unclear, we'll fix it.

At 16:43 14-02-2003, Mallikarjun C. wrote:
>* From the T10 Reflector (t10 at, posted by:
>* "Mallikarjun C." <cbm at>
>In looking through SPC-3 r09 for UA interlock (clause 8.4.6, table 223)
>semantics, we couldn't find the answer to this question:
>When UA interlock is enabled (UA_INTLCK_CTRL = 11b), does the
>device server establish a interlocked-UA condition for all initiators, or just
>for the initiator whose task just terminated with BUSY/TASK SET FULL/
>I am thinking that it's the latter - i..e the interlocked UA is 
>established only for
>the I_T nexus that just had a failed command - because I could not come up 
>a rationale for stalling all other initiators.  SPC-3 however, is not 
>explicit about it.
>Mallikarjun Chadalapaka
>Networked Storage Architecture
>Network Storage Solutions
>Hewlett-Packard MS 5668
>Roseville CA 95747
>cbm at

Edward A. Gardner               eag at
Ophidian Designs                719 593-8866 voice
1262 Hofstead Terrace           719 210-7200 cell
Colorado Springs, CO  80907

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