SRP Response IU consideration

Simpson, Cris cris.simpson at intel.com
Fri Mar 8 17:53:03 PST 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* "Simpson, Cris" <cris.simpson at intel.com>
*

Yaning said:

> What I mean by "system cause the failure so that the
>   CMD or MGMT IU can not proceeding" is the system may 
> temporarily out of
> recourses, such as memory. For this case, we don't want to 
> disconnect the
> channel, because system can be recovery by himself later, we 
> want to send
> back a response with reason, like "SYSTEM FAILURE", or more 
> general, like
> "COMMAND or TASK MANAGEMENT FUNCTION NOT COMPLETE", or "OTHER 
> REASON CAUSED
> CMD or MGMT NOT COMPLETE" etc. Right now, there are only 4 
> RSP_CODE have
> been defined, when I implement SRP, I feel it is not sufficient.

 
  I'm at a disadvantage in not having the history, but 
incomplete information has never stopped me from 
jumping in with an opinion before...

  Yaning, it appears that you want a response to indicate 
that the target was unable to process a command or task 
mgmt request (TMR) due to a temporary condition such as a
lack of resources.   

  Is this an SRP problem?  It doesn't look like it to me, 
unless the resource is receive buffers.  If so, either I 
or T has violated the buffer management protocol.  Boom!

  If SRP is able to deliver syntactically correct IUs, 
the problem appears to be at a higher layer.  What you 
are requesting appears to be covered by the sense key
"NOT READY".  The sense codes 
   "LOGICAL UNIT NOT READY, CAUSE NOT REPORTABLE" or
   "LOGICAL UNIT IS IN PROCESS OF BECOMING READY"
have the flavor of "try again later" that you seem to 
be looking for.

Hope this helps,

Cris


--
Cris Simpson                                          503.712.4333         
Intel EPG/ACD Architecture                           Hillsboro, OR   
PGP Fingerprint:0DA0 418E A27B 0B76 5F02  3DD4 0546 6D13 F88A 1E60
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