SBC-2 power conditions and START STOP UNIT

Elliott, Robert (Server Storage) elliott at
Sat Oct 30 14:32:05 PDT 2004

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert (Server Storage)" <elliott at>
I've collected several editorial corrections to sbc2r15b that will be
incorporated into sbc2r16.  One technical issue has been identified.

This rule is buried in the START STOP UNIT command description:
"If the START STOP UNIT command is received with the POWER CONDITION
field set to ACTIVE, IDLE, or STANDBY, then:
d) the device server shall terminate any command received that requires
more power than allowed by the specified power condition. The command
shall be terminated with CHECK CONDITION status with the sense key set
to ILLEGAL REQUEST and the additional sense code set to LOW POWER

The power condition model, however, only describes a device server in
the ACTIVE and IDLE states accepting such commands and changing the
power condition to whatever level is needed to process them.  This is
how the states, if entered via the power condition timers, have always
been defined.

According to discussions when 02-464r3 (which rewrote the power
conditions text in SAM-3 SPC-3 and SBC-2) was developed (accepted May
2003), the intent was to change the START STOP UNIT command-based power
condition states to follow the timer-based model and accept commands.
The STOPPED state, only selectable via START STOP UNIT, does reject
commands; this differentiates it from STANDBY.

Unless there are objections, in sbc2r16 I plan to delete that item "d)"
and leave standing the power conditions model text.  The alternative
would be to fully restore both models.

Rob Elliott, elliott at 
Hewlett-Packard Industry Standard Server Storage Advanced Technology 
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