REQUEST SENSE LONG bit (01-199r3)

Ralph Weber ralphoweber at
Thu Feb 7 05:52:53 PST 2002

* From the T10 Reflector (t10 at, posted by:
* Ralph Weber <ralphoweber at>
I will change to the "if supported ... shall" wording before
the next SPC-3 revision is released.



"Elliott, Robert" wrote:

> * From the T10 Reflector (t10 at, posted by:
> * "Elliott, Robert" <Robert.Elliott at>
> *
> I'm a bit worried about "should" because it lets the logical unit return
> either format when LONG=1.  It could use short format for some commands
> and long for others.
> I'd rather see it say "if the LONG bit is supported by the target and
> the LONG bit is set to one, the long sense data format shall be
> returned."
> The top of PDF page 110 (spc3r03) has an example of such wording for the
> TUR (test unit ready) bit.  Slight difference: that wording says if the
> bit is not supported but is set to 1, a CHECK CONDITION is required.
> For the LONG bit, we want that handled per the logical unit's normal
> reserved field checking behavior.
> There are several ways to determine if LONG is supported:
> 1. Try it and look at the response code.  If you get back long format,
> it is supported.  (With shall, that's conclusive. With should, it's
> not.)
> 2. Use the INQUIRY CMDDT feature to see if that bit appears in the CDB
> bitmask.
> 3. Use the new REPORT SUPPORTED OPCODES command to see if that bit
> appears in the CDB bitmask.
> 4. If the control mode page LONG_SENSE bit is changeable (meaning that
> the long format is available for autosense and AER), the LONG bit is
> probably supported in REQUEST SENSE CDB.  The REQUEST SENSE description
> could mandate that they match.
> ---
> Rob Elliott, Compaq Server Storage
> Robert.Elliott at

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