Questions about RESERVATION CONFLICT
Bob.Snively at EBay.Sun.COM
Wed Oct 27 09:18:27 PDT 1999
* From the T10 Reflector (t10 at t10.org), posted by:
* Bob Snively <Bob.Snively at EBay.Sun.COM>
The SET LIMITS command was discussed interminably in some meeting or
other last year. The result was that the SET LIMITS command does not
really do anything to the media, and is normally meaningless except in
a linked chain of commands. It is the subsequent commands in the linked
chain that may or may not conflict, so it was decided to allow the SET LIMITS
to be permissive and let the subsequent commands be interpreted in the
light of the established reservations. Classic examples are cases where
read-only access is allowed, and the SET LIMITS command is a precursor
to a valid chained read.
FWIW, the MODE SENSE was treated by different logic. Since the MODE SENSE
is normally part of a sense/select sequence, it was decided to present
the warning right up front.
>>2) Why is SET LIMITS (for SBC) not subject to RESERVATION CONFLICT?
>>I would think that this would cause a conflict since any subsequent
>>command within the SET LIMITS link set will fail with RESERVATION
>A2. This looks like a mistake to me. When I look up SBC document, Set
>and (12) state that they are not allowed through reservations. The table in
>Annex B of SPC-2 states that these commands are allowed through reservations.
>This is a serious contradiction. I presume whoever put together the table in
>Annex B thought it was reasonable to let set limits through a reservation even
>though SBC requires reservation conflict in its wording. I presume we haven't
>encountered this problem sooner because very few targets implement this
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