Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E 141
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5.2.1.8.2
Extent Reservation
The disc drive may not support Extent reservations, in which case this bit must always be zero. See the rive
Product Manual section “SCSI Interface commands supported”. Since the Reservation Identification byte
and the Extent List Length are valid only for extent reservations, the disc drive ignores these fields if extent
reservations are not supported.
5.2.1.8.3
Third Party Reservation
The third party reservation option for the Reserve command allows an initiator to reserve a logical unit for
another SCSI device. If the drive supports third party reserve command, the disc drive also implements the
third party release option (see Section 5.2.1.9.3). This feature is intended for use in Multiple-initiator systems
that use the Copy command. Check the Drive Product Manual to see if the disc drive supports the third party
reservation option.
If the third party (3rdPty) bit is zero, the third party reservation option is not requested. If the 3rdPty bit is one
the Reserve command reserves the specified logical unit for the SCSI device specified in the third party
device ID field. The disc drive shall preserve the reservation until it is superseded by another valid Reserve
command from the initiator which made the reservation or until it is released by the same initiator, by a Bus
Device Reset message from any initiator, or a “hard” Reset condition. The disc drive shall ignore any attempt
to release the reservation made by any other initiator.
5.2.1.8.4
Superseding Reservations
An initiator which holds a current reservation may modify that reservation by issuing another Reserve com-
mand to the same logical unit. The superseding Reserve command shall release the previous reservation
state when the new reservation request is granted. The previous reservation shall not be modified if the new
reservation request cannot be granted.