Quantum DLT 8000 Product Manual page 294

SCSI Commands
PERSISTENT RESERVATION OUT Command (5Fh) (continued)
Table 5–67 PERSISTENT RESERVATION OUT Command's Service Action
Code Name
00h Register
01h Reserve
5-150
Descriptions
Description
When the command executes a Register service action, it registers a
reservation key with a device server without generating a reservation. The
device server holds these reservation keys from each initiator that performs a
PERSISTENT RESERVATION OUT command with a Register service action until
the key is changed by a new PERSISTENT RESERVATION OUT command with
Register service action from the same initiator, or until the initiator registration
is removed by:
Powering down the logical unit, if the last Activate Persist Through Power
Loss (APTPL; see Figure 5-69 and Table 5-69) received by the device server
was 0;
Performing a Clear service action;
Performing a Pre-empt service action;
Performing a Pre-empt and Clear service action; or
Performing a Register service action from the same initiator with the value
of the service action reservation key set to 0.
When a reservation key has not yet been established or when the reservation
key has been removed, a reservation key of 0 is used when the initiator
performs a PERSISTENT RESERVATION OUT with the Register service action.
When the reservation has been removed, no information is reported for the
initiator in the Read Keys service action of the resulting PERSISTENT
RESERVATION IN command..
A PERSISTENT RESERVATION OUT command with Reserve service action creates
a persistent reservation with a specified Scope and Type.
Persistent reservations are not superseded by a new persistent reservation
from any initiator except by the execution of a PERSISTENT RESERVATION OUT
command that specifies either a Pre-empt or Pre-empt and Clear service
action. New persistent reservations that do not conflict with an existing
persistent reservation execute normally. Persistent reservations of logical units
or extents having the same Type value are permitted if no conflicting
persistent reservations are held by another initiator. When these types of
overlapping reservations are released, each of the extent reservations and
logical unit reservations are removed with a separate Release service action.
Multiple identical reservations from the same initiator are all released
simultaneously via a single Release service action that matches the
reservations.
Quantum DLT 8000 Tape System
(continued)