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Quantum 10K II User Manual

Page 186

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SCSI Description

Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives

5–119

PERSISTENT RESERVATION IN Command (5Eh) (continued)

Table 5-56 presents the definitions of the characters of the available “Type” values from the Type
field of the PERSISTENT RESERVATION IN Read Reservations parameters.

Each of the codes provides handling instructions for READ operations, for WRITE operations,
and for subsequent attempts to establish persistent reservations (referred to as “Additional
Reservations Allowed” in the table).

Table 5–56 Persistent Reservation Type Codes and Their Meanings

Code

Name

Description

0h

READ Shared

READS: Shared; any application client on any initiator may execute

commands that perform transfers from the disk to the initiator.

WRITES: Prohibited; any command from any initiator that performs a

transfer from the initiator to the disk results in a reservation
conflict.

ADDITIONAL RESERVATIONS: Allowed; any initiator may reserve the

logical unit, extents, or elements as long as
the persistent reservations do not conflict
with any reservations already known to the
device server.

1h

WRITE Exclusive

READS: Shared; any application client on any initiator may execute

commands that perform transfers from the disk to the initiator.

WRITES: Exclusive; any command from any initiator other than the

initiator that holds the persistent reservation that attempts a
transfer to the disk results in a reservation conflict

ADDITIONAL RESERVATIONS: Allowed; any initiator may reserve the

logical unit, extents, or elements as long as
the persistent reservations do not conflict
with any reservations already known to the
device server.

2h

READ Exclusive

READS: Exclusive; any command from any initiator other than the initiator

that holds the persistent reservation that attempts a transfer from
the disk results in a reservation conflict

WRITES: Shared; any application client on any initiator may execute

commands that perform transfers to the disk from the initiator.

ADDITIONAL RESERVATIONS: Allowed; any initiator may reserve the

logical unit, extents, or elements as long as
the persistent reservations do not conflict
with any reservations already known to the
device server.

(continued)