Quantum 1200 Series DAT Autochanger Podręcznik Użytkownika Pobierz pdf (Strona 182)

PERSISTENT RESERVE IN Command (5Eh) SDLT 600 SCSI Interface Guide

4-140 January 2005 81-81200-02 REV A01

Figure 4-79. PERSISTENT RESERVE IN Read Reservations Descriptor — Data Format

Table 4-81 describes the available Type values from the Type field of the PERSISTENT RESERVE IN

Read Reservations parameters. Each of the codes provides handling instructions for READ and

WRITE operations and for subsequent attempts to establish persistent reservations (referred to as

“Additional Reservations Allowed” in the table).

Table 4-80. PERSISTENT RESERVE IN Read Reservations Descriptor — Field Descriptions

Field Name Description

Reservation

Key

Contains an 8-byte value that identifies the reservation key under which the

persistent reservation is held.

Scope-Specific

Address

Not supported. Must be set to 0.

Scope Indicates whether a persistent reservation applies to an entire logical unit, to

a part of the logical unit (defined as an extent), or to an element. The drive

only supports reservations of the entire logical unit. Must be set to 0.

Type Specifies the characteristics of the persistent reservation being established

for all data blocks within the extent or within the logical unit. Refer to

Table 4-81 for the applicable Type codes and their meanings.

Table 4-81. PERSISTENT RESERVATION IN Type Codes

Code Name Description

0h Obsolete ---

1h WRITE

Exclusive

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

commands that perform transfers from the drive to the host.

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

initiator that holds the persistent reservation that attempts a transfer to

the drive 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

drive.

2h Obsolete ---

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Quantum 1200 Series DAT Autochanger Podręcznik Użytkownika Strona 182