Persistent Reservation In Read Reservations Descriptor-Field Descriptions - Maxtor ATLAS 10K III Product Manual

SCSI Description
T a b l e 5 - 1 1 5 PERSISTENT RESERVATION IN Read Reservations Descriptor-Field Descriptions
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Reserva- The Reservation key field contains an 8-byte value that identifies the reservation key under
tion Key which the persistent reservation is held.
If the Scope field (Byte 13, bits 4 – 7) represents an "Extent" reservation, the Scope-Specific
Address field contains the logical block address (LBA) of the first block of the extent and the
Scope- Extent Length field (Bytes 14 – 15) contains the number of blocks in the extent.
Specific
Address If the Scope field represents an "Element" reservation, the Scope-Specific Address field con-
tains the Element address, zero-filled in the most significant bytes to fit the field and the Ex-
tent Length field is set to zero.
The value in this field 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 values for the Scope field are:
Code Name Description
0h LU Logical Unit. Persistent reservation applies to the full logical unit. The LU scope is
therefore implemented by all device servers that implement PERSISTENT RESERVATION
OUT.
1h Extent Persistent reservation applies to the specified extent. When Extent is the scope,
it indicates that the persistent reservation applies to the extent of the logical unit defined by
Scope the Scope-Specific Address and Extent Length fields in the PERSISTENT RESERVATION OUT
command's parameter list. Note that an extent is defined only for devices defining contigu-
ous logical block addresses. The Extent scope is optional for all device servers that imple-
ment PERSISTENT RESERVATION OUT.
2h Element Persistent reservation applies to the specified element. When Element is the
scope, it indicates that the persistent reservation applies to the element of the logical unit
defined by the Scope-Specific Address field in the PERSISTENT RESERVATION OUT param-
eter list. An element is as defined by the SCSI-3 Medium Changer Commands (SMC) stan-
dard. The Element scope is optional for all device servers that implement PERSISTENT
RESERVATION OUT.
3h – Fh Reserved
The value of the Type field specifies the characteristics of the persistent reservation being
Type established for all data blocks within the extent or within the logical unit. Refer to Table 5-
56 for the applicable Type codes and their meanings
Table 5-116 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).
5-92 Maxtor Atlas 10K III
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