Seagate SCSI Interface Product Manual page 170

156
Table 111: Persistent Reserve In Read Reservations Descriptor
Bit 7
Byte
0 (MSB)
7
8 (MSB)
11
12 Reserved
13
14
15
Notes.
[1] If a persistent reservation is present in the logical unit that does contain elements, there shall be a Reser-
vation descriptor in the list of parameter data returned by the device server in response to the Persistent
Reserve In command with a Read Reservation service action for the Logical Unit persistent reservation
that is held, if any, and each element persistent reservation that may be held. The Reservation descriptor
shall contain the Reservation Key under which the persistent reservation is held. The Type and Scope of
the persistent reservation as present in the Persistent Reserve Out command that created the persistent
reservation shall be returned [3] [4].
[2] If the Scope is an Element reservation, the Scope-specific Address field shall contain the Element
address, zero filled in the most significant bytes to fit the field. If the Scope is a Logical Unit reservation,
the Scope-specific Address fields shall be set to zero. The Obsolete field in Bytes 14 and 15 was used for
extent reservations as described in an earlier standard.
[3] The value in the Scope field shall indicate whether a persistent reservation applies to an entire logical unit,
to a portion of the logical unit defined as an extent, or to an element. The values in the Scope field are
defined in Table 112.
Table 112: Persistent Reservation Scope Codes
Code Name
00h LU
01h Extent
02h Element
03h-1Fh Reserved
[4] The value in the Type field shall specify the characteristics of the persistent reservation being established
within the element or within the logical unit. Table 113 defines the characteristics of the five different type
values. For each persistent reservation type, Table 113 lists code value and describes the required device
server support. In Table 113, the description of required device server support is divided into three para-
graphs. The first paragraph defines the required handling for read operations. The second paragraph
defines the required handling for write operations.
6 5
Reservation Key [1]
Scope-specific Address [2]
Scope [3]
Description
A Scope field value of LU shall indicate that the persistent reservation applies
to the entire logical unit. The LU scope shall be implemented by all device
servers that implement Persistent Reserve Out.
Obsolete.
Persistent reservation applies to the specified element. A Scope field value of
Element shall indicate that the persistent reservation applies to the element of
the logical unit defined by the Scope-specific address field in the Persistent
Reserve Out parameter list. An element is defined by the SCSI-3 Medium
Changer Commands (SMC) standard. The Element scope is optional for all
device servers that implement Persistent Reserve Out.
Reserved.
SCSI Interface Product Manual, Rev. J
4 3
Obsolete [2]
2 1
(LSB)
(LSB)
Type [4]
0