Seagate Ultra160 Product Manual page 261

SCSI Interface Product Manual, Rev. B
Table 174: PERSISTENT RESERVE IN Read Reservations Descriptor
Bit 7
Byte
0 (MSB)
7
8 (MSB)
11
12 Reserved
13
14
15
[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 PERSIS-
TENT 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 cre-
ated the persistent reservation shall be returned (see also notes [3] and [4]).
[2] If the SCOPE is an Element reservation, the SCOPE-SPECIFIC ADDRESS field shall contain the Ele-
ment address, zero filled in the most significant bytes to fit the field. If the SCOPE is a Logical Unit reser-
vation, the SCOPE-SPECIFIC ADDRESS bytes 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 175.
Table 175: 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 176 defines the characteristics of the five different type
values. For each persistent reservation type, Table 176 lists code value and describes the required device
server support. In Table 176, 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 PERSIS-
TENT RESERVE OUT parameter list. An element is defined by the SCSI
Medium Changer Commands (SMC) standard. The Element scope is optional
for all device servers that implement PERSISTENT RESERVE OUT.
Reserved.
4 3
OBSOLETE [2]
2 1
(LSB)
(LSB)
TYPE [4]
243
0