User Manual

SCSI Commands Reference Manual, Rev. J 387
www.seagate.com Parameters for direct access devices
5.3.6.1 Application Tag descriptor
The application tag descriptor format is described in Table 368.
LAST bit
1 A LAST bit set to one specifies that this Application Tag descriptor is the last valid Application Tag descriptor in the Application Tag
mode page.
0 A LAST bit set to zero specifies that the Application Tag descriptor is not the last valid Application Tag descriptor in the Application Tag
mode page.
LOGICAL BLOCK APPLICATION TAG field
The LOGICAL BLOCK APPLICATION TAG field specifies the value to be compared with the LOGICAL BLOCK APPLICATION TAG field associated
with data read or written to the LBA.
LOGICAL BLOCK ADDRESS field
The LOGICAL BLOCK ADDRESS field contains the starting LBA for this Application Tag descriptor. The LOGICAL BLOCK ADDRESS field in the first
Application Tag descriptor shall be set to 0000_0000_0000_0000h. For subsequent Application Tag descriptors, the contents of the LOGICAL
BLOCK ADDRESS field shall contain the sum of the values in:
a) the LOGICAL BLOCK ADDRESS field in the previous Application Tag descriptor; and
b) the LOGICAL BLOCK COUNT field in the previous Application Tag descriptor.
The sum of the LOGICAL BLOCK ADDRESS field in the Application Tag descriptor with the LAST bit set to one and the LOGICAL BLOCK COUNT
field in the Application Tag descriptor with the LAST bit set to one shall equal the RETURNED LOGICAL BLOCK ADDRESS field in the READ
CAPACITY (16) parameter data
(see 3.23.2).
If an invalid combination of the LAST bit, LOGICAL BLOCK APPLICATION TAG field, and LOGICAL BLOCK ADDRESS field are sent by the applica-
tion client, then the device server shall terminate the MODE SELECT command (see 3.10) with CHECK CONDITION status with the sense key set
to ILLEGAL REQUEST and the additional sense code set to INVALID FIELD IN PARAMETER LIST. The LOGICAL BLOCK COUNT field specifies the
number of logical blocks to which this Application Tag descriptor applies.
LOGICAL BLOCK COUNT field
A LOGICAL BLOCK COUNT field set to 0000_0000_0000_0000h specifies that this Application Tag descriptor shall be ignored.
Table 368 Application Tag descriptor format
Bit
Byte
7 6 5 4 3 2 1 0
0 LAST Reserved
1
Reserved. . .
5
6 (MSB)
LOGICAL BLOCK APPLICATION TAG
7 (LSB)
8 (MSB)
LOGICAL BLOCK ADDRESS. . .
15 (LSB)
16 (MSB)
LOGICAL BLOCK COUNT. . .
23 (LSB)