User Manual

SCSI Commands Reference Manual, Rev. J 303
www.seagate.com Parameters for direct access devices
5.2.2 Log page structure
This subclause describes the log page structure and the log pages that are applicable to all SCSI devices. Log pages specific to
each device type are described in the command standard that applies to that device type. The LOG SELECT command (see 3.7)
supports the ability to send zero or more log pages. The LOG SENSE command (see 3.8) returns a single log page specified in the
PAGE CODE field of the CDB.
5.2.2.1 Log page format
Each log page begins with a four-byte page header followed by zero or more variable-length log parameters defined for that log
page. The log page format is defined in table 265.
DS (DISABLE SAVE) bit
0 For the LOG SENSE command (see 3.8), if the DS bit is set to zero, the log parameters are saved when the SP bit is set to one.
1 For the LOG SENSE command, if the DS bit is set to one, the log parameters are not saved. For the LOG SELECT command (see 3.7), the
disable save (DS) bit operates in conjunction with the parameter code reset (PCR) bit, the save parameters (SP) bit, the page control (PC)
field, and the PARAMETER LIST LENGTH field in the CDB.
SPF (SUBPAGE FORMAT) bit
0 If the SPF bit is set to zero, the SUBPAGE CODE field shall contain 00h.
1 If the SPF bit is set to one, the SUBPAGE CODE field shall contain a value between 01h and FFh.
PAGE CODE field
The value in the PAGE CODE field is the number of the log page being transferred.
Table 265 Log page format
Bit
Byte
7 6 5 4 3 2 1 0
0
DS
SPF
PAGE CODE
1
SUBPAGE CODE
2
(MSB)
PAGE LENGTH (n-3)
3
(LSB)
Log parameter(s)
4
Log parameter (First)
(Length x)
. . .
x+3
. . .
. . .
n-y+1
Log parameter (Last)
(Length y)
. . .
n