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Chapter 8 SCSI Commands
When the SP bit is 0, the autoloader executes the specified LOG SENSE
command, but does not save Log Parameters.
The Page Control (PC) field specifies the type of parameter values. The values
specified in the Page Control field are shown in Table 8.4.2. The parameters
returned by the LOG SENSE command are determined as follows.
a) Last update (cumulative values updated by the LOG SELECT command or
LOG SENSE command, or automatically updated by the autoloader).
b) If there were no parameter updates since the most recent power-on, hard
reset, or received BUS DEVICE RESET message, the saved value.
c) If there were no parameter updates since the most recent power-on, hard
reset, or received BUS DEVICE RESET message and there is no saved value,
the autoloader default value.
Table 8.4.2 : Page control field
Current Cumulative Values (of event occurrences, for example) are updated by
the autoloader according to the internal autoloader rules or by a LOG SELECT
command from the host. Because the autoloader only supports Current
Cumulative Values (except page 2E), the Page Control field is 01b.
The Page Code field specifies the type of page data to requested by the host.
(See Table 8.4.1.1, below.) If this field is a value that the autoloader does not
support, the autoloader terminates the command with a CHECK CONDITION
status. The sense key is ILLEGAL REQUEST and ASC/ASCQ is INVALID
FIELD IN CDB.
The Parameter Pointer field specifies the start of the Parameter Data requested
by the host. The number of Parameter Data bytes returned by the autoloader is
limited to the lesser value between that specified in the Allocation Length field
specified by CDB and the maximum value supported by the autoloader. If the
specified page has a Parameter Code greater than the maximum valid Parameter
Code that can be returned by the autoloader is specified in the Parameter Pointer
field, then the autoloader terminates the command with a CHECK
CONDITION status. The sense key is ILLEGAL REQUEST and ASC/ASCQ
is INVALID FIELD IN CDB.
The Log Parameters within the specified Log Page are transferred in the
specified sequence.
Table 8.4.3 : Parameter Data Format
Type
LOG SELECT parameter values LOG SENSE parameter values
00b
Current threshold values
Threshold values
01b
Current cumulative values
Cumulative values
10b
Default threshold values
Default threshold values
11b
Default cumulative values
Default cumulative values
Bit
Byte
7
6
5
4
3
2
1
0
0
(MSB)
Parameter Code
1
(LSB)
2
DU(0)
DS(1)
TSD(0)
ETC
TMC
Reserved
LP
3
Parameter Length(n-3)
4
(MSB)
Parameter Value
n
(LSB)
