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Chapter 8 SCSI Commands
For example, the CDB Usage map of the autoloader INQUIRY command is
12h, 03h, FFh, 00h, FFh, 00h. Note: The first byte is the Operation Code, but
the remaining bytes are the Usage map.
8.3. LOG SELECT Command (4Ch)
The LOG SELECT command allows access to the autoloader statistics.
Parameters in Log Page determine how the LOG DATA is processed. The LOG
SELECT command sends the Log Page data in the DATA OUT phase.
Table 8.3.1 : LOG SELECT command
When the Parameter Code Reset (PCR) bit is 1 and the Parameter List Length
is 0, the Log Parameter implemented by the autoloader uses the default value(s).
However, if the PCR bit is 1 and Parameter List Length is greater than 0, the
command is terminated with a CHECK CONDITION status. The sense key is
ILLEGAL REQUEST and ASC/ASCQ is INVALID FIELD IN CDB. When the
PCR bit is 0, Log Parameter is not reset.
Because the autoloader does not support the Save Parameter (SP) bit, this field
is 0.
The Page Control (PC) field selects the parameter type. The Page Control field
is defined in Table 8.3.2.
Table 8.3.2 : Page control field
Because the Current threshold value and Current cumulative values are not
supported by the autoloader, if these values are set a CHECK CONDITION
status is returned. The sense key is ILLEGAL REQUEST and ASC/ASCQ is
INVALID FIELD IN CDB.
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation code (4Ch)
1
Logical unit number(0h)
Reserved(0h)
PCR
SP(0)
2
PC
Reserved(0h)
3
Reserved(0h)
4
Reserved(0h)
5
Reserved(0h)
6
Reserved(0h)
7
(MSB)
Parameter list length
8
(LSB)
9
Control(0h)
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
