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Chapter 8 SCSI Commands
To set the Current threshold value to its default value, set the PC field to 10b,
the Parameter List Length to 0, and issue the LOG SELECT command. (Note
that the host cannot set the Current threshold value to an arbitrary value using
the LOG SELECT command.) To set the Current cumulative values to default
values, set the PC field to 11b, the Parameter List Length to 0, and issue the
LOG SELECT command.
During the DATA OUT phase, the Parameter List Length field is the number
of parameter bytes to be transferred from the host to the autoloader. A Parameter
List Length of 0 indicates that there are no pages to be transferred. Because the
autoloader does not support the update by the host to arbitrary values of all Log
Parameter values, the Parameter List Length field is always 0. Therefore, if the
Parameter List Length is anything other than 0, the autoloader terminates the
command with a CHECK CONDITION status. The sense key is ILLEGAL
REQUEST and ASC/ASCQ is INVALID FIELD IN CDB.
8.4. LOG SENSE Command (4Dh)
The LOG SENSE command returns the autoloader LOG data to the host. This
command is in used in parallel with the LOG SELECT command.
Table 8.4.1 : LOG SENSE command
The Parameter Pointer Control (PPC) bit controls the parameter type requested
from the autoloader. Because the autoloader does not support the PPC bit, it is
0. When the PPC bit is 0, the Log Parameters requested to the autoloader start
from the Parameter Code defined in the Parameter Pointer field and continue in
the Parameter Code sequence specified by the Log Page format, in such a way
that the number of bytes specified in the Allocation Length field is returned.
When the PPC bit is zero and the Parameter Pointer field is zero, the number of
bytes to fill the Allocation Length for all valid Log Pages of Log Pages specified
is returned to the host.
The autoloader does not implement the Saving Log Parameter. The autoloader
saves Log Parameters according to its own internal rules. When the Save
Parameters (SP) bit is 1, the autoloader terminates the command with a CHECK
CONDITION status, sets the sense key to ILLEGAL REQUEST, and ASC/
ASCQ to INVALID FIELD IN CDB.
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation code (4Dh)
1
Logical unit number(0h)
Reserved(0)
PPC(0)
SP(0)
2
PC
Page code
3
Reserved(0h)
4
Reserved(0h)
5
(MSB)
Parameter pointer
6
(LSB)
7
(MSB)
Allocation length
8
(LSB)
9
Control(0h)
