Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
121
18.7
LOG SENSE (4D)
Table 92 Log Sense (4D)
Byte
Bit
7
6
5
4
3
2
1
0
0
Command Code = 4Dh
1
Reserved = 0
Reserved = 0
PPC=0
SP
2
PC
Page Code
3
Subpage Code = 0
4
Reserved = 0
5
6
(MSB)
Parameter Pointer
(LSB)
7
8
(MSB)
Allocation Length
(LSB)
9
Reserved = 0
FLAG
LINK
The LOG SENSE command allows the Initiator to retrieve the statistical data regarding the drive.
- PPC (Parameter Pointer Control) bit must be set to zero. This specifies that the drive start transferring data
starting from the field specified in the parameter pointer field for the number of bytes specified by the allocation
length. If the PPC bit is set to 1, Check Condition status is returned with a sense key of Illegal Request and
additional sense code of Invalid Field in CDB.
- SP (Save Parameters) bit set to 0 specifies that the drive does not save any log parameters. If it is set to 1, all
page parameters that are savable (those pages denoted by a DS = 0 in the parameter header control byte) are
saved.
- PC (Page Control) field defines the type of parameters to be selected. This field must be set to 01b to specify
the current cumulative values. Any other value in this field will cause the command to end with a Check
Condition status with a sense key of Illegal Request and an additional sense code of Invalid Field in CDB.
- Page Code field identifies which page is being requested. This field must be set to the values indicated in Page
0. If the Page Code value is invalid a Check Condition status is returned with a sense key of Illegal Request and
additional sense code of Invalid Field in CDB.
- SubPage Code This field specifies the subpage to select. This field is not supported and must be set to 0.
- Parameter Pointer Field specifies the beginning field for the transfer. This field must be set to 0000h. If the
Parameter Pointer Field is not zero a Check Condition status is returned with a sense key of Illegal Request and
additional sense code of Invalid Field in CDB.
- Allocation Length field specifies the maximum number of bytes the Initiator has allocated for returned Log
Sense Data. No bytes are transferred if the length is zero. This condition is not considered an error. The Target
terminates the Data in phase when all available Log Sense data has been transferred or when the number of
bytes equals the allocation length, whichever is less.