IBM Ultrastar 36LZX, Specifications

Page: 75 / 249

8.7 LOG SENSE (4D)
LINK FLAG Reserved = 0 9
(MSB) Allocation Length
(LSB)
7
8
(MSB) Parameter Pointer = 0
(LSB)
5
6
Reserved = 0
3
4
Page Code PC 2
SP PPC= 0 Reserved = 0 Reserved = 0 1
Command Code = 4Dh 0
0 1 2 3 4 5 6 7
Bit
Byte
Figure 64. LOG SENSE (4D)
The LOG SENSE command allows the initiator to retrieve the statistical data regarding the drive.
Ÿ
PPC (Parameter Pointer Control) bit must be set to zero. This specifies that the drive start trans-
ferring 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.
Ÿ
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.
Ÿ
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 or 11b to specify the default cumulative values. As the
drive does not support the threshold pages any other value in this field will cause the command to
end with a CHECK CONDITION with a sense key of illegal request and an additional sense code of
invalid field in CDB.
Ÿ
Page Code field identifies which page is being requested. This field must be set to the values indi-
cated 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.
Ÿ
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.
Ÿ
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 con-
sidered 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.
Ultrastar 36LZX hard disk drive specifications
75