Log Select (4C) - IBM Ultrastar 36LZX Specifications

8.6 LOG SELECT (4C)

Byte
7
0
1 Reserved = 0
2 PC
3
4
5
6
7 (MSB) Parameter List Length = 0
8
9
Figure 63. LOG SELECT (4C)
The LOG SELECT command provides a means for the initiator to clear statistical information maintained
by the drive and reported via the Log Sense command.
Ÿ PCR The Parameter Code Reset determines whether the Log Sense parameters will be cleared and
unit attention posted for all other initiators. A value of 1 indicates that the parameters be cleared,
while a value of zero (except when PC = 11b) indicates that the parameters not be cleared.
Ÿ SP The Save Parameters bit value of zero indicates that the page parameters not be saved. A value
of 1 indicates that the page parameters that are savable be saved after they have been changed.
Ÿ PC The Page Control field defines the type of parameters to be selected. The PC field set to 11b
(and PCR is then a don't care) indicates that the Default Cumulative values are set to their default
values of 0. If the PC field is set to 01b and PCR is set to 1, the Current Cumulative values are also
set to their default values.
Ÿ As the drive does not support the threshold pages any other value in this field will cause the com-
mand to end with a CHECK CONDITION with a sense key of illegal request and an additional sense
code of invalid field in CDB.
Ÿ Parameter List Length The Parameter List Length field specifies the length in bytes of the
parameter list that shall be located in the DATA OUT buffer. A parameter list length zero indicates
that no pages shall be transferred.
If one or more fields of the CDB are not set correctly the command will be terminated with a CHECK
CONDITION status. The Sense Key shall be set to Illegal Request and the additional sense code set to
Invalid Field in CDB.
The Log Select command will reset the counter variables to their default values of zero. These variables
are listed in the Log Sense command.
To indicate that parameters have changed, the target generates a unit attention condition for all initiators
except the one that issued the Log Select command.
Bit
6 5 4
Command Code = 4Ch
Reserved = 0
Reserved = 0
Reserved = 0
Reserved = 0
Ultrastar 36LZX hard disk drive specifications
3 2 1
PCR
(LSB)
FLAG
74
0
SP
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