6.Command Specification
LOG SENSE
6-16
SONY AIT-5 drive SDX-1100V series Ver.1.0
TSD:
A target save disable (TSD) bit of ZERO indicates a target-defined method for saving log parameters. This
implicit saving operation will be done frequently enough to insure that the cumulative parameter values retain
statistical significance (i.e. across power cycles). A TSD bit of one indicates that either the target does not provide
a target-defined method for saving log parameters or the target-defined method has been disabled by the initiator.
If the initiator sets both the DS and the TSD bits set to one, the target will terminate the command with a CHECK
CONDITION status. The sense key will be set to ILLEGAL REQUEST with the ASC set to INVALID FIELD IN
PARAMETER LIST.
ETC:
An enable threshold comparison (ETC) bit of one indicates that when the cumulative parameter value is
updated, it will be compared to the threshold parameter value and the action specified by the TMC field will be
taken. An (ET) bit of ZERO disables this comparison. The ET bit is the same for both the cumulative and threshold
log parameter. Thus when the ET bit is set to a value by the initiator, this value is returned for both the cumulative
and threshold values of the log parameter. This field is not supported.
TMC:
The threshold met criteria (TMC) field defines the binary relationship between the cumulative and threshold
log parameter values under which the threshold is met. If the ET bit is one and the threshold condition is met, a
Unit Attention condition will be posted to all initiators. When reporting the unit attention condition, the target will set
the sense key to UNIT ATTENTION, the ASC to LOG EXCEPTION, and the ASCQ to THRESHOLD CONDITION
MET.
The TMC field is the same for both the cumulative and threshold parameter. Thus when the TMC field is set to a
value by the initiator, this value is returned for both cumulative and threshold values of the log parameter.
Table 6-12: Threshold Met criteria
TMC
Threshold Met Criteria
00b
01b
10b
11b
Any update of the parameter
Cumulative = Threshold
Cumulative < > Threshold
Cumulative > Threshold
LP:
The LP bit field defines whether the parameter is a data counter or a list parameter. See the description of
each supported page below for information on the setting of this field.
Note:
If any of the other bit-fields in the control byte are set then the command will terminate with a CHECK
CONDITION status with a sense key of ILLEGAL REQUEST and an ASC of INVALID FIELD IN PARAMETER
LIST