Sony DDS-4 Product Description Manual page 71

6. COMMAND SPECIFICATION
TSD:
A target save disable (TSD) bit of zero indicates a target-defined method for saving log parameters. This implicit
saving operation shall 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 shall terminate the command with CHECK CONDI-
TION status. The sense key shall be set to ILLEGAL REQUEST with the additional sense code set to INVALID
FIELD IN PARAMETER LIST.
ETC:
This bit is not supported by this device.
An enable threshold comparison (ETC) bit of one indicates that when the cumulative parameter value is updated, it
shall be compared to the threshold parameter value and the action specified by the TMC field shall be taken. An
(ET) bit of zero disables this comparison. The ET bit is the same for both the cumulative and threshold log param-
eter. 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.
TMC:
This bit is not supported by this device.
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 shall be posted to all initiators. When reporting the unit attention condition, the target shall set
the sense key to UNIT ATTENTION, the additional sense code to LOG EXCEPTION, and the additional sense
code qualifier 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.
LP: The LP bit field defines whether the parameter is a data counter or a list parameter. An LP bit of one indicates that
the parameter is a list Parameter. An LP bit of Zero indicates that the parameter is a data counter. See the descrip-
tion 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 CONDI-
TION status with a sense key of ILLEGAL REQUEST and an additional sense code of INVALID FIELD IN
PARAMETER LIST.
6 - 20 SONY SDT-10000/SDT-11000 DDS Tape Drive
TMC
Threshold Met Criteria
00b Any update of the parameter
01b Cumulative = Threshold
10b Cumulative < > Threshold
11b Cumulative > Threshold
Table 6-9: Threshold Met criteria
LOG SENSE