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5-46 Quantum DLT 7000 Tape System
LOG SENSE Command (4Dh) (continued)
Table 5–21 Log Parameters for Read /Write Error LOG SENSE Page Field Descriptions
(continued)
Field Name Description
Parameter Code
(continued)
8000h - Vendor Unique
9000h - Vendor Unique
Note: Parameter codes 00h, 01h, and 04h always return a value of 0.
Parameter value for 05h is 8 bytes; the parameter length is set to 8.
DU Disable Update. This field with a value 0 indicates that the target will update
all log parameter values. This field set to 1 indicates that the target will not
update the log parameter values except in response to LOG SELECT. This bit is
set by the drive when accumulated values reach maximum. This is also
returned set to 1 if the host set the bit in the last LOG SELECT command.
Default is 0.
Note that for parameter types other than threshold and cumulative values, this
bit is always 0.
DS Disable Save. Not supported; always set to 1.
TSD Target Save Disable. Not supported; always set to 1.
ETC Enable Threshold Comparison. When set to 1, indicates that comparison to
threshold is performed. ETC of 0 indicates that the comparison is not
performed. This bit is set to 1 by MODE SELECT. Default is 0.
TMC Threshold Met Criteria. This field is valid only if host sets ETC to 1. It
determines the basis for comparison and is specified by host using LOG
SELECT. If the result of comparison is true (cumulative = threshold), and
MODE SELECT / SENSE Control Mode page RLEC bit is set to 1, then a UNIT
ATTENTION is granted for all initiators. The sense key is set to UNIT ATTENTION,
the additional sense code to LOG EXCEPTION, and ASCQ is set to THRESHOLD
CONDITION MET. If the RLEC bit in Control Mode page is 0, then UNIT
ATTENTION is not generated.
Note that comparison is performed in real time. A Log Sense command need
not be issued to get the check condition. Once ETC is selected, RLEC bit in
control mode page, the check condition is issued based on the criteria defined
in the TMC bits if the criteria are met in real time. Check condition will not
identify for which parameter code the criteria is met. Log Sense must be
issued to read the counters to determine for which parameter code criteria
has been met.