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Chapter 8 SCSI Commands
Each Log Parameter comprises a 4-byte Parameter Header, followed by one or
more bytes of Parameter Data.
The Parameter Code field indicates the Log Parameter(s) of the Log Page to be
transferred.
The DU, DS, TSD, ETC, TMC, and LP fields indicate Parameter control
references. These fields are defined as follows.
The Disable Update (DU) bit is always 0. The autoloader performs Log
parameter updates according to the internal autoloader specifications.
The DS bit is always 1. The autoloader does not support the LOG SELECT or
LOG SENSE commands when the SP bit is 1 to control Log Parameters saving.
The Target Save Disable (TSD) bit is always 0. A TSD of 0 indicates that the
Log Parameters saving by the autoloader is performed according to the method
defined internally by the autoloader. It is not possible to change this processing
by a directive to the autoloader.
An Enable Threshold Comparison (ETC) bit of 1 indicates that when the
autoloader updates a Cumulative Value, it is also compared with the Threshold
Value. When the ETC bit is 0, no comparison is performed. The ETC bit is the
same for the Cumulative Parameter and Threshold Parameter. Because this
function is not supported with the parameters supported by this page, this field
is 0.
Note
Support of this function depends on the MAINTENANCE DIP switch bit
setting at the back of the autoloader.
The Threshold Met Criteria (TMC) field (see Table 8.4.4) specifies the method
of comparing the Cumulative Value and Threshold Value. This field is valid
when the ETC bit is 1. The TMC bit is the same for the Cumulative Parameter
and Threshold Parameter. The autoloader supports 11b for TMC.
Table 8.4.4 : Threshold met criteria
When the MAINTENANCE DIP switch bit is on (1) and the comparison result
a true value, a UNIT ATTENTION CONDITION is issued to all hosts. When
the UNIT ATTENTION CONDITION is issued, the autoloader sets the sense
key to UNIT ATTENTION and ASC/ASCQ to THRESHOLD CONDITION
MET.
The List Parameter (LP) bit indicates the Log Parameter format. When the LP
bit is 0, the Log Parameters are shown as count information; when it is 1, the
Log Parameters are shown as list information.
Code
Basis for comparison
00b
Every update of the cumulative value
01b
Cumulative value equal threshold value
10b
Cumulative value not equal threshold value
11b
Cumulative value greater than threshold value
