Seagate Fibre Channel Interface User Manual
Page 207
Fibre Channel Interface Manual, Rev. D
193
Since the drive uses volatile memory to hold cumulative values, they will be lost when a power cycle occurs. Unless the ini-
tiator commands the drive to save them to nonvolatile memory using a Log Select or Log Sense command with the SP bit
set to one.
The DU bit is not defined for threshold values (indicated by the PC field of the Log Sense command descriptor block) nor
for list parameters (indicated by the LP bit). The drive ignores the value of DU bits in a Log Select command applicable to
threshold values or list parameters.
ETC (Enable Threshold Comparison)
1
A comparison to the threshold value is performed whenever the cumulative value is updated.
0
The comparison is not performed. The value of the ETC bit is the same for both the threshold and cumulative
parameters.
LBIN (List Binary)
0
The parameter list contains a string of ASCII characters.
1
The parameter list is in a binary format.
LP (List Parameter)
0
The parameter is a data counter.
1
The parameter is a list parameter.
This bit only has meaning for the Log Sense command Data In pages.
Data counters are associated with one or more events. The data counter is updated whenever one of these events occurs
by incrementing the counter value, provided the DU bit is zero. See the DU field description above.
An LP bit of one indicates that the parameter is a list parameter. List parameters are not counters and thus the ETC and
TMC fields are set to zero. A list parameter is a string of ASCII graphic codes (i.e., code values 20h through 73h). List
parameters are not supported by the drive at this time.
Parameter Code
The specific parameter that is being transferred with the Log Page. These codes are listed and explained in the individual
page code descriptions following Table 128.
Byte 2 is referred to as the Parameter Control byte. For a Log Select command these bits perform a control function, but on
a Log Sense command they only report the drive settings of these bits in this same format on the data-in part of the Log
Sense command.
Parameter Length
This field specifies the length (in bytes) of the parameter that follows. If the initiator sends a parameter length value that
results in the truncation of the parameter value, the drive terminates the command with a Check Condition status. The
sense key is set to Illegal Request with the additional sense code set to Invalid Field In Parameter List.
Parameter Value
This field uses one, two, four, or eight bytes to transmit an unsigned counter value. The initiator sends these counts to set
the counter values in the drive. The initiator is responsible to issue a Log Sense command to learn the parameter length the
target has selected.
When any counter in a log page reaches its maximum value, the drive ceases incrementing all counters in that log page. If
the RLEC bit of the Control Mode page is one, then the drive reports the exception condition as described in Disable
Update definition for this table.