Seagate Medalist 2160N (ST52160N), Product Manual

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Bytes
Bits
7 6 5 4 3 2 1 0
0–1 Parameter Code
2 DU DS TSD ETC TMC Reserved LP
3 Parameter length ( n–3)
4
Parameter value
n
Bytes 1–0 The page code is the code assigned to an attribute the drive
monitors.
Byte 2 The collective field in byte 2 is referred to as the parameter
control byte. For the Log Select command, these bits per-
form a control function; for the Log Sense command, they
report the drive settings. A description of each bit is provided
below:
The disable update (DU) bit determines whether the drive
updates cumulative log parameter values. When the DU bit
is 0, the drive updates the log parameter values to reflect
all events that should be noted by that parameter. When the
DU bit is 1, the drive does not update the log parameter
value except in response to a Log Select command that
specifies a new value for the parameter.
The drive uses volatile memory to hold cumulative values.
The values are lost during a power cycle unless the initiator
commands the drive to save them in nonvolatile memory.
The DU bit is not defined for threshold values or list parame-
ters.
The disable save (DS) bit indicates whether the drive saves
the log parameter. When DS is 0, the drive saves the current
cumulative or threshold parameter value when the SP bit in
the Log Select or Log Sense command is 1. When DS is 1,
the drive saves the current cumulative or threshold parame-
ter value when the SP bit in the Log Select or Log Sense
command is 1.
The target save disable (TSD) bit enables the drive to save
the log page data automatically to ensure statistical signifi-
cance. When TSD is 0, the drive saves at a frequency
determined by Seagate. When TSD is 1, the drive does not
automatically save.
When the enable threshold comparison (ETC) bit is 1, the
threshold value is compared to the cumulative value each
80 Medalist Pro 2160N/2160WC Product Manual, Rev. A