Hitachi HTS542525K9SA00 Specifications page 136

Feature Code State Definition
0001h 0001h : Allow write cache operation to be determined by Set Feature
command
0002h : Force write cache enabled
0003h : Force write cache disabled
If State 0001h is selected, the ATA Set Feature command will determine the
operation state of write cache. If State 0002h or 0003h is selected, write cache
will be forced into the corresponding operation state, regardless of the current
ATA Set Feature state. Any attempt to change the write cache setting through
Set Feature shall be accepted, but otherwise ignored, and not affect the
operation state of write cache and complete normally without reporting an
error.
In all cases, bit 5 of word 85 in the Identify Device information will reflect the
true operation state of write cache, one indicating enabled and zero indicating
disabled.
The default state is 0001h.
0002h 0001h : Enable Write Cache Reordering
0002h : Disable Write Cache Reordering
The default state is 0001h.
The drive does not return error for setting state 0002h, but the state is ignored.
0003h Set time interval for temperature logging.
0000h is invalid.
0001h to FFFFh logging interval in minutes.
This value applies to the Absolute HDA Temperature History queue. Issuing
this command will cause the queue to be reset and any prior values in the
queue will be lost. Queue Index shall be set to zero and the first queue
location will be set to the current value. All remaining queue locations are set
to 80h. The Sample Period, Max Op Limit, Over Limit, Min Op Limit and Under
Limit values are preserved.
Default value is 0001h.
0004h-CFFFh Reserved
D000h-FFFFh Vendor Specific
Deskstar 7K160 Hard Disk Drive Specification
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