Hitachi HTS542525K9SA00 Specifications page 134

10.22.2.4 Feature Control Command (action code: 0004h)
Inputs (Key Sector)
Word Name
0 Action Code
1 Function Code
2 Feature Code
3 State
4 Option Flags
255:5 reserved
Outputs: (TF Data)
Value Description
0004h Set or return the state of drive features described in
Error! Reference source not found.
0001h Set state for a feature
0002h Return the current state of a feature
0003h Return feature option flags
See Error! Reference source not found. for a list of
Word
the feature codes
Word Feature code dependent value
Word Bit15:1 = Reserved
If the function code is 0001h, setting bit 0 to one
causes the requested feature state change to be
preserved across power cycles.
If the function code is 0001h, setting bit 0 to zero
causes the requested feature state change to be
volatile. A hard reset causes the drive to revert to
default, or last non-volatile setting.
0000h
Deskstar 7K160 Hard Disk Drive Specification
120