Comreset Preservation Requirements - Hitachi HTS542525K9SA00 Specifications

equivalent to hardware reset, in the case of an asynchronous loss of signal some software settings may be lost
without legacy software knowledge. In order to avoid losing important software settings without legacy driver
knowledge, the software settings preservation ensures that the value of important software settings is maintained
across a COMRESET. Software settings preservation may be enabled or disabled using SET FEATURES with a
subcommand code of 06h. If a device supports software settings preservation, the feature shall be enabled by
default.

10.20.1 COMRESET Preservation Requirements

The software settings that shall be preserved across COMRESET are listed below. The device is only required to
preserve the indicated software setting if it supports the particular feature/command the setting is associated with.
INITIALIZE DEVICE PARAMETERS: Device settings established with the INITIALIZE DEVICE
PARAMETERS command.
Power Management Feature Set Standby Timer: The Standby timer used in the Power Management feature set.
Read/Write Stream Error Log: The Read Stream Error Log and Write Stream Error Logs (accessed using READ
LOG EXT and WRITE LOG EXT).
Security mode state: The security mode state established by Security Mode feature set commands (refer to section
6.13 of the ATA/6 specification). The device shall not transition to a different security mode state based on a
COMRESET. For example, the device shall not transition from the SEC5: Unlocked / not Frozen state to state
SEC4: Security enabled / Locked when a COMRESET occurs, instead the device shall remain in the SEC5:
Unlocked / not Frozen state.
SECURITY FREEZE LOCK: The Frozen mode setting established by the SECURITY FREEZE LOCK
command.
SECURITY UNLOCK: The unlock counter that is decremented as part of a failed SECURITY UNLOCK
command attempt.
SET ADDRESS MAX (EXT): The maximum LBA specified in SET ADDRESS MAX or SET ADDRESS MAX
EXT.
SET FEATURES (Write Cache Enable/Disable): The write cache enable/disable setting established by the SET
FEATURES command with subcommand code of 02h or 82h.
SET FEATURES (Set Transfer Mode): PIO, Multiword, and UDMA transfer mode settings established by the
SET FEATURES command with subcommand code of 03h.
SET FEATURES (Advanced Power Management Enable/Disable): The advanced power management enable/
disable setting established by the SET FEATURES command with subcommand code of 05h or 85h. The advanced
power management level established in the Sector Count register when advanced power management is enabled
(SET FEATURES subcommand code 05h) shall also be preserved.
SET FEATURES (Read Look-Ahead): The read look-ahead enable/disable setting established by the SET
FEATURES command with subcommand code of 55h or AAh.
SET FEATURES (Reverting to Defaults): The reverting to power-on defaults enable/disable setting established
by the SET FEATURES command with a subcommand code of CCh or 66h.
SET MULTIPLE MODE: The block size established with the SET MULTIPLE MODE command.
Deskstar 7K160 Hard Disk Drive Specification
103