Hitachi HTS542516K9SA00 Specifications page 143

14.39.1.9 S.M.A.R.T. Disable Operations (Subcommand D9h)
This subcommand disables all S.M.A.R.T.capabilities within the device including the device's
attribute autosave feature. After receipt of this subcommand the device disables all S.M.A.R.T.
operations. Non self-preserved Attribute Values will no longer be monitored. The state of
S.M.A.R.T. (either enabled or disabled) is preserved by the device across power cycles. Note that
this subcommand does not preclude the device's power mode attribute autosaving.
Upon receipt of the S.M.A.R.T. Disable Operations subcommand from the host, the device disables
S.M.A.R.T. capabilities and functions.
After receipt of the device of the S.M.A.R.T. Disable Operations subcommand from the host, all other
S.M.A.R.T. subcommands—with the exception of S.M.A.R.T. Enable Operations—are disabled, and
invalid and will be aborted by the device (including the S.M.A.R.T. Disable Operations subcommand),
returning the error code as specified in "Table 123 S.M.A.R.T. Error Codes" on Page 153.
Any Attribute Values accumulated and saved to volatile memory prior to receipt of the S.M.A.R.T.
Disable Operations command will be preserved in the device's Attribute Data Sectors. If the device is
re-enabled, these Attribute Values will be updated, as needed, upon receipt of a S.M.A.R.T. Read
Attribute Values or S.M.A.R.T. Save Attribute Values command.
14.39.1.10 S.M.A.R.T. Return Status (Subcommand DAh)
This command is used to communicate the reliability status of the device to the host's request. Upon
receipt of the S.M.A.R.T. Return Status subcommand the device asserts BSY, saves any updated
Attribute Values to the reserved sector and compares the updated Attribute Values to the Attribute
Thresholds.
If the device does not detect a Threshold Exceeded Condition, or detects a Threshold Exceeded
Condition but involving attributes are advisory, the device loads 4Fh into the LBA Mid register, C2h
into the LBA High register.
If the device detects a Threshold Exceeded Condition for prefailure attributes, the device loads F4h
into the LBA Mid register, 2Ch into the LBA High register. Advisory attributes never result in
negative reliability condition.
14.39.1.11 S.M.A.R.T. Enable/Disable Automatic Off-Line
(Subcommand DBh)
This subcommand enables and disables the optional feature that cause the device to perform the set
of off-line data collection activities that automatically collect attribute data in an off-line mode and
then save this data to the device's non-volatile memory. This subcommand may either cause the
device to automatically initiate or resume performance of its off-line data collection activities or
cause the automatic off-line data collection feature to be disabled. This subcommand also enables
and disables the off-line read scanning feature that cause the device to perform the entire read
scanning with defect reallocation as the part of the off-line data collection activities.
The Sector Count register shall be set to specify the feature to be enabled or disabled.
Sector Count
00h
01h
F8h
F9h
A value of zero written by the host into the device's Sector Count register before issuing this
subcommand shall cause the automatic off-line data collection feature to be disabled. Disabling this
feature does not preclude the device from saving attribute values to non-volatile memory during
some other normal operation such as during a power-on or power-off sequence or during an error
recovery sequence.
A value of one written by the host into the device's Sector Count register before issuing this
subcommand shall cause the off-line read scanning feature to be disabled. The Device does not
perform the off-line read scanning at the off-line data collection activities which is initiated by the
Feature Description
Disable Automatic Off-line
Disable Off-line Read Scanning
Enable Automatic Off-line
Enable Off-line Read Scanning
Page 143 of 171
5K250 (SATA) OEM Specification