Hitachi HTS421212H9AT00 - Travelstar 120 GB Hard Drive Specifications page 189

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
auto saving.
Upon receipt of the S.M.A.R.T. Disable Operations subcommand from the host, the device asserts BSY, disables
S.M.A.R.T. capabilities and functions, clears BSY, and asserts INTRQ.
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 132: "S.M.A.R.T. Error Codes" on page 187.
Any Attribute Values accumulated and saved to volatile memory prior to receipt of the S.M.A.R.T. Disable Opera-
tions 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 a S.M.A.R.T. Save
Attribute Values command.
13.39.1.10 S.M.A.R.T. Return Status (subcommand DAh)
This subcommand 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,
clears BSY, and asserts INTRQ.
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, clears BSY, and asserts INTRQ. Advisory attributes never result in a
negative reliability condition.
13.39.1.11 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 nonvolatile 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 dis-
abled. This subcommand also enables and disables the off-line read scanning feature that cause the device to per-
form 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 Disable Automatic Off-line
01h Disable Off-line Read Scanning
F8h Enable Automatic Off-line
F9h Enable Off-line Read Scanning
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 nonvolatile memory during some other normal operation such as during a
power-on, during a 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
Feature Description
Travelstar 4K120 Hard Disk Drive Specification
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