Hitachi 7K100 - Travelstar - Hard Drive Specifications page 182

13.39.1.11 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.
13.39.1.12 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
the off-line data collection activities which is initiated by the S.M.A.R.T. Execute Off-line Immediate (Subcom-
mand D4h) or automatically if the off-line read scanning feature is disabled.
A value of F8h 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 enabled.
A value of F9 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 enabled. The Device perform the off-line read scanning at the off-line
data collection activities which is initiated by the S.M.A.R.T. Execute Off-line Immediate (Subcommand D4h)
even if the automatic off-line feature is disabled.
Any other non-zero value written by the host into this register before issuing this subcommand is vendor specific
and will not change the current Automatic Off-Line Data Collection and Off-line Read Scanning status. However,
the device may respond with the error code specified in Table 125: "S.M.A.R.T. Error Codes" on page 180.
Feature Description
Travelstar 7K100 Hard Disk Drive Specification
168