Hitachi IC25N040ATCS04-0 - Travelstar 40GN 40GB UDMA/100 4200RPM 2MB 2.5" IDE Hard Drive Specifications page 181

13.32.1.8 S.M.A.R.T. Enable Operations (subcommand D8h)
This subcommand enables access to all S.M.A.R.T. capabilities within the device. Prior to receipt of a
S.M.A.R.T. Enable Operations subcommand, Attribute Values are neither monitored nor saved by the
device. The state of S.M.A.R.T.—either enabled or disabled—will be preserved by the device across
power cycles. Once enabled, the receipt of subsequent S.M.A.R.T. Enable Operations subcommands will
not affect any of the Attribute Values.
Upon receipt of the S.M.A.R.T. Enable Operations subcommand from the host, the device asserts BSY,
enables S.M.A.R.T. capabilities and functions, clears BSY, and asserts INTRQ.
13.32.1.9 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
auto save 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 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 Figure 133 on page 181.
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
a S.M.A.R.T. Save Attribute Values command.
13.32.1.10 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 Cylinder Low register, C2h into the
Cylinder High register, clears BSY, and asserts INTRQ.
If the device detects a Threshold Exceeded Condition for prefailure attributes, the device loads F4h into
the Cylinder Low register, 2Ch into the Cylinder High register, clears BSY, and asserts INTRQ. Advisory
attributes never result in a negative reliability condition.
13.32.1.11 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 automati-
cally 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 scan-
ning feature that cause the device to perform the entire read scanning with defect reallocation as the part
of the off-line data collection activities.
Hitachi Travelstar 60GH & 40GN hard disk drive specifications
168