IBM DTTA-351010 - Deskstar 10.1 GB Hard Drive Specifications page 157

Upon receipt of the subcommand from the host, the device sets BSY to one, begins or resumes its set of
off-line activities, clears BSY to zero and asserts INTRQ.
During execution of its off-line activities the device will not set BSY nor clear DRDY.
12.31.1.6 SMART Enable Operations (Subcommand D8h)
This subcommand enables access to all S.M.A.R.T. capabilities within the device. Prior to receipt of an
SMART 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 SMART Enable Operations subcommands will not affect any of the
Attribute Values.
Upon receipt of the SMART Enable Operations subcommand from the host, the device enables
S.M.A.R.T. capabilities and functions, and then saves any updated Attribute Values to the Attribute Data
sector.
12.31.1.7 SMART 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.
Upon receipt of the SMART Disable Operations subcommand from the host, the device disables
S.M.A.R.T. capabilities and functions, and then saves any updated Attribute Values to the Attribute Data
sector.
After receipt of the device of the SMART Disable Operations subcommand from the host, all other
S.M.A.R.T. subcommands -- with the exception of SMART Enable Operations -- are disabled and invalid
and will be aborted by the device (including the SMART Disable Operations subcommand), returning the
error code as specified in Figure 119 on page 156.
Any Attribute Values accumulated and saved to volatile memory prior to receipt of the SMART 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 SMART Read Attribute Values or
SMART Save Attribute Values command.
12.31.1.8 SMART 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 SMART Return Status subcommand the device saves any updated Pre-failure type 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, the device loads 4Fh into the Cylinder Low
register, C2h into the Cylinder High register.
If the device detect a Threshold Exceeded Condition, the device loads F4h into the Cylinder Low register,
2Ch into the Cylinder High register.
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Command Descriptions