Maxtor 4320 manual A.R.T. Command Set, Execute S.M.A.R.T

INTERFACECOMMANDS

S.M.A.R.T. Command Set

Execute S.M.A.R.T.

The Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.) command has been implemented to improve the data integrity and data availability of hard disk drives. In some cases, a S.M.A.R.T. capable device will predict an impending failure with sufficient time to allow users to backup their data and replace the drive before data loss or loss of service.

The S.M.A.R.T. sub-commands (listed below) comprise the ATA S.M.A.R.T. feature set that provide access to S.M.A.R.T. attribute values, attribute thresholds and other logging and reporting information.

Prior to writing a S.M.A.R.T. command to the device’s command register, key values must be written by the host into the device’s Cylinder Low and Cylinder High registers, or the command will be aborted. For any S.M.A.R.T. sub-command, if a device register is not specified as being written with a value by the host, then the value in that register is undefined and will be ignored by the device. The key values are:

Key	Register
4Fh	Cylinder Low (1F4h)
C2h	Cylinder High (1F5h)

The S.M.A.R.T. sub-commands use a single command code (B0h) and are differentiated from one another by the value placed in the Features register. In order to issue a command, the host must write the sub- command-specific code to the device’s Features register before writing the command code to the command register. The sub-commands and their respective codes are:

D0h	S.M.A.R.T. Read Attribute Value
	This feature returns 512 bytes of attribute information to the host.
D1h	S.M.A.R.T. Read Attribute Thresholds
	This feature returns 512 bytes of warranty failure thresholds to the host.
D2h	Enable/Disable Autosave
	To enable this feature, set the sector count register to F1h (enable) or 0 (disable). Attribute values are
	automatically saved to non-volatile storage on the device after five minutes of idle time and before
	entering idle, sleep or standby modes. This feature is defaulted to “enabled” when S.M.A.R.T. is
	enabled via the S.M.A.R.T. Enable Operations commands. The autosave feature will not impact host
	system performance and does not need to be disabled.
D3h	S.M.A.R.T. Save Attribute Value
	This feature saves the current attribute values to non-volatile storage.
D4h	Perform Off-Line Data Collection
	Data is collected from random seeks, timed pattern seek times and head margin tests.
D8h	Enable S.M.A.R.T.
D9h	Disable S.M.A.R.T.
DAh	S.M.A.R.T. Return Status
	This feature allows the host to assess the status of a S.M.A.R.T. capable device by comparing all saved
	attribute values with their corresponding warranty failure thresholds. If no thresholds are exceeded, the
	drive is declared to have a positive health status. If any warranty failure threshold is exceeded, the drive
	is declared to have a negative health status. Executing this sub-command results in all attribute values
	being saved to non-volatile storage on the device.
DBh	Enable/Disable Automatic Off-Line
	To enable this feature, set the Sector Count register to F1h or 0 to disable.

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