Fujitsu MHY2040BH Features Field values subcommands and functions 3/3, Smart Disable Operations

5.3 Host Commands

Table 5.9 Features Field values (subcommands) and functions (3/3)

Features Field	Function
X 'D9'	SMART DISABLE OPERATIONS:
	This subcommand disables SMART. The setting is maintained even when
	the device is turned off and then on.
	When the device receives this subcommand, it disables SMART, then
	transfers the RegDH.
X 'DA'	SMART RETURN STATUS:
	When the device receives this subcommand, it saves the current device attribute
	values. Then the device compares the device attribute values with guarantee
	failure threshold values. If there is an attribute value exceeding the threshold,
	F4h and 2Ch are loaded into the Cylinder Low and Cylinder High field. If there
	are no attribute values exceeding the thresholds, 4Fh and C2h are loaded into the
	Cylinder Low and Cylinder High field. After the settings for the Cylinder Low
	and Cylinder High field have been determined, the device transfers the RegDH.
X 'DB'	SMART ENABLE/DISABLE AUTO OFF-LINE:
	This sets automatic off-line data collection in the enabled (when the Sector
	Count field specification ≠ 00h) or disabled (when the Sector Count field
	specification = 00) state. This setting is preserved whether the drive's power
	is switched on or off.
	If 24 hours have passed since the power was switched on, or since the last
	time that off-line data were collected, off-line data collection is performed
	without relation to any command from the host computer.

The host must regularly issue the SMART READ DATA subcommand (Features field = D0h), SMART SAVE ATTRIBUTE VALUES subcommand (Features field = D3h), or SMART RETURN STATUS subcommand (Features field = DAh) to save the device attribute value data on a medium.

Alternative, the device must issue the SMART ENABLE-DISABLE ATTRIBUTE AUTOSAVE subcommand (Features field = D2h) to use a feature which regularly saves the device attribute value data to a medium.

In this drive, this function is enabled at the shipment from the factory.

The host can predict failures in the device by periodically issuing the SMART RETURN STATUS subcommand (Features field = DAh) to reference the Cylinder Low and Cylinder High field.

If an attribute value is below the guarantee failure threshold value, the device is about to fail or the device is nearing the end of its life. In this case, the host recommends that the user quickly backs up the data.

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