Fujitsu MHC2040AT, MHC2032AT, MHD2021AT, MHD2032AT manual Features Resister Function

5.3 Host Commands

Features Resister	Function
X’DA’	SMART Return Status:
	When the device receives this subcommand, it asserts the BSY bit and saves
	the current device attribute values. Then the device compares the device
	attribute values with insurance failure threshold values. If there is an
	attribute value exceeding the threshold, F4h and 2Ch are loaded into the CL
	and CH registers. If there are no attribute values exceeding the thresholds,
	4Fh and C2h are loaded into the CL and CH registers. After the settings for
	the CL and CH registers have been determined, the device clears the BSY bit

The host must regularly issue the SMART Read Attribute Values subcommand (FR register = D0h), SMART Save Attribute Values subcommand (FR register = D3h), or SMART Return Status subcommand (FR register = DAh) to save the device attribute value data on a medium.

Alternative, the device must issue the SMART Enable-Disable Attribute AutoSave subcommand (FR register = D2h) to use a feature which regularly save the device attribute value data to a medium.

The host can predict failures in the device by periodically issuing the SMART Return Status subcommand (FR register = DAh) to reference the CL and CH registers.

If an attribute value is below the insurance 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.

At command issuance (I-O registers setting contents)

1F7H(CM)	1	0	1	1	0	0	0	0
1F6H(DH)	×	×	×	DV	xx
1F5H(CH)	Key (C2h)
1F4H(CL)	Key (4Fh)
1F3H(SN)	xx
1F2H(SC)	xx
1F1H(FR)	Subcommand

C141-E050-02EN 5-55