Interface

Table 5.10 Features Field values (subcommands) and functions (3/3)

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

 

save 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.

5-58

C141-E249

Page 132
Image 132
Fujitsu MHW2120BS Features Field values subcommands and functions 3/3, Smart Disable Operations, ’DA’ Smart Return Status