
Interface
Table 5.10 Features Field values (subcommands) and functions (3/3)
X’D9’ |
| SMART DISABLE OPERATIONS: |
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| This subcommand disables SMART. The setting is maintained even when |
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| the device is turned off and then on. |
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| When the device receives this subcommand, it disables SMART, then |
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| transfers the RegDH. |
X’DA’ |
| SMART RETURN STATUS: |
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| When the device receives this subcommand, it saves the current device attribute |
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| values. Then the device compares the device attribute values with guarantee |
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| failure threshold values. If there is an attribute value exceeding the threshold, |
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| F4h and 2Ch are loaded into the Cylinder Low and Cylinder High field. If there |
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| are no attribute values exceeding the thresholds, 4Fh and C2h are loaded into |
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| the Cylinder Low and Cylinder High field. After the settings for the Cylinder |
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| Low and Cylinder High field have been determined, the device transfers the |
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| RegDH. |
X’DB’ |
| SMART ENABLE/DISABLE AUTO |
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| This sets automatic |
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| Count field specification ≠ 00h) or disabled (when the Sector Count field |
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| specification = 00) state. This setting is preserved whether the drive’s power |
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| is switched on or off. |
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| If 24 hours have passed since the power was switched on, or since the last |
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| time that |
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| 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 | |
| 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. |