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12.55.1.8 SMART Enable Operations (Subcommand D8h)
This subcommand enables access to all SMART capabilities within the device. Prior to receipt of a SMART Enable
Operations subcommand, Attribute Values are neither monitored nor saved by the device. The state of SMART (either
enabled or disabled) will be preserved by the device across power cycles. Once enabled, the receipt of subsequent
SMART Enable Operations subcommands will not affect any of the Attribute Values.
Upon receipt of the SMART Enable Operations subcommand from the host, the device enables SMART capabilities
and functions, and then saves any updated Attribute Values to the Attribute Data sector.
Table 228 SMART Enable Operations (B0h-D8h)
Command Input
Field
Description
FEATURE
D8h
COUNT
N/A
LBA
Bit Description
27:24 N/A
23:8 C24Fh
7:0 N/A
DEVICE
Bit Description
7 Obsolete
6 N/A
5 Obsolete
4 Transport Dependent
3:0 Reserved
Command
7:0 B0h
Normal Outputs
See Normal Outputs in Section 12.7 Flush Cache (E7h)
Error Outputs
See Error Outputs in Section 12.12 Idle (E3h / 97h)
12.55.1.9 SMART Disable Operations (Subcommand D9h)
This subcommand disables all SMART capabilities within the device including the device’s attribute autosave feature.
After receipt of this subcommand the device disables all SMART operations. Non self-preserved Attribute Values will
no longer be monitored. The state of SMART (either enabled or disabled) is preserved by the device across power
cycles.
Upon receipt of the SMART Disable Operations subcommand from the host, the device disables SMART capabilities
and functions, and then saves any updated Attribute Values to the Attribute Data sector.
After receipt of the device of the SMART Disable Operations subcommand from the host, all other SMART
subcommands – with the exception of SMART Enable Operations – are disabled, and invalid and will be aborted by
the device (including the SMART Disable Operations subcommand), returning the error code as specified in Table
242.
Any Attribute Values accumulated and saved to volatile memory prior to receipt of the SMART Disable Operations
command will be preserved in the device’s Attribute Data Sectors. If the device is re-enabled, these Attribute Values
will be updated, as needed, upon receipt of a SMART Read Attribute Values or SMART Save Attribute Values
command.
309
Hard Disk Drive Specification