Seagate ST2000NM0054 ユーザーズマニュアル

Seagate Enterprise Capacity 3.5 HDD v4 SAS Product Manual, Rev. C

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This section provides information relating to the physical and electrical characteristics of the drive.

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Drives using the load/unload architecture provide programmable power management to tailor systems for performance and greater energy 
efficiency.

The table below lists the supported PowerChoice modes. The further down the user goes in the table, the more power savings the user 
gets. For example, Idle_B mode results in greater power savings than Idle_A mode. Standby_Z mode results in the greatest power 
savings. 

Reduced electronics

Heads unloaded. Disks spinning at full RPM

Heads unloaded. Disks spinning at reduced RPM

Heads unloaded. Disks spinning at reduced RPM.
Recovery requires the NOTIFY (Enable Spinup) command.

Heads unloaded. Motor stopped (disks not spinning)
Recovery requires the NOTIFY (Enable Spinup) command.

PowerChoice

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can be invoked using one of these two methods:

• Power Condition mode page method—Enable and initialize the idle condition timers and/or the standby condition timers. The timer val-

ues are based on the values set in the Power Condition mode page. 

• START STOP UNIT command method—Use the START STOP UNIT command (OPERATION CODE 1Bh). This allows the host to 

directly transition the drive to any supported PowerChoice mode. 

If both the Power Condition mode page and START STOP UNIT command methods are used, the START STOP UNIT command request 
takes precedence over the Power Condition mode page power control and may disable the idle condition and standby condition timers. 
The REQUEST SENSE command reports the current PowerChoice state if active and also the method by which the drive entered the 
PowerChoice state.

When the drive receives a command, all power condition timers are suspended if they were enabled via the Power Condition mode page. 
Once all outstanding commands are processed, the power condition timers are reinitialized to the values defined in the Power Condition 
mode page

PowerChoice

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 provides these reporting methods for tracking purposes:

• Current power condition
• Method of entry

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• Idle conditions enabled / disabled
• Idle condition timer values (100ms increments) (default, saved, current, changeable)

• Supported power conditions
• Typical recovery time from power conditions (1ms increments)

• Specified and accumulated Start/Stops and Load/Unload cycles

• Accumulated transitions to Active, Idle_A, Idle_B, Idle_C, Standby_Y, Standby_Z

 Processing the Request Sense command does not impact the drive’s power save state.