Seagate ST9500622SS, 100620418 Physical/electrical specifications, PowerChoiceTM power management

7.0Physical/electrical specifications

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

7.1PowerChoiceTM power management

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

The table below lists the supported PowerChoice modes. The further you go down in the table, the more power savings you get. For example, Idle2 mode results in greater power savings than Idle1 mode. Standby mode results in the greatest power savings.

PowerChoice modes

Mode	Description
Idle_A	Reduced electronics
Idle_B	Heads unloaded. Disks spinning at full RPM
Idle_C	Heads unloaded. Disks spinning at reduced RPM
Standby_Y	Heads unloaded. Disks spinning at reduced RPM.
	Recovery requires the NOTIFY (Enable Spinup) command.
Standby_Z	Heads unloaded. Motor stopped (disks not spinning)
	Recovery requires the NOTIFY (Enable Spinup) command.

PowerChoiceTM 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 con- dition timers. The timer values 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.

22 Constellation.2 SAS Product Manual, Rev. H