Seagate ST9160511NS Manuale Utente

14

Constellation Serial ATA Product Manual, Rev. D

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, Idle_B mode results in greater power savings than Idle_A mode. Standby mode 
results in the greatest power savings.

PowerChoice can be invoked using one of these two methods:

• Extended Power Conditions (EPC) Set Features Command method-Enable and initialize the idle condition 

timers. 

• Standby Immediate and Idle Immediate command method-Use the EPC Set Features Command. This allows 

the host to directly transition the drive to any supported PowerChoice mode. The drive preserves the existing 
idle power settings. 

PowerChoice

TM

 provides these reporting methods for tracking purposes:

Check Power Mode Reports

• Current power condition

Power Condition Log Reports 

• Idle condition enabled/disabled

• If timer is changeable

• Typical recovery time from extended power conditions

• Current timer setting and Manufacturer default timer settings

SMART Read Data Attribute - Load/ Unload Cycle Counter

Idle_A

Reduced electronics

Idle_B

Heads unloaded. Disks spinning at full RPM

Idle_C

Heads unloaded. Disks spinning at reduced RPM

Standby

Heads unloaded. Motor stopped (disks not spinning)