Power-Management Modes - Seagate Momentus 5400.4 ST9120817AS Product Manual

2.9.5

Power-management modes

The drive provides programmable power management to provide greater energy efficiency. In most systems,
you can control power management through the system setup program. The drive features the following
power-management modes:
Table 4: Power management modes
Power modes
Active (operating)
Idle, performance
Idle, active
Idle, low power
Standby
Sleep
• Active mode
The drive is in Active mode during the read/write and seek operations.
• Idle mode
The buffer remains enabled, and the drive accepts all commands and returns to Active mode any time disc
access is necessary.
• Standby mode
The drive enters Standby mode when the host sends a Standby Immediate command. If the host has set the
standby timer, the drive can also enter Standby mode automatically after the drive has been inactive for a
specifiable length of time. The standby timer delay is established using a Standby or Idle command. In Standby
mode, the drive buffer is in Self Refresh Low Power mode, the heads are parked and the spindle is at rest.
The drive accepts all commands and returns to Active mode any time disc access is necessary.
• Sleep mode
The drive enters Sleep mode after receiving a Sleep command from the host. In Sleep mode, the drive buffer
is in Self Refresh Low Power mode, the heads are parked and the spindle is at rest. The drive leaves Sleep
mode after it receives a Hard Reset or Soft Reset from the host. After receiving a reset, the drive exits Sleep
mode and enters Standby mode with all current translation parameters intact.
• Idle and Standby timers
Each time the drive performs an Active function (read, write or seek), the standby timer is reinitialized and
begins counting down from its specified delay times to zero. If the standby timer reaches zero before any
drive activity is required, the drive makes a transition to Standby mode. In both Idle and Standby mode, the
drive accepts all commands and returns to Active mode when disc access is necessary.
10
Heads
Tracking
Tracking
Bias against crash stops
Parked
Parked
Parked
Spindle Buffer
Rotating Full power
Rotating Low power
Rotating Self refresh—low power
Rotating Self refresh—low power
Stopped Self refresh—low power
Stopped Self refresh—low power
Momentus 5400.4 SATA Product Manual, Rev. A