Power-Management Modes - Seagate ST9120822A - Momentus 5400.3 120 GB Hard Drive Product Manual

2.9.4

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 3: 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 in performance mode, 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.
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Heads Spindle
Tracking Rotating
Tracking Rotating
Floating Rotating
Parked Rotating
Parked Stopped
Parked Stopped
Buffer
Full power
Self refresh—low power
Self refresh—low power
Self refresh—low power
Self refresh—low power
Self refresh—low power
Momentus 5400.3 PATA Product Manual, Rev. C