Seagate MOMENTUS 42.2 ST9100822A, Product Manual

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10 Momentus 42.2 Product Manual, Rev. A
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:
• 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 enabled, 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 disabled, 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.
Table 3: Power management modes
Power modes Heads Spindle Buffer
Active (operating) Tracking Rotating Enabled
Idle, performance Tracking Rotating Enabled
Idle, active Floating Rotating Disabled
Idle, low power Parked Rotating Disabled
Standby Parked Stopped Disabled
Sleep Parked Stopped Disabled