Power Management Feature; Power Mode; Power Management Commands; Standby/Sleep Command Completion Timing - IBM DBCA-204860 - Travelstar 4.8 GB Hard Drive Specifications

10.4 Power Management Feature

The power management feature set permits a host to modify the behavior in a manner which reduces the
power required to operate. The power management feature set provides a set of commands and a timer that
enables a device to implement low power consumption modes.
DBCA-2xxxxx implement the following set of functions.
1. A Standby timer
2. Idle command
3. Idle Immediate command
4. Sleep command
5. Standby command
6. Standby Immediate command

10.4.1 Power Mode

Sleep Mode The lowest power consumption when the device is powered on occurs in Sleep
Mode. When in sleep mode, the device requires a reset to be activated. The time to
respond could be as long as the power on reset time.
Standby Mode The device interface is capable of accepting commands, but as the media may not
immediately accessible, there is a delay while waiting for the spindle to reach oper-
ating speed.
Idle Mode Refer to the section of Adoptive Battery Life Extender Feature.
Active Mode The device is in execution of a command or accessing the disk media with read look-
ahead function or write cache function.

10.4.2 Power Management Commands

The Check Power Mode command allows a host to determine if a device is currently in, going to or leaving
standby mode.
The Idle and Idle Immediate commands move a device to idle mode immediately from the active or standby
modes. The idle command also sets the standby timer count and starts the standby timer.
The sleep command moves a device to sleep mode. The device's interface becomes inactive at the com-
pletion of the sleep command. A reset is required to move a device out of sleep mode. When a device exits
sleep mode it will enter idle mode.
The Standby and Standby Immediate commands move a device to standby mode immediately from the
active or idle modes. The standby command also sets the standby timer count.

10.4.3 Standby/Sleep command completion timing

1. Confirm the completion of writing cached data in the buffer to media
2. Unload heads on the ramp
3. Set D R D Y bit and DSC bit in Status Register
4. Set I N T R Q (completion of the command)
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O E M Specifications of DBCA-2xxxxx 2.5 inch H D D