Advanced Configuration and Power Interface Specification

A.11.1 Power State Definitions
A.11.1.1 Hard Disk, CD-ROM and IDE/ATAPI Removable Storage Devices
State Status Definition
D0 Required Drive controller (for example, interface and control electronics) is functional.
Interface mode context (for example, communications timings) is programmed.
D1 Optional Drive controller (for example, interface and control electronics) is functional.
Interface mode context (for example, communications timings) is preserved.
Drive motor (for example, spindle) is stopped, with fast-start mode enabled, if
available.
Laser (if any) is off.
Recommended latency to return to D0 is less than 5 seconds.
Power consumption in D1 should be no more than 80% of power consumed in D0.
Note: For ATA devices, this state is invoked by the Standby Immediate command.
D2 N/A This state is not defined for storage devices.
D3 Required Drive controller (for example, interface and control electronics) is not functional;
context is lost.
Interface mode (for example, communications timings) is not preserved.
Drive motor (for example, spindle) is stopped.
Laser (if any) is off.
Power consumption in D3 is no more than 10% of power consumed in D0.
Note: For ATA devices, this state is invoked by the “sleep” command.
A.11.1.2 Floppy Disk Devices
State Status Definition
D0 Required Drive controller (for example, interface and control electronics) is functional.
Drive motor (for example, spindle) is turning.
D1 N/A This state is not defined for floppy disk drives.
D2 N/A This state is not defined for floppy disk drives.
D3 Required Drive controller (for example, interface and control electronics) is not functional;
context is lost.
Drive motor (for example, spindle) is stopped.
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