The Power Manager

Just as Windows Plug and Play features require support from a system’s hardware, its power-management capabilities require hardware that complies with the Advanced Configuration and Power Interface (ACPI) specification (available at

The ACPI standard defines various power levels for a system and for devices. The six system power states are described in Table 8-8. They are referred to as S0 (fully on or working) through S5 (fully off). Each state has the following characteristics:

  • Power consumption The amount of power the computer consumes

  • Software resumption The software state from which the computer resumes when moving to a “more on” state

  • Hardware latency The length of time it takes to return the computer ...

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