Power Management

For the OnNow system to work correctly, Windows 2000 Professional must be aware of how power management features integrate throughout the computer. This is done through the Advanced Configuration and Power Interface (ACPI), a system interface that provides a standard method for managing power consumption by the computer hardware. ACPI allows the motherboard to describe its device configuration and the interface of its power control hardware to Windows 2000 Professional. This allows the operating system to automatically turn on and turn off standard devices, such as disk drives, network adapters, and printers, as well as other electronic devices that might be connected to the computer, such as VCRs, TVs, telephones, or stereos.

ACPI allows the operating system to have direct control over how the computer consumes power. It can control when the computer enters and leaves sleep states. It also allows the operating system to put individual devices, including the CPU, into low-power states based on usage. The parameters that determine the behavior of the power management system can be configured using power schemes . Power schemes determine battery management policy and also allow you to define the point at which the system, the monitor, and the disk drive enter a sleep state in different circumstances. For more information about power schemes, see Configuring Power Schemes in this chapter.