ACPI is an acronym stands for Advance Configuration and Power Interface. It is an open standard specification and platform-independent interfaces for hardware discovery, device configuration, monitoring and power management by operating system. It puts unused components to sleep and do status monitoring for managing power.
ACPI was designed to replace Advanced Power Management (APM), the MultiProcessor Specification, and the Plug and Play BIOS (PnP) Specification. It was first released in December 1996. It brings the power management under the control of operating system as opposed to the previous BIOS centric system. It was originally developed and used by Intel, Microsoft and Toshiba, HP and Phoenix also participated later.
ACPI is responsible for the power distribution among the components of a computer system. It specifies how a computer's basic input/output system, operating system, and peripheral devices communicate with each other about power usage.
In its initial phase, it supports only 16 and 32-bit addressing spaces. In August 2000, ACPI received 64-bit address support as well as. Now it also supports for multiprocessor workstations and servers with revision 2.0.
ACPI has three main components: