The ACPI Component Architecture Project
The ACPI Component Architecture (ACPICA) project provides an operating system (OS)-independent reference implementation of the Advanced Configuration and Power Interface Specification (ACPI). It can be easily adapted to any host OS. The ACPICA code is meant to be directly integrated into the host OS, as a kernel-resident subsystem. Hosting the ACPICA requires no changes to the core ACPICA code. However, it does require a small OS-specific interface layer, which must be written specifically for each host OS.
The complexity of the ACPI specification leads to a lengthy and difficult implementation in OS software. The purpose of the ACPI Component Architecture is to simplify ACPI implementations for operating system vendors (OSVs) by providing major portions of an ACPI implementation in OS-independent ACPI modules that can be easily integrated into any OS.
News
30 July 2009: The implementation of ACPI 4.0 support within ACPICA is complete with version 20090730.05 April 2010: Acpi 4.0a is officially released. The document can be obtained at the acpi.info website here
There are no ACPICA changes required for ACPI 4.0a.
02 July 2010: The iASL Data Table Compiler has been released to simplify creation of non-AML ACPI tables (FADT, MADT, etc.)