Technical Overview

ACPICA defines and implements a group of software components that together create an implementation of the ACPI specification for both 32-bit and 64-bit platforms. A major goal of the architecture is to isolate all operating system dependencies to a relatively small translation or conversion layer (called the OS Services Layer) so that the bulk of the ACPICA code is independent of any individual OS. Therefore, hosting the ACPICA code on new operating systems requires no source code changes within the ACPICA code itself.

The major kernel-level components of the architecture include:

  • AML Interpreter
  • ACPI Table Manager
  • ACPI Namespace Manager
  • ACPI Resource Manager
  • ACPI Fixed and General Purpose Event Support
  • ACPI Hardware Support
  • AML Disassembler (optional)
  • AML Debugger (optional)

There are also several user-space tools and utilities that are built upon the above components (The ACPICA components run in both kernel mode and user mode):

  • ACPI Source Code Compiler & Disassembler (iASL)
  • ACPI Simulator/Executer (AcpiExec)
  • ACPI System Table dump to ASCII utility
  • ACPI Table Extractor (inverse of acpidump utility)
  • ACPI Help Utility (AcpiHelp)

Generation Environments

ACPICA is written in ANSI C, and can be generated under many different 32-bit and 64-bit OS development environments. Source code packages are provided for the following environments: Microsoft Windows* and UNIX*.

  1. The Windows package includes Visual C++* project files and other ACPI utilities that run under Windows.
  2. The UNIX package has a format and licensing suitable for inclusion by commercial OS vendors.

There is no standalone Linux* source code package since ACPICA updates for Linux are provided periodically in patch form. The ACPICA subsystem is modified to integrate smoothly with the Linux kernel source. This includes conversion of the ACPICA source code to the Linux kernel coding standard and licensing under the GNU General Public License.