Extensible Firmware Interface Specification
8 12/12/00 Version 1.02
1.5 Prerequisite Specifications
In general, this specification requires that functionality defined in a number of other existing
specifications be present on a system that implements this specification. This specification requires
that those specifications be implemented at least to the extent that all the required elements are
present.
This specification prescribes the use and extension of previously established industry specification
tables whenever possible. The trend to remove runtime call-based interfaces is well documented.
The ACPI (Advanced Configuration and Power Interface) specification and the SAL (System
Access Layer) specification are two examples of new and innovative firmware technologies that
were designed on the premise that OS developers prefer to minimize runtime calls into firmware.
ACPI focuses on no runtime calls to the BIOS, and the SAL specification only supports runtime
services that make the OS more portable.

1.5.1 ACPI Specification

The interface defined by the Advanced Configuration and Power Interface (ACPI) Specification is
the current state-of-the-art in the platform-to-OS interface. ACPI fully defines the methodology
that allows the OS to discover and configure all platform resources. ACPI allows the description of
non-Plug and Play motherboard devices in a plug and play manner. ACPI also is capable of
describing power management and hot plug events to the OS. (For more information on ACPI,
refer to the ACPI web site at http://www.teleport.com/~acpi).

1.5.2 WfM Specification

The Wired for Management (WfM) Specification defines a baseline for manageability that can be
used to lower the total cost of ownership of a computer system. WfM includes the System
Management BIOS (SMBIOS) table-based interface that is used by the platform to relate platform-
specific management information to the OS or an OS-based management agent. The format of the
data is defined in the System Management BIOS Reference Specification, and it is up to higher level
software to map the information provided by the platform into the appropriate schema. Examples
of schema would include CIM (Common Information Model) and DMI (Desktop Management
Interface). For more information on WfM or to obtain a copy of the WfM Specification, visit
http://developer.intel.com/ial/WfM. To obtain the System Management BIOS Reference
Specification, visit http://developer.intel.com/ial/WfM/design/BIBLIOG.HTM.