UEFI
is a community effort by many companies in the personal-computer
industry to modernize the booting process. UEFI capable systems are
already shipping, and many more are in preparation. During the
transition to UEFI, most platform firmware will continue to support
legacy (BIOS) booting as well, to accommodate legacy-only operating
systems.
UEFI stands for "Unified Extensible Firmware Interface". The UEFI
specification defines a new model for the interface between
personal-computer operating systems and platform firmware. The interface
consists of data tables that contain platform-related information, plus
boot and runtime service calls that are available to the operating
system and its loader. Together, these provide a standard environment
for booting an operating system and running pre-boot applications.