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.
The Unified EFI Forum is the group responsible for developing, managing and promoting UEFI specifications. Further information about the UEFI specification and membership opportunities can be found throughout this Web site. The "Adopter" membership category is free. For additional information please contact UEFI Administration.
The Unified EFI Forum is a non-profit collaborative trade organization formed to promote and manage the UEFI standard. As an evolving standard, the UEFI specification is driven by contributions and support from member companies of the UEFI Forum.
The UEFI Forum board of directors include representatives from the following eleven leading companies:
|• American Megatrends Inc.
|• Apple Computer, Inc.
|• Hewlett Packard
|• Phoenix Technologies
With support and innovation from all UEFI Forum member companies, work is being done continually to evolve the UEFI specification to meet industry needs.
Q: What is UEFI?
A: UEFI (Unified Extensible Firmware Interface) will be a specification detailing an interface that helps hand off control of the system for the pre-boot environment (i.e.: after the system is powered on, but before the operating system starts) to an operating system, such as Windows* or Linux*. UEFI will provide a clean interface between operating systems and platform firmware at boot time, and will support an architecture-independent mechanism for initializing add-in cards.
Q: What is the relationship between EFI and UEFI?
A: The UEFI specification will be based on the EFI 1.10 specification published by Intel with corrections and changes managed by the Unified EFI Forum. Intel still holds the copyright on the EFI 1.10 specification, but has contributed it to the Forum so that the Forum can evolve it. There will not be any future versions of the EFI specification, but customers who license it can still use it under the terms of their license from Intel. The license to the Unified EFI Specification will come from the Forum, not from Intel.
Q: Is there a charge to use the specification?
A: Not for the specification itself. The Promoters of UEFI have agreed that any IP needed to implement the specification will be made available on reasonable and non-discriminatory terms.
Q: Can anyone build their own Unified EFI implementations?
A: Yes. UEFI expect BIOS vendors, OS vendors and add-in card vendors to all implement products based on the Unified EFI Specification.
Q: What is the BIOS? What does it do?
A: The BIOS (basic input/output system) is the program originally conceived to get a PC started after power-on. The BIOS also manages pre-boot data flow between the computer's operating system and attached devices such as the hard disk, video adapter, keyboard, and mouse. When the BIOS starts up your computer, it first determines whether all of the attachments are in place and operational and then it loads the operating system (or key parts of it) into the computer's memory from local storage (floppy, hard disk, CD-ROM, USB) or network.
Q: How does UEFI differ from BIOS?
A: The Basic Input/Output System (BIOS) served as the OS-firmware interface for the original PC-XT and PC-AT computers. This interface has been expanded over the years as the "PC clone" market has grown, but was never fully modernized as the market grew. UEFI defines a similar OS-firmware interface, known as "boot services" and "runtime services", but is not specific to any processor architecture. BIOS is specific to the Intel x86 processor architecture, as it relies on the 16-bit "real mode" interface supported by x86 processors.
Q: Does UEFI completely replace a PC BIOS?
A: No. While UEFI uses a different interface for "boot services" and "runtime services", some platform firmware must perform the functions BIOS uses for system configuration (a.k.a. "Power On Self Test" or "POST") and Setup. UEFI does not specify how POST & Setup are implemented.
Q: How is UEFI implemented on a computer system?
A: UEFI is an interface. It can be implemented on top of a traditional BIOS (in which case it supplants the traditional "INT" entry points into BIOS) or on top of non-BIOS implementations.
Q: What problem is the Forum trying to solve?
A: Interest in EFI has been growing steadily, and the Promoter companies believe that broad adoption requires industry management and control.
Q: How will the Forum ensure compatibility between different implementations of UEFI?
A: UEFI member companies will make compatibility test code available. Information will be available at www.uefi.org.
Q: When will products using UEFI technology be available in the market place?
A: Platforms using the existing EFI 1.10 specification are already in the market place. Platforms using the UEFI specification will enter the market as the specification is developed by the Forum.
Q: Does UEFI increase security risks from viruses and the like?
A: Any firmware implementation has to take care to address security. UEFI does not change that for better or worse.