UEFI

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.

EFI

The UEFI specification is based on the EFI 1.10 specification published by Intel®, with corrections and changes managed by the UEFI 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.

FAQ

Can all systems disable UEFI Secure Boot?

While it is designed to protect the system by only allowing authenticated binaries in the boot process, UEFI Secure Boot is an optional feature for most general-purpose systems. By default, UEFI Secure Boot can be disabled on the majority of general-purpose machines. It is up to the system vendors to decide which system policies are implemented on a given machine. However, there are a few cases—such as with kiosks, ATM or subsidized device deployments—in which, for security reasons, the owner of that system doesn’t want the system changed.

Can UEFI Secure Boot be adopted and implemented by a variety of operating systems?

UEFI specifications are platform-independent, supporting multiple platforms and architectures. In addition, UEFI specifications are designed to promote cross-functionality, as well as to support broad adoption across multiple operating systems, including Windows as well as Linux-based operating systems. The specifications are robust and can potentially complement—or even advance—other distributions, such as Linux-based distributions.

What are the benefits of UEFI specifications?

UEFI specifications have benefits for both the business and consumer end-user. Across multiple interfaces, they support a more secure system, faster boot times, innovation and a faster time-to-market. In contrast to prior coding structures, UEFI standards allow for extensibility, modularity and easy prototyping during development. The UEFI Forum promotes the implementation of UEFI specifications by BIOS vendors, operating system vendors and add-in card vendors. UEFI specifications promote more efficient development because they allow developers to reuse code during the building process.

How do UEFI specifications differ from BIOS?

BIOS is typically used to refer to an Intel® Architecture firmware implementation rooted in the IBM PC design. Based on older standards and methods, BIOS was originally coded in 16-bit real mode x86 assembly code and remained substantially unchanged until its recent decline in use. By contrast, UEFI standards reflect the past 30 years of PC evolution by describing an abstract interface set for transferring control to an operating system or building modular firmware from one or more silicon and firmware suppliers. The abstractions of UEFI Forum specifications are designed to decouple development of producer and consumer code, allowing each to innovate more independently and with faster time-to-market for both. UEFI also overcame the hardware scaling limitations that the IBM PC design assumed, allowing its broad deployment across high-end enterprise servers to the embedded devices. UEFI is “processor architecture-agnostic,” supporting x86, x64, ARM and Itanium.

Do UEFI specifications completely replace the BIOS?

The UEFI specifications define an interface and the BIOS refers to a specific implementation of the firmware that initializes the platform and loads an OS setup. UEFI specifications define an interface in which the implementation of UEFI performs the equivalent of the BIOS, by initiating the platform and loading the operating system.

How is UEFI implemented on a computer system?

Today, UEFI implementation enables the ability for modern, high-level programming principals to be applied to the firmware space. There are many possible implementations of UEFI that encourage code reuse, modularization, flexibility and modernization. UEFI specifications contain interfaces that streamline and aid in firmware innovation by promoting interoperability between devices, software and systems. One typical implementation is done in high-level C programming language, which is fundamentally different than the Legacy BIOS by encouraging the use of modern software practices.

Is there a charge to use the UEFI specification?

There is no charge for use of the specification itself. The promoters of UEFI specifications have agreed that any IP needed to implement the specification will be made available on reasonable and non-discriminatory terms.

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