# Unified Extensible Firmware Interface

> specification that defines a software interface between an operating system and platform firmware

**Wikidata**: [Q859398](https://www.wikidata.org/wiki/Q859398)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/UEFI)  
**Source**: https://4ort.xyz/entity/unified-extensible-firmware-interface

## Summary
Unified Extensible Firmware Interface (UEFI) is a specification that defines a software interface between an operating system and platform firmware. It replaces the traditional BIOS firmware interface and provides a more flexible and extensible framework for booting operating systems and running pre-boot applications.

## Key Facts
- UEFI is a specification that defines a software interface between an operating system and platform firmware
- It replaces the traditional BIOS firmware interface
- Developed by the Unified EFI Forum
- Uses the GUID Partition Table (GPT) standard for storage device layout
- Has 41 sitelinks across Wikipedia language editions
- Instance of both computer interface and technical standard
- Freebase ID: /m/03jsyw
- GitHub topic: uefi

## FAQs
### Q: What is the main purpose of UEFI?
A: UEFI provides a modern replacement for BIOS, offering a more flexible and extensible framework for booting operating systems and running pre-boot applications. It supports larger storage devices, faster boot times, and more sophisticated pre-boot environments than traditional BIOS.

### Q: How does UEFI differ from BIOS?
A: UEFI replaces the traditional BIOS interface with a more modern specification that supports larger storage devices, faster boot times, and more sophisticated pre-boot environments. Unlike BIOS, UEFI uses a modular architecture and supports graphical user interfaces during the boot process.

### Q: What partition scheme does UEFI use?
A: UEFI uses the GUID Partition Table (GPT) standard for the layout of partition tables on physical storage devices. This allows for support of larger storage devices and more partitions compared to the older Master Boot Record (MBR) scheme used by BIOS.

## Why It Matters
UEFI represents a fundamental shift in how computers initialize hardware and boot operating systems. By replacing the decades-old BIOS interface, UEFI enables support for modern hardware capabilities including 64-bit firmware, secure boot functionality, and support for storage devices larger than 2.2TB. The specification's modular architecture allows for easier updates and customization, while its support for graphical interfaces during boot provides users with more informative and interactive pre-boot experiences. UEFI's adoption has become nearly universal in modern computing devices, from personal computers to servers, making it a critical component in the evolution of computer firmware and system initialization.

## Notable For
- Replacing the traditional BIOS interface with a more modern, extensible specification
- Enabling support for storage devices larger than 2.2TB through GPT partitioning
- Introducing secure boot functionality to help prevent malware attacks during the boot process
- Providing a modular architecture that allows for easier updates and customization
- Supporting graphical user interfaces during the boot process, improving user experience

## Body
### Technical Foundation
UEFI is built on a modular architecture that separates the boot services, runtime services, and driver execution environment. This design allows for greater flexibility and extensibility compared to the monolithic BIOS architecture. The specification defines protocols that enable communication between different firmware components and allows for the development of platform-independent drivers.

### Storage and Partitioning
UEFI requires the use of GUID Partition Table (GPT) for storage devices, which overcomes the limitations of the older Master Boot Record (MBR) scheme. GPT supports storage devices up to 9.4 zettabytes and allows for a virtually unlimited number of partitions. This is particularly important for modern high-capacity storage devices and enterprise storage solutions.

### Security Features
One of UEFI's most significant contributions is the introduction of Secure Boot, a security standard that helps ensure that a device boots using only software that is trusted by the Original Equipment Manufacturer (OEM). Secure Boot verifies the digital signature of boot loaders and operating system kernels before execution, helping to prevent malware from loading during the boot process.

### Development and Governance
The UEFI specification is developed and maintained by the Unified EFI Forum, an industry consortium that includes computer manufacturers, chip companies, and operating system vendors. This collaborative approach ensures that the specification meets the needs of various stakeholders while maintaining compatibility across different hardware platforms.

### Implementation and Adoption
UEFI has been widely adopted across the computing industry, with virtually all new personal computers, servers, and mobile devices using UEFI firmware. The specification continues to evolve, with regular updates adding support for new hardware capabilities and security features. Major operating systems including Windows, Linux, and macOS have implemented support for UEFI, making it a universal standard for modern computing platforms.

## References

1. [New 16 High-Severity UEFI Firmware Flaws Discovered in Millions of HP Devices](https://thehackernews.com/2022/03/new-16-high-severity-uefi-firmware.html)
2. Freebase Data Dumps. 2013