The Unified Extensible Firmware Interface, or UEFI, is a specification for a software program that connects a computer’s firmware to its operating system.
UEFI can do neat things like enabling larger hard drives and faster boot times than traditional BIOS (the older type of firmware).
This article will walk you through the basics of the UEFI interface, how it works, and what you should expect from it if you decide to use it.
UEFI – A Replacement For The Older BIOS Firmware Interface
UEFI is a replacement for the older BIOS firmware interface.
While UEFI has its roots in EFI, an Intel initiative, it became mainstream with Apple’s adoption of Intel processors and its switch to UEFI firmware.
Since then, almost all PCs now ship with UEFI firmware instead of BIOS firmware; here are some things you need to know about this new type of firmware.
Unlike the BIOS (Basic Input/Output System) that preceded it, UEFI doesn’t just provide services to enable the operating system to boot and handle low-level I/O operations.
It also includes code directly dealing with hardware initialization and bootstrap loading on top of optional security measures like Secure Boot.
The main advantage of UEFI over BIOS is that it offers more advanced features than BIOS does; for example:
- Graphical user interface (GUI) rather than text mode
- Networking support through PXE or TFTP protocols
- Support for hard drives larger than 2TB
- Better mouse support is not limited to just two buttons compared to text-only UI used by older PC systems using a PS/2 keyboard and mouse port.
UEFI specifications are a set of standards that describe the protocols for a computer’s firmware.
Systems manufacturers use the standards to make their hardware and software compatible with other products on the market.
UEFI specifications are maintained by the UEFI Forum, which comprises various members.
The UEFI specifications have a version number and a revision number, similar to how software has versions.
UEFI can download these specifications from the [UEFI Forum](https://uefi.org/specifications) website, but you have to have an account.
Significant Difference Between EFI and UEFI
Now that you know about EFI and BIOS let’s talk about UEFI’s significant difference.
UEFI is an updated version of EFI that exists as a replacement for BIOS. While BIOS only works with MBR, UEFI supports both MBR and GPT.
This means that you can use larger hard drives with UEFI than with BIOS.
UEFI also offers faster boot times than traditional BIOS firmware and is more secure than its predecessor.
This makes it more challenging to take advantage of your hardware remotely when connected online—a great thing for people worried about security!
It also includes many other features like mouse support (something I wish I had back in my MS-DOS days!). It even provides access to the internet via PXE booting (boot from the network).
What are UEFI Classes?
So what are UEFI classes?
UEFI classes define the features that are available to a system. An application can check the class of a platform and determine which features it supports.
UEFI classes are defined in the specification. By reading that document, you can find out which features each class supports.
The specification defines several classes, but all systems must support Class 0x00 (Basic UEFI).
The 6 Classes of UEFI Specification
As a technology, UEFI is something of a paradox. The name implies “user-friendly,” but it seems the most challenging part of the PC architecture to understand.
UEFI stands for Unified Extensible Firmware Interface, and it’s a specification. Not just any specification, either.
It’s meant for computers rather than televisions or other gadgets with their own rules. It’sIt’s intended to be used in combination with Windows 8 or 10.
Still, unfortunately, both the manufacturers and software vendors are often reluctant to use it—at least when compared to their usual preference for something else.
UEFI specifications are meant to make things easier for users by making the BIOS code more modular (instead of being written as one gigantic blob-like in older versions) and doing some things differently (so you don’t have to reboot your computer just because you need something done).
Why is UEFI Important?
To understand why it’s important, you first need to know what UEFI does. UEFI is a firmware interface that replaces BIOS.
The purpose of the UEFI interface is to help the operating system run on hardware and provide a way for the operating system to communicate with the hardware.