If you've been around computers for any serious length of time, chances are you've heard the term "BIOS." The "basic input/output system" has been the standard interface for interacting with a computer's firmware at boot time since, well, since the beginning of home computers. But all that is gradually changing thanks to the Unified Extensible Firmware Interface, aka UEFI.
This new take on firmware interfaces brings the BIOS into the 21st century, and makes possible lots of things the dusty old interface just can't. Here's our rundown of basic facts about UEFI, and why you should care what happens on your computer before the operating system even starts.
1. UEFI is long overdue. When the BIOS was introduced on the first IBM PC in the early 1980s (the one that just
2. UEFI does not completely replace the BIOS. UEFI uses a separate interface for boot services and runtime services, but does not specify how the Power-On Self Test (POST) and Setup are implemented. Some platform firmware must still perform these crucial functions, however. Because UEFI is an interface (as its name suggests), it may be implemented "on top" of a traditional BIOS (or, for that matter, a non-BIOS system).
3. Technical changes abound in UEFI. UEFI has room for more useful and usable features than could ever be crammed into the BIOS. Among these are cryptography, network authentication, support for extensions stored on non-volatile media, an integrated boot manager, and even a shell environment for running other EFI applications such as diagnostic utilities or flash updates. In addition, both the architecture and the drivers are CPU-independent, which opens the door to a wider variety of processors (including those using the ARM architecture, for example). If you're running Windows 8, you'll even be able to secure boot into the operating system if you have a motherboard with UEFI.
4. UEFI enables better use of bigger hard drives. Though UEFI supports the traditional master boot record (MBR) method of hard drive partitioning, it doesn't stop there. It's also capable of working with the GUID Partition Table (GPT), which is free of the limitations the MBR places on the number and size of partitions. GPT ups the maximum partition size from 2.19TB to 9.4 zettabytes. (One zettabyte is equivalent to one trillion gigabytes.) For more information about this aspect of UEFI, read our story "The Problem with Big Hard Drives."
5. UEFI is easier to use and look at. That extra space isn't just devoted to hard-core tech features. There's enough room to fit in graphics, which gives UEFI much better-looking interfaces than the text-based blue-and-white ones DIYers have been squinting at for three decades. Also a big plus: The user can interact with the UEFI with a mouse instead of just a keyboard.
6. UEFI may be faster than the BIOS. Various tweaks and optimizations in the UEFI may help your system boot more quickly it could before. For example: With UEFI you may not have to endure messages asking you to set up hardware functions (such as a RAID controller) unless your immediate input is required; and UEFI can choose to initialize only certain components. The degree to which a boot is sped up will depend on your system configuration and hardware, so you may see a significant or a minor speed increase. But the potential is there.
7. UEFI is not a new idea. Companies have known for years that the BIOS was losing its relevance; Intel and HP complained about the firmware's limitations when they developed the first 64-bit Itanium systems back in the mid 1990s. This led to the Intel Boot Initiative (which started in 1998), which was later renamed EFI. Intel stopped hammering away at the spec in 2005 and passed it on the UEFI forum (though technically the company still owns and licenses the original), which in turn released the first updated version in (2.1) in 2007. The most recent version of the spec 2.3.1, was released this spring.
8. UEFI is still not widespread. Though major hardware companies such as Intel and Asus have switched over almost exclusively to UEFI use, you still won't find the new firmware in use on all motherboards—or in quite the same way across the spectrum. Gigabyte, for example, uses a "hybrid" version that offers almost all of the UEFI benefits but retains the old-school BIOS look. Certainly, many older and less expensive motherboards also still use the BIOS system, so don't expect it to go completely away any time soon. In fact, we'd even expect the name to stick around long after the transition is complete, based strictly on how well known and easy to say BIOS is compared to UEFI. Already the two are starting to be used interchangeably. This probably won't cause much confusion, but best to know what your system supports so you know to use the right term—just in case.
