What Is UEFI, and How Is It Different from BIOS?

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The BIOS will quickly be useless: Intel has introduced plans to utterly exchange it with UEFI on all their chipsets by 2020. However what’s UEFI, and how is it completely different from the BIOS we’re all aware of?

Each UEFI and BIOS are low-level software program that begins whenever you boot your PC earlier than booting your working system, however UEFI is a extra fashionable answer, supporting bigger onerous drives, quicker boot occasions, extra security measures, and—conveniently—graphics and mouse cursors.

We’ve seen newer PCs that ship with UEFI nonetheless check with it because the “BIOS” to keep away from complicated people who find themselves used to a standard PC BIOS. Even when your PC makes use of the time period “BIOS”, fashionable PCs you purchase right this moment virtually actually ship with UEFI firmware as a substitute of a BIOS. Right here’s why.

What Is a BIOS?

BIOS is brief for Fundamental Enter-Output system. It’s low-level software program that resides in a chip in your pc’s motherboard. The BIOS masses when your pc begins up, and the BIOS is answerable for waking up your pc’s parts, ensures they’re functioning correctly, and then runs the bootloader that boots Home windows or no matter different working system you will have put in.

You’ll be able to configure varied settings within the BIOS setup display. Settings like your pc’s configuration, system time, and boot order are positioned right here. You’ll be able to entry this display by urgent a selected key—completely different on completely different computer systems, however usually Esc, F2, F10, or Delete—whereas the pc boots. Once you save a setting, it’s saved to the reminiscence in your motherboard itself. Once you boot your pc, the BIOS will configure your PC with the saved settings.

The BIOS goes by a POST, or Energy-On Self Take a look at, earlier than booting your working system. It checks to make sure your configuration is legitimate and working correctly. If one thing is improper, you’ll see an error message or hear a cryptic sequence of beep codes. You’ll must search for what completely different sequences of beeps imply within the pc’s handbook.

When your pc boots—and after the POST finishes—the BIOS seems to be for a Grasp Boot Report, or MBR, saved on the boot system and makes use of it to launch the bootloader.

You might also see the acronym CMOS, which stands for Complementary Metallic-Oxide-Semiconductor. This refers back to the battery-backed reminiscence the place the BIOS shops varied settings on the motherboard. It’s really not correct anymore, since this methodology has been changed with flash reminiscence (additionally known as EEPROM) in up to date techniques.

Why the BIOS Is Outdated

The BIOS has been round for a very long time, and hasn’t advanced a lot. Even MS-DOS PCs launched within the 1980s had a BIOS!

In fact, the BIOS has advanced and improved over time. Some extensions have been developed, together with ACPI, the Superior Configuration and Energy Interface. This permits the BIOS to extra simply configure units and carry out superior energy administration capabilities, like sleep. However the BIOS hasn’t superior and improved almost as a lot as different PC expertise has because the days of MS-DOS.

The normal BIOS nonetheless has critical limitations. It can solely boot from drives of two.1 TB or much less. three TB drives are actually frequent, and a pc with a BIOS can’t boot from them. That limitation is as a result of manner the BIOS’s Grasp Boot Report system works.

The BIOS should run in 16-bit processor mode, and solely has 1 MB of area to execute in. It has bother initializing a number of units directly, which ends up in a slower boot course of when initializing all of the interfaces and units on a contemporary PC.

The BIOS has wanted alternative for a very long time. Intel began work on the Extensible Firmware Interface (EFI) specification again in 1998. Apple selected EFI when it switched to the Intel structure on its Macs in 2006, however different PC producers didn’t comply with.

In 2007, Intel, AMD, Microsoft, and PC producers agreed on a brand new Unified Extensible Firmware Interface (UEFI) specification. That is an industry-wide commonplace managed by the Unified Prolonged Firmware Interface Discussion board, and isn’t solely pushed by Intel. UEFI help was launched to Home windows with Home windows Vista Service Pack 1 and Home windows 7. The overwhelming majority of computer systems you should buy right this moment now use UEFI quite than a standard BIOS.

How UEFI Replaces and Improves on the BIOS

UEFI replaces the standard BIOS on PCs. There’s no technique to swap from BIOS to UEFI on an present PC. It’s good to purchase new that helps and consists of UEFI, as most new computer systems do. Most UEFI implementations present BIOS emulation so you possibly can select to put in and boot outdated working techniques that anticipate a BIOS as a substitute of UEFI, in order that they’re backwards suitable.

This new commonplace avoids the constraints of the BIOS. The UEFI firmware can boot from drives of two.2 TB or bigger—in reality, the theoretical restrict is 9.four zettabytes. That’s roughly thrice the estimated dimension of all the info on the Web. That’s as a result of UEFI makes use of the GPT partitioning scheme as a substitute of MBR. It additionally boots in a extra standardized manner, launching EFI executables quite than operating code from a drive’s grasp boot report.

UEFI can run in 32-bit or 64-bit mode and has extra addressable handle area than BIOS, which implies your boot course of is quicker. It additionally signifies that UEFI setup screens might be slicker than BIOS settings screens, together with graphics and mouse cursor help. Nevertheless, this isn’t necessary. Many PCs nonetheless ship with text-mode UEFI settings interfaces that look and work like an outdated BIOS setup display.

UEFI is filled with different options. It helps Safe Boot, which implies the working system might be checked for validity to make sure no malware has tampered with the boot course of. It can help networking options proper within the UEFI firmware itself, which might help in distant troubleshooting and configuration. With a standard BIOS, you must be sitting in entrance of a bodily pc to configure it.

It’s not only a BIOS alternative, both. UEFI is basically a tiny working system that runs on high of the PC’s firmware, and it could do much more than a BIOS. It could also be saved in flash reminiscence on the motherboard, or it could be loaded from a tough drive or community share at boot.

Different PCs with UEFI may have completely different interfaces and options. It’s all as much as your PC producer, however the fundamentals would be the similar on every PC.

How to Entry UEFI Settings on Fashionable PCs

For those who’re a traditional PC person, switching to a pc with UEFI received’t be a noticeable change. Your new pc will boot up and shut down quicker than it will have with a BIOS, and you should utilize drives of two.2 TB or extra in dimension.

If it’s good to entry low-level settings, there could also be a slight distinction. You could have to entry the UEFI settings display by the Home windows boot choices menu quite than urgent a key whereas your pc begins. With PCs now booting so rapidly, PC producers don’t wish to decelerate the boot course of by ready to see in case you press a key. Nevertheless, we’ve additionally seen PCs with UEFI that permit you to entry the BIOS in the identical manner, by urgent a key in the course of the boot-up course of.

Whereas UEFI is a giant improve, it’s largely within the background. Most PC customers won’t ever discover—or have to care—that their new PCs use UEFI as a substitute of a standard BIOS. They’ll simply work higher and help extra fashionable and options.

For extra detailed info, learn Adam Williamson of Pink Hat’s clarification of how the UEFI boot course of is completely different. You may also learn the official UEFI FAQ.

Picture Credit score: Wikimedia Commons

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