Processors

10 things you should know about UEFI

If you're a bit fuzzy on what UEFI is all about -- and how it will significantly change modern PC functionality -- these quick facts will get you up to speed.

You may have heard about unified extensible firmware interface (UEFI) but been unsure what it means. I usually hear it in reference to some "secret sauce" Macintoshes use "to keep Windows from being loaded on them" or perhaps, "to keep regular PCs from loading OS X." While it is true that Macs use UEFI, there is a lot more to the story than that. Here are 10 things you should know about UEFI.

1: UEFI is the replacement for BIOS

The BIOS (basic input/output system) has been at the heart of the PC design for well over 30 years now. It is the piece of firmware that provides the operating system with a standard interface to the functionality of the computer. Unfortunately, its design is quite outdated, carrying a number of limitations that are not acceptable in the current age of computing. UEFI is the replacement for BIOS, and it brings with it a host of modern functionality to carry PCs through the next few decades.

2: It enables better disk support

UEFI finally breaks free of the old DOS-style master boot record (MBR) disks, taking us into the GUID partition table (GPT) future. While not all operating systems support booting from GPT disks (notably, 32-bit versions of Windows), GPT support at the firmware layer will allow disks of enormous size to be used, even for booting the operating system.

3: Apple already uses it

Haven't heard of UEFI much? That's because while it is already in use, the most mainstream system out there using it is Apple, which isn't terribly friendly to tinkerers. It has also been used in Itanium systems for some time, as well as many embedded systems.

4: It can be emulated

Already, a number of virtualization platforms can emulate UEFI firmware, which allows you to load UEFI-dependent operating systems within them. Some examples are VirtualBox and Qemu. And yes, this means that it is technically possible to run OS X in a virtual machine under those environments.

5: Boot loaders are no longer needed

UEFI takes the place of the traditional operating system boot loader, which relegates any boot loading tasks to be done within the operating system itself (like asking to boot in a Safe Mode). As a result, you have one fewer thing to break or make decisions about.

6: It does not have to replace BIOS...

UEFI can sit on top of the traditional BIOS and act as an interface between it and the operating system. Like BIOS, it presents a standardized view of the hardware to the operating system, allowing operating system makers to build on top of it and have their OSes work on a variety of motherboards.

7: ...but it can use BIOS alternatives

At the same time, UEFI acts as an abstraction layer between the firmware that acts as a BIOS and the operating system. This means that an equipment maker can use whatever it wants to in the role that the BIOS fills and put UEFI on top of it and an operating system that uses UEFI will work just fine. Indeed, makers are free to build UEFI implementations that are complete top-to-bottom and do not need any firmware below them in the stack.

8: There is widespread industry support

The UEFI standard enjoys a large amount of support within the industry already. The UEFI standards organization has companies like Intel, AMD, Apple, Microsoft, and a number of BIOS and motherboard makers on it. As a result, UEFI will be the way forward, not just some dead standard left in the industry's wake like so many other initiatives. Modern operating systems are all compatible with UEFI as well.

9: Your job won't change much

Unless you are working as an embedded systems engineer or write low-level code for an operating system, UEFI probably won't affect your daily tasks. Sure, there are some IT roles that involve digging into the BIOS, but for the work they typically do, the differences between BIOS and UEFI will not make an impact on their work life. The big thing for IT staff to learn will be how to work with GPT disks in more recent operating systems.

10: UEFI can be a device driver target

One advantage of UEFI is that device drivers can target it instead of the specific hardware. This means that instead of needing to write drivers for different platforms, they can just write it once. Well, you are a PC person, what do you care, right? This will be huge for Windows 8, which will run on both x64 and ARM architecture. As a result, Windows 8 on ARM could very well come out of the gate with better driver support than Windows Vista.

About

Justin James is the Lead Architect for Conigent.

12 comments
TheObituary
TheObituary

@jelabarre did you re-install your OS in UEFI mode? mine seemed just as slow as traditional BIOS until i did that. And the slow boot up times may be due to overclocking software....my MSI board has an OC Genie setting and it will fire up the PC and i assume try different clock speeds/multipliers until it finds a stable one then finally boot up. Turning off this feature and having an SSD i boot in under 30 seconds. 

aTechMate
aTechMate

we found a lot to read about EFI or UEFI's but could not find out how it would really look like and how it would be the interface untill we got this ASUS at our place. We have created a small but intuitive simulation so that others can have a taste of it before they jump on it. Please find the link on sidebar at http://tools.atechmate.com

bjswm
bjswm

Is this susceptible to malaware - ie. in a significantly greater manner than BIOS? On the surface, without knowing too much about it, it appears to hold a lot more capability for hijacking.

Shadeburst
Shadeburst

Thanks to TCP/IP, my tablet can talk to big iron. In the near future, developers may not have to write different incarnations of software for every platform it has to run on. OS X apps will run just fine on Droid or Windows too. That will bust the market wide open.

jelabarre
jelabarre

My experience with uEFI is that it is significantly *SLOWER* to boot than BIOS-cased systems. Perhaps not a big deal if you never reboot, but if you do system support and lots of reconfigurations on a daily basis, you can be spending 1/3 your day waiting for uEFI systems to reboot and go through whatever mindless busywork they're doing. I've seen pSeries systems boot faster...

sysop-dr
sysop-dr

Thanks for the info Justin, I always wondered about UEFI and now I know enough to not worry about it.

spdragoo
spdragoo

UEFI is specifically designed to counter rootkits by preventing them from accessing the motherboard settings.

nwallette
nwallette

The author mentions universal driver support, in that the OS can support EFI, and EFI can support specific hardware. But that driver will have to be written for every OS (Win32, Win64, Linux, OSX...) The advantage is that you wouldn't have to write drivers for every little change in motherboard chipsets or what-have-you. Applications are entirely different. The API is tied to the OS, not the hardware platform or firmware. Consider that a Mac and PC are already running the same hardware under the hood, but you still can't run the others' apps.

TheObituary
TheObituary

@jelabarre  did you re-install your OS in UEFI mode? mine seemed just as slow as traditional BIOS until i did that. And the slow boot up times may be due to overclocking software....my MSI board has an OC Genie setting and it will fire up the PC and i assume try different clock speeds/multipliers until it finds a stable one then finally boot up. Turning off this feature and having an SSD i boot in under 30 seconds. 

nwallette
nwallette

I don't think one leads to the other. Maybe the implementations you've seen have a long hardware test cycle or something. In fact, many newer motherboards are already using EFI. The traditional BIOS is an interface, but the framework is there. The question is: Why aren't we using it? The PC platform takes for...EVER... to respond to architecture changes. I suspect it's due to OS support, and MS is probably in no hurry to make any "unnecessary" changes.

Shadeburst
Shadeburst

Perhaps that means that all boot software will have to reside on a chip. I know some guys who use solid state drives and their Windows boxes are ready to go in 15 seconds.

jelabarre
jelabarre

the OS boot code on a chip won't help. The major slowdown is all the activity that goes on even *before* the system starts booting an OS