What is EFI?
2 February 2006 in Apple | Comments enabled

In my previous post I mentioned that one of the reason that getting Windows XP running on the new Intel powered Macs was because of something called EFI. Allan followed up asking what that meant so here is my, by no means complete, understanding of EFI and why it poses such a challenge at the moment. If you see anything that is incorrect then feel free to comment :-)

For starters, EFI stands for Extensible Firmware Interface. EFI is a new interface that allows the system to interact with the hardware. It effectively replaces the BIOS which is what nearly all IBM-compatible machines are using. Intel has been pushing forward on EFI adoption with it’s recent high end server processors (Itanium and IA-32) and with the new Apple Mac systems. One complaint that has been circling is that a complete implementation of EFI should provide an emulated BIOS for the support of legacy environments (I have no idea when this would be useful other than for dual booting with Windows on the Mac at the moment) and the implementation used by Apple does not do this.

Now Windows has not supported EFI at all up until Microsoft released Windows for the Itanium. Vista will also (supposedly) support EFI out of the box in all flavours and should dual boot happily with OS X. In terms of the competition to boot Windows on the Mac, it expressly requires that you dual boot with Windows XP – which is what makes it somewhat tougher.

There has been some suggestion that Linux boot loaders (Grub for example) may be enough to get Windows going however there seems to be a strong view that this won’t work. Part of the reason that much of this is theory at the moment is simply because there just aren’t that many Intel Macs out in the wild yet to test on.

You can read more about EFI including presentations about it here.
For Microsoft specific information about EFI, you can read about that here.

Update: According to some information from Scott Hanselmans blog it would seem Vista does not have the EFI support enabled at the moment.

- JD


Leave a Comment

Name (required)

E-mail (required - not published)

Website

Your comment: