Back when Vista was brewing, there was a lot of questions about how EFI would play on Intel-based Macs… the first consumer systems with EFI fully enabled. Most Intel-based systems today actually have the capability to support EFI, but have it disabled in their BIOS. Intel’s new Santa Rosa systems are the first that enforce EFI be enabled, with a CSM present to support Vista booting.
What wound up happening was Microsoft scrapped x86 support for EFI, leaving it as an IA-64 only option. However, they did promise to support x86-64 EFI booting with Vista SP1.
So, now we’re at Vista SP1 beta. What’s up with EFI? Well, right now, not much. Updating an already-installed Vista partition leaves it with BIOS support. This is actually quite intelligent. Adding EFI to a Vista configuration could screw things up and leave a previously-bootable system, un-bootable without a reinstall. It remains to be seen if slipstreammed discs (ones with Vista SP1 added to the installer, work properly as EFI-enabled installs).
Why is EFI so important? EFI finally puts closes the door on the 1980s-style BIOS. While it is more secure, it will also allow for greater flexibility. Vista, Mac, and Linux will finally be able to share time, sound, and other PRAM-based settings between boots. More importantly though, it will allow for system makers to utilize advanced applications in-firmware.
For example, Apple will be able to integrate their Hardware Test Disc software into firmware, so that if you hold, say, the H key, at bootup, you’ll get the Hardware Test suite. That will make it much easier for Genius Bars, and IT admins to quickly test out a Mac for problems. The need for Windows to add this, is because they need that 200 MB GPT partition that allows for more advanced utilities.
Down the road, Dell will be able to bundle a virus scanner, Microsoft will be able to bundle a Home Server restore tool, and Gateway will be able to install remote tech support… and any mix of the options you can think of. All of these tools will run independent of the OS, so no matter how screwed up it is, there is a much better chance the user can get back up-and-running quickly.