EFI replaces the Basic input/output system (BIOS) that has been used for thepast 20 years. Both technologies give a computer its first instructions when itis turned on and allows operating system to be loaded. EFI however has anadvantage over BIOS in that it allows for shorter boot times and lets hardwarevendors to create device drivers that are independent of operating systems.
Microsoft had initially said that it would support the technology for 64-bitsystems, but decided to make the changes because there will be too few 64-bitprocessors in the market when Windows Vista ships later this year.
"A combination of factors changed our plans," Microsoft development managerAndrew Ritz said in a session at the Intel Developer Forum in San Franciscoaccording toAPCmag.com.
"The big one, in my opinion was platform availability. With this huge move to64-bit based platforms and for us to support it, we needed to see a largeheterogeneous sample of 64 bit implementations out there for us to feelcomfortable in supporting it."
Intel developed EFI and supports the technology in its chips. While Apple isusing EFI in its Intel powered systems, Microsoft for now only supports it inits 64-bit version of Windows XP. The software developer in the past hascautioned that it targets the operating system at PC enthusiasts and cautionednot to use it in real production environments.
Microsoft's decision throws up a hurdle for Mac users who were hoping to load both Windows and OS X on their Intel Mac hardware. The Intel Macs rely on EFIand lack a BIOS.
This so-called double booting would allow gaming enthusiasts to use Applehardware to play PC games that are not available on the OS X platform.