On Apr 15, 2011, at 1:51 PM, Lawrence Sica wrote: > > On Apr 15, 2011, at 3:48 PM, Scott Lewis wrote: > >> On Apr 15, 2011, at 03:44 PM, Lawrence Sica <[email protected]> wrote: >> >>> Are you sure about this? Everything I've read is that it can boot off of >>> USB. In fact Apple officially supports it with some specific notes. >>> http://support.apple.com/kb/ht1948 They only mention windows and os x but I >>> am sure you could boot linux this way assuming everything is setup >>> correctly. >> >> >> Considering the USB recovery stick my MB Air came with, I'm going to guess >> you can boot off of USB. > > I forgot about that. *looks at his macbook air* I need coffee. Also I > thought GUID supports much larger disks?
Yes, but GPT requires (U)EFI. The CSM BIOS doesn't deal with GPT for booting, it needs MBR. That's one of the functions of bootcamp is to read the GPT and write an MBR - hence the partition scheme is hybrid MBR+GPT. This tells EFI to use EFI boot for Mac OS (using the GPT partition), and tells EFI to load the CSM BIOS which uses the MBR and bootloader to boot Windows (or other OS's). But when using the CSM BIOS, you're stuck with all of its limitations because at that point EFI isn't directly available. The OS you're booting thinks it's dealing with a BIOS machine. And that BIOS layer doesn't support a lot of things including USB boot, GPT or large disk sizes. If Apple used UEFI, we wouldn't have this issue, and wouldn't need the CSM BIOS. Just use UEFI for everything. Chris_______________________________________________ MacOSX-admin mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-admin
