GPT was or could be used as far back as 2003 server and Windows XP x64 on data storage drives .. So you could use GPT but just couldn't use on boot drive
Q. Is UEFI required for a GPT disk? A. No. GPT disks are self-identifying. All the information needed to interpret the partitioning scheme of a GPT disk is completely contained in structures in specified locations on the physical media. Quote from that previous link. EFI requires booting into fat32 device. Said device does not need to be GPT formatted. GPT will allow you to have more than 4 partitions and has some more clearly defined definitions. In Windows 8, the actual boot partition is likely in fat32, which makes sense when combined with UEFI as the size is usually 300mb, so no files over 4gb. That doesn't mean the main data partition is in fat32, just that the boot partition is...
*edit: Actually from what I understand... that doesn't sound right... I'm going to test it though by running diskpart and converting gpt on a fresh win7x64 setup
If your not in UEFI mode then how can it boot from a GPT drive? If your booting in bios/legacy mode, then the drive must be MBR..
Very interesting stuff... I don't have a UEFI system, nor a GPT disk, but I started reading up on this stuff in c't magazin (probably the best computer mag in the world, unfortunately for some, in German). One thing I already know (loosely translated from German): "The forced marriage between UEFI and GPT is a Microsoft 'thing' only". So they're not necessarily linked, only on systems that want the "Windows 8" logo. In these systems, Secure Boot has to be enabled by default (you can usually turn it off later). For secure boot, UEFI is needed, and there the ball starts rolling... I vote for a FAQ by murphy78... (at least then we know *everything* is tested, not assumed).
No. it's not true.. You can boot from GPT on non-UEFI.. Infact, GPT contains MBR scheme hidden in itself..
Well I don't know what to say... It boots MBR in/out of UEFI... It boots GPT in/out of UEFI. They are all independent.
You know it could be that they've been ramping up support for UEFI using MBR and GPT in the background and that some of the technet articles are just old. I know from just testing it right now that x64 win7sp1 ultimate retail iso from digitalriver does install and reboot onto both boot methods in and out of UEFI boot mode...
Actually you don't need to have a EFI mobo, or swap disks to test and know; make 2 VMWare machines, one is EFI boot and install windows EFI, the other is BIOS boot and install windows MBR.
That's pretty much how I tested it with vmware. First I made sure there was no line: firmware = "efi" Then I converted gpt in shift-f10 during setup using diskpart and finished the setup. That confirmed that GPT can boot from bios without EFI boot. Then I added the line: firmware = "efi" re-ran setup, cleaned the hd, convert mbr so that it was mbr whilst booting in EFI boot. Finished setup and it booted just fine. I have no idea why the technet articles say that you need GPT for UEFI boot, but it certainly was not the case for my vmware test. The only thing left to test is to manually format my system. I'm just reluctant to do that because I have a 990fx mobo that definitely boasts uefi support and I wouldn't want it to auto-detect my boot option and "fix" it for me.
Do they mention Secure Boot as well? In that case, I guess GPT *is* required. Also, from the c't article: - When you've installed Windows (8) in BIOS mode (that's the compatibily mode of your UEFI), a Master Boot Record (MBR) is required. - When you've installed Windows in UEFI mode, a GPT is required. This also is a "Windows thing" ("marrying" the two), it's not a technical restriction... Are you taking the compatibily mode into account?