Originally Posted by pgmer6809
So the bottom line is:
1. If you have a 64bit OS you can use GPT disks. I am not sure if you need GPT support in firmware, i.e. UEFI. You might not.
2. GPT disks can boot in MBR mode.
3. I don't see any advantage to booting in UEFI mode frankly. Of course if you are running Windows8 you have to, but for any other OS why?
Be careful assuming too much from your one experience with GPT and UEFI.
1. A 32-bit OS can support booting from a GPT (using either BIOS or UEFI). Not all 64-bit operating systems support GPT booting with a BIOS (Windows doesn't support BIOS booting for GPT). Although they are not common, there are 32-bit UEFI systems that require a 32-bit OS. Windows 32-bit doesn't support UEFI booting or GPT.
2. This is true only if the computer's motherboard firmware supports BIOS booting. Some UEFI motherboards do not support BIOS booting from a hard disk. In that case the only way to boot is using an EFI system partition (the MBR boot sector is ignored). Some UEFI firmware can support an MBR with no GPT but it still ignores the MBR boot sector (and uses the EFI system partition).
3. At the moment you are probably right assuming that BIOS booting works on the motherboard. However, BIOS booting will be supported less and less as time goes on. Some new computers may not support BIOS booting, and even if they do that may not be tested very well. Of course, UEFI may turn into another VESA bus or RDRAM and fade away without really becoming popular.
The configuration that you have does not use or require the EFI System Partition, although it doesn't hurt to have one. You can install a boot loader such as GRUB 2 in the EFI System Partition and then have the ability to boot using either BIOS or UEFI. I'm assuming that your motherboard has UEFI firmware.
The computer landscape is much different now than when BIOS was first introduced. Computer retailers are the normal way to buy computers, so they are more likely to affect what boot methods and operating systems are supported. It is nearly impossible to buy a consumer computer without Windows or to get support for a different OS. Some business class computers support Linux, but they may be limited to a specific distro and version of Linux. I think that we are going to see a separation between embedded computers, consumer PCs and business PCs as time goes on. They may have vastly different hardware, operating systems, applications and prices. In a way that is a return to the past when we had that sort of separation. For a while the IBM compatible PC filled all three roles.
Where does Linux fit in? I think that we are going to eventually see "Linux computers" versus "Windows computers". I don't want that, but it seems to be likely. Windows computers are becoming less and less standard, and Linux is going to be challenged to keep up with the sheer number of hardware variations. What's really needed to avoid that is a universal instruction language for writing hardware drivers that are compatible with any OS. Microsoft doesn't want that, of course, for many reasons. UEFI tries to do something like that but its drivers (especially graphics) are much too slow to be used as a replacement for OS drivers. They are fine for booting.
One reason to use UEFI booting is to learn how and be prepared for the eventuality that BIOS booting becomes unsupported.