UEFI Big Drive question

[Chris Murphy]

On May 12, 2014, at 3:05 PM, Stephen Morris <samorris at netspace.net.au> wrote:

> On 05/12/2014 09:36 AM, Chris Murphy wrote:
>> On May 9, 2014, at 6:05 PM, Stephen Morris <samorris at netspace.net.au> wrote:
>> 
>>> The one limitation with GPT as I understand it is that in order to use GPT you must also have UEFI active in the Bios.
>> No. First, BIOS ≠ UEFI they are not the same thing and it's easy to remember because there's nothing basic about UEFI. Second, while it's true GPT is defined in the UEFI spec, it's entirely up to the BIOS firmware implementation whether it'll work. There's no blanket proscription using GPT on BIOS computers, I have an old Dell Latitude laptop that permits booting with GPT partitioned drives.
>> 
>> But there are enough firmwares out there that crater when encountering some aspect of GPT partitions, that on BIOS computers, the Fedora installer doesn't use GPT by default unless the drive is larger than ~2.2TB.
>> 
>>>    From experience I have also found that you can't install the windows system partition on a GPT device and I thought I read somewhere that you also can't put Linux /boot on GPT either.
>> The first part is true, the second part is not true. Windows' installer will only install and boot from GPT drives on UEFI computers, and boot from MBR drives on BIOS computers.
> I'm probably a bit off topic here but Win 8 would not install on my machine onto a GPT device with UEFI enabled in the bios. I had to finish up configuring the partition on the 2TB hard disk with a DOS partition and also turn off UEFI because I could not boot my system because UEFI did not support my Nvidia GTX 650 graphics card.

It's not off topic but the vernacular is incorrect, no doubt due to manufacturers who have been using it incorrectly. Many of them continue to refer to firmware updates for UEFI based firmwares as BIOS updates.

If you have UEFI firmware you do not have a BIOS firmware. If you have BIOS firmware you don't have UEFI firmware. If you have UEFI firmware you can't enable or disable it, although some manufacturers have used this UI convention to indicate whether a UEFI Compatibility Support Module is to be used. The CSM presents an (emulated) BIOS interface to an OS, and it's there for legacy OS support for OS's like Windows XP which have no idea what UEFI is or how to talk to it.

The fact your firmware with UEFI "enabled" (CSM disabled) caused Windows 8 install failure with a GPT is a bug either in the Windows 8 installer, or with the firmware. If you have already confirmed that you have the latest firmware applied to your hardware, I'd take my case to their support service because there's no good reason why you should have to install Windows 8 with a compatibility module enabled.


Chris Murphy