MBR vs. UEFI
In earlier times, there was only one way to boot a PC-compatible computer. All of our desktops and servers had standard firmware called the "PC BIOS," all our hard drives used Master Boot Records at the beginning of the disk, where the PC BIOS would "look" to find boot loader code which would in turn load Linux, and our hard drives were partitioned into different regions using the standard MBR partition scheme. That was just how it was done. And we liked it that way!
Then, along came EFI and UEFI, which are new-style firmware designed to boot systems, along with GPT partition tables to define disk partitions on disks larger than 2.2TB. All of the sudden, we had a variety of options for installing and booting Linux systems, turning what once was a one-method-fits-all approach into something a lot more complex.
Let's take a moment to review the options available to you for configuring a hard drive to boot Funtoo Linux. This Install Guide uses, and recommends, the old-school method of BIOS booting and using an MBR. It works and (except for rare cases) is universally supported. There's nothing wrong with it. If your system disk is 2TB or smaller in size, it won't prevent you from using all of your disk's capacity, either.
But, there are some situations where the old-school method isn't optimal. If you have a system disk >2TB in size, then MBR partitions won't allow you to access all your storage. So that's one reason. Another reason is that there are some so-called "PC" systems out there that don't support BIOS booting anymore, and force you to use UEFI to boot. So, out of compassion for people who fall into this predicament, this Install Guide documents UEFI booting too.
Our recommendation is still to go old-school unless you have reason not to. The boot loader we will be using to load the Linux kernel in this guide is called GRUB, so we call this method the BIOS + GRUB (MBR) method. It's the traditional method of setting up a PC-compatible system to boot Linux.
If you need to use UEFI to boot, we recommend not using the MBR at all for booting, as some systems support this, but others don't. Instead, we recommend using UEFI to boot GRUB, which in turn will load Linux. We refer to this method as the UEFI + GRUB (GPT) method.
And yes, there are even more methods, some of which are documented on the Boot Methods page. We used to recommend a BIOS + GRUB (GPT) method but it is not consistently supported across a wide variety of hardware.
Which to Use?
The big question is -- which boot method should you use? Here's how to tell.
- Principle 1 - Old School
- If you can reliably boot System Rescue CD and it shows you an initial light blue menu, you are booting the CD using the BIOS, and it's likely that you can thus boot Funtoo Linux using the BIOS. So, go old-school and use BIOS booting, unless you have some reason to use UEFI, such as having a >2.2TB system disk. In that case, see Principle 2, as your system may also support UEFI booting.
- Principle 2 - New School
- If you can reliably boot System Rescue CD and it shows you an initial black and white menu -- congratulations, your system is configured to support UEFI booting. This means that you are ready to install Funtoo Linux to boot via UEFI. Your system may still support BIOS booting, but just be trying UEFI first. You can poke around in your BIOS boot configuration and play with this.
Advanced Users May Wonder: What's the Big Difference between Old School and New School?: Here's the deal. If you go with old-school MBR partitions, your
/boot partition will be an ext2 filesystem, and you'll use
fdisk to create your MBR partitions. If you go with new-school GPT partitions and UEFI booting, your
/boot partition will be a vfat filesystem, because this is what UEFI is able to read, and you will use
gdisk to create your GPT partitions. And you'll install GRUB a bit differently. That's about all it comes down to, in case you were curious.
To install Funtoo Linux to boot via the New School UEFI method, you must boot System Rescue CD using UEFI. If you successfully boot sysresccd with UEFI, you will see an initial black and white screen to select the mode in which you will boot system rescue cd. Otherwise, if you see a blue screen with black text, UEFI will not be active and you will not be able to set up UEFI booting later in the install process!
Some motherboards may appear to support UEFI, but don't. Do your research. For example, the Award BIOS in my Gigabyte GA-990FXA-UD7 rev 1.1 has an option to enable UEFI boot for CD/DVD. This is not sufficient for enabling UEFI boot for hard drives and installing Funtoo Linux. UEFI must be supported for both removable media (so you can boot System Rescue CD using UEFI) as well as fixed media (so you can boot your new Funtoo Linux installation.) It turns out that later revisions of this board (rev 3.0) have a new BIOS that fully supports UEFI boot. This may point to a third principle -- know thy hardware.