GPT, an acronym for GUID Partition Table, is likely something you've never heard of before. Perhaps that's a good thing. Throughout my usage of GPT, I've come to see that it's a total and complete waste of time.
What is GPT, anyway? Wikipedia defines it as a partition layout standard for a hard disk. They go own to say that "it is a part of the Extensible Firmware Interface (EFI) standard proposed by Intel as a replacement for the outdated PC BIOS, one of the few remaining relics of the original IBM PC."
GPT actually features a number of improvements over the old Master Boot Record (MBR) method of partitioning used with PC BIOS. You might recall that MBR-based partition tables have a limit of 4 primary partitions. The user is then forced to create an extended partition in order to expand the limits. GPT on the other hand, has a limit of by default, 128 primary partitions. And because of this huge amount, Intel thought it was rather pointless to have extended partitions. One other important feature of GPT is that it has two tables: a primary one, and a secondary one, for backup purposes.
Great! So how come everyone isn't using this obvious improvement? Well... let's see. GPT isn't backwards-compatible, therefore PC BIOSes are incapable of booting GPT-enabled disks. And there's actually a very limited range of machines that have EFI, so this is probably the biggest reason why GPT isn't used.
Except for Macs. Apple has decided to use them in all of the Intel Macs. That sounds like an obvious improvement, right? Not. The most important use of a partition is for holding an operating system, correct? That's wonderful, when GPT is so poorly-supported by most operating systems. I'm serious, only a handful of operating systems support them, and Windows is not one of them. So that basically takes away the whole point of GPT, does it not?
Ah, but I forgot something. Intel designed the GPT so that it can exist alongside an MBR partition table. In other words, a special utility called
gptsync can sync the MBR to the GPT, creating backwards compatibility with legacy operating systems. Except there's a catch: remember how it was mentioned that MBR can only support 4 primary partitions? And how GPT doesn't support extended partitions? That's right, you're limited to exactly 4 partitions with a MBR/GPT hybrid partition table. Kind of takes away the point of GPT, doesn't it? To make matters worse, the syncing is a one-way process: you can't edit the MBR and sync the GPT to it. Therefore, changes you make to your partition table must be done with a partition tool that supports GPT. Oh brother.
Some of the readers may be saying, "Ah, but what does it matter? Macs are one of the largest EFI-enabled computers, and how many Mac users edit their partition tables?" I'd like to point out that the people who don't edit their partition tables won't care if it's MBR or GPT anyway. For the ignorant people, GPT won't make an ounce of difference. And it creates nothing but a hinderance for those who actually want to utilize it.
And, let me point out that GPT isn't necessary on EFI-enabled systems. Indeed, EFI systems are just as capable of booting from MBR disks as any regular PC is. Great, Apple, just great. Do as all a favor and stop using this crap from Intel.