GPT stands for GUID Partition Table. It is made to replace MBR partitioning.
|LBA 0||Protective Master Boot Record (PMBR). Holds a partition pointing to GPT to avoid accidental overwrite by old programs.|
|LBA 1||partition header, can be identified by 8 bytes magic "EFI PART" (45h 46h 49h 20h 50h 41h 52h 54h)|
|LBA 2..33||partition table entires|
|...data on disk...|
|LBA -33..-2||mirror of partition table|
|LBA -1||mirror of partition header on last addressable sector|
The following utilities can handle GPT:
- parted, gparted, gdisk on Linux
- diskutil on MacOSX
- diskpart on Windows (Vista and upwards)
- gpt on MacOSX and BSDs.
EFI firmware is capable of booting from a specific GPT partition, EFI System Partition which is basically a FAT32 partition. It should contain a slightly modified PE-executable, like ELILO. On old machines with legacy BIOS only you can use GRUB, or you can write a custom boot code.