Acronym for GUID Partition Table
GPT was introduced for iA64 systems, to get around a fixed 32 bit issue (2 to the power of 32 is 4 billion times a 512 byte block equals 2 Terabytes) in the PC-BIOS Partition table. Partitions larger than 2 TB require using a GPT disklabel, which differs from the PC-BIOS Partition table in a number of ways:
Most partitioning tools under Linux will fail to do anything sensible with a > 2 TB Partition. As of this writing (June 22, 2005), parted(8) is the only one that understands them and will let you set the GPT label on the disk.
There is a lot of information stating that you cannot boot off a GPT enabled device. Most of the claims imply that the fault is with LILO or GRUB not understanding GPT devices. We've not tested this, but GPT and traditional MBRs will coexist.