Guid Partition Table

In computer hardware, GUID Partition Table is a standard for the layout of the partition table on a physical hard disk. Although it forms a part of the Extensible Firmware Interface standard, it is also used on some BIOS systems because of the limitations of MBR partition tables, which restrict maximum disk size to 2 TiB. Windows XP and earlier Windows systems cannot read or write to drives formatted with a GUID partition table, however, Vista and Windows 7 include this capability.