Acronym for GUID partition table
Computers with an Intel Itanium processor use the Extensible Firmware Interface (EFI) between firmware, hardware, and OS. EFI has a new type of disk partitioning system, called the GUID (globally unique identifier) partition table (GPT). Unlike Master Boot Record (MBR) partitioned disks, data critical to platform operation is located in partitions instead of unpartitioned or hidden sectors. GPT partitioned disks have redundant primary and backup partition tables for improved partition data structure integrity.