The GUID Partition Table (GPT) replaces the previous master boot record (MBR). GPT partitions can hold 18 exabytes compared to 2.2TB for the MBR.

The GPT partition type, part of the Unified Extensible Firmware Interface (UEFI) initiative, is a modern disk partitioning method. Unlike the older MBR scheme, GPT offers greater flexibility and ...

Note that this command works only on Intel Macs with hard disks formatted using the GPT (GUID Partition Table) format with a journaled Hierarchical File System Plus (HFS+) file system.

For example, the maximum partition size of an MBR disk that's formatted with a 512-byte unit allocation size is a measly 2 TB compared to the 9.3 ZB (over 9 billion TB) that GPT disks allow.