GUID Partition Table

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What is a GUID Partition Table (GPT)?

  • The GUID Partition Table is a 512 byte space created on the primary partition of a drive at the first and last sectors of a drive.
  • It stores the partition data in a similar fashion as the MBR
  • GUID stands for globally unique identifier and uniquely stores 128 bit partition signatures to identify partitions.
  • GPT is stronger than a traditional master boot record because it has a checksum at the beginning and end of the drive, so if one copy is corrupted, the disk will rely upon the valid copy and use it to repair the first.
  • GPT also contains a protective master boot record, so that older machines that do not recognize GPT will not overwrite the data on the disk.
  • GPT can format disks of large size (theoretically larger than standard disks currently support) while a master boot record can only format the first 2 terabytes of a drive.
  • GPT supports any number of primary (bootable) partitions on a drive, where MBR limits this to 4, with unlimited logical (nonbootable) partitions.

Applies to

Windows 32 bit (x86) operating systems:

  • Vista, 7, 8, 8.1, 10 can read/write data
  • 8, 8.1, 10 can boot from GPT formatted drives, but require UEFI.

Windows 64 bit (x64) operating systems:

  • XP, Vista, 7, 8, 8.1, 10 can read/write data
  • Vista, 7, 8, 8.1, 10 can boot from GPT formatted drives, but require UEFI.

Linux operating systems:

  • Fedora 8 and above have read/write/boot support.
  • Ubuntu 8.04 and above have read/write/boot support.
  • Tools such as GRUB 2 are GPT-enabled.

See Other

External Links