GUID Partition Table (GPT) is a modern disk partitioning scheme that serves as an alternative to the legacy Master Boot Record (MBR) partitioning scheme. GPT is designed to work with the Unified Extensible Firmware Interface (UEFI) but can also be used with legacy BIOS systems in some scenarios. The GPT partitioning scheme provides several advantages over MBR:
- Larger Disks: GPT supports disks larger than 2 terabytes (TB), whereas MBR is limited to 2 TB.
- More Partitions: While MBR supports a maximum of four primary partitions (or three primary and one extended partition, which can contain multiple logical partitions), GPT supports up to 128 partitions by default in Windows. Other systems can potentially support more.
- Partition and Disk IDs: GPT uses Globally Unique Identifiers (GUIDs) for both the disk and individual partitions. This ensures a unique identifier for each partition and disk.
- Robustness: GPT includes a protective MBR, and the GPT header contains both a primary and a backup copy. This redundancy improves the chances of data recovery if the partitioning data gets damaged.
- CRC32 Checksums: GPT uses CRC32 checksums to verify the integrity of the partition table, which can help detect if the data has been tampered with or corrupted.
- Compatibility with UEFI: GPT is the standard partitioning scheme for UEFI-based systems. While UEFI systems can boot from MBR disks in a legacy mode, native UEFI booting requires GPT.
- Well-defined Structure: GPT has a clear specification, which reduces ambiguities present in MBR’s definition.
When setting up a new disk on a modern PC, especially those booting with UEFI, GPT is the recommended choice for partitioning. However, for older hardware or systems that need to ensure compatibility across a broad range of devices, MBR might still be appropriate. Transitioning from MBR to GPT or vice versa often requires repartitioning the disk and reformatting, so it’s essential to back up data before making such changes.