GPT, or GUID Partition Table, is an alternative to MBR for defining the partition layout on a hard drive. GPT was introduced as part of the UEFI specification, which is a modern replacement for the BIOS firmware that is used to boot up a computer.
What is GPT?
GPT is a partitioning scheme that is designed to overcome the limitations of MBR. GPT uses a globally unique identifier (GUID) to identify each partition on the hard drive. GPT partitions can be up to 9.4 zettabytes in size, compared to the 2.2 terabyte limit of MBR partitions.
GPT also includes a backup partition table, which is stored at the end of the hard drive. This backup partition table can be used to recover the partition layout if the primary partition table becomes corrupted.
Functions of GPT
GPT has several functions that make it a powerful and flexible partitioning scheme:
Increased partition size
As mentioned earlier, GPT partitions can be much larger than MBR partitions. This makes GPT ideal for use with large hard drives and storage systems.
Multiple partition types
GPT supports multiple partition types, including primary, secondary, and logical partitions. This makes it possible to define complex partition layouts that can include multiple operating systems or data storage areas.
Secure boot
GPT is also used in combination with UEFI firmware to support secure booting of operating systems. Secure boot is a feature that helps prevent the loading of unauthorized or malicious software during the boot process.
Compatibility
Although GPT was designed to be used with UEFI firmware, it is also compatible with older BIOS systems. This means that GPT can be used on most modern computer systems.
Differences between GPT and MBR
There are several key differences between GPT and MBR:
Partition size
As mentioned earlier, GPT supports much larger partition sizes than MBR. This is due to the use of 64-bit disk addresses in GPT, compared to the 32-bit addresses used in MBR.
Number of partitions
GPT also supports a much larger number of partitions than MBR. GPT can support up to 128 partitions, compared to the four primary partitions that MBR can support.
Backup partition table
GPT includes a backup partition table, which is stored at the end of the hard drive. This provides an additional layer of protection against partition table corruption, which can be a significant problem with MBR.
Compatibility
Although GPT is compatible with most modern computer systems, older systems may not support GPT. This means that it may be necessary to use MBR on older systems.
Conclusion
In conclusion, GPT is a powerful and flexible partitioning scheme that is designed to overcome the limitations of MBR. GPT supports larger partition sizes, a larger number of partitions, and includes a backup partition table for improved reliability. While GPT is compatible with most modern computer systems, it may not be compatible with older systems, which may require the use of MBR.