It is a framework of disk partition based on Expandable Firmware Interface (EFI) in Itanium. Compared with Master Boot Record (MBR), GPT has more advantages. It permits every disk having up to 128 partitions and supports maximum volume of 18KM bytes. And primary disk partition table and backup of disk partition table can be used in redundancy. In addition, it also supports sole disk and partition ID (GUID)
Comparison of GPT and MBR
Features of GPT
GPT can not be transfered to computer based on x86 running Windows NT 4.0, Windows 2000, Windows XP or Windows Server 2003. However, GPT disk can be transfered from computer based on x64 or computer based on x86 running Windows Server 2003 with SP1 to computer based on Itanium running Windows Server 2003 or Windows XP, or vice versa.
The Windows edition based on Itanium can not be applied to transfer GPT disk from computer based on Itnium to computer based on x64 or computer based on x86 running Windows 2003 with SP1 and to start he operating system. In the computer based on non-Itanium, GPT disk must be applied only for data storage.
MBR disk and GPT disk can coexist in single group of dynamic disks. And basic GPT and MBR disks can be mixed to use but they are not a part of the disk group.. MBR and GPT disks can simultaneously be applied to build mirrored volume, stripped volume, spanned volume and RAID 5 volume. But the limits of Cylinder alignment make it difficult to build mirrored volume. The MBR disk can be mirrored to GPT disk to avoid cylinder alignment.Disadvantages of GPTMBR disk can be transfered into GPT disksand only the disk is empty, can GPT disk be transfered into MBR disk. Of course, the third-party tools must be used. And MiniTool Partition Wizard is recommended. It can easily exchange disk types of MBR and GPT. More help informations are provided in How to initialize disk to GPT disk or MBR disk?
GPT is not in support of mirror of EFI system partition. The command bootcfg must be applied to copy EFI system partition.
GPT partition type can not be applied in removable media or cluster disk connected to Fibre Channel trunk or sharing SCSI applied in cluster service.
The command DiskPart.exe can be applied to run utility program or EFI program (Diskpart.efi ) to built partitions in basic GPT disk.
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