GPT & MBR partition
Posted: Sat Feb 07, 2015 10:01 amMBR (Master Boot Record) and GPT (GUID Partition Table) are two different ways of storing the partitioning information on a drive. This information includes where partitions start and begin, so your operating system knows which sectors belong to each partition and which partition is bootable.GPT is meant as a replacement to hard drives using a MBR partition table It is a part of the Extensible Firmware Interface (EFI) standard proposed by Intel as a replacement for the outdated PC BIOS. Mac OS X, Linux, Windows and other operating systems can use GPT. Some, including OS X and Microsoft Windows on x86, only support booting from GPT partitions on systems with EFI firmware, but FreeBSD and most Linux distributions can boot from GPT partitions on systems with either legacy BIOS firmware interface or EFI.GPT replaces the clunky old MBR partitioning system with something more modern. It’s called GUID Partition table because every partition on your drive has a “globally unique identifier,” or GUID — a random string so long that every GPT partition on earth likely has its own unique identifier.
MBR only supports up to four primary partitions — if you want more, you have to make one of your primary partitions an “extended partition” and create logical partitions inside it.GPT doesn’t have MBR’s limits. Drives can be much, much larger and size limits will depend on the operating system and its file systems. With GPT, you can create theoretically unlimited partitions on the hard disk, even though it is generally restricted to 128 partitions by most OSes system. On an MBR disk, the partitioning and boot data is stored in one place. If this data is overwritten or corrupted, you’re in trouble. In contrast, GPT stores multiple copies of this data across the disk, so it’s much more robust and can recover if the data is corrupted. Unlike MBR that limits each partition to only 2TB in size, each partition in GPT can hold up to 2^64 blocks in length (as it is using 64-bit), which is equivalent to 9.44ZB for a 512-byte block (1 ZB is 1 billion terabytes).
MBR only supports up to four primary partitions — if you want more, you have to make one of your primary partitions an “extended partition” and create logical partitions inside it.GPT doesn’t have MBR’s limits. Drives can be much, much larger and size limits will depend on the operating system and its file systems. With GPT, you can create theoretically unlimited partitions on the hard disk, even though it is generally restricted to 128 partitions by most OSes system. On an MBR disk, the partitioning and boot data is stored in one place. If this data is overwritten or corrupted, you’re in trouble. In contrast, GPT stores multiple copies of this data across the disk, so it’s much more robust and can recover if the data is corrupted. Unlike MBR that limits each partition to only 2TB in size, each partition in GPT can hold up to 2^64 blocks in length (as it is using 64-bit), which is equivalent to 9.44ZB for a 512-byte block (1 ZB is 1 billion terabytes).