Understanding partition schemes (1.3.2)

The disk partition is a disk's logical pision so that an operating system can manage data. In general, there are two partition schemes:

• Master Boot Record (MBR): This is an old partition scheme known today as a legacy boot option. It operates on a 512-byte disk sector with a maximum of four primary partitions, or three primary partitions and one extended partition. An extended partition can have up to 26 logical partitions. The MBR uses logical block addressing (LBA) to support disks up to 2 TB. The MBR, in the past and currently, has proven to be a very useful partition scheme for multiboot platforms.
• GUID Partition Table (GPT): This coexists with the MBR and is a new partition scheme that overcomes the limitations of the MBR. The globally unique identifier (GUID) in a GPT is a 128-bit number that Microsoft uses to identify resources. In a GPT, block sizes from 512 bytes and up are supported, where the most common default these days is 4K or 4,096 bytes, and the size of the partition entry is 128 bytes. The GPT is part of the Unified Extensible Firmware Interface (UEFI) standard that replaces the old basic input/output system (BIOS) to support modern hardware. By its nature, the GPT is fault tolerant and supports up to 18 EB disk storage, and up to 128 partitions on each disk.