MBR and GPT table what are you using?

Source: Internet
Author: User

Since the launch of the Vista operating system in 2007, the major hardware manufacturers for the rapid speed of hardware development, which for the speed and capacity of the hard disk, from the earliest 5400 rpm, 160G capacity, to upgrade to the current 7200 RPM or even the mechanical disk, capacity has also appeared on the TB level. 4Tb capacity appears on a single hard drive.

Because of increasing disk capacity, traditional MBR partition tables (master boot records) have not been able to meet the needs of large-capacity disks. The traditional MBR partition table can only identify about 2.2TB of space on the front of the disk, the extra space can only be wasted, and for Tan Pan 4TB disks, only half of the capacity can be used. As a result, GPT (globally unique identity partition table) is available.

In addition, MBR partitioned tables can only support 4 primary partitions or 3 primary partition +1 extended partitions (which contain arbitrary numbers of logical partitions), while GPT supports up to 128 primary partitions under Windows.

Here's a detailed distinction between MBR and GPT.

MBR partition table:

In traditional hard disk partitioning mode, the boot sector is the first sector of each partition (Partition), and the primary boot sector is the first sector of the hard disk. It consists of three parts, master boot record MBR, hard disk partition table DPT and hard disk valid flag. The MBR occupies 446 bytes in a total of 512 bytes of the primary boot sector, the second part is the partition table area (partitioned tables), that is, DPT, 64 bytes, the number of partitions on the hard disk and the size of each partition are recorded. The third part is magic number, which occupies 2 bytes and is fixed to 55AA.

One sector's hard drive master boot record MBR consists of 4 parts.

• The primary bootstrapper (offset address 0000h--0088h), which is responsible for loading from the active partition and running the system boot program.

• Error information data area, offset address 0089h--00e1h error message, 00E2H--01BDH all 0 bytes.

• The partition table (Dpt,disk Partition table) contains 4 partition entries, the offset address 01BEH--01FDH, each partition table entry is 16 bytes long, a total of 64 bytes is the partition item 1, the partition item 2, the partition item 3, the partition item 4.

• End flag word, offset address 01fe--01ff 2 byte value is end flag 55AA, if the flag error system can not start.

GPT Partition table:

GPT partition information is in the partition, not as MBR in the primary boot sector, in order to protect GPT against MBR-class disk management software, GPT has established a protected partition (protective MBR) MBR partition table (not necessary for this partition) in the primary boot sector. This type of partition is identified as 0xEE, the size of this protection partition under Windows is 128mb,mac OS x 200MB, in the window Disk Manager named GPT Protection Partition, allows MBR class disk management software to consider GPT as an unknown format of the partition, Instead of mistakenly being an unpartitioned disk.

In addition, to protect the partition table, GPT partition information is saved at the head and tail of each partition so that the partition table is recovered after it is lost.

For X86/64 windows that want to boot from a GPT disk, the motherboard's chipset must support UEFI (this is mandatory, but there is no limit to using GPT as a data disk), such as win8/ Win8.1 native support is launched from the UEFI-guided GPT partition table, and most computers pre-installed with WIN8 systems gradually adopt GPT partitioning tables. As to how to determine whether the motherboard chipset supports UEFI, you can generally check the motherboard instructions or the manufacturer's Web site, or you can see if the BIOS settings have uefi words.

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