What is mbr?

MBR is the master boot record, the full name is Main Boot Record, which is a piece of boot (Loader) code located at the front of the disk. It is responsible for determining the legality of partitions and locating partition boot information when the disk operating system (DOS) reads and writes the disk. It is generated by the disk operating system (DOS) when initializing the hard disk.

Usually, we call the sector containing the MBR boot code the main boot sector. Because the boot code occupies most of the space in this sector, it is customary to call this sector the MBR sector (MBR for short). Since this sector assumes special management functions that are different from other ordinary storage spaces on the disk, as a special space that manages the entire disk space, it does not belong to any partition on the disk, so the formatting command in the partition space cannot clear the main disk space. Any information logged by the boot.

The master boot sector consists of three parts (occupies 512 bytes in total):

1. The master boot program is the master boot record (MBR) (occupies 446 bytes)

Can be found in the FDISK program, which is used to transfer system control to an operating system specified by the user and registered in the partition table when the hard disk is started.

2. Disk Partition Table (DPT, Disk Partition Table)

consists of four partition table entries (16 bytes each).

is responsible for describing the partition situation on the disk. Its content is determined by the disk media and the user when using FDISK to define the partition. (Details omitted)

3. End flag (occupies 2 bytes)

The value is AA55. When stored, the low bit is in front and the high bit is in the back, that is, it looks like 55AA (ten hexadecimal).

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