Master Boot Record(MBR)

Master Boot Record/MBR is a type of boot sector popularized by the IBM personal computer.it consists of sequence of 512 byte located at the first sector of a data storage device such as a hard disk.MBRs are usually placed on storage devices such as a hard disk.MBRs are usually placed on storage devices intended for use with IBM PC-compatible systems.

the MBR may be used for one or more of the following:

holding a partition table which describes the partitions of a storage device,in this context the boot sector may also be called a partition sector.

• Bootstrapping an operating system. The BIOS built into a PC-compatible computer loads the MBR from the storage device and passes execution to machine code instructions at the beginning of the MBR.
• Uniquely identifying individual disk media, with a 32-bit disk signature, even though it may never be used by the operating system.

Because of the broad popularity of PC-compatible computers, the MBR format is widely used, to the extent of being supported by computer operating systems in addition to other pre-existing or cross platform standards for bootstrapping and partitioning.

Disk Partition

IBM PC-DOS introduced the conventional IBM PC(fdisk) partitioning scheme, which took advantage of the space reserved for the master boot record. When a storage device has been partitioned with this scheme, its MBR contains a partition table describing the locations, sizes, and other attributes of linear regions referred to as partitions.

The partitions themselves may also contain data to describe more complex partitioning schemes, such as extended boot records(EBRs), BSD disklabels or Logical Disk Manager metadata partitions

a schema from Mster boot record or hardisk :