MBR (Master Boot Record)

What is the MBR?
At the end of the ROM BIOS bootstrap routine, the BIOS reads and executes the first physical sector of the first floppy or hard disk on the system. This first sector of the hard disk is called the master boot record (or sometimes the partition table or master boot block). There is a small program at the beginning of this sector of the hard disk. The partition information, or partition table, is stored at the end of this sector. This program uses the partition information to determine which partition is bootable (usually the first primary DOS partition) and attempts to boot from it. 



Master Boot Record (MBR) or Boot Key Notes Intel x86 systems and x86-64 is the name for Sector file system.
The partition table that lists any partitions contained in the hard disk in question.
At the time of the boot process, the Master Boot Record has the following tasks
Looking for an active partition (which can make the boot process) in the partition table.
Finding the first sector of the active partition to get the boot sector of partition.
Load a copy of the boot sector of the active partition into memory.
Give further control to the executable code in the boot sector.

The Master Boot Record (MBR) will be created when you create the first partition on the hard disk. It is very important data structure on the disk. The Master Boot Record contains the Partition Table for the disk and a small amount of executable code for the boot start. The location is always the first sector on the disk.