Definition - What does Master Boot Record (MBR) mean?
The master boot record is a category of boot sector and the very first sector found in computer mass storage media such as fixed disks and removable computer drives. The master boot record provides the information on loading the operating system and also on the partition of the hard disk. The programs residing in master boot record help determine which partition needs to be used while booting. The master boot record is absent on non-partitioned devices such as super floppies, floppies or other devices configured in such a manner.
A master boot record has the following features:
It is always located in the first sector of the hard disk.
Cylinder 0, Head 0, Sector 1 is the specific address of the master boot record on the hard disk.
It holds information about the organization of the partitions and the file system.
A master boot record is generally 512 bytes or more.
With help of the command FDISK or MBR, users can create a master boot record in Dos and Windows systems.
The master boot record is capable of functioning as a chain boot loader independent of the operating system.
The three main components of the master boot record are the master partition table, master boot code and disk signature.
A corrupted master boot record can be repaired in Windows 7 and Windows Vista using the command "bootrec," available in system recovery options. In Windows XP, the command to be used for repairing is "fixmbr."
One of the latest alternatives to to the master boot record is the GUID partition table. It’s a component of the unified extensible firmware interface specification.