Storage devices
Types of HDD
Partition Series
Linux
Operating Systems
Windows
Master Boot Record (MBR)
- The main window of the program in the view as Partition table mode is shown below. As you can see the disk is empty and contains no partitions.
On screens above you can see that all fields for displaying information about disk partitions are empty and contain only zeroes. No hard disk sectors allocated for partitions yet that completely correspond to the picture above: hard disk space is completely free (Unallocated).
As a hard disk can contain only 4 primary partitions, 4 lines on the screen are allocated for information about partitions. A hard disk partition is characterized by the following parameters:
• Type, for example, FAT16/32, NTFS, etc
• Boot patch flag - whether partition is bootable or not
• Begin partition cylinder
• Begin partition head
• Begin partition sector
• End partition cylinder
• End partition head
• End partition sector
• Number of hard disk sectors allocated for partition
Hard disk partitions are described in the Partition table in two ways simultaneously: (1) in CHS co-ordinates (Cylinder - Head - Sector; limited and obsolete variant) - coordinates of initial and end partition sectors, and (2) partition heading and its length in sectors.
Each record of the Partition table contains a so-called partition boot patch flag indicating the main loader what partition to boot. The boot patch flag can be assigned to one partition only.
At the lowest (byte) level MBR structure containing the master boot record and the Partition table can be described as follows:
• Bytes 000h - 1BDh - load code of active partition's bootsector
• Bytes 1BEh - 1CDh, 1CEh - 1DDh, 1DEh - 1EDh, 1EEh - 1FDh - partition records
• Bytes 1FEh - 1FF - Partition Table signature equal to AA55h