Boot sector

A boot sector is usually the first sector of a bootable medium. It contains information or a program that is necessary to start the operating system, or even the operating system. It can also be involved further subsequent sectors ( data blocks).

Use of the term

The term boot sector (English boot sector or boot sector ) usually describes a launcher that was used on the most common computer architectures at the beginning of the era of the personal computer to start the actual operating system. Here, a small program is executed, which is intended to start the kernel. Due to rapid advancement in the field of operating systems, however, this principle is pushed to its limits. While IBM PCs to integrate the concept through complicated chain loader enhanced by new features, the firmware has been at the Macintosh, Apple developed further so that it reads the relevant information to start the operating system from the boot sector and the driver or the kernel loads directly.

On, like many other external storage media that are PC - and Windows - compatible, a " Master Boot Record" (MBR ) is located in the boot sector. The partition table contained therein is supported by all major operating systems, which provides access to the individual partitions. Strictly speaking, but also have eg car radio or MP3 player, audio files, for example, a USB stick can play, can deal with such a boot sector.

Since the replacement of the BIOS with UEFI boot sector is no longer used in the IA- 32 architecture directly to start the operating system, even though he, for reasons of compatibility is still a partition table including launcher (MBR, see also "protective MBR " ) contains, but which are no longer used.

Common boot sectors

IBM PC compatible computer ( x86):

  • Master boot record is the first sector on the hard drive or other partitions are
  • Volume Boot Record, also called Partition Boot Record, from the first sector on the partition (for non- partitioned media such as floppy disks, the only boot sector )

Apple Macintosh ( m68k and PowerPC):

  • Boot block (mainly on floppy disks )
  • Driver Descriptor Map

Amiga ( m68k and PowerPC):

  • Rigid Disk Block (RDB )

Pictures of Boot sector

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