Master Boot Record
 
The Master Boot Record is located at the physical beginning of a hard disk, editable using the
Disk Editor. It  consists  of a  master  bootstrap loader  code (446 bytes) and  four subsequent,
identically structured partition records. Finally, the hexadecimal signature 55AA completes a valid
Master Boot Record.
 
 
硬盘的主引导记录在硬盘的0磁头 0 柱面1 扇区。
主引导记录由三部分组成：
(1)主引导程序；
(2)四个分区表；
(3)主引导记录有效标志字。
详见表1。
[表1主引导记录结构]
 
 位    置  内    容 
0000H －00D9H  主引导记录代码区 
00DAH －01BDH  空闲区 
01BEH  －01CDH  分区 1 结构信息 
01CEH  －01DDH  分区 2 结构信息 
01DEH －01EDH  分区 3 结构信息 
01EEH －01FDH  分区 4 结构信息 
01FEH  －01FFH  55 AAH 主 引 导 记 录 有 效 标 志 
 说明:
A,分区表自偏移 1BEH 处开始，分区表共 64 个字节，表中可填入四个分区信息，每十六
个字节为一个分区说明项，这16个字节含义详见表 2。
B,必须注意：扇区号的高二位占用柱面号所在字节的最高二位，即柱面号为 10 位，扇区
号6位。

Offset  Size Description
0    8 bit A value of 80 designates an active partition.
 
1    8 bit Partition start head
2    8 bit Partition start sector (bits 0-5)
3    8 bit Partition start track (bits 8,9 in bits 6,7 of sector)
4    8 bit Operating system indicator
5    8 bit Partition end head
 4

6    8 bit Partition end sector (bits 0-5)
7    8 bit Partition end track (bits 8,9 in bits 6,7 of sector)
8    32 bit  Sectors preceding partition
C    32 bit  Length of partition in sectors
 
Operating system indicators: (hexadecimal, incomplete list)
00  Empty partition-table entry
01  DOS FAT12
04  DOS FAT16 (up to 32 MB)
05  DOS 3.3+ extended partition
06  DOS 3.31+ FAT16 (over 32 MB)
07  OS/2 HPFS, Windows NT NTFS, Advanced Unix
08  OS/2 v1.0-1.3, AIX bootable partition, SplitDrive
09  AIX data partition
0A  OS/2 Boot Manager
0B  Windows 95+ FAT32
0C  Windows 95+ FAT32 (using LBA-mode INT 13 extensions)
0E  DOS FAT16 (over 32 MB, using INT 13 extensions)
0F  Extended partition (using INT 13 extensions)
17  Hidden NTFS partition
 
1B  Hidden Windows 95 FAT32 partition
1C  Hidden Windows 95 FAT32 partition (using LBA-mode INT 13 extensions)
1E  Hidden LBA VFAT partition
42  Dynamic disk volume
50  OnTrack Disk Manager, read-only partition
51  OnTrack Disk Manager, read/write partition
81  Linux
82  Linux Swap partition, Solaris (Unix)
83  Linux native file system (ext2fs/xiafs)
85  Linux EXT
86  FAT16 volume/stripe set (Windows NT)
87  HPFS fault-tolerant mirrored partition, NTFS volume/stripe set
BE  Solaris boot partition
C0  DR-DOS/Novell DOS secured partition
C6  Corrupted FAT16 volume/stripe set (Windows NT)
C7  Corrupted NTFS volume/stripe set
F2  DOS 3.3+ secondary partition