Format of hard disk master boot sector:
Offset  Size  Description  (Table 0435)
 00h 446 BYTEs  Master bootstrap loader code
1BEh 16 BYTEs  partition record for partition 1 (see #0436)
1CEh 16 BYTEs  partition record for partition 2
1DEh 16 BYTEs  partition record for partition 3
1EEh 16 BYTEs  partition record for partition 4
1FEh  WORD  signature, AA55h indicates valid boot block

Format of partition record:
Offset  Size  Description  (Table 0436)
 00h  BYTE  boot indicator (80h = active partition)
 01h  BYTE  partition start head
 02h  BYTE  partition start sector (bits 0-5)
 03h  BYTE  partition start track (bits 8,9 in bits 6,7 of sector)
 04h  BYTE  operating system indicator (see #0437)
 05h  BYTE  partition end head
 06h  BYTE  partition end sector (bits 0-5)
 07h  BYTE  partition end track (bits 8,9 in bits 6,7 of sector)
 08h  DWORD  sectors preceding partition
 0Ch  DWORD  length of partition in sectors

(Table 0437)
Values for operating system indicator:
 00h  empty
 01h  DOS 12-bit FAT
 02h  XENIX root file system
 03h  XENIX /usr file system (obsolete)
 04h  DOS 16-bit FAT
 05h  DOS 3.3+ extended partition
 06h  DOS 3.31+ Large File System
 07h  QNX
 07h  OS/2 HPFS
 07h  Advanced Unix
 08h  AIX bootable partition, SplitDrive
 09h  AIX data partition
 09h  Coherent filesystem
 0Ah  OS/2 Boot Manager
 0Ah  OPUS
 0Ah  Coherent swap partition
 10h  OPUS
 18h  AST special Windows swap file
 24h  NEC MS-DOS 3.x
 40h  VENIX 80286
 50h  Disk Manager, read-only partition
 51h  Disk Manager, read/write partition
 51h  Novell???
 52h  CP/M
 52h  Microport System V/386
 56h  GoldenBow VFeature
 61h  SpeedStor
 63h  Unix SysV/386, 386/ix
 63h  Mach, MtXinu BSD 4.3 on Mach
 63h  GNU HURD
 64h  Novell NetWare
 65h  Novell NetWare (3.11)
 70h  DiskSecure Multi-Boot
 75h  PC/IX
 80h  Minix v1.1 - 1.4a
 81h  Minix v1.4b+
 81h  Linux
 81h  Mitac Advanced Disk Manager
 82h  Linux Swap partition
 83h  Linux native file system (ext2fs/xiafs)
 84h  OS/2-renumbered type 04h partition (related to hiding DOS C: drive)
 93h  Amoeba file system
 94h  Amoeba bad block table
 B7h  BSDI file system (secondarily swap)
 B8h  BSDI swap partition (secondarily file system)
 C1h  DR-DOS 6.0 LOGIN.EXE-secured 12-bit FAT partition
 C4h  DR-DOS 6.0 LOGIN.EXE-secured 16-bit FAT partition
 C6h  DR-DOS 6.0 LOGIN.EXE-secured Huge partition
 DBh  CP/M, Concurrent CP/M, Concurrent DOS
 DBh  CTOS (Convergent Technologies OS)
 E1h  SpeedStor 12-bit FAT extended partition
 E4h  SpeedStor 16-bit FAT extended partition
 F2h  DOS 3.3+ secondary
 FEh  LANstep
 FFh  Xenix bad block table

 
