Structure of MBR,partition File type list.

Structure of a master boot record

Address			Description		Size in
0000	0000	0	code area		440 (max. 446)
01B8	0670	440	disk signature (optional)		4
01BC	0674	444	Usually nulls; 0x0000		2
01BE	0676	446	Table of primary partitions (Four 16-byte entries, IBM partition table scheme)		64
01FE	0776	510	55h	MBR signature; 0xAA55	2
01FF	0777	511	AAh
MBR, total size: 446 + 64 + 2 =512

Offset

Field
length
(bytes)

Description

0x00

1

status (0x80 = bootable (active), 0x00 = non-bootable, other = invalid )

0x01

3

of first absolute sector in partition. The format is described by 3 bytes, see the next 3 rows.

0x01

1

h7-0								head
x	x	x	x	x	x	x	x

0x02

1

c9-8		s5–0						sector is in bits 5–0; bits 9–8 of cylinder are in bits 7–6
x	x	x	x	x	x	x	x

0x03

1

c7-0								bits 7–0 of cylinder
x	x	x	x	x	x	x	x

0x04

1

0x05

3

of last absolute sector in partition. The format is described by 3 bytes, see the next 3 rows.

0x05

1

h7-0								head
x	x	x	x	x	x	x	x

0x06

1

c9-8		s5–0						sector is in bits 5–0, bits 9–8 of cylinder are in bits 7–6
x	x	x	x	x	x	x	x

0x07

1

c7-0								bits 7–0 of cylinder
x	x	x	x	x	x	x	x

0x08

4

of first absolute sector in the partition

0x0C

4

Number of sectors in partition, in little-endian format

Notes:

a Formally, status values other than 0x00 and 0x80 are undefined.

b Starting Sector fields are limited to 1024 cylinders, 255 heads, and 63 sectors;^[] Ending Sector fields have the same limitations.

c The range for sector is 1 through 63; the range for cylinder is 0 through 1023; the range for head is 0 through 254 inclusive.^[]

d The 10-bit cylinder value is split into two bytes. The value can be reassembled using this formula: cylinder = ((byte[2] & 0xc0) << 2) | byte[3]

e Used by OSes only in certain circumstances; in such cases the CHS addresses are ignored.

System ID	Developer	Description
0x00		Empty partition
0x01
0x02	Microsoft &	root
0x03	Microsoft & SCO	XENIX usr
0x04	Microsoft	with less than 65536 sectors (32 MB)
0x05	IBM	with addressing
0x06		with 65536 or more sectors
0x07	Microsoft	or or
0x08	IBM
0x09	IBM	AIX bootable
0x0A	Microsoft & IBM	Boot Manager
0x0B	Microsoft	with addressing
0x0C	Microsoft	with
0x0E	Microsoft	with
0x0F	Microsoft	with
0x11	Microsoft	Hidden FAT12
0x12	Compaq	Compaq diagnostics () or another OEM partition[2]
0x14	Microsoft	Hidden FAT16
0x17	Microsoft	Hidden HPFS or hidden NTFS
0x1B	Microsoft	Hidden FAT32
0x1C	Microsoft	Hidden FAT32 with LBA
0x1D	Microsoft	Hidden FAT16 with LBA
0x27		Windows recovery partition (hidden )
0x64		286
0x65		386
0x78	Geurt Vos	bootloader filesystem[]
0x80		Old file system
0x81
0x82	or	or
0x83	GNU/Linux	Any native
0x84	Microsoft	Hibernation (suspend to disk, S2D)[2]
0x85	GNU/Linux	Linux
0x86	Microsoft	Legacy FT FAT16
0x87	Microsoft	Legacy FT NTFS
0x88	GNU/Linux	Linux plaintext
0x89	GNU/Linux
0x8B	Microsoft	Legacy FT FAT32
0x8C	Microsoft	Legacy FT FAT32 with LBA
0xA0		Diagnostic partition for HP laptops[2]
0xA5
0xDE		Dell diagnostic partition[2]
0xEB		( or )
0xEE		protective
0xEF		can be a file system
0xFB		VMware VMFS
0xFC		VMware VMKCORE
0xFD	GNU/Linux	Linux auto
0xFE		IBM IML partition[2]

This is not an exhaustive list, notably ambiguous or obscure partition types are not covered.