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Appendix E. An Introduction to Disk Partitions

As Figure E 5, shows, the partition table is divided into four sections. Each section can hold the

information necessary to define a single partition, meaning that the partition table can define no more

than four partitions.

Each partition table entry contains several important characteristics of the partition:

The points on the disk where the partition starts and ends

Whether the partition is "active"

The partition's type

Let us take a closer look at each of these characteristics. The starting and ending points actually define

the partition's size and location on the disk. The "active" flag is used by some operating systems' boot

loaders. In other words, the operating system in the partition that is marked "active" will be booted.

The partition's type can be a bit confusing. The type is a number that identifies the partition's antic 

ipated usage. If that statement sounds a bit vague, that is because the meaning of the partition type

is a bit vague. Some operating systems use the partition type to denote a specific file system type, to

flag the partition as being associated with a particular operating system, to indicate that the partition

contains a bootable operating system, or some combination of the three.

Table E 1, contains a listing of some popular (and obscure) partition types, along with their numeric

values.

Partition Type

Value

Partition Type

Value

Empty

00

Novell Netware 386

65

DOS 12 bit FAT

01

PIC/IX

75

XENIX root

02

Old MINIX

80

XENIX usr

03

Linux/MINUX

81

DOS 16 bit

=32M

04

Linux swap

82

Extended

05

Linux native

83

DOS 16 bit

=32

06

Linux extended

85

OS/2 HPFS

07

Amoeba

93

AIX

08

Amoeba BBT

94

AIX bootable

09

BSD/386

a5

OS/2 Boot Manager

0a

OpenBSD

a6

Win95 FAT32

0b

NEXTSTEP

a7

Win95 FAT32 (LBA)

0c

BSDI fs

b7

Win95 FAT16 (LBA)

0e

BSDI swap

b8

Win95 Extended (LBA)

0f

Syrinx

c7

Venix 80286

40

CP/M

db

Novell

51

DOS access

e1

Microport

52

DOS R/O

e3

GNU HURD

63

DOS secondary

f2

Novell Netware 286

64

BBT

ff