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1. List of partition identifiers for PCs

Below a list of the known partition IDs (system indicators) of the various operating systems, file systems, boot managers, etc. For the various systems, short descriptions are given, in the cases where I have some info. There seem to be two other major such lists: Ralf Brown's (see interrupt list under Int 19) and Hale Landis' but the present one is more correct and more complete. (However, these two URLs are a valuable source for other information.) See also the Powerquest table and the specification for DOS-type partition tables.

Copyright (C) Andries E. Brouwer 1995-2002. Link to this list - do not copy it. It is being updated regularly. Additions, corrections, explanations are welcome. (Mail to

Some systems use systematic ways of modifying partition IDs. The best known type of modification is ORing with 0x10 to `hide' a partition. Some discussion of that below.

Some partition IDs imply a particular method of disk access. In particular, IDs c,e,f (the LBA versions of b,6,5) go with partition table entries that have C/H/S = 1023/255/63 and expect access via the extended INT-13 functions (AH=4x) of the BIOS.

ID Name

0 Empty

To be precise: this is not used to designate unused area on the disk, but marks an unused partition table entry. (All other fields should be zero as well.) Unused area is not designated. Plan9 assumes that it can use everything not claimed for other systems in the partition table.

1 DOS 12-bit FAT

DOS is a family of single-user operating systems for PCs. 86-DOS (`QDOS' - Quick and Dirty OS) was a CP/M-like operating system written by Tim Paterson of Seattle Computer Products (1979). Microsoft bought it, renamed it to MS-DOS 1.0 and sold it to IBM (1980) to be delivered together with the first IBM PCs (1981). MS-DOS 2.0 (1983) was rather different, and designed to be somewhat Unix-like. It supported a hard disk (up to 16MB; up to 32MB for version 2.1). Version 3.3+ added the concept of partitions, where each partition is at most 32MB. (Compaq DOS 3.31 relaxed this restriction.) Since version 4.0 partitions can be 512 MB. Version 5.0 supports partitions up to 2 GB. Several clones exist: DR-DOS (from Digital Research, later part of Novell and called NovellDOS or NDOS, then owned by Caldera and called OpenDOS, then by its subsidiary Lineo who named it back to DR-DOS. See, PC-DOS (from IBM), FreeDOS, ... See Types of DOS. See comp.os.msdos.* and MSDOS partitioning summary. The type 1 is for partitions up to 15 MB.

2 XENIX root

3 XENIX /usr

Xenix is an old port of Unix V7. Microsoft Xenix OS was announced August 1980, a portable and commercial version of the Unix operating system for the Intel 8086, Zilog Z8000, Motorola M68000 and Digital Equipment PDP-11. Microsoft introduces XENIX 3.0 in April 1983. ( Timeline of Microcomputers) SCO delivered its first Xenix for 8088/8086 in 1983. See comp.unix.xenix.sco.

4 DOS 3.0+ 16-bit FAT (up to 32M)

Matthias Paul writes: Some old DOS versions have had a bug which requires this partition to be located in the 1st physical 32 Mb of the hard disk, hence for compatibility with these old issues, partitions located elsewhere should better be assigned the ID FAT16B (06h).

5 DOS 3.3+ Extended Partition

Supports at most 8.4 GB disks: with type 5 DOS/Windows will not use the extended BIOS call, even if it is available. See type f below. An extended partition is a box containing a linked list of logical partitions. This chain (linked list) can have arbitrary length, but some FDISK versions refuse to make more logical partitions than there are drive letters available (e.g. MS-DOS LASTDRIVE=26 is good for at most 24 disk partitions; Novell DOS 7+ allows LASTDRIVE=32).

6 DOS 3.31+ 16-bit FAT (over 32M)

Partitions, or at least the FAT16 filesystems created on them, are at most 2 GB for DOS and Windows 95/98 (at most 65536 clusters, each at most 32 kB). Windows NT can create up to 4 GB FAT16 partitions (using 64 kB clusters), but these cause problems for DOS and Windows 95/98. Note that VFAT is 16-bit FAT with long filenames; FAT32 is a different filesystem.

7 OS/2 IFS (e.g., HPFS)

IFS = Installable File System. The best known example is HPFS. OS/2 will only look at partitions with ID 7 for any installed IFS (that's why the EXT2.IFS packet includes a special "Linux partition filter" device driver to fool OS/2 into thinking Linux partitions have ID 07). (Kai Henningsen (

7 Windows NT NTFS

It is rumoured that the Windows NT boot partition must be primary, and within the first 2 GB of the disk.

7 Advanced Unix

7 QNX2.x pre-1988 (see below under IDs 4d-4f)

8 OS/2 (v1.0-1.3 only)

8 AIX boot partition

8 SplitDrive

8 Commodore DOS

8 DELL partition spanning multiple drives

8 QNX 1.x and 2.x ("qny")

(according to QNX Partitions)

9 AIX data partition

Some reports interchange AIX boot & data. AIX is IBM's version of Unix. See comp.unix.aix.

9 Coherent filesystem

Coherent was a UNIX-type OS for the 286-386-486, marketed by Mark Williams Company led by Bob Swartz, renowned for its good documentation. It was introduced in 1980 and died 1 Feb 1995. The last versions are V3.2 for 286-386-486 and V4.0 (May 1992, using protected mode) for 386-486 only. It sold for $99 a copy, and the FAQ says that 40000 copies have been sold. See comp.os.coherent and this page. A Coherent partition has to be primary.

9 QNX 1.x and 2.x ("qnz")

(according to QNX Partitions)

a OS/2 Boot Manager

OS/2 is the operating system designed by Microsoft and IBM to be the successor of MS-DOS. Dropped by Microsoft. See comp.os.os2. Windows 2000 actively tries to destroy OS/2 Boot Manager. See below.

a Coherent swap partition


Open Parallel Unisys Server. See Unisys.

b WIN95 OSR2 32-bit FAT

Partitions up to 2047GB. See Partition Types

c WIN95 OSR2 32-bit FAT, LBA-mapped

Extended-INT13 equivalent of b.

e WIN95: DOS 16-bit FAT, LBA-mapped

f WIN95: Extended partition, LBA-mapped

Windows 95 uses e and f as the extended-INT13 equivalents of 6 and 5. For the problems this causes, see Windows 95 fdisk problems and Possible data loss with LBA and INT13 extensions. (Especially when going back and forth between MSDOS and Windows 95, strange things may happen with a type e or f partition.) Windows NT does not recognize the four W95 types b, c, e, f ( Win95 Partition Types Not Recognized by Windows NT).

10 OPUS (?)

Maybe decimal, for type a.

11 Hidden DOS 12-bit FAT

When it boots a DOS partition, OS/2 Boot Manager will hide all primary DOS partitions except the one that is booted, by changing its ID: 1, 4, 6 becomes 11, 14, 16. Also 7 becomes 17.

12 Configuration/diagnostics partition

ID 12 (decimal 18) is used by Compaq for their configuration utility partition. It is a FAT-compatible partition (about 6 MB) that boots into their utilities, and can be added to a LILO menu as if it were MS-DOS. (David C. Niemi) Stephen Collins reports a 12 MB partition with ID 12 on a Compaq 7330T. Tigran A. Aivazian reports a 40 MB partition with ID 12 on a 64 MB Compaq Proliant 1600. ID 12 is used by the Compaq Contura to denote its hibernation partition. (

NCR has used ID 0x12 MS-DOS partitions for diagnostics and firmware support on their WorldMark systems since the mid-90s. DataLight's ROM-DOS has replaced MS-DOS on more recent systems. Partition sizes were once 72M (MS-DOS) but are now 40M (ROM-DOS).

Intel has begun offering ROM-DOS based "Service Partition" support on many OEM systems. This support initially used ID 0x98 but has recently changed to ID 0x12. Intel provides their own support for this partition in the form of a System Resource CD. Partition size has remained constant at 40M. See e.g. sds2.pdf. (Chuck Rouillard)

14 Hidden DOS 16-bit FAT <32M

(Ralf Brown's interrupt list adds: `ID 14 resulted from using Novell DOS 7.0 FDISK to delete Linux Native partition') (Powerquest's list adds: `AST DOS with logical sectored FAT', whatever that may be. See ID 18 for AST.)

16 Hidden DOS 16-bit FAT >=32M

17 Hidden IFS (e.g., HPFS)

18 AST SmartSleep Partition

Ascentia laptops have a `Zero Volt Suspend Partition' or `SmartSleep Partition' of size 2MB+memory size. See AST. Ralf Brown calls this the "AST Windows swapfile".

19 Unused

Claimed for Willowtech Photon coS (completely optimized system) by Willow Schlanger See dejanews.

1b Hidden WIN95 OSR2 32-bit FAT

1c Hidden WIN95 OSR2 32-bit FAT, LBA-mapped

1e Hidden WIN95 16-bit FAT, LBA-mapped

20 Unused

Rumoured to be used by Willowsoft Overture File System (OFS1), if there is such a thing.

21 Reserved

(according to delorie). And Powerquest writes `Officially listed as reserved (HP Volume Expansion, SpeedStor variant)'. See also ID a1.)

21 Unused

Claimed for FSo2 (Oxygen File System) by Dave Poirier ( See dejanews.

22 Unused

Claimed for Oxygen Extended Partition Table by See dejanews.

23 Reserved

24 NEC DOS 3.x

26 Reserved

31 Reserved

32 NOS

Simon Butcher ( writes: This type is being used by an operating system being developed by Alien Internet Services in Melbourne Australia called NOS. The id '32' was chosen not only because it's one of the few that are left available, but 32k is the size of the EEPROM the OS was originally targetted for.

33 Reserved

34 Reserved

35 JFS on OS/2 or eCS

David van Enckevort ( writes: Type 0x35 is used by OS/2 Warp Server for e-Business, OS/2 Convenience Pack (aka version 4.5) and eComStation (eCS, an OEM version of OS/2 Convenience Pack) for the OS/2 implementation of JFS (IBM AIX Journaling Filesystem). Since JFS is a non-bootable file system, you cannot install eCS to a JFS partition.

36 Reserved

38 THEOS ver 3.2 2gb partition

39 Plan 9 partition

Plan 9 is an operating system developed at Bell Labs for many architectures. Source is available. See comp.os.plan9. Originally Plan 9 used an unallocated portion at the end of the disk. Plan 9 3rd edition uses partitions of type 0x39, subdivided into subpartitions described in the Plan 9 partition table in the second sector of the partition.

39 THEOS ver 4 spanned partition

3a THEOS ver 4 4gb partition

3b THEOS ver 4 extended partition

THEOS is a multiuser multitasking OS for PCs founded by Timothy Williams in 1983. Current release 4.0, previous release 3.2. They say about themselves: `THEOS with over 150,000 customers and over 1,000,000 users around the world brings a mainframe look and feel to computers without the complexity and high maintenance costs. Hundreds of applications exist with networking and Windows integration.' See the Theos home page

3c PartitionMagic recovery partition

Cody Batt ( writes: When a PowerQuest product like PartitionMagic or Drive Image makes changes to the disk, it first changes the type flag to 0x3C so that the OS won't try to modify it etc. At the end of the process, it gets changed back to what it was at first. So, the only time you should see a 0x3C type flag is if the process was interrupted somehow (power outage, user reboot etc). If you change it back manually with a partition table editor or something then most of the time everything is okay.

3d Hidden NetWare

According to Powerquest.

40 Venix 80286

A very old Unix-like operating system for PCs.

41 Linux/MINIX (sharing disk with DRDOS)

Very old FAQs recommended to use 41 etc instead of 81 etc on a disk shared with DRDOS because DRDOS allegedly disregards the high order bit of the partition type. These types are not used anymore today. Roger Wolff ( confirms: I remember installing DRDOS, and getting a few extra drive letters that I didn't expect. Turns out those are my Minix partitions. It is looking at them as a FAT filesystem. Looks like a big mess. After finding no other possibility than to just "not touch those drive letters" I continue with the install. After a few minutes DRDOS automatically decides to write a copy of the FAT into a file on one of my MINIX partitions. Bye bye Minix partition.

41 Personal RISC Boot

41 PPC PReP (Power PC Reference Platform) Boot

42 Linux swap (sharing disk with DRDOS)

42 SFS (Secure Filesystem)

SFS is an encrypted filesystem driver for DOS on 386+ PCs, written by Peter Gutmann.

42 Windows 2000 marker

If a partition table entry of type 0x42 is present in the legacy partition table, then W2K ignores the legacy partition table and uses a proprietary partition table and a proprietary partitioning scheme (LDM or DDM). As the Microsoft KnowledgeBase writes: Pure dynamic disks (those not containing any hard-linked partitions) have only a single partition table entry (type 42) to define the entire disk. Dynamic disks store their volume configuration in a database located in a 1-MB private region at the end of each dynamic disk.

43 Linux native (sharing disk with DRDOS)

44 GoBack partition

GoBack is a utility that records changes made to the disk, allowing you to view or go back to some earlier state. It takes over disk I/O like a Disk Manager would, and stores its logs in its own partition.

45 Boot-US boot manager

Ulrich Straub ( writes: The boot manager can be installed to MBR, a separate primary partition or diskette. When installed to a primary partition this partition gets the ID 45h. This partition does not contain a file system, it contains only the boot manager and occupies a single cylinder (below 8 GB). See

45 Priam

According to Powerquest. See also ID 5c.

45 EUMEL/Elan

46 EUMEL/Elan

47 EUMEL/Elan

48 EUMEL/Elan

Eumel, and later Ergos L3, are multiuser multitasking systems developed by Jochen Liedtke at GMD. It was used at German schools for the computer science education. ( Elan was the programming language used.)

4a AdaOS Aquila (Default)

Nick Roberts ( writes: I am a member of a project creating a new operating system, called AdaOS, see, with storage manager called Aquila. We wish to use partition type code 4a to allow Aquila to know which partitions to (attempt to) 'mount' during bootup. Aquila will support striping, ghosting, and coagulation. Every Aquila partition will have the byte sequence <41 51 55 49 4C 41> hex at offset 0 of the first actual sector of the Aquila volume. Aquila will only recognise a primary partition.

4a ALFS/THIN lightweight filesystem for DOS

According to Powerquest.

4c Oberon partition

See This partition type (decimal 76) is used for the Aos filesystem. Type 4f is used for the Nat filesystem. One may have several partitions of this type.

4d QNX4.x

4e QNX4.x 2nd part

4f QNX4.x 3rd part

QNX is a POSIX-certified, microkernel, distributed, fault-tolerant OS for the 386 and up, including support for the 386EX in embedded applications. For info see or See also comp.os.qnx. ID 7 is outdated - QNX2 used 7, QNX4.x uses 77, and optionally 78 and 79 for additional QNX partitions on a single drive. These values 77, 78, 79 seem to be the decimal values in view of QNX Partitions and Neutrino filesystems.

4f Oberon partition

See (The partition ID is given in this posting in comp.lang.oberon. The install instructions say that at most one partition can have this type (decimal 79), and that one needs a different type, like 50 (decimal 80) for a second Oberon system. Moreover, that users of System Commander must avoid types containing the 0x10 bit.) See also type 4c (decimal 76) above.

50 OnTrack Disk Manager (older versions) RO

Disk Manager is a program of OnTrack, to enable people to use IDE disks that are larger than 504MB under DOS. For info see Linux kernel versions older than 1.3.14 do not coexist with DM.

50 Lynx RTOS

"Beginning with version 3.0, LynxOS gives users the ability to place up to 14 partitions of 2 GB each on both SCSI and IDE drives, for a total of up to 28 GB of file system space." See

50 Native Oberon (alt)

51 OnTrack Disk Manager RW (DM6 Aux1)

51 Novell

52 CP/M

52 Microport SysV/AT

53 Disk Manager 6.0 Aux3

54 Disk Manager 6.0 Dynamic Drive Overlay

55 EZ-Drive

EZ-Drive is another disk manager (by MicroHouse, 1992). Linux kernel versions older than 1.3.29 do not coexist with EZD. (On 990323 MicroHouse International was acquired by EarthWeb; MicroHouse Solutions split off and changed its name into StorageSoft. MicroHouse Development split off and changed its name into ImageCast. It is StorageSoft that now markets EZDrive and DrivePro.)

56 Golden Bow VFeature Partitioned Volume.

This is a Non-Standard DOS Volume. (Disk Manager type utility software)

56 DM converted to EZ-BIOS

57 DrivePro

Doug Anderson (, with his brother Steve cofounder of MicroHouse (1989), writes: We actually use three different partition types: $55: `StorageSoft EZ-BIOS' - EZ-Drive, Maxtor, MaxBlast, and DriveGuide install this type if the drive needs to be handled by our INT13 redirector. $56: `StorageSoft EZ-BIOS DM Conversion' - Same as $55 but used when a DiskManager "skewed" partition has been converted to EZ-BIOS. $57: `StorageSoft DrivePro' - Used by our DrivePro product.

57 VNDI Partition

(According to disk.c in the Netware source. Not in actual use.)

5c Priam EDisk

Priam EDisk Partitioned Volume. This is a Non-Standard DOS Volume. (Disk Manager type utility software)

61 SpeedStor

Storage Dimensions SpeedStor Volume. This is a Non-Standard DOS Volume. (Disk Manager type utility software)

63 Unix System V (SCO, ISC Unix, UnixWare, ...), Mach, GNU Hurd

A Unixware 7.1 partition must start below the 4GB limit. (If the /stand/stage3.blm is located past this limit, booting will fail with "FATAL BOOT ERROR: Can't load stage3".)

64 PC-ARMOUR protected partition

Used by PC-ARMOUR, a disk protection by Dr. A.Solomon, intended to keep the disk inaccessible until the right password was given (and then an int13 hook was loaded above top-of-memory that showed c/h/s 0/0/2, with a copy of the real partition table, when 0/0/1 was requested). (

64 Novell Netware 286, 2.xx

65 Novell Netware 386, 3.xx or 4.xx

(Novell Netware used to be the main Network Operating System available. Netware 68 or S-Net (1983) was for a Motorola 68000, Netware 86 for an Intel 8086 or 8088. Netware 286 was for an Intel 80286 and existed in various versions that were later merged to Netware 2.2. Netware 386 was a rewrite in C for the Intel 386, later renamed 3.x - it existed at least in versions 3.0, 3.1, 3.10, 3.11, 3.12. Its successor Netware 4.xx had versions 4.00, 4.01, 4.02, 4.10, 4.11. Then came Intranetware.) Netware >= 3.0 uses one partition per drive. It allocates logical Volumes inside these partitions. The volumes can be split over several drives. The filesystem used is called "Turbo FAT"; it only very vaguely resembles the DOS FAT file system. (Kai Henningsen (

66 Novell Netware SMS Partition

According to disk.c in the Netware source. SMS: Storage Management Services. No longer used.

67 Novell

Roman Gruber reports: this code has frozen my version of norton disk-editor (so I think it has to be something special). Jeff Merkey says: 67 is for Wolf Mountain.

68 Novell

69 Novell Netware 5+, Novell Netware NSS Partition

According to disk.c in the Netware source. NSS = Novell Storage Services.

6e ??

Reported once.

70 DiskSecure Multi-Boot

71 Reserved

73 Reserved

74 Reserved

74 Scramdisk partition

Scramdisk is freeware and shareware disk encryption software. It supports container files, dedicated partitions (type 0x74) and disks hidden in WAV audio files. (Shaun Hollingworth (


76 Reserved

77 M2FS/M2CS partition

Jeff Merkey writes: 77 is one we are using internally for M2FS/M2CS partitions.

77 VNDI Partition

(According to disk.c in the Netware source. Not in actual use.)


XOSL Bootloader filesystem, see


Used for F.I.X. by See dejanews.

80 MINIX until 1.4a

81 MINIX since 1.4b, early Linux

Minix is a Unix-like operating system written by Andy Tanenbaum and students at the Vrije Universiteit, Amsterdam, around 1989-1991. It runs on PCs (8086 and up), MacIntosh, Atari, Amiga, Sparc. Ref: Operating Systems: Design and Implementation, Andrew S. Tanenbaum, Prentice-Hall, ISBN 0-13-637406-9 Since 950601 Minix is freely available - site: See also comp.os.minix.

81 Mitac disk manager

82 Prime

82 Solaris x86

Solaris creates a single partition with id 0x82, then uses Sun disk labels within the partition to split it further. (Brandon S. Allbery (

82 Linux swap

83 Linux native (usually ext2fs)

Linux is a Unix-like operating system written by Linus Torvalds and many others on the internet since Fall 1991. It runs on PCs (386 and up) and a variety of other hardware. It is distributed under GPL. Software can be found numerous places, like, and See also comp.os.linux.* and Various filesystem types all use ID 83. Some systems mistakenly assume that 83 must mean ext2.

84 OS/2 hidden C: drive

OS/2-renumbered type 04 partition.

84 Hibernation partition

(following Appendix E of the Microsoft APM 1.1f specification). Reported for various laptop models. E.g., used on Dell Latitudes (with Dell BIOS) that use the MKS2D utility.

85 Linux extended partition

86 Old Linux RAID partition superblock

See fd.

86 NTFS volume set

Legacy Fault Tolerant FAT16 volume. Windows NT 4.0 or earlier will add 0x80 to the partition type for partitions that are part of a Fault Tolerant set (mirrored or in a RAID-5 volume). Thus, one gets types 86, 87, 8b, 8c. See also Windows NT Boot Process and Hard Disk Constraints.

87 NTFS volume set

Legacy Fault Tolerant NTFS volume. HPFS Fault-Tolerant mirrored partition.

8a Linux Kernel Partition (used by AiR-BOOT)

Martin Kiewitz ( writes: I'm currently writing a pretty nice boot-loader. For this I'm using Linux Boot Loader ID A0h, and partitition type 8Ah for the partition holding the kernel image.

8b Legacy Fault Tolerant FAT32 volume

8c Legacy Fault Tolerant FAT32 volume using BIOS extd INT 13h

8d Free FDISK hidden Primary DOS FAT12 partitition

Free FDISK is the FDISK used by FreeDOS. It hides types 1, 4, 5, 6, b, c, e, f by adding decimal 140 (0x8c).

8e Linux Logical Volume Manager partition

See pvcreate(8) as found under (For a while this was 0xfe.)

90 Free FDISK hidden Primary DOS FAT16 partitition

91 Free FDISK hidden DOS extended partitition

92 Free FDISK hidden Primary DOS large FAT16 partitition

93 Hidden Linux native partition

93 Amoeba

94 Amoeba bad block table

Amoeba is a distributed operating system written by Andy Tanenbaum, together with Frans Kaashoek, Sape Mullender, Robert van Renesse and others since 1981. It runs on PCs (386 and up), Sun3, Sparc, 68030. It is free for universities for research/teaching purposes. For information, see

95 MIT EXOPC native partitions (Andrew Purtell,

97 Free FDISK hidden Primary DOS FAT32 partitition

98 Free FDISK hidden Primary DOS FAT32 partitition (LBA)

98 Datalight ROM-DOS Super-Boot Partition

See, and type 12 above.

99 DCE376 logical drive

No, it's not a hibernation partition; it's closest to a DOS extended partition. It's used by the Mylex DCE376 EISA SCSI adaptor for partitions which are beyond the 1024th cylinder of a drive. I've only seen references to type 99 with the DCE376. (Christian Carey, ccarey@CapAccess.ORG)

9a Free FDISK hidden Primary DOS FAT16 partitition (LBA)

9b Free FDISK hidden DOS extended partitition (LBA)


Current sysid for BSDI. The types b7 and b8 given below are for an older version of the filesystem used in pre-v3.0 versions of the OS. These days the system is v4.1 BSD/OS. BSDI reports 2.1 million installed servers and 12 million licenses sold. See

a0 Laptop hibernation partition

Reported for various laptops like IBM Thinkpad, Phoenix NoteBIOS, Toshiba under names like zero-volt suspend partition, suspend-to-disk partition, save-to-disk partition, power-management partition, hibernation partition. Usually at the start or end of the disk area. (This is also the number used by Sony on the VAIO. Recent VAIOs can also hibernate to a file in the filesystem, the choice being made from the BIOS setup screen.)

a1 Laptop hibernation partition

Reportedly used as "Save-to-Disk" partition on a NEC 6000H notebook. Types a0 and a1 are used on systems with Phoenix BIOS; the Phoenix PHDISK utility is used with these.

a1 HP Volume Expansion (SpeedStor variant)

According to Powerquest IDs 21, a1, a3, a4, a6, b1, b3, b4, b6 are for HP Volume Expansion (SpeedStor variant).

a3 Reserved

See also ID a1.

a4 Reserved

See also ID a1.

a5 BSD/386, 386BSD, NetBSD, FreeBSD

386BSD is a Unix-like operating system, a port of 4.3BSD Net/2 to the PC done by Bill Jolitz around 1991. When Jolitz seemed to stop development, an updated version was called FreeBSD (1992). The outcome of a Novell vs. UCB law suit was that Net/2 contained AT&T code, and hence was not free, but that 4.4BSD-Lite was free. After that, FreeBSD and NetBSD were restructured, and FreeBSD 2.0 and NetBSD 1.0 are based on 4.4BSD-Lite. FreeBSD runs on PCs. See For NetBSD, see below - it changed partition type to a9. 386BSD seems to be dead now. The kernel source is being published - see Operating System Source Code Secrets by Bill and Lynne Jolitz. See comp.os.386bsd.*. See for NetBSD boot and partitioning info.

a6 OpenBSD

OpenBSD, led by Theo de Raadt, split off from NetBSD. It tries to emphasize on security. See

See also ID a1.


Based on Mach 2.6 and features of Mach 3.0, is a true object-oriented operating system and user environment. See

a8 Mac OS-X

Apple's OS-X ( Darwin Intel) uses this type for its filesystem partition (a UFS file system, in NeXT flavour, only differing from the *BSD formats in the first 8 kB). See also type ab.

a9 NetBSD

NetBSD is one of the children of *BSD (see above). It runs on PCs and a variety of other hardware. Since 19-Feb-98 NetBSD uses a9 instead of a5. See It is freely obtainable - see

aa Olivetti Fat 12 1.44Mb Service Partition

Contains a bare DOS 6.22 and a utility to exchange types 06 and aa in the partition table. (

ab Mac OS-X Boot partition

Apple's OS-X (Darwin Intel) uses this type for its boot partition. The image (/usr/standalone/i386/boot) starts at sector 1. See also type a8.

ab GO! partition

Unused. Claimed by Stanislav Karchebny for his GO! OS.

ae ShagOS filesystem

af ShagOS swap partition

Unused. Claimed by Frank Barrus for his ShagOS.

b0 BootStar Dummy

The boot manager BootStar manages its own partition table, with up to 15 primary partitions. It fills unused entries in the MBR with BootStar Dummy values. See If you use this, don't use a disk manager, do not put LILO in the MBR and do not use fdisk.

b1 Reserved

See also ID a1.

b3 Reserved

See also ID a1.

b4 Reserved

See also ID a1.

b6 Reserved

See also ID a1.

b6 Windows NT mirror set (master), FAT16 file system

(According to Delorie.)

b7 Windows NT mirror set (master), NTFS file system

(According to Delorie.)

b7 BSDI BSD/386 filesystem

b8 BSDI BSD/386 swap partition

BSDI (Berkeley Software Design, Inc.) was founded by former CSRG (UCB Computer Systems Research Group) members. Their operating system, based on Net/2, was called BSD/386. After the USL (Unix System Laboratories, Inc./Novell Corp.) vs. BSDI lawsuit, new releases were based on BSD4.4-Lite. Now they are announcing BSD/OS V2.0.1. This is an operating for PCs (386 and up), boasting 3000 customers. (That was long ago. The current partition id is f, see above.)

bb Boot Wizard hidden

(PTS) BootWizard 4.0 and its new version Acronis OS Selector 5.0 use this id (i) when hiding partitions with types other than 1, 4, 6, 7, b, c, e, and (ii) when creating a partition without file system. See The boot software was purchased on 2001-01-05 by SWsoft. See

be Solaris 8 boot partition


c0 REAL/32 secure small partition

See d0 below.

c0 NTFT Partition

According to disk.c in the Netware source.

c0 DR-DOS/Novell DOS secured partition

According to Delorie.

c1 DRDOS/secured (FAT-12)

c2 Reserved for DR-DOS 7+

According to Powerquest IDs c2, c3, c8, c9, ca, cd are reserved for DR-DOS 7+.

c2 Hidden Linux

c3 Hidden Linux swap

Benedict Chong ( writes: BlueSky Innovations LLC does a boot manager product called Power Boot and we use, in addition, 0C2h and 0C3h for hidden Linux partitions (swap and ext2fs). See also ID c2.

c4 DRDOS/secured (FAT-16, < 32M)

c5 DRDOS/secured (extended)

c6 DRDOS/secured (FAT-16, >= 32M)

DR-DOS 6.0 will add 0xc0 to the partition type for a LOGIN.EXE-secured partition (so that people cannot avoid the password check by booting from an MS-DOS floppy). Otherwise it seems that the types c1, c4, c5, c6 and d1, d4, d5, d6 are used precisely like 1, 4, 5, 6.

c6 Windows NT corrupted FAT16 volume/stripe set

NTFS will add 0xc0 to the partition type for disabled parts of a Fault Tolerant set. Thus, one gets types c6, c7. See also Windows NT Boot Process and Hard Disk Constraints and Switching from DR-DOS 6.0 to MS-DOS 5.0.

c7 Windows NT corrupted NTFS volume/stripe set

c7 Syrinx boot


See also ID c2.


See also ID c2.


See also ID c2.

cb reserved for DRDOS/secured (FAT32)

cc reserved for DRDOS/secured (FAT32, LBA)

cd CTOS Memdump?

See also ID c2.

ce reserved for DRDOS/secured (FAT16, LBA)

d0 REAL/32 secure big partition

REAL/32 is a continuation of DR Multiuser DOS. Andrew Freeman ( writes: REAL/32 supports the standard FAT12, FAT16 partition types and will shortly support FAT32. For partitions which have been marked as secure we use 0xC0 and 0xD0 as partition markers (C0 < 32mb, D0 >= 32mb). REAL/32 is an advanced 32-bit multitasking & multi-user MS-DOS & Windows compatible operating system. Home page is

d1 Old Multiuser DOS secured FAT12

d4 Old Multiuser DOS secured FAT16 <32M

d5 Old Multiuser DOS secured extended partition

d6 Old Multiuser DOS secured FAT16 >=32M

d8 CP/M-86

da Non-FS Data

Added on request of John Hardin (

db Digital Research CP/M, Concurrent CP/M, Concurrent DOS

db CTOS (Convergent Technologies OS -Unisys)

db KDG Telemetry SCPU boot

Mark Morgan Lloyd ( writes: KDG Telemetry uses type 0xdb to store a protected-mode binary image of the code to be run on a 'x86-based SCPU (Supervisory CPU) module from the DT800 range.

dd Hidden CTOS Memdump?

de Dell PowerEdge Server utilities (FAT fs)

df DG/UX virtual disk manager partition

Glenn Steen ( writes: When I made an old Aviion 2000 triple-boot (DOS, DG/UX and Linux) I saw that Linux fdisk reported the DG/UX virtual disk manager partition as type 0xdf.

df BootIt EMBRM

The boot manager BootIt manages its own partition table, with up to 255 primary partitions. See If you use this, don't use a disk manager, do not put LILO in the MBR and do not use fdisk. Reference for the ID: BOOTIT.TXT.

e0 Reserved by STMicroelectronics for a filesystem called ST AVFS.

e1 DOS access or SpeedStor 12-bit FAT extended partition

Kevin Cummings reports in alt.os.linux: it's a SSTOR partition on cylinders > 1023.

e3 DOS R/O or SpeedStor

e4 SpeedStor 16-bit FAT extended partition < 1024 cyl.

e5 Tandy DOS with logical sectored FAT

According to Powerquest.

e5 Reserved

e6 Reserved

eb BeOS

BeOS is an operating system that runs on Power PCs and, since recently, on Intel PCs. See

ed Reserved for Matthias Paul's Spryt*x

Matthias Paul ( writes: Sprytix is currently a project name for an OS related project of mine, partially based on DOS and Linux technologies. It is still in the very early stages and not publically available. ("ED" was chosen in reminescence of the Digital Research European Development Centre, EDC, and because it's nearby the other DR-DOS and Multiuser DOS partition IDs.)

ee Indication that this legacy MBR is followed by an EFI header

ef Partition that contains an EFI file system

Bob Griswold ( writes: MS plans on using EE and EF in the future for support of non-legacy BIOS booting. Mark Doran ( adds: these types are used to support the Extensible Firmware Interface specification (EFI); go to and search for EFI. (For the types ee and ef, see Tables 16-6 and 16-7 of the EFI specification, EFISpec_091.pdf.)

f0 Linux/PA-RISC boot loader

Paul Bame ( writes: the F0 partition will be located in the first 2GB of a drive and used to store the Linux/PA-RISC boot loader and boot command line, optionally including a kernel and ramdisk.

f1 SpeedStor

f2 DOS 3.3+ secondary partition

Powerquest writes: Unisys DOS with logical sectored FAT.

f3 Reserved

Powerquest writes: Storage Dimensions SpeedStor.

f4 SpeedStor large partition

f4 Prologue single-volume partition

f5 Prologue multi-volume partition

The type F4 partition contains one volume, and is not used anymore. The type F5 partition contains 1 to 10 volumes (called MD0 to MD9). It supports one or more systems (Prologue 3, 4, 5, Twin Server). Each volume can have as file system the NGF file system or TwinFS file system. NGF (old): volume size at most 512 MB, at most 895 files per directory, at most 256 directories per volume. TwinFS (new): volume size up to 4 GB. No limit in number of files and directories. See Prologue.

f6 Reserved

Powerquest writes: Storage Dimensions SpeedStor.

fa Bochs

Rob Judd writes: MandrakeSoft's Bochs x86 emulator (similar to VMWare) uses fa as a partition identifier.

fb VMware File System partition

fc VMware Swap partition

VMware offers virtual machines in which one can run Linux, Windows, FreeBSD. These partition IDs announced by Dan Scales (

fd Linux raid partition with autodetect using persistent superblock

See the HOWTO and the kernel patches. Earlier, 86 was used instead of fd.

Powerquest writes: Reserved for FreeDOS (

fe SpeedStor > 1024 cyl.

fe LANstep

fe IBM PS/2 IML (Initial Microcode Load) partition, located at the end of the disk.

fe Windows NT Disk Administrator hidden partition

Mark Morgan Lloyd ( writes: Windows NT Disk Administrator marks hidden partitions (i.e. present but not to be accessed) as type 0xfe. A primary partition of this type is also used by IBM to hold an image of the "Reference Diskettes" on many of their machines, particularly newer PS/2 systems (at a rough guess, anything built after about 1994). This clash can cause major confusion and grief if running NT on IBM kit. When this Reference Partition is activated, it changes its type into 1 (FAT12) and hides all other partitions by adding 0x10 to the type.

fe Linux Logical Volume Manager partition (old)

This has been in use since the early LVM days back in 1997, and has now (Sept. 1999) been renamed 0x8e.

ff Xenix Bad Block Table

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