The partition type (or partition ID) in a partition's entry in the partition table inside a

master boot record A master boot record (MBR) is a type of boot sector in the first block of disk partitioning, partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond. The concept ...

(MBR) is a byte value intended to specify the file system the partition contains or to flag special access methods used to access these partitions (e.g. special CHS mappings, LBA access, logical mapped geometries, special driver access, hidden partitions, secured or encrypted file systems, etc.).

Overview

Lists of assigned partition types to be used in the partition table in the MBR were originally maintained by

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

and

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

internally. When the market of PC operating systems and disk tools grew and liberated, other vendors had a need to assign special partition types to their products as well. As Microsoft neither documented all partition types already assigned by them nor wanted to maintain foreign assignments, third parties started to simply assign partition types on their own behalf in a mostly uncoordinated trial-and-error manner. This led to various conflicting assignments sometimes causing severe compatibility problems between certain products. Several industry experts including Hale Landis, Ralf D. Brown, Matthias R. Paul, and

Andries E. Brouwer Andries Evert Brouwer (born 1951) is a Dutch mathematician and computer programmer, Professor Emeritus at Eindhoven University of Technology (TU/e). He is known as the creator of the greatly expanded 1984 to 1985 versions of the roguelike compute ...

in the 1990s started to research partition types and published (and later synchronized) partition type lists in order to help document the industry

de facto standard A ''de facto'' standard is a custom or convention that is commonly used even though its use is not required. is a Latin phrase (literally " of fact"), here meaning "in practice but not necessarily ordained by law" or "in practice or actuality, ...

and thereby reduce the risk of further conflicts. Some of them also actively helped to maintain software dealing with partitions to work with the updated lists, indicated conflicts, devised additional detection methods and work-arounds for vendors, or engaged in coordinating new non-conflictive partition type assignments as well. It is up to an

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

boot loader A bootloader, also spelled as boot loader or called bootstrap loader, is a computer program that is responsible for booting a computer and booting an operating system. If it also provides an interactive menu with multiple boot choices then it's o ...

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learnin ...

how to interpret the value. So the table specifies which

s or disk-related products introduced an ID and what file system or special partition type they mapped it to. Partitions with partition types unknown to the software should be treated as reserved but occupied disk storage space which should not be dealt with by the software, save for

partition manager This is a list of utilities for performing disk partitioning Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions. It i ...

Local or Experimental Use

While the list is not officially maintained, ''new'' assignments should be coordinated. In particular temporary partition type assignments for local or experimental projects can utilize type 7Fh in order to avoid conflicts with already assigned types. This type was specially reserved for individual use as part of the ''Alternative OS Development Partition Standard'' (AODPS) initiative since 2002.

List of partition IDs

This is a list of known master boot record partition types on

IBM PC compatible An IBM PC compatible is any personal computer that is hardware- and software-compatible with the IBM Personal Computer (IBM PC) and its subsequent models. Like the original IBM PC, an IBM PC–compatible computer uses an x86-based central p ...

computers:

Notes

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...

/ PC DOS 2.0-3.1 cannot cope with hard disk partitions outside the first 32 MB of the disk. Therefore,

FAT12 File Allocation Table (FAT) is a file system developed for personal computers and was the default file system for the MS-DOS and Windows 9x operating systems. Originally developed in 1977 for use on floppy disks, it was adapted for use on ...

and

FAT16 File Allocation Table (FAT) is a file system developed for personal computers and was the default file system for the MS-DOS and Windows 9x operating systems. Originally developed in 1977 for use on floppy disks, it was adapted for use on Ha ...

volumes in primary partitions physically residing outside this area must not use partition IDs 01h and 04h, even if they were otherwise small enough to be recognized by these DOS versions. In order to hide these volumes from these DOS issues 06h can be used instead. DOS distinguishes FAT types by their number of clusters, not by their partition ID, therefore, this does not cause any problems for DOS 3.31 and higher except for a possibly wrong file system type display in

FDISK fdisk is a command-line utility for disk partitioning. It has been part of DOS, DR FlexOS, IBM OS/2, and early versions of Microsoft Windows, as well as certain ports of FreeBSD, NetBSD, OpenBSD, DragonFly BSD and macOS for compatibilit ...

. Used by

OS/2 OS/2 is a Proprietary software, proprietary computer operating system for x86 and PowerPC based personal computers. It was created and initially developed jointly by IBM and Microsoft, under the leadership of IBM software designer Ed Iacobucci, ...

Boot Manager: 0Ah, 11h, 14h, 15h, 16h, 17h, 1Bh, 1Ch, 1Eh, 1Fh. Used by Free

FreeDOS FreeDOS (formerly PD-DOS) is a free software operating system for IBM PC compatible computers. It intends to provide a complete MS-DOS-compatible environment for running Legacy system, legacy software and supporting embedded systems. FreeDOS ca ...

: 8Dh, 90h, 91h, 92h, 97h, 98h, 9Ah, 9Bh. Known partition IDs for

logical sectored FAT File Allocation Table (FAT) is a file system developed for personal computers and was the default file system for the MS-DOS and Windows 9x operating systems. Originally developed in 1977 for use on floppy disks, it was adapted for use on Ha ...

s include: 08h (

Commodore Commodore may refer to: Ranks * Commodore (rank), a naval rank ** Commodore (Royal Navy), in the United Kingdom ** Commodore (India), in India ** Commodore (United States) ** Commodore (Canada) ** Commodore (Finland) ** Commodore (Germany) or ' ...

MS-DOS 3.x), 11h (

Leading Edge The leading edge is the part of the wing that first contacts the air;Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, 1997. alternatively it is the foremost edge of an airfoil sectio ...

MS-DOS 3.x), 14h (AST MS-DOS 3.x), 24h (NEC MS-DOS 3.30), 56h (

AT&T AT&T Inc., an abbreviation for its predecessor's former name, the American Telephone and Telegraph Company, is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the w ...

MS-DOS 3.x), E5h (

Tandy Tandy may refer to: Companies * Tandy Corporation (1919–2000), a leather supply company which became the RadioShack Corporation in 2000 ** Hinckley-Tandy Leather Company, name used from 1919 to 1956 ** TRS-80 Color Computer, rebranded as Tandy C ...

MS-DOS), F2h (

Sperry IT Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the 20th century. Sperry ceased to exist in 1986 following a prolonged takeover, hostile takeover bid engineered by ...

MS-DOS 3.x,

Unisys Unisys Corporation is a global technology solutions company founded in 1986 and headquartered in Blue Bell, Pennsylvania. The company provides cloud, AI, digital workplace, logistics, and enterprise computing services. History Founding Unis ...

MS-DOS 3.3 — also used by

Digital Research Digital Research, Inc. (DR or DRI) was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser ...

DOS Plus DOS Plus (erroneously also known as DOS+) was the first operating system developed by Digital Research's OEM Support Group in Newbury, Berkshire, UK, first released in 1985. DOS Plus 1.0 was based on CP/M-86 Plus combined with the PCM ...

2.1). While non-standard and sub-optimal these FAT variants are perfectly valid according to the specifications of the file system itself, although default issues of

/ PC DOS 3.x were not able to cope with them. Most of these vendor specific FAT12 and FAT16 variants can be mounted by more flexible file system implementations in operating systems such as

DR-DOS DR-DOS is a disk operating system for IBM PC compatibles, originally developed by Gary A. Kildall's Digital Research, Inc. and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86. Upon its introduction in 198 ...

simply by changing the partition ID to one of the recognized types. Also, if they no longer need to be recognized by their original operating systems, existing partitions can be "converted" into FAT12 and FAT16 volumes compliant with versions of MS-DOS/PC DOS like 5.0-6.3, which do not support logical sector sizes different from 512 bytes, by switching to a BPB with 32-bit entry for the number of sectors, as introduced since DOS 3.31, keeping the cluster size and reducing the logical sector size in the BPB down to 512 bytes, while at the same time increasing the counts of logical sectors per cluster, reserved logical sectors, total logical sectors, and logical sectors per FAT by the same factor. HP ''Volume Expansion'' is a variant of ''SpeedStor'' and uses partition IDs 21h, A1h, A3h, A4h, A6h, B1h, B3h, B4h, and B6h.

Apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

uses partition IDs A8h, ABh, ACh, and AFh. Versions of

DR DOS DR-DOS is a disk operating system for IBM PC compatibles, originally developed by Gary A. Kildall's Digital Research, Inc. and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86. Upon its introduction in 1988, ...

6.0 and higher use several of these partition IDs for secured FAT partitions with single-user security: C0h, C1h, C4h, C5h, C6h, CBh, CCh, CEh, CFh. Versions of Multiuser DOS use these partition IDs for secured FAT partitions with multi-user security: D0h, D1h, D4h, D5h, D6h. Versions of

IMS Ims is a Norwegian surname. Notable people with the surname include: * Gry Tofte Ims (born 1986), Norwegian footballer * Rolf Anker Ims (born 1958), Norwegian ecologist See also * IMS (disambiguation) Ims is a Norwegian surname Heritable famil ...

REAL/32 Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

use partition IDs C0h and D0h for multi-user security.

QNX QNX ( or ) is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. The product was originally developed in the early 1980s by Canadian company Quantum Software Systems, founded March 30, 1980, and l ...

partition IDs 07h, 08h, 09h, 4Dh (77), 4Eh (78), 4Fh (79), as well as B1h (177), B2h (178) and B3h (179).

Overview

Local or Experimental Use

List of partition IDs

See also

Notes

References

Further reading