Computing » Filesystem interoperability

A list of antique and contemporary single-medium file systems and platforms through which their files can be accessed.

This is by no means an exhaustive list, so please do contact me if you have any update suggestions, though not before checking my to-do list. Last updated 25 October 2022.

Synonyms & terms

For concision, direct descendants of the original UNIX are grouped as follows:

  1. Ancient UNIX: UNIX Time-Sharing Systems v1 through v7
  2. AT&T UNIX: UNIX Systems III, IV and V
  3. UnixWare: UnixWare, and Open UNIX 8


ADFS / Advanced Disc Filing System

Acorn’s successor to DFS. Also known as Filecore on Arthur and RISC OS.[1]

AdvFS / Advanced File System

Highly reliable filesystem.[4]

Needs further research.

AFFS / Amiga Fast File System

see: FFS

AFMS / Atari File Management System

see: FMS

AFS / Acer Fast Filesystem

Bitmapped variant of the System V Release 4 filesystem.[2] See also: EAFS.

Not much else is known; needs research.

AFS / Amiga File System

see: OFS

AFS / Ami-FileSafe

Seemingly a third-party Amiga filesystem.[8]

AFS / AthFS / AtheOS File System

Built on top of Be File System.[10]

AMSDOS filesystem

Seemingly an Amstrad variant of the CP/M filesystem.[11]

APF Imagination Machine disk filesystem

Not much is known aside from name[13]; needs research.

APFS / Apple File System

Apple’s proprietary “next-generation” filesystem to supersede HFS+.[14]


Experimental Bε-tree filesystem released in 2015.[18]

BFS / BeFS / Be File System

Journaling, case-sensitive alternative to NTFS.[19]

BFS / Boot File System

Simple filesystem from which some old UNIX OSes booted.[24][25]

BFS / Byte File System

Unix application filesystem over top z/VM.[27]

Not much else is known; needs research.

BTOS filesystem

see: CTOS filesystem

Btrfs / B-tree file system

Increasingly popular copy-on-write filesystem for Linux.[28]

CBMFS / Commodore Business Machine filesytem

Filesystem used by the embedded OS on certain Commodore floppy disk drives.[31] Sometimes called FS1541.[9]

CDFS / Compact Disc Filing System

see: ISO 9660

CDVDFS / CD/DVD filesystem

Amiga-specific optical media filesystem.[33]


Filesystem for flash devices.[3]

Not much else is known; needs research.

CMDFS / Creative Micro Designs filesystem

Extension to CBMFS for 3½″ floppy disks.[34]

Not much else is known; needs research.

CMS filesystem

Native filesystem of IBM’s CMS minidisks.[35]

Commodore 1581 filesystem

Variant of CBMFS for 3½″ disks.[32]

Compucolor filesystem

Tape-like file management for the Compucolor II.[37]

CP/M filesystem

Disk format for the original CP/M.[38]

CrosStor filesystem

see: HTFS

CSI-DOS filesystem

Soviet microcomputer filesystem.[41]

CTOS filesystem (Convergent Technologies)

Convergent Technologies disk layout.[42]

CTOS filesystem (Datapoint)

Cassette layout for the Datapoint 2200.[43]

DDFS / Data Domain File System

Filesystem related to the Dell EMC Data Domain OS.[44]

Not much else is known; needs research.

DECtape filesystem

Block-based tape format for PDP-6 and later; originally called Microtape.[45]

Not much else is known; needs research.

DOS 3.𝑥 filesystem

Floppy disk format for DOS on the Apple II, succeeded by the ProDOS file system on the Apple III.[46]

DOS II filesystem

Disk layout for Atari 8-bit computers.[48]

DTFS / Desktop File System

Default filesystem for SCO OpenServer Desktop.[6]

Information is spotty; needs research.

EAFS / Extended Acer Fast Filesystem

Presumably a direct successor to AFS.

Not much else is known; needs research.

EFS / Enhanced Filing System

Not much else is known; needs research.

EFS / Extent File System

Block-device filesystem for early IRIX; superseded by XFS.[49]

EOS filesystem

Coleco ADAM cassette filesystem.[50]

EROFS / Enhanced Read-Only File System

Lightweight, modern filesystem.[51]


Commercial FAT32 variant sometimes known as FAT64.[34]

Not much else is known; needs research.

exFAT / Extensible File Allocation Table

Alter to FAT32 for flash memory.[52]

ext / Extended filesystem

First Linux-exclusive filesystem, intended to replace the MINIX filesystem. Superseded by ext2.[57]

ext2 / Second extended filesystem

Successor to ext. Superseded by ext3.[57]

ext3 / Third extended filesystem

Successor to ext2. Superseded by ext4.[57]

ext3cow / Third extended filesystem with copy-on-write

Fork of ext3 with versioning.[73]

ext4 / Fourth extended filesystem

Successor to ext3.[57]

F2FS / Flash-friendly Filesystem

What it says on the tin.

FAT / File Allocation Table

Original 8-bit structure for Microsoft’s early BASIC disks.[78]

Might be forward-compatible with later FAT variants; needs research/testing.

FAT12 / 12-bit File Allocation Table

Twelve-bit extension of FAT.[78] Still widely used on “IBM-formatted” floppy disks.

Might be forward-compatible with later FAT variants; needs research/testing.

FAT16 / 16-bit File Allocation Table

Extension to FAT12 which allowed access of large (at the time) hard disks.[78] Note that, when most people talk about FAT16, they actually mean FAT16B, which has 32-bit sector entries, as opposed to FAT16’s 16-bit entries.[78]

Might be forward-compatible with later FAT variants; needs research/testing.

FAT16B / 16-bit File Allocation Table (version B)

Revision of FAT16 with 32-bit sector entries.[78] Also known as BIGDOS.[78]

Version information is lacking on Concurrent DOS and derivatives; needs research.

FAT32 / 32-bit File Allocation Table

32-bit extension to FAT16B.


see: ETRFS

FATX / File Allocation Table for Xbox

Microsoft’s incompatible FAT32-based filesystem for Xbox.[78]

FFS / Fast File System (Amiga)

Replacement for OFS.[104]

FFS / Fast File System (BSD)

see: UFS

FFS2 / Amiga Fast File System, version 2

Successor to FFS.


see: ADFS


see: ODS-1, ODS-2, ODS-5

FMS / Atari File Management Subsystem

Filesystem for Atari 810 floppy disks.[109]


Plan 9 filesystem featuring snapshots.[110]


see: CBMFS


High-availability B+ tree filesystem.[111]


Update to HAMMER.[112]

HFS / Hierarchical File System (Apple)

Successor to MFS; also known as Mac OS Standard.[113]

HFS / Hierarchical File System (IBM)

Predecessor to ZFS.[116]

HFS / High-performance Filesystem

Not much else is known; needs research.

HFS Plus / HFS+ / Hierarchical File System Plus

Successor to HFS; also known as Mac OS Extended.[115]

High Sierra Format

Direct predecessor to ISO 9660.[118]

HPFS / High Performance File System

B+ tree filesystem intended to replace FAT on OS/2.[123]

HTFS / High Throughput Filesystem

Also known as the CrosStor filesystem.[2]

Not much else is known; needs research.

IceFS / IceFileSystem

Reliable 64-bit filesystem.[128]

IDE64 filesystem

Seemingly the only filesystem on LUnix.[129]

ISO 9660

Typical CD-ROM filesystem, often called CDFS or CD9660.[118]

JFFS / Journaling Flash File System

Filesystem specialised for flash memory devices; superseded by JFFS2.[142]

JFFS2 / Journaling Flash File System, version 2

Successor to JFFS.[143]

JFS / Journaled Filesystem

IBM filesystem.[144]

Not much else is known; needs research.


AmigaOS file system.[105]

LanyFS / Lanyard File System

Theoretical file system intended for removable devices.[145]

Lisa filesystem

Predecessor to MFS for the Apple Lisa.[147]

LTFS / Linear Tape File System

IBM’s novel approach to magnetic tape file storage.[148]

Sensible OS compatibility information is difficult to find; needs research.

Mac OS Standard

see: HFS

Mac OS Extended

see: HFS+


FAT-like floppy disk filesystem for Yamaha Electone organs.[149]

Not much else is known; needs research.

MFS / Macintosh File System

Original Macintosh filesystem, preceding HFS.[113]

MINIX filesystem

Primary filesystem for the eponymous OS.[151]

NGFS / New Generation File System

Filesystem designed for the DOS vector-port API.[105]

NILFS / New Implementation of a Log-structured File System

Circular-buffer filesystem built for Linux.[153]

NILFS2 / New Implementation of a Log-structured File System, version 2

Successor to NILFS.[153]

North Star DOS filesystem

Disk filesystem for North Star Horizon floppies.[155]

Not much else is known; needs research.

NOVA / NOn-Volatile memory Accelerated log-structured file system

High-performance NVDIMM (and the like) filesystem.[156]

NSS / Novell Storage Services

Presumably the successor to NWFS 386.[2]

NTFS / New Technology File System

Microsoft’s successor to HPFS.[157]

NWFS 286 / NetWare Filesystem, 16-bit

Novell’s proprietary filesystem; succeeded by NWFS 386.[2]

NWFS 386 / NetWare Filesystem, 32-bit

32-bit successor to NWFS 286.[2]

OFS / Amiga Old File System

Predecessor to FFS; known as Amiga File System before then.[162]

ODS-1 / On-disk structure level 1

Flat file system for RSX-11; superseded by ODS-2 and ODS-5.[121]

ODS-2 / On-disk structure level 2

Extension to ODS-1 with nested directories.[121]

ODS-3 / On-disk structure level 3

see: ISO 9660[121]

ODS-4 / On-disk structure level 4

see: High Sierra[121]

ODS-5 / On-disk structure level 5

Variant of ODS-2 with additional features.[121]

OS/8 filesystem

Simple flat filesystem for PDP-8 mass storage.[164]

πfs / pifs / Pi filesystem

Proof-of-concept filesystem using indices of π.[165]

PFS / Professional File System

Backwards-compatible successor to Ami-FileSafe.[166]

PFS2 / Professional File System II

Successor to PFS.[9]

Not much else is known; needs research.

PFS3 / Professional File System III

Successor to PFS2.[9]

ProDOS filesystem

Apple II and III disk filesystem introduced with the Apple III.[167]

QNX filesystem, version 2

Predecessor to QNX v4.

Not much else is known; needs research.

QNX filesystem, version 4

Successor to QNX v2.

Not much else is known; needs research.

RDS0 / RSTS Directory Structure 0

Original RSTS/E filesystem.[171]

RDS1 / RSTS Directory Structure 1

Successor to RDS0.[171]

RedSea File System

Simple filesystem superficially similar to FAT32.[172]

ReFS / Resilient File System

Microsoft’s successor to NTFS.[173]


General-purpose filesystem noted for technical issues.[174]


Not much else is known aside from name[122]; needs research.

RT-11 filesystem

DEC’s tape and disk filesystem for RT-11.[54]

Not much else is known; needs research.

S51K / System V 1kB Filesystem

Variant on the Unix filesystem.[2]

SFS / Smart Filesystem

Third-party filesystem for Amiga computers.[177]

SFS2 / Smart Filesystem 2

Successor to SFS[105].

Sinclair QL filesystem

Originally for microdrive cassettes on QL systems.[178]

SkyFS / SkyOS filesystem

Implementation of BFS for SkyOS.[179]

SOS filesystem

see: ProDOS filesystem


Shallow database which can barely be considered a filesystem.[180]

SpadFS / Systém pro Psychopaty a Debily

Experimental filesystem.[34]

Spiralog filesystem

High-performance log-structured B-tree filesystem.[2]

System V filesystem

see: Unix filesystem


Replacement for ZFS on Redox OS.[181]

TOPS-20 filesystem

File structure unique to DEC disk packs.[182]

TR-DOS filesystem

Filesystem for the ZX Spectrum.[183]

TRSDOS filesystem

Umbrella term for various, usually-compatible filesystem implementations on TRS-80 computers.[184]

Needs better research.

UBIFS / Unsorted Block Image File-System

Direct-access MTD equivalent of JFFS2.[185]

UCSD p-System filesystem

Companion filesystem for UCSD Pascal.[186]

UDF / Universal Disk Format

DVD equivalent of ISO 9660.[187] Sometimes called UDFS.[140]

UFS / Unix filesystem (original)

Filesystem used in Ancient and AT&T Unices.[188]

UFS / Unix File System (rewrite)

BSD’s improvement to the UNIX filesystem, initially known as BSD Fast File System (FFS).[188]

UFS / ULTRIX File System

Might be the same thing as UFS.[195]

UFS2 / Unix File System, version 2

FreeBSD’s successor to UFS with modern features.[192]

VMUFAT / Virtual Memory Unit File Allocation Table

FAT extension for Sega Dreamcast VMUs.[196]

VxFS / VERITAS File System

Extent-based filesystem primarily for HP-UX.[197]


Experimental filesystem slated to replace NTFS.[34]

Allegedly only available from within Microsoft’s labs.[34]


Short-lived alternative to the MINIX filesystem on Linux.[58]


Silicon Graphics’ EFS replacement.[198]

YAFFS / Yet Another Flash File System

NAND-specialised filesystem.[34]

Not much else is known; needs research.

zFS (z/OS)

Successor to HFS.[199]

ZFS / Zettabyte File System

Sun’s stab at volume management.[200]

Footnotes & references

  1. Wikipedia: Advanced Disc Filing System
  2. The Linux Documentation Project: Filesystems HOWTO §9
  3. NetBSD source tree: CHANGES.prev
  4. Tru64 Unix manpages: advfs(4)
  5. Symbolics: Open Genera User’s Guide
  6. What are the filesystem types and the corresponding limitation sizes that can be used on SCO OpenServer 5?
  7. Filesystem mount options (HTFS, EAFS, AFS, S51K)
  8. AN!Wiki: Ami File Safe
  9. MorphOS Library: Filesystems
  10. Let’s Solve the File Format Problem! wiki: AtheOS File System
  11. SymbOS Facts: File-Manager
  12. rewk: AmsdosFS
  13. Let’s Solve the File Format Problem! wiki: APF Imagination Machine disk file system
  14. Wikipedia: Apple File System
  15. knightjp: Mounting APFS partition
  16. ArchWiki: File systems
  17. sgan81: apfs-fuse
  18. Github: BetrFS
  19. Wikipedia: Be File System
  20. The Be Book: File System Architecture
  21. BeFS driver for Linux
  22. OSnews: Syllable Desktop 0.6.5 Released (comments on)
  23. Wikipedia: magnussoft ZETA
  24. Martin Hinner: UnixWare boot filesystem for Linux
  25. BitSavers: System V Release 4 manual, pg. 5-10
  26. Tigran A. Aivazian: Linux Implementation of SCO UnixWare BFS
  27. Wikipedia: List of file systems
  28. Wikipedia: Btrfs
  29. Haiku source: src/add-ons/kernel/file_systems/Jamfile
  30. maharmstone: WinBtrfs
  31. Let’s Solve the File Format Problem! wiki: CBMFS
  32. Let’s Solve the File Format Problem! wiki: Commodore 1581 filesystem
  33. AROS source: /rom/filesys/CDVDFS/
  34. AN!Wiki: Filesystem List
  35. Wikipedia: CMS file system
  36. Commodore 1581 (archive of)
  37. Compucolor II Disk Format
  38. Let’s Solve the File Format Problem! wiki: CP/M file system
  39. Cromemco: CDOS User's Manual
  40. Wikipedia: Comparison of DOS operating systems
  41. Wikipedia: CSI-DOS
  42. BTOS/CTOS Disk Structures
  43. Datapoint: Cassette Tape Operating System
  44. Let’s Solve the File Format Problem! wiki: DDFS
  45. Wikipedia: DECtape
  46. Let’s Solve the File Format Problem! wiki: Apple DOS file system
  47. 6502 Disassembly: GS/OS System 6.0.1 FST Disassembly
  48. Paul Lefebvre: Understanding the Atari DOS 2 File Format, Part 1
  49. EFS for Linux
  50. Let’s Solve the File Format Problem! wiki: EOS file system (Coleco)
  51. Wikipedia: EROFS
  52. Wikipedia: exFAT
  53. MDGX: MS-DOS 5.00 - 9.00 Undocumented + Hidden Secrets § exFAT
  54. Wikipedia: Comparison of file systems
  55. HelenOS source: uspace/srv/fs/
  56. The 5.4 hernel has been released
  57. IBM Developer: Anatomy of ext4 § A short history of the extended file system
  58. Wikipedia: Xiafs
  59. ReactOS: ReactOS 0.4.2 Released
  60. ReactOS Wiki: File Systems FAQ
  61. FreeBSD manual pages: ext2fs(5) at 11.0-RELEASE
  62. KolibriOS Wiki: FAQ
  63. Wikipedia: ext2
  64. OpenBSD manpages: fstab(5) at 2.5
  65. OpenBSD manpages: fstab(5) at 2.6, as compared to 2.5[64]
  66. SerenityOS source: Kernel/FileSystem/
  67. Syllable: Frequently Asked Questions
  68. About Visopsys
  69. Ext2 Installable File System For Windows
  70. FreeBSD manual pages: ext2fs(5) at 10.4-RELEASE, as compared to 11.0-RELEASE[61]
  71. linux-kernel mailing list: 2.4.15-final
  72. NetBSD Wiki: Implement ext3 file system support
  73. Wikipedia: ext3cow
  74. FreeBSD manual pages: ext2fs(5) at 12.1-RELEASE, as compared to 11.0-RELEASE[61]
  75. Lawrence Abrams: Windows 10 now lets you mount Linux ext4 filesystems in WSL 2
  76. Microsoft: Mount a Linux disk in WSL 2
  77. Phoronix: F2FS File-System Merged Into Linux 3.8 Kernel
  78. Wikipedia: File Allocation Table
  79. David Hansel: Altair 8800 Simulator
  80. Wikipedia: ANDOS
  81. AROS source: rom/filesys/
  82. Workbench 3.0 User’s Guide § 7
  83. EmuTOS source: doc/old_changelog.txt
  84. Operating System Documentation Project: MenuetOS
  85. Beta Wiki: MSX-DOS
  86. NetBSD 1.0 source tree: msdosfs_fat.c
  87. OpenBSD manpages: fstab(5) at 2.2
  88. Wikipedia: OS/2
  89. Wikipedia: IBM PC DOS
  90. RISC OS Open: Hardware Support
  91. Wikipedia: SkyOS
  92. James Youngma: TOS (Atari ST) filesystem on floppy
  93. Wikipedia: Windows 95
  94. Wikipedia: FlexOS
  95. Wikipedia: DR-DOS
  96. EmuTOS source: doc/fat16.txt
  97. Eugenia Loli: Introduction & Review of AtheOS 0.3.7
  98. Wikipedia: TSX-32
  99. stellarpower: Best File System for Multi Boot
  100. Phantom userland source: etc/attic
  101. Wikipedia: Multiuser DOS
  102. Emily: How to Format USB Flash Drive for Xbox 360 on PC?
  103. mborgerson: fatx
  104. Let’s Solve the File Format Problem! wiki: FFS
  105. AmigaOS Wiki: AmigaOS File Systems
  106. Amiga Fast File System (AFFS)
  107. OpenBSD manpages: fstab(5)
  108. OpenBSD manpages: fstab(5) at 4.2 as compared to 4.1[107]
  109. Wikipedia: Atari 8-bit family § Disk Operating System
  110. Wikipedia: Fossil (file system)
  111. Wikipedia: HAMMER (file system)
  112. Wikipedia: HAMMER
  113. Wikipedia: Hierarchical File System
  114. Linux source: fs/hfs
  115. Wikipedia: HFS Plus
  116. Wikipedia: Hierarchical File System (IBM MVS)
  117. HFS+ for Windows
  118. Wikipedia: ISO-9660
  119. Apple Discussions: How to Read a CD on 7.5.5?
  120. OSF/1 V1.0 manpages: fstab(4)
  121. Wikipedia: Files-11
  122. SunOS 4.1.3 manpages: fstab(5)
  123. Wikipedia: High Performance File System
  124. Linux source: fs/hpfs
  125. ucb.os.os2: Can Windows 95 read HPFS?
  126. OS/2 Site: Drivers - Filesystem - HPFS
  127. comp.os.os2.misc: Reading HPFS files from Windows XP
  128. Leif Salomonsson: IceFileSystem
  129. LUnix 0.21 sources
  130. Adventures in Amiga Land: Installing AmigaOS 3.2 - First Impressions!
  131. FreeBSD 13.1 manpages: cd9660(5)
  132. HP Support Community: How can access the Cd/DVD rom from FreeDos?
  133. HP/UX 10.20 manpages: fstab(4)
  134. IRIX 6.5.30 manpages: fstab(4)
  135. Linux source: fs/isofs
  136. MorphOS: Hardware Compatibility
  137. Microsoft Help and Support: History of Microsoft MS-DOS CD-ROM Extensions (MSCDEX) (archive of)
  138. RISC OS PRM volume 5a chapter 113
  139. Indiana University Information Technology Services: In Windows 95 or Windows 98, how do I access my CD-ROM drive under safe mode?
  140. Microsoft Support: A CD is not mounted on a Windows Embedded CE 6.0 R3-based device that supports CDFS and UDFS
  141. TP General - Installing Windows NT 4.0 from a non-supported CD-ROM drive
  142. Linux Devices: ELJonline: Flash Filesystems for Embedded Linux Systems (archive of)
  143. David Woodhouse: JFFS2
  144. Linux source: fs/jfs
  145. danrl: lanyfs-docs
  146. danrl: lanyfs-linux
  147. Lisa Filesystem Shell Tool
  148. Wikipedia: Linear Tape File System
  149. serge45: Files on a MDR Floppy disk
  150. Apple: Technote 1096: Mac OS 7.6.1 (archive of)
  151. Wikipedia: MINIX file system
  152. Probe House Software: Mint Extended filesystem
  153. Let’s Solve the File Format Problem! wiki: NILFS
  154. Linux source tree: fs/nilfs2
  155. Let’s Solve the File Format Problem! wiki: North Star DOS file system
  156. NVSL: linux-nova
  157. Wikipedia: NTFS
  158. FreeBSD 3.2 Release Notes
  159. Avira: NTFS4DOS Personal (archive of)
  160. OpenBSD 4.9 Changelog
  161. NTFS plugin for NetDrive
  162. Let’s Solve the File Format Problem! wiki: OFS
  163. VMS2Linux: ods5 file system
  164. Wikipedia: OS/8
  165. Philip Langdale: pifs
  166. Wikipedia: Professional File System
  167. Let’s Solve the File Format Problem! wiki: ProDOS file system
  168. KG7PFS: Why didn't somebody tell me about this!!!!!!!!!!!!!!!!!!!!
  169. bobbimanners: ProDOS-Utils
  170. Wikipedia: RSTS/E
  171. RedSea File Sysyem
  172. Resilient File System (ReFS) overview
  173. Wikipedia: ReiserFS
  174. What's the difference between the standard S51K filesystem and Acer filesystem?
  175. igb: I'd do it the slow but secure way.
  176. John Hendrikx: Home
  177. Let’s Solve the File Format Problem! wiki: Sinclair QL filesystem
  178. Let’s Solve the File Format Problem! wiki: SkyFS
  179. Wikipedia: Soup (Apple)
  180. Redox OS GitHub: TFS
  181. Digital: TOPS-20 User's Guide
  182. Let’s Solve the File Format Problem! wiki: TR-DOS filesystem
  183. Let’s Solve the File Format Problem! wiki: TRSDOS file system
  184. Memory Technology Devices: UBIFS - UBI File-System
  185. Let’s Solve the File Format Problem! wiki: UCSD p-System Filesystem
  186. Wikipedia: Universal_Disk_Format
  187. Gunkies: BSD Fast File System
  188. Gunkies: A/UX
  189. Gunkies: UNIX file system
  190. Wikipedia: Unix File System
  191. FreeBSD Handbook
  192. Linux source tree: fs/ufs
  193. Linux source tree: fs/xfs
  194. ULTRIX man pages: fstab(5)
  195. Adrian McMenamin: VMUFAT filesystem - v2
  196. Wikipedia: Veritas File System
  197. Let’s Solve the File Format Problem! wiki: XFS
  198. Wikipedia: zFS (z/OS file system)
  199. Wikipedia: ZFS