Filesystems HOWTO

Table of Contents

  1. Introduction
     1.1 Contacting the author
     1.2 HOWTO Maintenance
     1.3 Copyright
     1.4 Filesystems mailing-list
        1.4.1 Linux kernel filesystems mailing-list
        1.4.2 FreeBSD filesystems mailing-list
     1.5 Filesystems collection at
     1.6 Credits
     1.7 Filesystems accessibility map
     1.8 Introduction to contiguous allocation filesystems
     1.9 Introduction to linked-list allocation filesystems
     1.10 Introduction to FAT-based filesystems
     1.11 Introduction to Inode filesystems
     1.12 Introduction to extent filesystems
     1.13 Introduction to filesystems using balanced trees
     1.14 Introduction to logging/journaling filesystems
     1.15 Other filesystem features
        1.15.1 Quota
        1.15.2 Snapshot
        1.15.3 ACLs

  2. Volumes
     2.1 PC Partitions
        2.1.1 GNU parted
        2.1.2 Repairing corrupted partition table
     2.2 Other partitions
        2.2.1 ADFS partitions
        2.2.2 Amiga partitions
        2.2.3 ATARI partitions
        2.2.4 Macintosh partitions
        2.2.5 OSF partitions
        2.2.6 Sun partitions
        2.2.7 Ultrix partitions
     2.3 Unix disklabels
        2.3.1 BSD disklabel
        2.3.2 UnixWare disklabel
        2.3.3 SCO OpenServer disklabel
        2.3.4 Sun Solaris disklabel
     2.4 Windows NT volumes
        2.4.1 Repairing "fault tolerant" NTFS disks using FTEdit
     2.5 MD - Multiple Devices driver for Linux
     2.6 LVM - Logical Volume Manager (HP-UX LVM?)
     2.7 VxVM - Veritas Volume Manager
     2.8 IBM OS/2 LVM
     2.9 StackVM
     2.10 Novell NetWare volumes

  3. DOS FAT 12/16/32, VFAT
     3.1 VFAT: Long filenames
     3.2 UMSDOS: Linux LFN/attributes on FAT filesystem
     3.3 OS/2 Extended Attributes on FAT filesystems
     3.4 Star LFN
     3.5 Accessing VFAT from OS/2 (VFAT-OS2)
     3.6 Accessing VFAT from DOS (LFNDOS driver)
     3.7 Accessing VFAT from DOS (Free LFNDOS driver)
     3.8 Accessing VFAT from DOS (Odi's LFN tools)
     3.9 Accessing FAT32 from OS/2 (FAT32.IFS)
     3.10 Accessing FAT32 from Windows NT 4.0
     3.11 Accessing FAT32 from Windows NT 4.0
     3.12 Accessing Stac/Dblspaced/Drvspaced drives from Linux (DMSDOS)
     3.13 Accessing Dblspaced/Drvspaced drives from Linux (thsfs)
     3.14 Fsresize - FAT16/32 resizer
     3.15 FIPS - FAT16 resizer

  4. High Performance FileSystem (HPFS)
     4.1 Accessing HPFS from DOS (iHPFS)
     4.2 Accessing HPFS from DOS (hpfsdos)
     4.3 Accessing HPFS from DOS (hpfsa)
     4.4 Accessing HPFS from DOS (amos)
     4.5 Accessing HPFS from Linux
     4.6 Accessing HPFS from FreeBSD
     4.7 Accessing HPFS from Windows NT 3.5
     4.8 Accessing HPFS from Windows NT 4

  5. New Technology FileSystem (NTFS)
     5.1 Accessing NTFS from DOS (NTFSDOS.EXE)
     5.2 Accessing NTFS from DOS (ntpwd)
     5.3 Accessing NTFS from OS/2
     5.4 Accessing NTFS from Linux
     5.5 Accessing NTFS from FreeBSD and NetBSD
     5.6 Accessing NTFS from BeOS
     5.7 Accessing NTFS from BeOS (another)
     5.8 Repairing NTFS using NTFSDOS Tools
     5.9 Repairing NTFS using NTRecover

  6. Extended filesystems (Ext, Ext2, Ext3)
     6.1 Extended filesystem (ExtFS)
     6.2 Second Extended Filesystem (Ext2 FS)
        6.2.1 Motivations
        6.2.2 ``Standard'' Ext2fs features
        6.2.3 ``Advanced'' Ext2fs features
        6.2.4 Physical Structure
        6.2.5 Performance optimizations
     6.3 Third Extended Filesystem (Ext3 FS)
     6.4 E2compr - Ext2fs transparent compression
     6.5 Accessing Ext2 from DOS (Ext2 tools)
     6.6 Accessing Ext2 from DOS, Windows 9x/NT and other Unixes (LTools)
     6.7 Accessing Ext2 from OS/2
     6.8 Accessing Ext2 from Windows 95/98 (FSDEXT2)
     6.9 Accessing Ext2 from Windows 95 (Explore2fs)
     6.10 Accessing Ext2 from Windows NT (ext2fsnt)
     6.11 Accessing Ext2 from BeOS
     6.12 Accessing Ext2 from MacOS (MountX)
     6.13 Accessing Ext2 from MiNT
     6.14 Ext2fs defrag
     6.15 Ext2fs resize
     6.16 Ext2end
     6.17 Repairing/analyzing/creating Ext2 using E2fsprogs
     6.18 Ext2 filesystem editor - Ext2ed
     6.19 Linux filesystem editor - lde
     6.20 Ext2 undelete utilities

  7. Macintosh Hierarchical Filesystem - HFS
     7.1 Accessing HFS from Linux
     7.2 Accessing HFS from OS/2 (HFS/2)
     7.3 Accessing HFS from Windows 95/98/NT (HFV Explorer)
     7.4 Accessing HFS from DOS (MAC-ETTE)
     7.5 HFS utils
     7.6 MacFS: A Portable Macintosh File System Library

  8. ISO 9660 - CD-ROM filesystem
     8.1 RockRidge extensions
     8.2 Joliet extensions
     8.3 Hybrid CD-ROMs
     8.4 Novell NetWare indexes on ISO9660
     8.5 Accessing Joliet from Linux
     8.6 Accessing Joliet from BeOS
     8.7 Accessing Joliet from OS/2
     8.8 Accessing Audio CD as filesystem from Linux
     8.9 Accessing Audio CD as filesystem from BeOS
     8.10 Accessing all tracks from Linux (CDfs)
     8.11 Creating Hybrid CD-ROMs (mkhybrid)

  9. Other filesystems
     9.1 ADFS - Acorn Disc File System
     9.2 AFFS - Amiga fast filesystem
     9.3 BeFS - BeOS filesystem
     9.4 BFS - UnixWare Boot Filesystem
     9.5 CrosStor filesystem
     9.6 DTFS - Desktop filesystem
     9.7 EFS - Enhanced filesystem (Linux)
     9.8 EFS - Extent filesystem (IRIX)
        9.8.1 Accessing EFS from Windows NT/95
        9.8.2 EFS and FFS library, libfs
     9.9 FFS - BSD Fast filesystem
        9.9.1 Accessing FFS from MacOS
     9.10 GPFS - General Parallel Filesystem
     9.11 HFS - HP-UX Hi performance filesystem
     9.12 HTFS - High throughput filesystem
     9.13 JFS - Journaled filesystem (HP-UX, AIX, OS/2 5, Linux)
     9.14 LFS - Linux log structured filesystem
     9.15 MFS - Macintosh filesystem
     9.16 Minix filesystem
     9.17 NWFS - Novell NetWare filesystem
        9.17.1 NetWare filesystem / 286
        9.17.2 NetWare filesystem / 386
        9.17.3 Accessing NWFS-386 from Linux
     9.18 NSS - Novell Storage Services
     9.19 ODS - On Disk Structure filesystem
     9.20 QNX filesystem
     9.21 Reiser filesystem
     9.22 RFS (CD-ROM Filesystem)
     9.23 RomFS - Rom filesystem
     9.24 SFS - Secure filesystem
     9.25 Spiralog filesystem (OpenVMS)
     9.26 System V and derived filesystems
        9.26.1 AFS - Acer Fast Filesystem
        9.26.2 EAFS - Extended Acer Fast Filesystem
        9.26.3 Coherent filesystem
        9.26.4 S5
        9.26.5 S51K - SystemV 1K
        9.26.6 Version 7 filesystem
        9.26.7 Xenix filesystem
     9.27 Text - (Philips' CD-ROM Filesystem)
     9.28 UDF - Universal Disk Format (DVD-ROM filesystem)
     9.29 UFS
     9.30 V7 Filesystem
     9.31 VxFS - Veritas filesystem (HP-UX, SCO UnixWare, Solaris)
        9.31.1 VxTools
     9.32 XFS - Extended filesystem (IRIX)
     9.33 Xia FS

  10. Raw partitions
     10.1 Backing up raw partitions using DBsnapshot

  11. Appendix
     11.1 Network filesystems
        11.1.1 AFS - Andrew Filesystem
        11.1.2 CODA
        11.1.3 NFS - Network filesystem (Unix)
        11.1.4 NCP - NetWare Core Protocol (Novell NetWare)
        11.1.5 SMB - Session Message Block (Windows 3.x/9x/NT)
        11.1.6 Intermezzo
     11.2 Encrypted filesystems
        11.2.1 CFS
        11.2.2 TCFS
        11.2.3 SFS
        11.2.4 VS3FS: Steganographic File System for Linux
     11.3 Filesystem benchmarking utilities
        11.3.1 IOzone
     11.4 Writing your own filesystem driver
        11.4.1 DOS
        11.4.2 OS/2
        11.4.3 Windows NT
     11.5 Related documents


  1.  Introduction

  The Filesystems HOWTO is about filesystems and accessing filesystems
  from various OS. Although this document has been put together to the
  best of my knowledge, it may and probably does contain mistakes.
  Please if you find some mistake or outdated information, let me know.
  I will try to keep this document up to date and as error free as
  possible. Any contributions are also welcome, so if you want to write
  anything about filesystems, please contact me via e-mail.

  Update: Please note that this HOWTO wasn't updated for more than 5
  years and it DOES contain some out of date information. I will try to
  find some time to set-up WIKI site for filesystems related information
  so as anybody can contribute. For more information see next chapter.

  Before you read this HOWTO it's recommended to read Stein Gjoen's
  Disk-HOWTO (you can obtain it from
  <> ).

  This HOWTO can be obtained from  <> or

  If you are Japanese user, you might be interested that FUJIWARA
  Teruyoshi translated this HOWTO to Japanese.  It is available at
  <>.  SGML
  source file can be downloaded from

  1.1.  Contacting the author

  You can contact me at I welcome any suggestions
  and corrections, but please before you ask a question, try searching
  the internet first.  You should also check my homepage (
  <>) for any updates or additional
  information.  Please note that I am very busy with my other projects
  (like automotive diagnostics, ARM-based microprocessors development
  tools) and I have a full time job (I am working for SECONS Ltd. and
  Fintera Ltd.), so my time to answer e-mails is very limited.

  1.2.  HOWTO Maintenance

  If you want to contribute to this HOWTO or take over the maintenance,
  please look at author's website ( <>) and
  contact him.

  I will also try to set-up a wiki-style website for filesystems related
  information so as anyone can contribute and this website will be later
  merged with this HOWTO. All of these activities depend on my free

  1.3.  Copyright

  The Filesystems HOWTO, Copyright (c) 1999-2000 Martin Hinner

  This HOWTO is free document; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This HOWTO is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this document or GNU CC; if not, write to the: Free
  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

  1.4.  Filesystems mailing-list

  You may want to join Filesystems mailing list. It's intended to be a
  good source of information for both end-users and developers. So if
  you have anything to do with filesystems, join ;-) To subscribe send
  email to <> and in the BODY (not the subject) of
  the email message put (without quotes): "subscribe fs-l".

  1.4.1.  Linux kernel filesystems mailing-list

  To join Linux kernel filesystems mailing list linux-, send e-mail to Put
  "subscribe linux-fsdev" in message body.

  1.4.2.  FreeBSD filesystems mailing-list

  To join techical FreeBSD filesystems mailing list freebsd-, send e-mail to Put "subscribe
  freebsd-fs" in message body.

  1.5.  Filesystems collection at

  Filesystems collection is FTP/WWW site providing useful information
  about filesystems and filesystem-related programs and drivers. It
  lives at <>, or FTP-only at

  1.6.  Credits

  The original "Filesystems access HOWTO" was written by Georgatos
  Photis (see his homepage at  <>).
  This HOWTO contains a lot of information from his webpage. Thanks,

  FUJIWARA Teruyoshi <> translated this HOWTO to

  Other people who have contributed or helped me (directly or
  indirectly) with this HOWTO are, in alphabetical order:

  ·  Mariusz Borkowski <> - ISO9660/RR info

  ·  Remy Card <> - Ext2 filesystem introduction

  ·  Peter A. Dinda <> - HFS filesystem description

  ·  Alfonso De Gregorio <> - TCFS filesystem info

  ·  Radek Machacka <> - Thanks for SCO UnixWare and SCO

  ·  Andrey Shedel <> - Misc. updates

  ·  Peter Todd <> - SFS filesystem info

  ·  Theodore Ts'o <> - Ext2 filesystem introduction

  ·  Stephen Tweedie <> - Ext2 filesystem introduction

     Many thanks to the above people. If I have forgotten anyone, please
     let me know.

  1.7.  Filesystems accessibility map

  This is filesystem accessibility "map", alphabetically ordered by
  operating system. You may find this list a little bit chaotic. It's
  because Linux sgmltools don't know tables.


  FreeBSD: ``BSD FFS'' | ``Ext2'' | ``HPFS'' | ``NTFS''

  Linux: ``AFFS''| ``BeFS''| ``BFS''| ``Ext2 FS''| ``BSD FFS''|
  ``HPFS''| ``Qnx4 FS''| ``Xia''

  NetBSD: ``BSD FFS'' | ``FAT12/16'' | ``ISO9660''

  NetWare 2.x: ``NWFS-286''

  NetWare 3.x, 4.x: ``NWFS-386'' | ``ISO9660''

  NetWare 5.x: ``NWFS-386'' | ``NSS'' | ``ISO9660''

  OpenBSD: ``BSD FFS'' | ``FAT12/16''

  OS/2: ``Ext2 FS'' | ``FAT12/16/32'' | ``HPFS'' | ``HPFS'' | ``ISO
  9660'' | ``JFS'' | ``VFAT''

  QNX 4: ``FAT12/16'' | ``ISO 9660'' | ``Qnx4 FS''

  SCO OpenServer: ``AFS''| ``DTFS''| ``EAFS''| ``HTFS''| ``ISO 9660'' |

  SCO UnixWare: ``BFS''| ``DTFS''| ``ISO 9660'' | ``System V''| ``VxFS''

  1.8.  Introduction to contiguous allocation filesystems

  Some contiguous filesystems: ``BFS'', ``ISO9660 and extensions''.

  1.9.  Introduction to linked-list allocation filesystems

  1.10.  Introduction to FAT-based filesystems


  Some FAT filesystems: ``FAT12/16/32, VFAT'' and ``NetWare filestem''.

  1.11.  Introduction to Inode filesystems


  1.12.  Introduction to extent filesystems


  Some 'extent' filesystems: ``EFS'' and ``VxFS''.

  1.13.  Introduction to filesystems using balanced trees


  Some filesystems which use B+ trees: ``HFS'', ``NSS'', ``Reiser FS''
  and ``Spiralog filesystem''.
  1.14.  Introduction to logging/journaling filesystems

  File systems update their structural information (called metadata) by
  synchronous writes. Each metadata update may require many separate
  writes, and if the system crashes during the write sequence, metadata
  may be in inconsistent state.

  At the next boot the filesystem check utility (called fsck) must walk
  through the metadata structures, examining and repairing them.  This
  operation takes a very very long time on large filesystems.  And the
  disk may not contain sufficient information to correct the structure.
  This results in misplaced or removed files.

  A journaling file system uses a separate area called a log or journal.
  Before metadata changes are actually performed, they are logged to
  this separate area. The operation is then performed. If the system
  crashes during the operation, there is enough information in the log
  to "replay" the log record and complete the operation.

  This approach does not require a full scan of the file system,
  yielding very quick filesystem check time on large file systems,
  generally a few seconds for a multiple-gigabyte file system. In
  addition, because all information for the pending operation is saved,
  no removals or lost-and-found moves are required. Disadvantage of
  journaling filesystems is that they are slower than other filesystems.

  Some journaling filesystems: ``BeFS'', ``HTFS'', ``JFS'', ``NSS'',
  ``Spiralog filesystem'', ``VxFS'' and ``XFS''.

  1.15.  Other filesystem features

  1.15.1.  Quota

  1.15.2.  Snapshot

  1.15.3.  ACLs

  2.  Volumes

  2.1.  PC Partitions

  ·  <> Partition types document
     by Andries Brouwer <>

  2.1.1.  GNU parted

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Authors: Andrew Clausen <>, Lennert Buytenhek
     <> and Matt Wilson <>.

  ·  Bug reports: <>,

  ·  Access: varies for each filesystem, see below.

  ·  License: GPL

     GNU Parted is a program for creating, destroying, resizing,
     checking and copying partitions, and the filesystems on them.

  This is useful for creating space for new operating systems,
  reorganising disk usage, copying data between hard disks, and "disk
  imaging" - replicating installations over many computers.

  Parted has support for these operations:

  Filesystem      detect  create  resize  copy    check
  ext2            *       *       *1      *2      *3
  fat             *       *       *4      *4      *
  linux-swap      *       *       *       *       *


  (1) The start of the partition must stay fixed for ext2.

  (2) The partition you copy to must be bigger (or exactly the same
  size) as the partition you copy from.

  (3) Limited checking is done when the filesystem is opened.  This is
  the only checking at the moment.  All commands (including resize) will
  gracefully fail, leaving the filesystem in tact, if there are any
  errors in the file system (and the vast majority of errors in

  (4) The size of the new partition, after resizing or copying, is
  restricted by the cluster size for fat (mainly affects FAT16).  This
  is worse than you think, because you don't get to choose your cluster
  size (it's a bug in Windows, but you want compatibility, right?).

  So, in practise, you can always shrink your partition (because Parted
  can shrink the cluster size), but you may not be able to grow the
  partition to the size you want.  If you don't have any problems with
  using FAT32, you will always be able to grow the partition to the size
  you want.

  Summary: you can always shrink your partition.  If you can't use FAT32
  for some reason, you may not be able to grow your partition.

  2.1.2.  Repairing corrupted partition table  Fixdisktable

  ·  Homepage:  <>

  ·  Download: ?

  ·  Author: ?

  ·  Access: ?

  ·  License: ?

     This is a utility that handles ext2, FAT, NTFS, ufs, BSD disklabels
     (but not yet old Linux swap partitions); it actually will rewrite
     the partition table, if you give it permission.  gpart

  ·  Homepage:  <>

  ·  Download: ?

  ·  Author: ?

  ·  Access: ?

  ·  License: ?

     GPART is a utility that handles ext2, FAT, Linux swap, HPFS, NTFS,
     FreeBSD and Solaris/x86 disklabels, minix, reiser fs; it prints a
     proposed contents for the primary partition table, and is well-
     documented.  rescuept

  ·  Homepage: util-linux ?

  ·  Download: ?

  ·  Author: ?

  ·  Access: ?

  ·  License: ?

     Recognizes ext2 superblocks, FAT partitions, swap partitions, and
     extended partition tables; it may also recognize BSD disklabels and
     Unixware 7 partitions.  It prints out information that can be used
     with fdisk or sfdisk to reconstruct the partition table.  It is in
     the non-installed part of the util-linux distribution.  findsuper

  ·  Homepage: e2progs ?

  ·  Download: ?

  ·  Author: ?

  ·  Access: ?

  ·  License: ?

     Small utility that finds blocks with the ext2 superblock signature,
     and prints out location and some info.  It is in the non-installed
     part of the e2progs distribution.

  2.2.  Other partitions

  Because I use only Intel x86 machines, any contributions (or non-x86
  machine donation ;-) ) are very welcome. If you can provide any useful
  information, don't hesitate to mail me.

  2.2.1.  ADFS partitions

  2.2.2.  Amiga partitions

  2.2.3.  ATARI partitions

  2.2.4.  Macintosh partitions

  2.2.5.  OSF partitions

  2.2.6.  Sun partitions

  2.2.7.  Ultrix partitions

  2.3.  Unix disklabels


  2.3.1.  BSD disklabel


  2.3.2.  UnixWare disklabel

  UnixWare VTOC (Volume Table Of Contents) divides disk partition to 16
  logical partitions. Linux kernel supports UnixWare VTOC, you must
  check "UnixWare slices support (EXPERIMENTAL)" and recompile your
  kernel.  Another way of reading UnixWare disklabel is using GPL port
  of prtvtoc(1) command, which is in ``vxtools'' package.

  2.3.3.  SCO OpenServer disklabel


  2.3.4.  Sun Solaris disklabel


  2.4.  Windows NT volumes

  ·  Homepage:  <>

  ·  Author: Martin Hinner <>

  ·  Access: Read-only, supports OS/2 Volumes, Windows NT Stripe sets
     and volumes.

  ·  Download:  <>

  ·  License: GPL

     This linux-kernel driver allows you to access and mount linear and
     stripe set volumes.

  2.4.1.  Repairing "fault tolerant" NTFS disks using FTEdit

  ·  Homepage:  ? MS ARTICLE ID: Q131658

  ·  Download:  <ftp://ftp.rhrz.uni->

  ·  Author: Microsoft Corp.

  ·  License: ?

     If you have a Windows NT Workstation or Server configured for fault
     tolerant (FT) partitions (such as stripes with parity and volume
     sets), and those partitions are inaccessible and appear in Disk
     Administrator as type Unknown, you can possibly make them
     accessible again by using the utility FTEDIT.

  2.5.  MD - Multiple Devices driver for Linux

  ·  Homepage:?

  ·  Author: Marc Zyngier <>

  ·  Access: Read-write, supports linear mode, RAID-1, RAID-4 and

  ·  Download: Linux kernel, tools are available at <ftp://sweet->

  ·  License: GPL

     This driver lets you combine several hard disk partitions into one
     logical block device. This can be used to simply append one
     partition to another one or to combine several redundant hard disks
     to a RAID1/4/5 device so as to provide protection against hard disk
     failures. This is called "Software RAID" since the combining of the
     partitions is done by the kernel.

  2.6.  LVM - Logical Volume Manager (HP-UX LVM?)

  Linux implementation is available here:

  ·  Homepage:  <>

  ·  Author: Heinz Mauelshagen <>

  ·  Access: ?

  ·  Download:  <>

  ·  License: GPL

  2.7.  VxVM - Veritas Volume Manager

  For more information about Veritas Volume Manager see

  See also: ``VxFS (Veritas Journaling Filesystem)''.

  2.8.  IBM OS/2 LVM

  Logical Volume Manager is available in OS/2 WarpServer 5. It allows
  you to create linear volumes on several disks/partitions. Some people
  say that it's compatible with IBM AIX Logical Volume Manager.

  See also: ``HPFS'', ``JFS''

  2.9.  StackVM

  StackVM is CrosStor's volume manager. Using StackVM the administrator
  can combine multiple physical disk slices into a single logical device
  know as a vdisk. Vdisk is short for virtual disk. The physical disks
  can be combined to form a concatenation, RAID 0 (stripe), RAID 1
  (mirror), RAID 4 or RAID 5. In addition a single disk partition can be
  subdivided into multiple simple vdisks. For more information see
  CrosStor homepage at  <>.

  2.10.  Novell NetWare volumes

  NetWare volumes are used for NWFS-386 filesystem.

  3.  DOS FAT 12/16/32, VFAT

  3.1.  VFAT: Long filenames

  Windows 95/98 and Windows NT/2000 store long filenames on FAT in
  special directory entries with set attributes ReadOnly, Hidden, System
  and Volume, so if you access FAT volume from DOS you don't see these
  "files". These special entries have this mad structure:

  byte              sequence number for slot
  string(10)        first 5 characters in name
  byte              attribute byte
  byte              always 0
  byte              checksum for 8.3 alias
  string(12)        6 more characters in name
  word              starting cluster number, 0 in long slots
  string(4)         last 2 characters in name

  Problem occur when you delete or modify file with long name from
  system without VFAT support, because only DOS 8+3 entry will be
  deleted or modified. Scandisk from Windows 95/98 can repair this

  3.2.  UMSDOS: Linux LFN/attributes on FAT filesystem

  Linux has it's own FAT extensions which gives you long filenames,
  permissions and owners, links and special devices on FAT partition,
  called UMSDOS.  Each directory contains file named "--linux-.---".
  There are stored long names and other necessary fields. For more
  information see file
  /usr/src/linux/Documentation/filesystems/umsdos.txt. Author of Linux
  umsdos driver is Jacques Gelinas <> and it is
  currently maintained by Matija Nalis <>.

  3.3.  OS/2 Extended Attributes on FAT filesystems

  OS/2 Warp version 3,4 and 5 stores long filenames and extended
  attributes on FAT volume in files "\ea data. sf" and "\wp root. sf"
  (both files are in root directory of filesystem). AFAIK there is no
  known implementation of OS/2 EAs for any other OS. If you can supply
  any information about EA structure, don't hesitate to mail them to me.

  3.4.  Star LFN

  Star LFN is an emulator that allows programs, running under DOS 4.0 or
  above, to use the long filename functions present in Windows'95 DOS
  boxes. Currently, it can only read and write long filenames from and
  into a system+hidden file, which means you can't either read or write
  real Windows'95 long filenames. For more information see

  3.5.  Accessing VFAT from OS/2 (VFAT-OS2)

  ·  Homepage:  <>

  ·  Author: Daniel Steiner <>

  ·  Access: Read-Write, no EAs supported.

  ·  Mirror:  <>

  ·  License: GPL

     VFAT-OS2 is a package that will allow OS/2 to seamlessly access
     Windows 95 VFAT formatted partitions from OS/2 as if they were
     standard OS/2 drive letters. The ultimate aim of this package is to
     be able to use the VFAT file system as a replacement of FAT. It can
     now also access NTFS partitions in read-only mode.

  3.6.  Accessing VFAT from DOS (LFNDOS driver)

  Some people say that Microsoft has released a driver called LFNDOS
  that provides the Microsoft Long Filename API under DOS. If you know
  where can this driver be downloaded, send me e-mail please.

  3.7.  Accessing VFAT from DOS (Free LFNDOS driver)

  ·  Homepage:  <>

  ·  Author: Chris Jones <>

  ·  Access: Read-Write

  ·  Mirror:

  ·  License: Free, source code available

     LFNDOS provides the Windows95 Long Filename (LFN) API to DOS
     programs.  It uses the same format for storing the names on disk as
     Windows95 does, so you can view and use long filenames under both
     systems interchangeably. It runs as a memory-resident program, and
     while resident requires about 60k of conventional memory.

  Under Windows95, a DOS program can use long filenames by calling a set
  of interrupt functions, which Windows provides. For example,
  COMMAND.COM will allow long filenames when run as a DOS Prompt from
  Windows, but not if you restart in MS-DOS mode. Other programs such as
  EDIT.COM and all DJGPP programs use long filenames if available.

  3.8.  Accessing VFAT from DOS (Odi's LFN tools)

  ·  Homepage:  <>

  ·  Author: Ortwin Glueck <>

  ·  Access: Read-Write, only DOS utilities

  ·  Mirror:

  ·  License: ?

     These tools provide easy file management under DOS with long
     filenames created by Windows 95/98 on FAT32, FAT16 and FAT12 file
     systems.  Typing LDIR brings up the directory with its long
     filenames. Copying a file with LCOPY preserves long filenames.  You
     can even create directories (LMD) with long names or rename files
     (LREN) with long names.

  3.9.  Accessing FAT32 from OS/2 (FAT32.IFS)

  ·  Homepage:  <>

  ·  Author: Henks Kelder < >

  ·  Access: Read-Write, long filenames, no EAs support.

  ·  Download:  <>

  ·  License: Free

     FAT32.IFS for OS/2 will allow you to access FAT32 partitions from
     OS/2. You cannot create FAT32 partitions, you'll still need Win95
     OSR2 to do that.  Also, OS/2s CHKDSK cannot fix all possible errors
     that can occur, you'll have to use Windows 95 Scandisk to fix
     certain errors.

  3.10.  Accessing FAT32 from Windows NT 4.0

  ·  Download:  <>

  ·  Author: Anonymous

  ·  License: Free or GPL ?

     FAT32 filesystem driver for NT 4.0 and NT 3.51.

  3.11.  Accessing FAT32 from Windows NT 4.0

  ·  Homepage:  <>

  ·  Author: Mark Russinovich <> and Bryce Cogswell

  ·  Access: Read-only in free version, RW in commercial.

  ·  Download: ?

  ·  License: Free(read-only) or Commercial(read-write)

     This is a FAT32 file system driver for Windows NT(R) 4.0. Once
     installed, any FAT32 drives present on your system will be fully
     accessible as native Windows NT volumes. Free version provides
     read-only capabilities. A read/write version is for sale.

  3.12.  Accessing Stac/Dblspaced/Drvspaced drives from Linux (DMSDOS)

  ·  Homepage:  <http://fb9nt.uni->

  ·  Author: Frank Gockel <> and Pavel Pisa

  ·  Access: Stacker, Dblspace and Drvspace in Read-Write mode, long

  ·  Download:  <>

  ·  Freshmeat: Console/Filesystems

  ·  License: GPL

     DMSDOS reads and writes compressed DOS filesystems (CVF-FAT). The
     following configurations are supported:

  ·  DoubleSpace / DriveSpace (MS-DOS 6.x)

  ·  DoubleSpace / DriveSpace (Windows 95)

  ·  DriveSpace 3 (Windows 95 with Plus! pack)

  ·  Stacker 3

  ·  Stacker 4

     It works with FAT32, NLS, codepages (tested with fat32 patches
     version 0.2.8 under Linux 2.0.33 and with fat32 in standard 2.1.xx
     kernels and 2.0.34+35). Dmsdos can run together with vfat or umsdos
     for long filenames. It has been redesigned to be ready for SMP and
     should now compile completely under libc6.

  3.13.  Accessing Dblspaced/Drvspaced drives from Linux (thsfs)

  ·  Download:  <>

  ·  Author: Thomas Scheuermann <>

  ·  Access: Dblspace and Drvspace in Read-only mode.

  ·  License: See copyright on files. Basically free

  3.14.  Fsresize - FAT16/32 resizer

  ·  Homepage:  <>

  ·  Author: Andrew Clausen <>

  ·  Download:

  ·  Freshmeat: Console/Filesystems

  ·  Access: Read/Write, full FAT16/FAT32 support

  ·  License: GPL

     Resizes FAT16/FAT32 filesystems.  It doesn't require any other
     programs (like a defrager).  It has --backup and --restore options,
     so if there's a power failure, (or a bug), you can always go back.
     The backup files are usually < 1 meg.

  The author  probably won't be releasing any more versions of fsresize,
  because he is working on parted - a Partition Magic clone. It will be
  able to resize, copy, create and check filesystems/partitions.

  3.15.  FIPS - FAT16 resizer

  ·  Homepage: ?

  ·  Author: Arno Schaefer <>

  ·  Download:

  ·  License: GPL

  4.  High Performance FileSystem (HPFS)

  Good HPFS links:

  ·  <>

  ·  <>

  ·  <> - a good page
     about HPFS accessibility

  ·  <
     adv/c2j.html> - IBM OS/2 Warp Server : Features & Benefits : File &

  4.1.  Accessing HPFS from DOS (iHPFS)

  ·  Homepage: <>

  ·  Author: Marcus Better

  ·  Download:

  ·  Access: Read-only

  ·  License: GPL

  iHPFS makes possible for OS/2 users to use their HPFS partitions when
  they boot plain DOS.  The HPFS partition is assigned a drive letter,
  and can be accessed like any DOS drive.iHPFS is restricted to read-
  only access.

  This program is no longer being developed, because author doesn't use
  OS/2. If you are willing to maintain the program, let him know.

  4.2.  Accessing HPFS from DOS (hpfsdos)

  ·  Homepage: ?

  ·  Author: Robert Muchsel <> (this e-mail doesn't

  ·  Access: Read-only

  ·  License: Shareware ($23)

  4.3.  Accessing HPFS from DOS (hpfsa)

  ·  Homepage:  <>

  ·  Author: Andreas Kinzler <>
     (this email doesn't work)

  ·  Download: <>

  ·  Access: Read/Write

  ·  License: Shareware ($40)

  4.4.  Accessing HPFS from DOS (amos)

  ·  Homepage: ?

  ·  Author:  Allan Mertner <> (this email doesn't

  ·  Download:  <>

  ·  License: Shareware ($50)

  4.5.  Accessing HPFS from Linux

  ·  Homepage:

  ·  Download:
     for 2.0 kernels; and
     for 2.2 kernels
  ·  Author: Mikulas Patocka < >

  ·  Access: Read-Write, extended attributes, long names.

  ·  License: GPL

     This driver is part of Linux kernel (2.1.x+). It can read and write
     to HPFS partions. Access rights and owner can be stored in extended
     attributes. Few bugs in original read-only HPFS are corrected.  It
     supports HPFS386 on Warp Server Advanced.

  If you have kernel with HPFS support, say "Y"es to 'OS/2 HPFS
  filesystem support' in Filesystems submenu. Then recompile kernel
  using 'make dep bzImage', reboot and try to mount your HPFS partition
  (e.g. mount /dev/hda2 /mnt -t hpfs).

  4.6.  Accessing HPFS from FreeBSD

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Semen A. Ustimenko < >

  ·  Access: Read/Only

  ·  License: BSD

     Driver allows to mount HPFS volume into Unix namespace.  ReadOnly
     access is only supported for now.

  4.7.  Accessing HPFS from Windows NT 3.5

  ·  Homepage: <>

  ·  Download: <>

  ·  Author: Chris Behnken < >

  ·  License: Freeware

     This program will edit the Windows NT registry and enable HPFS
     support.  Pinball.sys is the HPFS filesystem driver for Windows NT.
     It can be found on NT 3.5x's CD-ROM.  Microsoft no longer supports
     HPFS.  Installing this program will void your warranty and possibly
     the license agreement.

  4.8.  Accessing HPFS from Windows NT 4

  ·  Download: <>

  ·  Author: ?

  ·  License: ?

     HPFS driver for Windows NT 4.0

  5.  New Technology FileSystem (NTFS)


  ·  <> NTFS 5

  ·  Rajeev Nagar, Windows NT File System Internals (O'Reilly).

  ·  Helen Custer, Inside the Windows NT File System, ISBN:

  ·  NTFS documentation by Regis Duchesne <>,
     <> or

  ·  Microsoft TechNet, February 97, Windows NT Training: Support, NTFS

  ·  <>

  5.1.  Accessing NTFS from DOS (NTFSDOS.EXE)

  ·  Homepage:

  ·  Authors: Mark Russinovich <> and Bryce
     Cogswell <>.

  ·  Access: Read-only, Long filenames under DOS 7 and Win9x.

     NTFSDOS.EXE is a network file system redirector for DOS/Windows
     that is able to recognize and mount NTFS drives for transparent
     access.  It makes NTFS drives appear indistinguishable from
     standard FAT drives, providing the ability to navigate, view and
     execute programs on them from DOS or from Windows, including from
     the Windows 3.1 File Manager and Windows 95 Explorer.

  5.2.  Accessing NTFS from DOS (ntpwd)

  ·  Homepage:  <>

  ·  Author: Grenier Christophe <  >

  ·  Access: Read-only (rw experimental), long filenames supported, no
     driver letter (dos tools)

  ·  License: GPL

  NTPwd contains command line tools to access NTFS partition, it'a a Dos
  port of the driver used by Linux. It contains too a little utility to
  change NT password.

  5.3.  Accessing NTFS from OS/2

  ·  Homepage:  <>

  ·  Mirror:  <ftp://ftp->,
  ·  Author: Daniel Steiner < >

  ·  Access: Read-only, Long filenames supported archive contains only command line tools to acccess a
     NTFS partition in OS/2. A true IFS for accessing NTFS is included
     in ``VFAT-OS2'' v0.05.

  5.4.  Accessing NTFS from Linux

  ·  Homepage:  <>

  ·  Author: Martin von Lwis

  ·  Freshmeat: Console/Filesystems

  ·  Homepage:  <

  ·  Mirror: Included in official Linux kernel

  ·  Access: RO, experimental RW, compression, no encryption

  ·  License: GPL

     Works both as a kernel driver, as well as a set of command line

  5.5.  Accessing NTFS from FreeBSD and NetBSD

  ·  Homepage:  <>

  ·  Author: Semen A. Ustimenko <

  ·  Download: As part of FreeBSD (
     <>), and NetBSD (

  ·  Mirror: Lookup for FreeBSD's and NetBSD's mirrors

  ·  Access: Read + limited writing, doesn't support codepages

  ·  License: BSD

     Driver allows to mount NTFS volumes under FreeBSD and NetBSD. We
     also support limited writing ability: you can write into not
     comressed files without holes, but you can't change the size of
     file yet. Write support was made to swap on NTFS volume.

  5.6.  Accessing NTFS from BeOS

  ·  Homepage:  <>

  ·  Author: Travis Geiselbrecht < >

  ·  Download:

  ·  Access: ?

  ·  License: Free

     This is a ALPHA version of a NTFS driver for BeOS. It is not the
     most polished thing in the world, but every release that author
     puts out is more stable than the last. He just implemented
     compressed file reads, so be careful with those.  He also finally
     worked with NTFS 5 volumes, and managed to root out a few bugs.

  Author now works for Be Inc, so you will not see his NTFS and ext2
  filesystem support updated on the web much more. The drivers will be
  pulled into future BeOS releases.

  5.7.  Accessing NTFS from BeOS (another)

  ·  Homepage:

  ·  Author: Standard & Western Software,

  ·  Download:

  ·  Access: Read-only.

  5.8.  Repairing NTFS using NTFSDOS Tools

  ·  Homepage:   <>

  ·  Author: Winternals Software <>

  ·  Access: Read-Write: Copy and replace files.

  ·  License: Commercial

     An add-on to NTFSDOS that allows one to rename existing files, or
     to overwrite a file with new data.  Very limited functionality.

  5.9.  Repairing NTFS using NTRecover

  ·  Homepage:  <>

  ·  Author: Winternals Software <>

  ·  Access: Freeware version is read-only, commercial version is

  ·  License: Freeware read-only version, commercial read/write version

     Uses a boot floppy and a serial connection to a second NT system to
     provide full access to a NTFS drives on dead NT systems.  Ideal for
     salvaging data or replacing drivers.

  6.  Extended filesystems (Ext, Ext2, Ext3)

  Extended filesystem (ext fs), second extended filesystem (ext2fs) and
  third extended filesystem (ext3fs) were designed and implemented on
  Linux by Rmy Card, Laboratoire MASI--Institut Blaise Pascal,
  <>, Theodore Ts'o, Massachussets Institute of
  Technology, <> and Stephen Tweedie, University of
  Edinburgh, <>

  ·  <> - The ext2 homepage.
     This is the primary source of information about ext2.

  ·  <> - Document
     about ext2fs from John Newbigin.

  ·  <> - Ext2fs_Rec (ext2 recognizer for

  6.1.  Extended filesystem (ExtFS)

  This is old filesystem used in early Linux systems.

  6.2.  Second Extended Filesystem (Ext2 FS)

  The Second Extended File System is probably the most widely used
  filesystem in the Linux community. It provides standard Unix file
  semantics and advanced features. Moreover, thanks to the optimizations
  included in the kernel code, it is robust and offers excellent

  Since Ext2fs has been designed with evolution in mind, it contains
  hooks that can be used to add new features. Some people are working on
  extensions to the current filesystem: access control lists conforming
  to the Posix semantics, undelete, and on-the-fly file compression.

  Ext2fs was first developed and integrated in the Linux kernel and is
  now actively being ported to other operating systems. An Ext2fs server
  running on top of the GNU Hurd has been implemented. People are also
  working on an Ext2fs port in the LITES server, running on top of the
  Mach microkernel and in the VSTa operating system. Last, but not
  least, Ext2fs is an important part of the Masix operating system,
  currently under development by one of the authors.

  6.2.1.  Motivations

  The Second Extended File System has been designed and implemented to
  fix some problems present in the first Extended File System. Our goal
  was to provide a powerful filesystem, which implements Unix file
  semantics and offers advanced features.

  Of course, we wanted to Ext2fs to have excellent performance.  We also
  wanted to provide a very robust filesystem in order to reduce the risk
  of data loss in intensive use. Last, but not least, Ext2fs had to
  include provision for extensions to allow users to benefit from new
  features without reformatting their filesystem.

  6.2.2.  ``Standard'' Ext2fs features

  The Ext2fs supports standard Unix file types: regular files,
  directories, device special files and symbolic links.

  Ext2fs is able to manage filesystems created on really big partitions.
  While the original kernel code restricted the maximal filesystem size
  to 2 GB, recent work in the VFS layer have raised this limit to 4 TB.
  Thus, it is now possible to use big disks without the need of creating
  many partitions.

  Ext2fs provides long file names. It uses variable length directory
  entries. The maximal file name size is 255 characters. This limit
  could be extended to 1012 if needed.

  Ext2fs reserves some blocks for the super user (root). Normally, 5% of
  the blocks are reserved. This allows the administrator to recover
  easily from situations where user processes fill up filesystems.

  6.2.3.  ``Advanced'' Ext2fs features

  In addition to the standard Unix features, Ext2fs supports some
  extensions which are not usually present in Unix filesystems.

  File attributes allow the users to modify the kernel behavior when
  acting on a set of files. One can set attributes on a file or on a
  directory. In the later case, new files created in the directory
  inherit these attributes.

  BSD or System V Release 4 semantics can be selected at mount time. A
  mount option allows the administrator to choose the file creation
  semantics. On a filesystem mounted with BSD semantics, files are
  created with the same group id as their parent directory. System V
  semantics are a bit more complex: if a directory has the setgid bit
  set, new files inherit the group id of the directory and
  subdirectories inherit the group id and the setgid bit; in the other
  case, files and subdirectories are created with the primary group id
  of the calling process.

  BSD-like synchronous updates can be used in Ext2fs. A mount option
  allows the administrator to request that metadata (inodes, bitmap
  blocks, indirect blocks and directory blocks) be written synchronously
  on the disk when they are modified.  This can be useful to maintain a
  strict metadata consistency but this leads to poor performances.
  Actually, this feature is not normally used, since in addition to the
  performance loss associated with using synchronous updates of the
  metadata, it can cause corruption in the user data which will not be
  flagged by the filesystem checker.

  Ext2fs allows the administrator to choose the logical block size when
  creating the filesystem. Block sizes can typically be 1024, 2048 and
  4096 bytes. Using big block sizes can speed up I/O since fewer I/O
  requests, and thus fewer disk head seeks, need to be done to access a
  file. On the other hand, big blocks waste more disk space: on the
  average, the last block allocated to a file is only half full, so as
  blocks get bigger, more space is wasted in the last block of each
  file. In addition, most of the advantages of larger block sizes are
  obtained by Ext2 filesystem's preallocation techniques.

  Ext2fs implements fast symbolic links. A fast symbolic link does not
  use any data block on the filesystem. The target name is not stored in
  a data block but in the inode itself. This policy can save some disk
  space (no data block needs to be allocated) and speeds up link
  operations (there is no need to read a data block when accessing such
  a link). Of course, the space available in the inode is limited so not
  every link can be implemented as a fast symbolic link. The maximal
  size of the target name in a fast symbolic link is 60 characters. We
  plan to extend this scheme to small files in the near future.

  Ext2fs keeps track of the filesystem state. A special field in the
  superblock is used by the kernel code to indicate the status of the
  file system. When a filesystem is mounted in read/write mode, its
  state is set to ``Not Clean''. When it is unmounted or remounted in
  read-only mode, its state is reset to ``Clean''. At boot time, the
  filesystem checker uses this information to decide if a filesystem
  must be checked. The kernel code also records errors in this field.
  When an inconsistency is detected by the kernel code, the filesystem
  is marked as ``Erroneous''. The filesystem checker tests this to force
  the check of the filesystem regardless of its apparently clean state.

  Always skipping filesystem checks may sometimes be dangerous, so
  Ext2fs provides two ways to force checks at regular intervals. A mount
  counter is maintained in the superblock. Each time the filesystem is
  mounted in read/write mode, this counter is incremented. When it
  reaches a maximal value (also recorded in the superblock), the
  filesystem checker forces the check even if the filesystem is
  ``Clean''. A last check time and a maximal check interval are also
  maintained in the superblock. These two fields allow the administrator
  to request periodical checks. When the maximal check interval has been
  reached, the checker ignores the filesystem state and forces a
  filesystem check.

  An attribute allows the users to request secure deletion on files.
  When such a file is deleted, random data is written in the disk blocks
  previously allocated to the file. This prevents malicious people from
  gaining access to the previous content of the file by using a disk

  Last, new types of files inspired from the 4.4 BSD filesystem have
  recently been added to Ext2fs. Immutable files can only be read:
  nobody can write or delete them. This can be used to protect sensitive
  configuration files. Append-only files can be opened in write mode but
  data is always appended at the end of the file. Like immutable files,
  they cannot be deleted or renamed. This is especially useful for log
  files which can only grow.

  6.2.4.  Physical Structure

  The physical structure of Ext2 filesystems has been strongly
  influenced by the layout of the BSD filesystem. A filesystem is made
  up of block groups. Block groups are analogous to BSD FFS's cylinder
  groups. However, block groups are not tied to the physical layout of
  the blocks on the disk, since modern drives tend to be optimized for
  sequential access and hide their physical geometry to the operating
  | Boot    | Block   | Block   |   ...   | Block   |
  | sector  | group 1 | group 2 |         | group n |

  Each block group contains a redundant copy of crucial filesystem
  control informations (superblock and the filesystem descriptors) and
  also contains a part of the filesystem (a block bitmap, an inode
  bitmap, a piece of the inode table, and data blocks). The structure of
  a block group is represented in this table:

  | Super   | FS      | Block   | Inode   | Inode   | Data    |
  | block   | desc.   | bitmap  | bitmap  | table   | blocks  |

  Using block groups is a big win in terms of reliability: since the
  control structures are replicated in each block group, it is easy to
  recover from a filesystem where the superblock has been corrupted.
  This structure also helps to get good performances: by reducing the
  distance between the inode table and the data blocks, it is possible
  to reduce the disk head seeks during I/O on files.

  In Ext2fs, directories are managed as linked lists of variable length
  entries. Each entry contains the inode number, the entry length, the
  file name and its length. By using variable length entries, it is
  possible to implement long file names without wasting disk space in

  6.2.5.  Performance optimizations

  In Linux, the Ext2fs kernel code contains many performance
  optimizations, which tend to improve I/O speed when reading and
  writing files.

  Ext2fs takes advantage of the buffer cache management by performing
  readaheads: when a block has to be read, the kernel code requests the
  I/O on several contiguous blocks. This way, it tries to ensure that
  the next block to read will already be loaded into the buffer cache.
  Readaheads are normally performed during sequential reads on files and
  Ext2fs extends them to directory reads, either explicit reads
  (readdir(2) calls) or implicit ones (namei kernel directory lookup).

  Ext2fs also contains many allocation optimizations. Block groups are
  used to cluster together related inodes and data: the kernel code
  always tries to allocate data blocks for a file in the same group as
  its inode. This is intended to reduce the disk head seeks made when
  the kernel reads an inode and its data blocks.

  When writing data to a file, Ext2fs preallocates up to 8 adjacent
  blocks when allocating a new block. Preallocation hit rates are around
  75% even on very full filesystems. This preallocation achieves good
  write performances under heavy load. It also allows contiguous blocks
  to be allocated to files, thus it speeds up the future sequential

  These two allocation optimizations produce a very good locality of:

  ·  related files through block groups

  ·  related blocks through the 8 bits clustering of block allocations.

  6.3.  Third Extended Filesystem (Ext3 FS)

  Ext3 support the same features as Ext2, but includes also Journaling.
  You can download pre- version from

  6.4.  E2compr - Ext2fs transparent compression

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Maintainer: Peter Moulder <>

  ·  Freshmeat: Console/Filesystems

  ·  Access: As for ext2 (Read/Write, Long filenames)

  ·  License: GPL except for compression algorithms (various licenses)

     Implements `chattr +c' for the ext2 filesystem.  Software consists
     of a patch to the linux kernel, and patched versions of various
     software (principally e2fsprogs i.e. e2fsck and friends).  Although
     some people have been relying on it for years, THIS SOFTWARE IS

  6.5.  Accessing Ext2 from DOS (Ext2 tools)

  ·  Download:

  ·  Access: Read-only, no drive letters (special utilites)

  ·  Author: Claus Tondering <>

  ·  Access: ?

  ·  License: ?

     A collection of DOS programs that allow you to read a Linux ext2
     file system from DOS.

  6.6.  Accessing Ext2 from DOS, Windows 9x/NT and other Unixes (LTools)

  ·  Homepage:  <>

  ·  Author: Werner Zimmermann <>

  ·  Homepage:  <>

  ·  Mirror:  <> (only major

  ·  Access: Read/Write/Modify, Long filenames

  ·  License: GPL

     The LTOOLS are under DOS/Windows 3.x/Windows 9x/Windows NT or non-
     Linux-UNIX, what the MTOOLS are under Linux. You can access (read,
     write, modify) your Linux files when running one of the other
     operating systems. The kernel of the LTOOLS is a set of command
     line programs.  Additionally a JAVA program as a stand alone
     graphical user interface is available. Alternatively, you can use
     your standard web browser as a graphical user interface. The LTOOLS
     do not only provide access to Linux files on your own machine, but
     also remote access to files on other machines.

  6.7.  Accessing Ext2 from OS/2

  ·  Homepage: <>

  ·  Author: Matthieu WILLM <> ,

  ·  Download:

  ·  Freshmeat: Console/Filesystems

  ·  Access: Read/Write, swapping and booting to/from ext2, removable
     media support, but NO extended attributes.

     EXT2-OS2 is a package that allows OS/2 to seamlessly access Linux
     ext2 formatted partitions from OS/2 as if they were standard OS/2
     drive letters.  The ultimate aim of this package is to be able to
     use the ext2 file system as a replacement of FAT or HPFS. For the
     moment the only lacking feature to achieve this goal is the support
     for OS/2 extended attributes.

  6.8.  Accessing Ext2 from Windows 95/98 (FSDEXT2)

  ·  Homepage:

  ·  Author: Peter van Sebille ,

  ·  Freshmeat: Console/Filesystems

  ·  Access: Read-only, Long filenames supported

  6.9.  Accessing Ext2 from Windows 95 (Explore2fs)

  ·  Homepage: <>

  ·  Access: Read/Write, Long filenames, symbolic links etc...

  ·  Author: John Newbigin <>

  ·  License: GPL

     A user space application which can read and write the second
     extended file system ext2.  Supports hard disks and removable
     media, including zip and floppy.  Uses a windows explorer like
     interface to show files and details.  Supports Drag& Drop, context
     menus etc.  Written for Windows NT, but has some support for
     Windows 95.  Large disks can cause problems.

  6.10.  Accessing Ext2 from Windows NT (ext2fsnt)

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Andrey Shedel < >

  ·  Freshmeat: Console/Filesystems

  ·  License: Free

  ·  Access: Read-write, LFN, Security, PageFile, Hardlinks.

  6.11.  Accessing Ext2 from BeOS

  ·  Homepage:  <>

  ·  Author: Travis Geiselbrecht < >

  ·  Download:
     for R4 and
     for R3.

  ·  Access: Read-only, long filenames supported.

  ·  License: Free

     This is a driver to allow BeOS to mount the Linux Ext2 filesystem.
     The version that is currently released author consider pretty
     stable. People have been using it for a long time, with no bug

  Authow now works for Be Inc, so you will not see his ext2 and NTFS
  filesystem support updated on the web much more. The drivers will be
  pulled into future BeOS releases.

  6.12.  Accessing Ext2 from MacOS (MountX)

  ·  Homepage:  <>

  ·  Author: ?

  ·  Download: ?

     MacOS driver which allows you to mount ext2 filesystems (Linux and
     MkLinux) on the Macintosh.

  6.13.  Accessing Ext2 from MiNT

  ·  Homepage:  <http://?>

  ·  Author: <>

  ·  Download: ?

  ·  License: GPL

     This is a full working Ext2 filesystem driver for FreeMiNT.  It can
     read and write the actual ext2 version as implemented in Linux for
     example. The partition size is not limited and the logical sector
     size can be 1024, 2048 or 4096 bytes. The only restriction is that
     the physical sector size is smaller or equal to the logical sector
     size.  The blocksize can be configured if you initialize the
     partition with mke2fs.

  6.14.  Ext2fs defrag

  ·  Download:  <>

  ·  Author: Stephen C. Tweedie < >

  ·  License: GPL

     Defragments your ext2 filesystem.  Needs updated for glib

  6.15.  Ext2fs resize

  ·  Homepage:  <>

  ·  Download:

  ·  Author: Lennert Buytenhek <>.

  ·  License: GPL

     Resizes second extended filesystem.

  6.16.  Ext2end

  ·  Homepage:  <>

  ·  Maintainer: Mike Field <>

  ·  License: Copyright Mike Field. To be GPLed once stable.

     For use with ``LVM'' Consists of 2 utilites. ext2endable
     reorganises an empty ext2 file systems to allow them to be
     extended, and ext2end that extends an unmounted ext2 file system.
     If ext2endable has not been run when the file system was created
     ext2end will only be able to extend it to the next multiple of

  6.17.  Repairing/analyzing/creating Ext2 using E2fsprogs

  ·  Homepage:  <>

  ·  Download:

  ·  Authors: and

  ·  Windows NT port:  <>

  ·  Freshmeat: Console/Filesystems

  ·  License: GPL

     The ext2fsprogs package contains essential ext2 filesystem
     utilities which consists of e2fsck, mke2fs, debugfs, dumpe2fs,
     tune2fs, and most of the other core ext2 filesystem utilities.

  6.18.  Ext2 filesystem editor - Ext2ed

  ·  Homepage: ?

  ·  Author:

  ·  Download:

  ·  License: GPL

     EXT2ED is a disk editor for the extended2 filesystem.  It will show
     you the ext2 filesystem structures in a nice and intuitive way,
     letting you easily "travel" between them and making the necessary

  6.19.  Linux filesystem editor - lde

  ·  Homepage: ?

  ·  Author: Scott D. Heavner <>.

  ·  Download:

  ·  License: GPL

     This allows you to view some Linux fs's,  hex block and inode
     editing are now supported and you can use it to dump an erased file
     to another partition with a little bit of work.  Supports ext2,
     minix, and xiafs.  Includes LaTeX Introduction to the Minix fs. You
     must patch sources to compile on 2.2.x and 2.3.x kernels beacuse of
     missing Xia header files in kernel.

  6.20.  Ext2 undelete utilities

  ·  Homepage:  <>

  ·  Authors: Gunther Costas, Wilfredo Lugo, Jerry Ramirez

  ·  Freshmeat: Console/Filesystems

  ·  License: GPL

     This is a patch for kernel 2.0.30 that adds undelete capabilities
     using the "undeletable" attribute provided by the ext2fs. This
     patch include man pages, the undelete daemon and utilities.  Check
     our web page for the latest and greatest version.

  7.  Macintosh Hierarchical Filesystem - HFS

  All Macintosh storage devices except floppy disks are partitioned into
  one or more volumes. Volumes can contain four kinds of items: files,
  directories, directory threads and file threads. Each item is
  described by a catalog record which is analogous to a Unix inode.
  Catalog records are organized in the on-disk catalog B-Tree. Directory
  contents are derived from searching the catalog B-Tree. Only a file
  can occupy space outside of its catalog record.

  A Macintosh "file" contains two components, or forks. The resource
  fork is an indexed file containing code segments, menu items, dialog
  boxes, etc. The data fork has the "stream of bytes" semantics of a
  Unix file contents. Each fork is comprised of one or more extents or
  contiguous runs of blocks. An extent descriptor encodes an extent's
  starting block and length into a 32bit quantity. The first extent
  record (three extent descriptors) of each fork is a part of the file's
  catalog record. Any further extent records are kept in the extents
  overflow B-Tree.

  In addition to file and B-Tree extents a volume also contains two boot
  blocks, a volume information block, and a free space bitmap. There is
  a remarkable amount of redundancy in the on diskdata structures which
  improves crash recovery. While not strictly a part of the filesystem,
  it should be noted that several catalog record fields are reserved for
  the exclusive use of Finder, a program which handles user access to
  the filesystem and automatically maintains associations between
  applications and data files. Thus, HFS must also maintain this Finder

  Every file and directory on an HFS volume has an identification
  number, similar to an inode number in the Unix filesystem. However, a
  file or directory is named by its parent's identification number and
  the file or directory's file name, which is a 32 character string that
  can contain nulls. This combination is the search key to the volume's
  catalog B-Tree. The catalog B-Tree differs from a traditional B-Tree
  structure in that all the nodes at each level of the B-Tree are linked
  together to form a doubly linked list and all of the records are in
  the leaf nodes. These variations permit accessing many items in the
  same directory by traversing the leaves using the linked list.
  Strictly speaking, the HFS B-Trees are a variant of B+-Trees although
  Apple's technical documentation calls them B*-Trees.

  Each directory, including the root directory, contains its directory
  thread, which has the empty filename. The directory thread record
  contains the name of the directory and the id of the parent of the
  directory.  Similarly, filethreads contain the name of a file and the
  id of the directory they are in. While every directory must contain a
  directory thread, file threads are very uncommon. In fact, both are
  examples of HFS redundancy - for undamaged trees, threads are not
  strictly necessary.  Both file and directory records contain 32 bytes
  of information used by Finder. The first three extent descriptors for
  the catalog B-Tree are kept in the volume information block. If the
  catalog B-Tree file grows beyond three extents, the remaining extent
  descriptors are kept in the extents overfow.

  HFS and HFS+ (also called Sequoia) filesystems are well documented.
  The best source of tech. information about HFS can be found in the
  Inside Macintosh series of books. Look at
  <>.  The
  HFS+ filesystem is described in Technote 1150, available online at
  <>.  A lot of
  information is available also in other technotes. This links are
  collected by Paul H. Hargrove:

  ·  <> - HFS

  ·  <> - Hey,
     Buddy, Can You Spare A Block?

  ·  <> - Alias
     Manager Q&As

  ·  <> - File
     Manager File Handling Q&As

  ·  <> - File
     Manager Volume Handling Q&As

  ·  <> - Bizarre
     Extension Loading Order: BackQuote Sorts Between "A" and "B"

  ·  <> - Finder

  7.1.  Accessing HFS from Linux

  ·  Homepage:  <>

  ·  Author: Paul. Hargrove <>

  ·  Freshmeat: Console/Filesystems

  ·  License: GPL

  7.2.  Accessing HFS from OS/2 (HFS/2)

  ·  Homepage:  <>

  ·  Author: Marcus Better <>

  HFS/2 lets OS/2 users seamlessly read and write files on diskettes
  formatted with the Hierarchical File System, the file system used by
  Macintosh computers. With HFS/2, Macintosh diskettes can be used just
  as if they were regular diskettes.

  This program is no longer being developed, because author doesn't use
  OS/2. If you are willing to maintain the program, let him know.

  7.3.  Accessing HFS from Windows 95/98/NT (HFV Explorer)

  ·  Homepage:  <>

  ·  Author: Lauri Pesonen <>

  ·  Access: R/W access to floppies, Zip disks and virtual volume files.
     Read access to HFS and hybrid CD's.

  ·  License: GPL

     An HFS volume browser for Windows NT and Windows 9x based on
     hfsutils. Launch pad support for all major Macintosh emulators
     running on Windows.

  7.4.  Accessing HFS from DOS (MAC-ETTE)

  ·  Homepage: ?

  ·  Author: Paul E. Thomson

  ·  Download:  <>

  ·  Access: Read-Only

  ·  License: Shareware ($34)

     Mac-ette is a PC utility which can read, write, format and
     duplicate Macintosh HFS format 1.4 Meg diskettes on a PC equipped
     with a 3.5 inch high density diskette drive.

  7.5.  HFS utils

  ·  Homepage:  <>

  ·  Author: Robert Leslie <>

  ·  OS/2 port:  <>

  The hfsutils package contains a set of command-line utilities such as
  hformat, hmount, hdir, hcopy, etc. They allow read-write access of
  files and directories on HFS volumes.

  7.6.  MacFS: A Portable Macintosh File System Library

  ·  Tech report:  <http://reports->

  ·  Author: Peter A. Dinda <>, George C. Necula,
     and Morgan Price

  ·  Download:  <>

  ·  Access: Read/Write, full open/read/write/seek/close support

  ·  License: Free for noncommercial and nonmilitary use, see

     This is a Macintosh file system library which is portable to a
     variety of operating systems and platforms. It presents a
     programming interface sufficient for creating a user level API as
     well as file system drivers for operating systems that support
     them. Authors implemented and tested such a user level API and
     utility programs based on it as well as an experimental Unix
     Virtual File System.  They also describe the Macintosh Hierarchical
     File System and their implementation and note that the design is
     not well suited to reentrancy and that its complex data structures
     can lead to slow implementations in multiprogrammed environments.
     Performance measurements show that our implementation is faster
     than the native Macintosh implementation at creating, deleting,
     reading and writing files with small request sizes, but slower than
     the Berkeley Fast File System (FFS.) However, the native Macintosh
     implementation can perform large read and write operations faster
     that either our implementation or FFS.

  8.  ISO 9660 - CD-ROM filesystem

  Useful ISO-9660 links:

  ·  <> - ISO-9660 (aka ECMA-119,
     aka High Sierra) specification

  8.1.  RockRidge extensions

  Extensions allowing long filenames and Unix-style symbolic links.

  Useful RockRidge links:

  ·  <> - System Usage Sharing
     Protocol (SUSP, IEEE P1281)

  ·  <> - Rock Ridge
     Interchange Protocol (RRIP, IEEE P1282)

  8.2.  Joliet extensions

  Joliet is a Microsoft extension to the ISO 9660 filesystem that allows
  Unicode characters to be used in filenames.  This is a benefit when
  handling internationalization.  Like the Rock Ridge extensions, Joliet
  also allows long filenames.

  8.3.  Hybrid CD-ROMs

  Hybrid CDs contains three filesystems on one disc - ISO9660/RR, Joliet
  and HFS. Such CD-ROMs are accessible under DOS, Unix, Macintosh and
  Windows 9x/NT.  All three filesystems use the same data, only metadata
  are the disc three times.

  8.4.  Novell NetWare indexes on ISO9660


  8.5.  Accessing Joliet from Linux

  ·  Homepage:  <>

  ·  License: GPL

  8.6.  Accessing Joliet from BeOS

  ·  Homepage:  <>

  ·  Author: Gertjan van Ratingen <>

  ·  License: ?

     It is updated ISO9660 driver to be able to use a Joliet ISO9660

  8.7.  Accessing Joliet from OS/2

  ·  Download:

  ·  Author: IBM

  ·  License: ? archive contains CDFS.IFS driver for OS/2 with Joliet
     level 3 support.

  8.8.  Accessing Audio CD as filesystem from Linux

  ·  Homepage:  <>

  ·  Download: ?

  ·  Author: Mariusz Borkowski <>

  ·  License: ?

     This kernel module allows you to access an audio CD as a regular

  8.9.  Accessing Audio CD as filesystem from BeOS

  ·  Homepage:  <>

  ·  Download:  <>
     (PPC/Intel archive)

  ·  Author: Marco ?

  ·  License: ?

     This filesystem add-on will allow you (if your CD drive supports
     it) to treat a regular audio CD as if it were a bunch of WAV files.
     You can copy the files, encode them to mp3, play them slower,
     faster, even backwards.

  8.10.  Accessing all tracks from Linux (CDfs)

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Michiel Ronsse <>

  ·  License: GPL

     CDfs is a file system for Linux systems that `exports' all tracks
     and boot images on a CD as normal files. These files can then be
     mounted (e.g. for ISO and boot images), copied, played (audio
     tracks), etc. The primary goal for developing this file system was
     to `unlock' information in old ISO sessions. The file system also
     allows you to access data on faulty multi session disks, e.g.
     disks with multiple single sessions instead of a multi session.

  8.11.  Creating Hybrid CD-ROMs (mkhybrid)

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: <>

  ·  License: ?

     Make an ISO9660/HFS/JOLIET shared hybrid CD volume

  9.  Other filesystems

  9.1.  ADFS - Acorn Disc File System

  The Acorn Disc Filing System is the standard filesystem of the RiscOS
  operating system which runs on Acorn's ARM-based Risc PC systems and
  the Acorn Archimedes range of machines.

  Linux kernel 2.1.x+ supports this filesystem. Author of Linux
  filesystem implementation is Russell King <>.

  9.2.  AFFS - Amiga fast filesystem

  The Fast File System (FFS) is the common filesystem used on hard disks
  by Amiga(tm) systems since AmigaOS Version 1.3 (34.20).

  Linux kernel 2.1.x+ supports this filesystem. Author of Linux
  filesystem implementation is Ray Burr <>.

  9.3.  BeFS - BeOS filesystem

  BeFS is ``journaling'' filesystem used in BeOS.  For more information
  about BeFS see Practical File System Design with the Be File System
  book or BeFS linux driver source code.

  Linux BeFS implementation:

  ·  Homepage:  <>

  ·  Download:

  ·  Author: Makoto Kato <>

  ·  Access: Read-only

  ·  License: GPL

     This driver supports x86 and PowerPC Linux platform.  Also, it only
     supports readable in hard disk and floppy disk.

  9.4.  BFS - UnixWare Boot Filesystem

  UnixWare BFS filesystem type is a special-purpose filesystem. It was
  designed for loading and booting UnixWare kernel. BFS was designed as
  a ``contiguous filesystem''. BFS supports only one (root) directory
  and you can create only regular files; no subdirs or special files
  such as devices or sockets can be created.

  For more information about BFS see

  ·  <> -

  ·  <> - inodes

  ·  <> - storage

  You can access BFS filesystem from Linux:

  ·  Homepage:  <>

  ·  Download: In the Linux kernel, patches available at homepage.

  ·  Author: Tigran A. Aivazian <>

  ·  License: GPL

  ·  Access: Read/write (write part is limited, no compactification yet)

     The support for BFS is included in the Linux kernel since version
     2.3.25. If you are using an earlier kernel, check if BFS homepage
     contains a patch which adds support for this filesystem. The
     homepage also contains bugfixes/enhancement which are not yet
     merged into the official kernel.

  There is also mine old implementation, which is now obsolete. My plan
  is to port this code to FreeBSD:

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Martin Hinner <>

  ·  License: GPL

  ·  Access: Read-only

     This is read-only UnixWare Boot filesystem support for Linux. You
     can use it to mount read-only your UnixWare /stand partition or
     floppy disks. I don't plan a read-write version, but if you want it
     mail me. You might be also interested in ``VxFS'' Linux support.

  9.5.  CrosStor filesystem

  This is new name for High throughput filesystem (HTFS). For more
  information see CrosStor homepage at  <>.

  9.6.  DTFS - Desktop filesystem

  Goals in designing the Desktop File System were influenced by
  impression of what environment was like for small computer systems.
  DTFS compress the data stored in regular files to reduce disk space
  requirements (directories remain uncompressed). Compression is
  performed a page at a time and occur 'on-the-fly'.  DTFS supports LZW
  and no-compression but you can add your own algorithms. Some space is
  saved by not pre-allocating inodes. Any disk block is fair game to be
  allocated as an inode. Each inode is stored as a B+tree. For more
  information see DTFS USENIX paper (you can download it from

  Read/Write commercial driver available from CrosStor for UnixWare and
  SUN Solaris:

  ·  Download:  <>

  ·  License: Commercial?

  ·  Access: Read/Write

  9.7.  EFS - Enhanced filesystem (Linux)

  The Enhanced Filing system project aims to create a new filing system
  for Linux and eventually other OSs which will allow the administrator
  to define mountable "file systems" on a set of block devices (either
  hard drives or partitions). The aim is to allow file systems to be
  added or removed from the partition set while the system is running
  and partitions may be added to a set (or removed if the remaining
  partitions have enough space to contain all the data) while the system
  is running.The two main aims are to allow a number of mountable file
  systems to share the same pool of storage space (IE have the user home
  dirs on the same drive as the news spool but have separate accounting
  for them), and to allow the easy addition of more hard drives to allow
  more space.

  Some other features that authors want to implement are
  ``logging/journaling'', support for as many OSs as possible (although
  all work will be initially done on Linux), and quotas in the FS so we
  don't need to waste ages running a silly quotacheck program at boot -
  the logging should avoid quotacheck the same way it avoids fsck! They
  want to be able to boot a system with 10gig of news spread over 4 hard
  drives with full quotas AFTER a power failure with less than 20
  seconds for mounting file systems!

  Homepage of Enhanced FS is at
  <>.  Contact Russell Coker
  <> for more information.

  9.8.  EFS - Extent filesystem (IRIX)

  The Extent File System (efs) is Silicon Graphics' early block-device
  filesystem, widely used on pre-6.0 versions of IRIX. Since 6.0, xfs
  has been bundled with IRIX and users are being encouraged to migrate
  to xfs filesystems. IRIX support for efs will be read-only in versions
  of IRIX beyond 6.5, however efs is still very much in use on SGI
  software distribution CDs.

  There are two kernel modules for linux to access EFS filesystem.

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Al Smith <>

  ·  License: GPL

  ·  Access: Read-only

     The efs kernel module is an implementation of the extent file
     system for linux 2.2 kernels. An efs implementation
     (efsmod-0.6.tar.gz) was originally written for 1.x kernels by
     Christian Vogelgsang.  In this implementation the code has
     undergone a complete rewrite and is also endian-clean. To use the
     efs module, you will need to have at least a 2.2 kernel. To mount
     IRIX CDs, your CD-ROM will need to be able to cope with 512-byte
     blocks.  This version of efs contains support for hard-disk
     partitions, and also contains a kernel patch to allow you to
     install the efs code into your linux kernel tree. Handling of large
     files has also been vastly improved.

  Original efsmod is also available:

  ·  Homepage:  <http://wwwcip.informatik.uni->

  ·  Download:  <http://wwwcip.informatik.uni->

  ·  Author: Christian Vogelgsang

  ·  License: GPL

  ·  Access: Read-only

     Efs-mod 0.6 is original EFS read/only module for Linux. Version 0.6
     finished but Project frozen due to lack of time and information for
     implementing the write part.

  9.8.1.  Accessing EFS from Windows NT/95

  ·  Download:  <>

  ·  Author: J.A. Gutierrez <>

  ·  License: GPL

  ·  Access: Read/Only IRIX EFS

     Simple program for accessing EFS from Windows 95 (compiled using MS

  9.8.2.  EFS and FFS library, libfs

  ·  Download:  <>

  ·  Author: J.A. Gutierrez <>

  ·  License: GPL

  ·  Access: Read/Only IRIX EFS and Sun UFS

     A C library to read EFS and FFS from WinNT x86, SunOS and IRIX.
     Easy to use (Posix like interface) and to links aginst existent
     code FTP server has also winefssh.exe and winufssh.exe, simple
     WinNT binaries to interactively read UFS and EFS file systems.  Not
     a very polished/documented package, but somebody may find it

  Useful links:

  ·  IRIX EFS filesystem brief description:

  9.9.  FFS - BSD Fast filesystem

  This is native filesystem for most BSD unixes (FreeBSD, NetBSD,
  OpenBSD, Sun Solaris, ...).

  See also: ``SFS, secure filesystem'', ``UFS''.

  9.9.1.  Accessing FFS from MacOS

  You can expand .tar.gz files to FFS filesystem with BSD Installer
  utility, with comes with OpenBSD. It lives at

  9.10.  GPFS - General Parallel Filesystem

  This is a UNIX(tm) operating system style file system designed for the
  RS/6000 SP(tm) server. It allows applications on multiple nodes to
  share file data. GPFS supports very large file systems and stripes
  data across multiple disks for higher performance. GPFS is based on a
  shared disk model which provides lower overhead access to disks not
  directly attached to the application nodes and uses a distributed
  locking protocol to provide full data coherence for access from any
  node. It offers many of the standard AIX(tm) file system interfaces
  allowing most applications to execute without modification or
  recompiling. These capabilities are available while allowing high
  speed access to the same data from all nodes of the SP system, and
  providing full data coherence for operations occurring on the various
  nodes. GPFS attempts to continue operation across various node and
  component failures assuming that sufficient resources exist to

  ·  <>

  9.11.  HFS - HP-UX Hi performance filesystem

  This is the second hfs that appears in this howto. It is used in older
  HP-UX versions.

  9.12.  HTFS - High throughput filesystem

  Useful links:

  ·  SCO OpenServer 5 filesystems whitepaper:

  Read/Write commercial driver available from CrosStor:

  ·  Download:  <>

  ·  License: Commercial?

  ·  Access: Read/Write

  9.13.  JFS - Journaled filesystem (HP-UX, AIX, OS/2 5, Linux)

  ·  Homepage:

  ·  Download:

  ·  Author: Steve Best <> and Dave Kleikamp

  ·  License: GPL

  ·  Access: ?

     JFS is IBM's journaled file system technology, currently used in
     IBM enterprise servers, and is designed for high-throughput server

  9.14.  LFS - Linux log structured filesystem

  Linux Log structured filesystem implementation called d(t)fs:

  ·  Homepage:  <>

  ·  Author: Christian Czezatke <>

  ·  License: GPL

  ·  Access: rw/long filenames, etc

     d(t)fs is a log-structured filesystem project for Linux.
     Currently, the filesystem is mostly up and running, but no cleaner
     has been written so far.

  There will also be a dtfs mailing list that will be announced on the
  homepage. For more information you can have a look at:

  ·  <> - The kfs Homepage Cornelius
     "Kees" Cook has started a Linux Log--Structured Filesystem project
     before dtfs came to live.

  ·  <> - Another (death) LFS
     implementation ;-)

  ·  <> - Margo Seltzer's
     <> LFS page
  9.15.  MFS - Macintosh filesystem

  MFS is original Macintosh filesystem. It has been replaced by HFS /
  HFS+.  If you can provide further information, mail me please.

  9.16.  Minix filesystem

  This is Minix native filesystem. It was also used in first versions of

  9.17.  NWFS - Novell NetWare filesystem

  NWFS is native in Novell NetWare OS. It is modified FAT-based
  filesystem.  Two variants of this filesystem exists. 16bit NWFS 286 is
  used in NetWare 2.x.  NetWare 3.x, 4.x and 5 use 32bit NWFS 386.

  9.17.1.  NetWare filesystem / 286


  9.17.2.  NetWare filesystem / 386


  9.17.3.  Accessing NWFS-386 from Linux

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Timpanogas Research Group, Inc. (

  ·  License: GPL

  ·  Access: Read-Only

     This driver allows you to mount NWFS-386 filesystem on Linux.

  9.18.  NSS - Novell Storage Services

  This is a new 64bit ``journaling'' filesystem using a ``balanced
  tree'' algorithms. It is used in Novell NetWare 5.

  ·  <> - NSS Whitepaper

  9.19.  ODS - On Disk Structure filesystem

  This is OpenVMS and VMS native filesystem.

  9.20.  QNX filesystem

  This filesystem is used in QNX. Two major filesystem version exists,
  version 2 is used by QNX 2 and version 4 by QNX 4. QNX 4 doesn't
  support version 2 and vice versa.

  QNX4 filesystem is now accessible from Linux 2.1.x+. Say "Y"es to 'QNX
  filesystem support';

  ·  Download: In the kernel ;)

  ·  Author: Frank Denis  <> (maintainer), Richard Frowijn

  ·  License: GPL

  ·  Access: Read (except for multi-extents files), Write (experimental)

     Driver for the QNX 4 filesystem.

  9.21.  Reiser filesystem

  Reiserfs is a file system using a variant on classical balanced tree
  algorithms. The results when compared to the ext2fs conventional block
  allocation based file system running under the same operating system
  and employing the same buffering code suggest that these algorithms
  are more effective for large files and small files not near node size
  in time performance, become less effective in time performance and
  more significantly effective in space performance as one approaches
  files close to the node size, and become markedly more effective in
  both space and time as file size decreases substantially below node
  size (4k), reaching order of magnitude advantages for file sizes of
  100bytes. The improvement in small file space and time performance
  suggests that we may now revisit a common OS design assumption that
  one should aggregate small objects using layers above the file system

  Useful links:

  ·  Reiser fs homepage <>

  9.22.  RFS (CD-ROM Filesystem)

  Sony's incremental packet-writing filesystem.

  9.23.  RomFS - Rom filesystem

  Author of Linux RomFS implemplementation is Janos Farkas
  <> For more information see
  /usr/src/linux/Documentation/filesystems/romfs.txt file.

  9.24.  SFS - Secure filesystem

  The sfs filesystem type is a variation of the FFS filesystem type. The
  boot block,superblock, storage blocks, and free blocks for the sfs
  filesystem type are, at the administrative level, identical to those
  for FFS.  The inodes differ from FFS inodes, however. Each odd-
  numbered inode is reserved for security information. The information
  contains Access Control List information. I'm not sure if SFS has any
  other abilities though.

  SFS links:

  ·  <> -
     UnixWare 7 documentation: SFS Filesystem

  9.25.  Spiralog filesystem (OpenVMS)

  Spiralog is a 64bit high-performance filesystem for the OpenVMS.  The
  Spiralog combines ``log-structured'' technology with more traditional
  ``B-tree'' technology to provide a general abstraction. The B-tree
  mapping mechanism uses write-ahead logging to give stability and
  recoverability guarantees.

  Spiralog-related links at Digital:

  ·  <> - Spiralog File System for
     OpenVMS Alpha

  ·  <> - Overview of the
     Spiralog File System

  ·  <> - Design of the Server
     for the Spiralog File System

  9.26.  System V and derived filesystems

  Homepage of System V Linux project is at
  <>. Maintainer of this project
  is <>.

  9.26.1.  AFS - Acer Fast Filesystem

  The Acer Fast Filesystem is used on SCO Open Server. It is similar to
  the System V Release 4 filesystem, but it is using bitmaps instead of
  chained free-list of blocks.

  9.26.2.  EAFS - Extended Acer Fast Filesystem

  The AFS filesystem can be 'extended' to handle file names up to 255
  characters, but directories entries still have 14-char names. This
  filesystem type is used on SCO Open Server.

  9.26.3.  Coherent filesystem

  9.26.4.  S5

  This filesystem is used in UnixWare. It's probably SystemV compatible,
  but I haven't verified it yet. For more information see

  9.26.5.  S51K - SystemV 1K

  9.26.6.  Version 7 filesystem

  This filesystem type is used on Version 7 Unix for PDP-11 machines.

  9.26.7.  Xenix filesystem

  9.27.  Text - (Philips' CD-ROM Filesystem)

  Philips' standard for encoding disc and track data on audio CDs.

  9.28.  UDF - Universal Disk Format (DVD-ROM filesystem)

  There is a Linux UDF filesystem driver:

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Dave Boynton <>

  ·  Mailing-list: <>

  ·  License: GPL

  ·  Access: Read-only

  9.29.  UFS

  Note: People often call ``BSD Fast Filesystem'' incorrectly UFS. FFS
  and UFS are *diferrent* filesystems. All modern Unixes use FFS
  filesystem, not UFS! UFS was used in early BSD versions. You can
  download source code at  <>.

  Useful links:

  ·  <> - Implementation
     of write-clustering for Sun's UFS

  See also: ``BSD FFS''

  9.30.  V7 Filesystem

  The V7 Filesystem was used in Seventh Edition of UNIX Time Sharing
  system (about 1980). For more information see 7th Ed. source code,
  which is available from the Unix Archive:

  9.31.  VxFS - Veritas filesystem (HP-UX, SCO UnixWare, Solaris)

  This is commercial filesystem developer by Veritas Inc. You can see it
  in HP-UX, SCO UnixWare, Solaris and probably other systems. It has
  very interesting features: Extent based allocation, Journaling, access
  control lists (ACLs), up to 2 terabyte large file support, online
  backup (snapshot filesystem), BSD style quotas and many more.

  Three VxFS versions are available with VxFS:

   Version 1: This is original VxFS, not commonly in use.

   Version 2: Support for filesets and dynamic inode allocation.

   Version 4: Latest version, supports large files and quotas.

  Note that HP-UX, Solaris and UnixWare versions use slightly different
  structures, so you may not be able to read VxFS when you connect it to
  different system.

  VxFS related links:

  ·  <> - Veritas Inc <>.

  ·  <> - VxFS ODM FS
     Admin - UnixWare 7 (documentation, really good).

  ·  <> - VxFS FS
     Manager - UnixWare 7 (documentation).

  ·  <;cd=3>
     - VxFS - Reliant Unix.

  See also: ``VxVM (Veritas volume manager)'' and ``journaling

  9.31.1.  VxTools

  Unix command-line utilities for accessing VxFS versions 2 and 4 are
  available under the GNU GPL:

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Martin Hinner <>

  ·  Mailing-list: <>

  ·  License: GPL

  ·  Access: Read-only, command-line utilites

     Vxtools is a set of command-line utilites which allow you to access
     your VxFS filesystem from Linux (and possibly other Unixes).
     Current version can read VxFS versions 2 and 4.

  I (mhi) plan also VxFS Linux kernel driver.

  AFAIK, Rodney Ramdas <> works on VxFS driver for
  FreeBSD. I don't know current status of his project, so if you want
  more info contact him directly.

  9.32.  XFS - Extended filesystem (IRIX)

  XFS(tm) is the next-generation file system for Silicon Graphics[TM]
  systems, from desktop workstations to supercomputers.  XFS provides
  full 64-bit file capabilities that scale easily to handle extremely
  large files and file systems that grow to 1 terabyte. The XFS file
  system integrates volume management, guaranteed rate I/O, and
  ``journaling'' technology for fast, reliable recovery. File systems
  can be backed up while still in use, significantly reducing
  administrative overhead.

  XFS is designed for a very high performance; sustained throughput in
  excess of 300MB per second has been demonstrated on CHALLENGE systems.
  The XFS file system scales in performance to match the CHALLENGE MP
  architecture. Traditional files, directories, and file systems have
  reduced performance as they grow in size. With the XFS file system,
  there is no performance penalty. For example, XFS directories have
  been tested with up to 32 million files in a single directory.

  XFS is a journalled file system.  It logs changes to the inodes,
  directories and bitmaps to the disk before the original entries are
  updated.  Should the system crash before the updates are done they can
  be recreated using the log and updated as intended.

  XFS uses a space manager to allocate disk space for the file system
  and control the inodes.  It uses a namespace manager to control
  allocation of directory files.  These managers use B-tree indexing to
  store file location information, significantly decreasing the access
  time needed to retrieve file information.

  Inodes are created as needed and are not restricted to a particular
  area on a disk partition.  XFS tries to position the inodes close to
  the files and directories they reference.  Very small files, such as
  symbolic links and some directories, are stored as part of the inode,
  to increase performance and save space.  Large directories use B-tree
  indexing within the directory file to speed up directory searches,
  additions and deletions.

  Useful XFS links:

  ·  <> XFS whitepaper

  XFS Linux port covered by the GNU General Public License is available
  from SGI Inc.:

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: SGI Inc.,  <>

  ·  License: GPL

  ·  Access: Read-write

  9.33.  Xia FS

  This filesystem was developed to replace old Minix filesystem in
  Linux. Author of this fs is Franx Xia <>

  10.  Raw partitions

  10.1.  Backing up raw partitions using DBsnapshot


  11.  Appendix

  11.1.  Network filesystems

  This HOWTO is not about Network filesystems, but I should mention

  There is a brief list of some which I know:

  11.1.1.  AFS - Andrew Filesystem

  ·  The AFS FAQ is at  <

  ·  Commercial clients and servers for almost all platforms (except
     win98) are available from IBM. See

  ·  A free client for Unix is available from the Arla Team at

  ·  A free Server is also in preparation, but not in production yet.

  11.1.2.  CODA

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: CMU Coda Group <>.

  ·  License: GPL

  ·  Access: R/W

     Coda is a distributed filesystem with novel features such as
     disconnected operation and server replication.
  11.1.3.  NFS - Network filesystem (Unix)

  11.1.4.  NCP - NetWare Core Protocol (Novell NetWare)

  11.1.5.  SMB - Session Message Block (Windows 3.x/9x/NT)

  This protocol is used in Windows world.

  11.1.6.  Intermezzo

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Author: Stelias and Redhat <>.

  ·  License: GPL

  ·  Access: R/W

     Intermezzo is a distributed file system for Linux. It was inspired
     from coda but uses the disk file system as a persistent cache.
     Intermezzo supports disconnected operation but does not yet
     implement an identification system.

  11.2.  Encrypted filesystems

  11.2.1.  CFS

  ·  Homepage: ?

  ·  Download: ?

  ·  Author: Matt Blaze <>.

  ·  License: ?

  ·  Access: Read/Write, using DES/3DES.

     CFS pushes encryption services into the Unix(tm) file system.  It
     supports secure storage at the system level through a standard Unix
     file system interface to encrypted files.  Users associate a
     cryptographic key with the directories they wish to protect.  Files
     in these directories (as well as their pathname components) are
     transparently encrypted and decrypted with the specified key
     without further user intervention; cleartext is never stored on a
     disk or sent to a remote file server.  CFS employs a novel
     combination of DES stream and codebook cipher modes to provide high
     security with good performance on a modern workstation.  CFS can
     use any available file system for its underlying storage without
     modification, including remote file servers such as NFS.  System
     management functions, such as file backup, work in a normal manner
     and without knowledge of the key.
  11.2.2.  TCFS

  ·  Homepage:  <>

  ·  Download:  <>

  ·  Authors: Luigi Catuogno <>, Aniello Del
     Sorbo <>, Luigi Della Monica
     <>, G.Cattaneo <>,
     G.Persiano ( <>), Ermelindo (Erry)
     Mauriello <>, Angelo Celentano
     <>, Andrea Cozzolino

  ·  License: GPL

  ·  Access: Read/Write transparently using CBC-

     The main difference between TCFS and CFS is the trasparency to user
     obtained by using TCFS. As a matter of fact, CFS works in user
     space while TCFS works in the kernel space thus resulting in
     improved performances and security.  The dynamic encryption module
     feature of TCFS allows a user to specify the encryption engine of
     his/her choiche to be used by TCFS.  Currently available only for
     Linux, TCFS will be relased soon also for NetBSD, and will support
     in a near future also other FS then NFS.

  11.2.3.  SFS

  ( TODO:  <> )

  11.2.4.  VS3FS: Steganographic File System for Linux

  ·  Homepage:  <>

  ·  License: ?

  ·  Access: ?

     fspatch is a kernel patch which introduces module support for the
     steganographic file system (formerly known as vs3fs, an
     experimental type of filesytem that not only encrypts all
     information on the disk, but also tries to hide that information in
     such a way that it cannot be proven to even exist on the disk. This
     enables you to keep sensitive information on a disk, while not be
     prone to being forced to reveal that information. Even under
     extreme circumstances, fake documents could be stored on other
     parts of the disk, for which a pasword may be revealed.  It should
     not be possible to find out whether any other information is stored
     on the disk.

  11.3.  Filesystem benchmarking utilities

  11.3.1.  IOzone

  ·  Homepage:  <>

  ·  Download:  <>

  ·  License: freely distributable

     IOzone is a filesystem benchmark tool. The benchmark generates and
     measures a variety of file operations. Iozone has been ported to
     many machines and runs under many operating systems.

  11.4.  Writing your own filesystem driver

  11.4.1.  DOS

  I haven't seen yet any good page about writing DOS filesystem drivers
  (Network redirectors) on the net. The best source is Ralf Brown's
  interrupt list and ``iHPFS'' source code.

  11.4.2.  OS/2

  ·  <>

  ·  <>
     - 32 bits OS/2 device driver and IFS support. Provides 32 bits
     kernel services (DevHelp) and utility functions to 32 bits OS/2
     ring 0 code (device drivers and installable file system drivers).

  11.4.3.  Windows NT

  Microsoft IFS kit page ( <>) will
  be useful as the best way to get into NT filesystems development (even
  for $1K it costs).

  For more information about writing FS drivers for Windows NT see
  <> by <>.

  11.5.  Related documents

  ·  <> - good
     page about filesystems

  ·  <> - Linux overlay filesystem by

  ·  <> - Linux trustees

  ·  <> - Transparent Cryptography Filesystem

  ·  <> - Large file summit -
     attacks the problem of 2gig+ of file in a 32bit computer
  ·  <> - The CODA project (a distributed
     file system based on AFS)

  ·  <> - LFS related papers

  ·  <> - Linux Kernel
     Hacker's guide

  ·  <> - Large disk

  ·  <> - The
     Linux devfs

  ·  <> - The Global File System (GFS)

  ·  <>
     - The Toronto Virtual Filesystem/2.

  ·  <>
     Dynamic RAM drive IFS driver for OS/2

  ·  <> - UnixWare and SCO Unix documentation online

  ·  <> - UnixWare 7 documentation online

  ·  <
     bin/bookmgr/BOOKS/SG244428/CCONTENTS> - Inside OS/2 LAN Server 4.0

  ·  <> - Linux UserFS, it
     allows you to write a Linux process which implements a filesystem.

  ·  <> - Stein Gjoen's Multi Disk
     System Tuning HOWTO.

  ·  <> - Linux Today: Kragen's
     Amazing List of Filesystems.

  ·  <> - Kristian
     Kohntopp's Unix Filesystems (in German).

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