Editing AmigaDOS (section)

== File systems ==
AmigaDOS supports various filesystems and variants. The first filesystem was simply called [[Amiga Old File System|Amiga FileSystem]], and was suitable mainly for floppy disks, because it did not support automatic booting from hard disks (on floppy, booting was done using code from the bootblock). It was soon replaced by [[Amiga Fast File System|FastFileSystem]] (FFS), and hence the original filesystem was known by the name of "Old" FileSystem (OFS). FFS was more efficient on space and quite measurably faster than OFS, hence the name.

With AmigaOS 2.x, FFS became an official part of the OS and was soon expanded to recognise cached partitions, international partitions allowing accented characters in file and partition names, and finally (with [[MorphOS]] and [[AmigaOS 4]]) long filenames, up to 108 characters (from 31).

Both AmigaOS 4.x and MorphOS featured a new version of FFS called FastFileSystem 2. FFS2 incorporated all of the features of the original FFS including, as its author put it, "some minor changes". In order to preserve backwards compatibility, there were no major structural changes. (However, FF2 on [[AmigaOS 4.1]] differs in that it can expand its features and capabilities with the aid of [[plug-in (computing)|plug-ins]]). As with FFS2, the AmigaOS 4 and MorphOS version of Smart FileSystem is a fork of original SFS and are not 100% compatible with it.

Other filesystems like [[FAT12]], [[FAT16]], [[FAT32]] from Windows or [[ext2]] from Linux are available through easily installable ([[drag and drop]]) system libraries or third party modules such as FAT95 <ref>{{cite web|url=http://aminet.net/package/disk/misc/fat95 |title=disk/misc/fat95.lha |publisher=Aminet |access-date=2016-07-15}}</ref> (features read/write support), which can be found on the [[Aminet]] software repository. MorphOS 2 has built-in support for FAT filesystems.

[[AmigaOS 4.1]] adopted a new filesystem called JXFS capable to support partitions over a [[terabyte]] of size.

Alternate filesystems from third-party manufacturers include [[Professional File System|Professional FileSystem]], which is a filesystem with an easy structure, based on [[metadata]], allowing high internal coherence, capable of [[defragmenting]] itself on the fly, and does not require to be unmounted before being [[mount (computing)|mounted]] again; and [[Smart File System|Smart FileSystem]] which is a [[journaling file system|journaling]] filesystem which performs journaled activities during system inactivities, and has been chosen by MorphOS as its standard filesystem.

=== Official variants of Amiga filesystems ===
'''Old File System'''/'''Fast File System'''
*OFS (DOS0)
*FFS (DOS1)
*OFS International (DOS2)
*FFS International (DOS3)
*OFS Directory Caching (DOS4)
*FFS Directory Caching (DOS5)

'''Fast File System 2 (AmigaOS4.x/MorphOS)'''
* OFS Long filenames (DOS6)
* FFS Long filenames (DOS7)

Both DOS6 and DOS7 feature International filenames featured in DOS2 and DO3, but not Directory Caching, which was abandoned due to bugs in the original implementation. DOS4 and DOS5 are not recommended for use for this reason.

Dostypes are [[backwards compatible]] with each other, but not [[forward compatible]]. A DOS7 formatted disk cannot be read on original Amiga FFS, and a DOS3 disk cannot be read on a KS1.3 Amiga. However, any disk formatted with DOS0 using FFS or FFS2 can be read by any version of the Amiga operating system. For this reason, DOS0 tended to be the format of choice of software developers distributing on floppy, except where a custom filesystem and bootblock was used - a common practice in Amiga games. Where software needed AmigaOS 2 anyway, DOS3 was generally used.

=== FastFileSystem2 plug-ins ===
With the July 2007 Update of [[AmigaOS 4.0]] in 2007, the first two plug-ins for FFS2 were released:
* '''fs_plugin_cache''': increases performance of FFS2 by introducing a new method of data buffering.
* '''fs_plugin_encrypt''': data encryption plug-in for partitions using the [[Blowfish (cipher)|Blowfish]] algorithm.