"Linux supports several different file systems. Some are
specialized network file systems or file systems developed for
other operating systems, but a surprising number may be used as
Linux native file systems--you can place your Linux root (/) and
system directories on such file systems. Currently, file systems in
this category include ext2, ext3, ReiserFS, XFS, and Journaled File
System (JFS). However, file system design and development are
ongoing, and new file systems are on the horizon.
"Perhaps the most important file system currently under
development for Linux is ext4--the fourth incarnation of the
original extended file system (ext or extfs) developed exclusively
for Linux. Given its heritage, it seems likely that ext4 will
become an important standard file system (perhaps the standard file
system) for Linux in the not-too-distant future..."