ext3, or
third extended filesystem, is a
journaled file system that is commonly used by the
Linux kernel. It is the default
file system for many popular
Linux distributions.
Stephen Tweedie first revealed that he was working on extending
ext2 in
Journaling the Linux ext2fs Filesystem in a 1998 paper, and later in a February 1999 kernel mailing list posting. The filesystem was merged with the mainline
Linux kernel in November 2001 from 2.4.15 onward. Its main advantage over ext2 is
journaling, which improves reliability and eliminates the need to check the file system after an unclean shutdown. Its successor is
ext4.