ext3
also: third extended filesystem
ext3 is a journaling filesystem for Linux that extends ext2 with a journal to prevent data corruption after unclean shutdowns or crashes.
ext3 (third extended filesystem) adds journaling capability to the ext2 filesystem, improving reliability and recovery time. A journal records pending filesystem operations before they're written to disk, allowing the system to recover quickly from crashes without needing lengthy disk checks.
When the system crashes, ext3 replays the journal on the next boot instead of running a full fsck scan, reducing recovery time from minutes to seconds on large partitions.
Example: After an unexpected power loss, ext3 filesystems typically mount and become available within seconds, whereas ext2 would require checking every inode and block allocation.
ext3 has largely been superseded by ext4, which offers better performance and larger capacity support, but remains stable and is still used in legacy systems.