ext2, ext3, and ext4 are file systems used in the Linux operating system. ext2 was introduced in 1993 and supports large file sizes and partitions. It does not have journaling, which means it can be slower in recovering from crashes. ext3 added journaling capabilities to ext2, improving data integrity and recovery speed. ext4, released in 2008, further enhances performance and supports larger files and volumes, along with features like extents and delayed allocation. These file systems are widely used for managing data on Linux servers and desktops.