Ext4, or Fourth Extended Filesystem, is a widely used file system for Linux operating systems. It offers improved performance, reliability, and features compared to its predecessor, Ext3. Ext4 supports larger file sizes and volumes, making it suitable for modern storage needs. One of the key features of Ext4 is its journaling capability, which helps protect data integrity by keeping a log of changes. This file system also includes support for extents, which improves performance by reducing fragmentation. Overall, Ext4 is a robust choice for both personal and enterprise-level applications.