The EXT2 File System

Summary

The first successful version of the ext family of file systems was ext2 released in the early 1990s. This file system is sometimes encountered in removable media that are created (and used exclusively) on a Linux system. It is no longer encountered on system disks on Linux systems, however, the subsequent ext versions (ext3 and ext4) are based on this file system. Therefore knowledge of ext2 will help the subsequent analysis of ext3 and ext4 file systems. This chapter will introduce the reader to the basic concepts that underlie all file systems in the ext family such as superblock, block groups, inodes, block pointers etc. and show how to interpret these structures in the ext2 file system. Many of these structures are similar (or sometimes even identical) in later versions of the file system.