Specifies how a system identifies the sector locations of files on a physical medium and generally includes other metadata such as a file's size, access permissions, and when it was created and modified. Operating systems generally have their own proprietary file system specifications, but some have been standardized for interchange across operating systems. A journaled file system is one that maintains a log (journal) of activity in the main data areas of the disk, which helps to ensure data integrity in the event of a system crash or other abnormal termination.

• Coda - distributed filesystem developed at Carnegie Mellon University and originating from AFS2
• ext2 - for Linux
• Ext2FS Anywhere - Paragon Software - software designed to mount Linux partitions under Windows operating systems as normal logical drives with appropriate drive letter
• ext3 - journaling extension to ext2 on Linux
• Global File System - Red Hat Software - shared disk cluster file system for Linux, which supports journaling
• Hard Disk Logical Structures and File Systems - PC Guide - describes file systems used on PCs, with particular focus on file allocation table (FAT) and its variants
• High Performance File System (HPFS) - introduced with IBM's OS/2 Version 1.2, designed to get around several limitations of MS-DOS, including file name length
• Journaled File System (JFS) for Linux - IBM
• Linux XFS - Silcon Graphics - supports journaling and extremely large disk farms
• Network File System (NFS) version 4 Protocol - (IETF RFC 3530, Obsoletes RFC 3010) distributed filesystem protocol which owes heritage to NFS protocol version 2, RFC 1094, and version 3, RFC 1813, but now supports traditional file access while integrating support for file locking and the mount protocol, support for strong security (and its negotiation), compound operations, client caching, internationalization and attention to the Internet environment, Spencer Shepler, et al., April 2003
• Overview of FAT, HPFS, and NTFS File Systems - Microsoft
• ReiserFS - originally designed by Hans Reiser, supports journaling and is based on balanced trees, which can improve performance, particularly when accessing small files
• Universal Disk Format (UDF) - specification from the Optical Storage Technology Association (OSTA), compliant with the ISO 13346, for optical data storage
• Volume and file structure of CD-ROM for information interchange (ISO 9660)
• Volume and file structure for write-once and rewritable media using non-sequential recording for information interchange (ISO 13346)