Editing Inode (section)

===inode number stability and non-Unix file systems===

When a file is relocated to a different directory on the same file system, or when a disk [[defragmentation]] alters its physical location, the file's inode number remains unchanged.

This unique characteristic permits the file to be moved or renamed even during read or write operations, thereby ensuring continuous access without disruptions.

This feature—having a file's metadata and [[Block (data storage)|data block]] locations persist in a central [[data structure]], irrespective of file renaming or moving—cannot be fully replicated in many [[List of file systems|non-Unix file systems]] like [[File Allocation Table|FAT]] and its derivatives, as they lack a mechanism to maintain this invariant property when both the file's directory entry and its data are simultaneously relocated. In these file systems, moving or renaming a file might lead to more significant changes in the data structure representing the file, and the system does not keep a separate, central record of the file's [[Block (data storage)|data block]] locations and [[metadata]] as inodes do in [[Unix-like]] systems.