File systems#
A file system defines how data is actually stored and retrieved on storage media. It usually consists of multiple layers. Towards the operating system the logical file system provides functions for file operations like open, read and close. Behind the scenes the file system implementation actually implements these functions and defines how data is actually organized on storage media.
Usually these file system implementations are shortly referred as file systems. There are many file systems available for Linux. Prominent examples are ext4, btrfs, FAT, NTFS (actually used in Windows) or xfs. There are less intuitive file systems like pseudo file systems which are not backed by any storage media but create the data upon request or network file systems which access their data over a network.
The Linux virtual file system (vfs) abstracts all these implementations, such that they appear all (more or less) equal to the operating system and the user.