File system formats

A file system format is used to manage the storage of files.

Terminology

File entry (file system entry): an object that represent an element within the file system, such as a file or directory. A file system typically stores metadata of a file entry, such as the name, size, permissions, date and time values, and location of the content.
Data fork (or data stream): a file system object that represents the content of a file entry. NTFS and HFS support multiple data forks (or data streams) for an individual file entry.
Extended attribute: A file system object that represents additional (or extended) metadata of an individual file entry.
Reparse point: a file system object that redirects to another location or implementation (filter driver), such as Windows Overlay Filter (WOF) compression. NTFS and ReFS support reparse points.
Data range: a contiguous storage space, such as a file system extent or sequence of blocks or sectors. Can be compressed, encrypted or sparse.