Not only is it expected that files will hold important data, but it is also assumed that a certain amount of metadata is kept to manage these files. The file control block holds all of this metadata for the file, including file permissions, owners, sizes, and create, modified, and access times.
Alongside this bookkeeping metadata, files can also have attributes that indicate special behavior. While this differs on the operating system, common attributes include:
- Hidden: Cannot be viewed by default in file managers.
- Immutable: Cannot be modified or deleted.
- Compressed: The file is in a compressed form to save space.
To the right are example images of file metadata, permissions, and attributes in MacOS (left) and Windows (top right and bottom right). This shows information such as when the file was created, who can read the file, and if it is ready to be archived.