What Are Extended File Attributes?

Extended file attributes are a feature of the file system. It allows users to associate computer files with metadata that is not interpreted by the file system. Corresponding to it is a regular file attribute, which has a meaning that is strictly defined by the file system (such as file system permissions or file creation and modification times, etc.). Unlike forks, which usually have the largest file size, extended file attributes are usually limited to much smaller than the maximum file size. Typical applications include character encoding or check codes for storing document authors, ordinary text files.

In 1.2 and later OS / 2 releases,

Like OS / 2, Windows NT supports FAT and

in

In FreeBSD 5.0 and later, UFS1 and UFS2 file systems support extended attributes. Each attribute is represented by a name and the data associated with it. The name must be a string and must exist in a namespace identified by a small integer namespace identifier. There are two types of namespaces: user namespaces and system namespaces. User namespaces have no constraints on naming or content. The system namespace is mainly used by the kernel in access control lists. ^[2]