The ISO 9660 standard allows an optional extended attributes record (XAR) stored at the beginning of the file′s extent which can contain additional file attribute information.
Extension attributes are simply a way to extend the attributes of files. Since attributes vary according to the user, most everyone has a different opinion on what a file attribute should specify.
The Rock Ridge:
- extensions is an example of extended attributes to make POSIX alike file attributes (much like UNIX).
- can also be used in a networked situation, since a single CD-ROM can be exported to a variety of different operating systems viewing the same files, while appearing to be in the local system′s native file structure format.
- is heading in the same "universal" direction of other file systems like the Network File System (NFS).