Rock ridge extension: It is used in UNIX file system for representing a CD-ROM. All the fields are same as in ISO 9660 file system, just that system use filed has extensions. System use field is used for making the CD-ROM to work in any computer.
Rock ridge extension contains the following fields:
1) PX: It is used for POSIX attributes. It contains standard UNIX rwxrwxrwx permission bits.
2) PN: It contains major and minor device numbers of a file. It is used for representing a directory in a CD-ROM.
3) SL: It represents symbolic link. It is used for referring a file system on another file system.
4) NM: It represents another name for the file.
5) CL: It is used for representing child location.
6) PL: It is used for representing parent location.
7) RE: It is used for representing relocation.
8) TF: It is used for representing time stamps. It contains 3 timestamps: 1) time file was created, 2) time file was last modified, 3) time file was last accessed.
Joliet extensions: Joliet extension was created by Microsoft to be used in Windows for representing a CD-ROM. Here are the important points in Joliet extensions: long file names, directory names with extensions, unicode character set, and directory nesting deeper than eight levels.