Rock Ridge
An ISO 9660 extension that smuggled Unix semantics — long names, permissions, symlinks — onto a CD.
The Rock Ridge Interchange Protocol (RRIP) was defined in 1994 to make ISO 9660 usable on Unix. It hides POSIX attributes — file permissions, ownership, symbolic links, device nodes and mixed-case names — inside System Use fields that older readers politely ignore. The same disc can therefore mount as a full-fledged directory tree on Linux and still read on a DOS box.
The name is a movie gag: Rock Ridge is the town in Mel Brooks's Blazing Saddles, just as its sibling Joliet borrows its name from a film.