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diff --git a/doc/genisoimage/README.joliet b/doc/genisoimage/README.joliet new file mode 100644 index 0000000..ab9bf5d --- /dev/null +++ b/doc/genisoimage/README.joliet @@ -0,0 +1,53 @@ +Some thoughts on Joliet - why it is a dumb idea to have a CD +with Joliet enhancements but without Rock Ridge. +It also helps you to understand why it it not possible to append +a new session to a multi-session Joliet CD when Rock Ridge is +missing. + +- Joliet is not an accepted independant international standard + like ISO-9660 or Rock Ridge (IEEE-P1282). + Joliet has been created in 1995 - Rock Ridge in 1990. + Rock Ridge became a IEEE standard around 1992. + +Joliet is an unjustified addition to ISO-9660. + +- The Joliet tree has no relation to the + ISO-9660 tree. Files from the ISO-9660 tree and from the + Joliet tree only share content. In general, it is not + possible to find the ISO-9660 name from a Joliet name + and vice versa if you check both trees on a CD. + + Rock Ridge extensions are located at the end of each + ISO-9660 directory record. This makes the Rock Ridge + tree closely coupled to the ISO-9660 tree. + +- Joliet does not allow all characters too, so the + Joliet filenames are not identical to the filenames + on disk. + + As the ISO-9660 tree is the standard reference tree + on a CD and the ISO-9660 filenames don't allow all + characters and there is a length limitation, the + ISO-9660 names cannot be mapped to the filenames on the + OS reference tree on disk for doing multi-session. + + Due to different limitations, the short ISO-9660 name + is in most cases not equal to the Joliet name or the + Rock Ridge name. + +- Joliet has a filename length limitation of 64 chars (independent + from the character coding and type e.g. European vs. Japanese) + This is annoying as modern filesystems all allow 255 chars + per path name component. + + Joliet uses UTF-16 coding while Rock Ridge uses ISO-8859 or + UTF-16 based chars and allows 255 octets. Using UTF-8, + Rock Ridge allows 85 Japanese characers or 255 US-ASCII chars. + +Other than slightly longer filenames, Joliet offers no new properties +over plain ISO 9660. Rock Ridge is an open extendable standard and +there is no filesystem property on Win32 that could not be implemented +using Rock Ridge. + +Except Linux and FreeBSD, there is no POSIX-like like OS that supports +Joliet. Never create Joliet only CD's for that reason. |