The AmigaOS Fast File System (FFS) was created back in 1988 and, believe it or not, is still in use today by some die hard enthusiasts who insist it is still pretty good. FFS has several modes which has enabled it to survive far past its expiry date. Two of those modes have never been described before. That is about to change.
Back in 1992, Randell Jesup added what is known as the Directory Caching File System (DCFS) mode to FFS. This was meant to speed up directory listings on floppy disks. A rarely used and mysterious mode with very little documentation.
Fast forward to 2001 when Olaf Barthel created a FFS reimplementation and added the Long Name File System (LNFS) mode. Up until this point users were stuck with 30 characters due to the original implementation.
Curious? Read all the gory details on the most complete and official AmigaOS Documentation Wiki.