Definitions for "JFS"
journaling file system. A file system that keeps a record of its activity in a 'journal', so to speak. In the event of a system crash, information can be quickly recovered about what files were contained in your hard disk. One of the early allegations of SCO was that Linux could not have developed the capability of using this kind of file system without misappropriating it from Unix code via IBM developers.
journaled file system. The local file system within a single instance of AIX.
Journaled File System [IBM