I understand there are 12 permission bits of which there are 3 groups of 3 bits for each of user, group, and others, which are RWX respectively. RW are read and write, but for X is
search for directories and
execute for files.
Here is what I don't get:
What are the 3 remaining mode bits and are they all stored in the inode?
I know the file directory itself is considered a file as well, since all things in UNIX are files (is this true?), but since UNIX systems use ACL to represent the file system, then the file system is a list of filename-inode_number pairs. Where does a file directory store it's own inode number and filename?