    DIRECTORY(V)                 9/10/73                 DIRECTORY(V)

    NAME
         dir - format of directories

    DESCRIPTION
         A directory behaves exactly like an ordinary file, save that
         no user may write into a directory.  The fact that a file is
         a directory is indicated by a bit in the flag word of its i-
         node entry.  Directory entries are 16 bytes long.  The first
         word  is  the i-number of the file represented by the entry,
         if non-zero; if zero, the entry is empty.

         Bytes 2-15 represent  the  (14-character)  file  name,  null
         padded  on the right.  These bytes are not cleared for empty
         slots.

         By convention, the first two entries in each  directory  are
         for  ``.'' and ``..''.  The first is an entry for the direc-
         tory itself.  The second is for the parent  directory.   The
         meaning  of ``..'' is modified for the root directory of the
         master file system and for the root directories of removable
         file systems.  In the first case, there is no parent, and in
         the second, the system does  not  permit  off-device  refer-
         ences.   Therefore in both cases ``..'' has the same meaning
         as ``.''.

    SEE ALSO
         file system(V)

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