1      A directory is a catalog of "segments." It serves like a file drawer,
 2 with segments being the file folders in that drawer.  There are many
 3 directories on Multics, some of them indigenous to Multics and others created
 4 by users.  Each contains its own segments.  No two segments in a directory can
 5 have the same name, but like-named segments can be kept in separate
 6 directories.
 7 
 8      Directories also catalog other directories, thereby creating hierarchies
 9 of directories.  For example, a directory named Smith could have three or
10 four directories under it, and those directories in turn could have
11 directories under them.  The hierarchy of a particular set of directories is
12 indicated by the greater-than character (>).  For example, the order of two
13 directories under Smith is:
14 
15 Smith>directory_1>directory_a
16 
17 This indicates that directory_1 is a directory under, or contained by, the
18 directory Smith and that directory_a is a directory under directory_1.
19 A segment contained in a directory would be in the last place in the line of
20 directories.  For example:
21 
22 Smith>directory_1>directory_a>my_segment
23 
24 If you wanted to indicate that the segment is in directory_1, you would
25 represent the hierarchy as follows:
26 
27 Smith>directory_1>my_segment
28 
29 A directory name cannot follow a segment name because directories are not
30 contained in segments.
31 
32      Directories are created with the create_dir "command." Names on
33 directories follow the same conventions as those on segments: they cannot
34 contain blank spaces and uppercase letters are distinguished from lowercase
35 letters.