1 07/14/87  Entrynames (general information)
 2 
 3 Entrynames are the names of objects used in the Multics filesystem,
 4 such as directories, segments and links.  An object of this sort must
 5 have at least one name, but may have many names, all of which reside in
 6 the same containing directory.
 7 
 8 
 9 Entrynames may be from 1 to 32 characters long, and must contain at
10 least one character which is not an ASCII space.  All of the characters
11 must be ASCII characters, from 000 to 177 octal, and the greater-than
12 character (">") is forbidden.  The greater-than character is used to
13 construct pathnames.
14 
15 
16 There are a number of other restrictions on entrynames which are
17 enforced by different parts of the system.  Because they are not
18 enforced by the filesystem itself, it is sometimes possible to violate
19 them, but it is not recommended.  The -name control argument to the
20 delete, delete_name and rename commands was provided to permit dealing
21 with illegal names.  Most of the restrictions reserve characters for
22 one purpose or another.  There is no way to protect these characters
23 from evaluation in contexts which implement the features for which they
24 are reserved.
25 
26 
27 List of restrictions on entrynames:
28 
29 1.  Entrynames should not contain null components.  Components are
30     parts of names delimited by periods (".").  For example,
31     "example.pl1" has two components, "example" and "pl1".  The last
32     component, or suffix often indicates the type of file which it
33     names.  A null component is a component of zero length, which would
34     occur in a name which begins or ends with a period, or which
35     contains two adjacent periods ("..").
36 
37 
38 2.  Entrynames should not contain less-than characters ("<").  The
39     less-than character is used to construct relative pathnames.
40 
41 3.  Entrynames should not contain two consecutive colons ("::").  This
42     compound delimiter is used to construct archive component
43     pathnames, which permit reading an archive component without
44     extracting it from the archive.
45 
46 4.  Entrynames should not contain asterisk ("*") or question mark ("?")
47     characters.  These characters are used by the star convention,
48     which is used to select entrynames by wildcard matching.
49 
50 
51 5.  Entrynames should not contain the equal ("=") or percent ("%")
52     characters.  These characters are used by the equal convention,
53     which is used to construct entrynames when a command takes several
54     arguments, particularly when the first argument can be a starname
55     so that matching names can be derived, but also as a typing aid.
56 
57 6.  Entrynames should not contain the dollar ("$") or vertical-bar
58     ("|") characters.  These characters are used to construct virtual
59     pointers and virtual entry values.  These "virtual" values are the
60     printable representations of Multics pointer and entry constants.
61 
62 7). Entrynames should not begin with a hyphen (-).  Many of the Multics
63     commands will interpret entrynames which start with hyphens to be
64     control arguments.
65 
66 
67 Notes: Please refer to the following info segments for additional
68 information:
69   pathname.gi.info
70   archive_convention.gi.info
71   starname.gi.info
72   equalname.gi.info
73   virtual_pointer.gi.info
74   virtual_entry.gi.info