1      A segment is a collection of information.  It is the basic unit of
 2 storage on Multics, analagous to a file on many other systems.  A single
 3 segment may be empty or contain up to over a million printed characters.
 4 Segments are usually created by entering information by way of a text editor
 5 and then assigning a name to that collection of information.  But segments can
 6 also be created with the create "command" or by programs, which are themselves
 7 segments.
 8 
 9      The name of a segment can be in either uppercase or lowercase letters,
10 though on Multics it is most common to use lowercase letters.  Multics
11 distinguishes between uppercase and lowercase, so the name SEGMENT is
12 different from segment.
13 
14      Segments may be known by several names.  You can put additional names on
15 a segment with the add_name command.  You can also change the name of a
16 segment by using the rename command.
17 
18      Segment names cannot contain blank spaces.  When you wish to use more
19 than one word, the underscore character is used in place of a blank space.
20 Words can also be separated by a period.  For example:
21 
22 segment.output
23 
24 A period usually indicates that the word following it is a meaningful suffix,
25 that is, the suffix is used on a number of segments to signify something about
26 those segments.  Multics has several suffixes that it uses in this way, and
27 you can invent your own for this purpose.