     A segment is a collection of information.  It is the basic unit of
storage on Multics, analagous to a file on many other systems.  A single
segment may be empty or contain up to over a million printed characters.
Segments are usually created by entering information by way of a text editor
and then assigning a name to that collection of information.  But segments can
also be created with the create "command" or by programs, which are themselves
segments.

     The name of a segment can be in either uppercase or lowercase letters,
though on Multics it is most common to use lowercase letters.  Multics
distinguishes between uppercase and lowercase, so the name SEGMENT is
different from segment.

     Segments may be known by several names.  You can put additional names on
a segment with the add_name command.  You can also change the name of a
segment by using the rename command.

     Segment names cannot contain blank spaces.  When you wish to use more
than one word, the underscore character is used in place of a blank space.
Words can also be separated by a period.  For example:

segment.output

A period usually indicates that the word following it is a meaningful suffix,
that is, the suffix is used on a number of segments to signify something about
those segments.  Multics has several suffixes that it uses in this way, and
you can invent your own for this purpose.
