[[!meta copyright="Copyright © 2007, 2008, 2010 Free Software Foundation,
Inc."]]

[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]

An extensible system is one that enables extensibility.  Enabling extensibility
means providing non-privileged mechanisms to extend existing objects and to
introduce new objects.  [[UNIX]] is generally not an extensible system as it does
not generally facilitate the hooking of [[system call]]s.  For instance, there is
no way to hook into the virtual file system.  This has motivated the introduction
of separate, parallel interfaces by both the GNOME and KDE projects to provide
users a more integrated view of their objects.