UserDir
The UserDir directive disables or enables and defines the directory (relative
to a local user’s /home directory) where that user can put public HTML
documents. It is relative because each user has her own HTML directory. This
setting is disabled by default but can be enabled to store user web content
under any directory.
The default setting for this directive, if enabled, is public_html. Each user
can create a directory called public_html under her /home directory, and
HTML documents placed in that directory are available as
[http://servername/~username, where username is the username of the](http://servername/~username, where username is the username of the)
particular user.
DirectoryIndex
The DirectoryIndex directive indicates which file should be served as
the index for a directory, such as which file should be served if the URL
[http://servername/_SomeDirectory/ is requested.](http://servername/_SomeDirectory/ is requested.)
It is often useful to put a list of files here so that if index.html (the default
value) isn’t found, another file can be served instead. The most useful
application of this is to have a CGI program run as the default action in a
directory. If you have users who make their web pages on Windows, you
might want to add index.htm as well. In that case, the directive looks like
DirectoryIndex index.html index.cgi index.htm.
Apache Multiprocessing Modules
Apache version 2.0 and later now uses a new internal architecture that
supports multiprocessing modules (MPMs). These modules are used by the
server for a variety of tasks, such as network and process management, and
are compiled into Apache. MPMs enable Apache to work much better on a
wider variety of computer platforms, and they can help improve server
stability, compatibility, and scalability.
Apache can use only one MPM at any time. These modules are different from
the base set included with Apache (see the “Apache Modules” section later in
this chapter) but are used to implement settings, limits, or other server actions.
Each module in turn supports numerous additional settings, called directives,
which further refine server operation.
The internal MPM modules relevant for Linux include the following: