\section{Special Filesystems}

\begin{frame}
   {Special Filesystems}

   \begin{itemize}

      \item
      Special filesystems are used to gain access to or tune
      system internals or to implement certain functions.
      \item
      Some have mount points (such as \textbf{proc}
      at\file{/proc} or \textbf{sys} at \file{/sys})
      \item
      Some have no mount points (such as \textbf{sockfs} or
      \textbf{pipefs})

      \item

      These special filesystems are really not true
      filesystems; they are kernel facilities or subsystems
      that find the filesystem structural abstraction to be a
      useful way to organize data and functionality.
   \end{itemize}

\end{frame}

\cprotect\note {

   \index{filesystems!special}

   \textbf{Linux} widely employs the use of \textbf{special
      filesystems} for certain tasks. These are particularly
   useful for accessing various kernel data structures and
   tuning kernel behaviour, or for implementing particular
   functions. A partial list:

   \input{specialtable.inc}

   Note that some of these special filesystems have no
   mount point; this means user applications do not
   interact with them, but the kernel uses them, taking
   advantage of \textbf{VFS} layers and code.

}
