\begin{exe} {Preparing to use Rescue/Recover Media}

   \begin{important}
      In the following exercises we are going to deliberately
      damage the system and then recover through the use of
      rescue media.  Thus, it is obviously prudent to make
      sure you can indeed boot off the rescue media before you
      try anything more ambitious.

      So first make sure you have rescue media, either a
      dedicated rescue/recovery image, or an install or Live
      image on either an optical disk or usb drive.

      Boot off it and make sure you know how to force the
      system to boot off the rescue media (you are likely to
      have to fiddle with the \textbf{BIOS} settings), and
      when the system boots, choose rescue mode.
   \end{important}

   \begin{info}
      If you are using a virtual machine, the procedure is
      logically the same with two differences:
      \begin{itemize}
         \item
         Getting to the \textbf{BIOS} might be difficult
         depending on the hypervisor you use.  Some of them
         require very rapid keystrokes, so read the
         documentation and make sure you know how to do it.
         \item
         You can use a physical optical disk or drive, making
         sure the virtual machine settings have it mounted, and
         if it is \textbf{USB} you may have some other hurdles
         to make sure the virtual machine can claim the
         physical device. It is usually easier to simply
         connect a \verb?.iso? image file directly to the
         virtual machine.
      \end{itemize}
      If you are working with a virtual machine, obviously
      things are less dangerous, and if you are afraid of
      corrupting the system in an unfixable way, simply make a
      backup copy of the virtual machine image before you do
      these exercises, you can always replace the image with
      it later.
   \end{info}
   \begin{important}
      \textbf{Do not do the following exercises unless you are
         sure you can boot your system off rescue/recovery
         media!}
   \end{important}
\end{exe}

