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<topic xml:lang="en-us" id="storage-cds">
            <title>CD/DVD Support</title>
            
            <body>
               <p>Virtual CD/DVD drives by default support only reading. The medium configuration is changeable at runtime. You can select between the following options to provide the medium data:</p>
               <ul>
                  <li>
                     <p><b outputclass="bold">Host Drive</b> defines that the guest can read from the medium in the host drive.</p>
                  </li>
                  <li>
                     <p><b outputclass="bold">Image file</b> gives the guest read-only access to the data in the image. This is typically an ISO file.</p>
                  </li>
                  <li>
                     <p><b outputclass="bold">Empty</b> means a drive without an inserted medium.</p>
                  </li>
               </ul>
               <p>Changing between the above, or changing a medium in the host drive that is accessed by a machine, or changing an image file will signal a medium change to the guest OS. The guest OS can then react to the change, for example by starting an installation program.</p>
               <p>Medium changes can be prevented by the guest, and <ph conkeyref="vbox-conkeyref-phrases/product-name"/> reflects that by locking the host drive if appropriate. You can force a medium removal in such situations by using the VirtualBox Manager or the <userinput>VBoxManage</userinput> command line tool. Effectively this is the equivalent of the emergency eject which many CD/DVD drives provide, with all associated side effects. The guest OS can issue error messages, just like on real hardware, and guest applications may misbehave. Use this with caution.</p>
               <note>
                  <p>The identification string of the drive provided to the guest, displayed by configuration tools such as the Windows Device Manager, is always VBOX CD-ROM, irrespective of the current configuration of the virtual drive. This is to prevent hardware detection from being triggered in the guest OS every time the configuration is changed.</p>
               </note>
            </body>
            
         </topic>
