title: How To Access External and internal storage?
body: <p>I actually want to access the files on android  system. I manage to read the files and directories in the external storage of android.
  My questions are :</p>
  
  <ol>
  <li>How can I access the directories and files of the internal storage(Specially videos, pics all of the applications which runs in android).</li>
  <li>Where are stored the data of each application which installed in internal storage?</li>
  <li>Is it possible to transfer data which exists in the internal storage (from internal memory to external storage?</li>
  <li>I read that external storage is world-readable? what does that mean?(if a create an application then this application can access all the files that installed in external storage?) </li>
  </ol>