/**
  * Retrieve data in json format
  *
  * @return void
  * @author
  **/
 function get_data($serial_number = '')
 {
     $obj = new View();
     if (!$this->authorized()) {
         $obj->view('json', array('msg' => array('error' => 'Not authenticated')));
         return;
     }
     $out = array();
     $model = new Disk_report_model();
     foreach ($model->retrieve_records($serial_number) as $res) {
         $out[] = $res->rs;
     }
     $obj->view('json', array('msg' => $out));
 }