code: public long fetchUserData(long instanceid)
      throws IOException
      {
          for ( int i = 0; i < NUM_USER_WORDS; i++ ) {
              if ( userData[i][0] == instanceid ) {
                  return userData[i][1];
              }
          }
          return 0;
      }
docs: ************************************************************************
  Fetch userdata associated with instanceid
  
  @param instanceid This is the unique identifier for this userdata
  
  @return the data if it can be found.  Throw exception otherwise.
  
  @throws IOException if disk write fails.
  ***********************************************************************