3    BASE/2018 Open error (DISKSPACE())
------------------------------------------------------------------------------

      Problem: The DISKSPACE() function is unable to
      access the specified disk.

      Solution: There are two likely causes for this
      error: the drive number argument is invalid or the
      specified drive is not ready. If the drive supports
      removable media, make certain that the drive door
      is closed and the disk is properly seated in the
      drive.

      Note: The default handling for this error is to
      return an empty value.