public VolumeID setDriveType(int n) throws ShellLinkException {
		if (n == DRIVE_UNKNOWN || n == DRIVE_NO_ROOT_DIR || n == DRIVE_REMOVABLE || n == DRIVE_FIXED 
				|| n == DRIVE_REMOTE || n == DRIVE_CDROM || n == DRIVE_RAMDISK) {
			dt = n;
			return this;
		} else 
			throw new ShellLinkException("incorrect drive type");
	}