-#define RXIOC_FORMAT _IOW(d, 1, int) /* format the disk */
-#define RXIOC_WDDS _IOW(d, 2, int) /* write `deleted data' mark */
- /* on next sector */
-#define RXIOC_RDDSMK _IOR(d, 3, int) /* did last read sector contain */
- /* `deleted data'?*/
-#define RXIOC_GDENS _IOR(d, 4, int) /* return density of current disk */
+#define RXIOC_FORMAT _IOW('d', 1, int) /* format the disk */
+#define RXIOC_WDDS _IOW('d', 2, int) /* write `deleted data' mark */
+ /* on next sector */
+#define RXIOC_RDDSMK _IOR('d', 3, int) /* did last read sector */
+ /* contain `deleted data'?*/
+#define RXIOC_GDENS _IOR('d', 4, int) /* return density of current */
+ /* disk */