Minix1.1/usr/src/fs/dev.h

/* Device table.  This table is indexed by major device number.  It provides
 * the link between major device numbers and the routines that process them.
 */

EXTERN struct dmap {
  int (*dmap_open)();
  int (*dmap_rw)();
  int (*dmap_close)();
  int dmap_task;
} dmap[];