diff --git a/include/signal.h b/include/signal.h
index 9f38bf576d1e..f17820be0854 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -65,23 +65,6 @@ int	sigpending __P((sigset_t *));
 int	sigprocmask __P((int, const sigset_t *, sigset_t *));
 int	sigsuspend __P((const sigset_t *));
 
-#ifdef _POSIX4_VISIBLE_HISTORICALLY
-
-/* Async event notification */
-
-union sigval {
-	int	sival_int;
-	void	*sival_ptr;
-};
-struct sigevent {
-	int	sigev_notify;		/* Notification type */
-	int	sigev_signo;		/* Signal number */
-	union sigval sigev_value;	/* Signal value */
-};
-#define	SIGEV_NONE	0		/* No async notification */
-#define	SIGEV_SIGNAL	1		/* Queue signal with value */
-
-#endif /* _POSIX4_VISIBLE_HISTORICALLY */
 
 #ifdef _POSIX4_VISIBLE
 
diff --git a/sys/sys/aio.h b/sys/sys/aio.h
index 09627da41789..8e5a8136e830 100644
--- a/sys/sys/aio.h
+++ b/sys/sys/aio.h
@@ -16,11 +16,37 @@
  * bad that happens because of using this software isn't the responsibility
  * of the author.  This software is distributed AS-IS.
  *
- * $Id: aio.h,v 1.3 1997/12/08 02:18:14 dyson Exp $
+ * $Id: aio.h,v 1.4 1998/03/08 17:25:30 dufault Exp $
  */
 
 #include <sys/types.h>
 
+/**************************************************************************/
+/* Additions to signal.h -- hack alert.                                   */
+/**************************************************************************/
+/*
+ * sigval structure:
+ */
+union sigval {
+	int	sival_int;
+	void	*sival_ptr;
+};
+
+/*
+ * this is the sigevent structure:
+ */
+struct sigevent {
+	int	sigev_notify;		/* Notification */
+	int	sigev_signo;		/* Signal number */
+	union sigval sigev_value;	/* Not used yet in FreeBSD */
+};
+
+/*
+ * values for sigev_notify:
+ */	
+define	SIGEV_NONE	0		/* Don't post a signal */
+#define	SIGEV_SIGNAL	1		/* Post specified signal */
+
 /*
  * Returned by aio_cancel:
  *  (Note that FreeBSD's aio is not cancellable -- yet.)
@@ -42,6 +68,11 @@
 #define	LIO_NOWAIT		0x0
 #define	LIO_WAIT		0x1
 
+/*
+ * Maximum number of allowed LIO operations
+ */
+#define	AIO_LISTIO_MAX		16
+
 /*
  * Private mode bit for aio.
  * (This bit is set by the library routine
@@ -51,11 +82,6 @@
 #define AIO_PMODE_SYNC		0x1
 #define AIO_PMODE_DONE		0x2
 #define AIO_PMODE_SUSPEND	0x4
-
-/*
- * I/O active flag -- used for compat
- * with kernel.
- */
 #define AIO_PMODE_ACTIVE	0x2357c0de
 
 /*