diff --git a/lib/utils/tick_delay.c b/lib/utils/tick_delay.c
index 985234c05..ce97f5f4f 100644
--- a/lib/utils/tick_delay.c
+++ b/lib/utils/tick_delay.c
@@ -6,7 +6,14 @@
 PUBLIC int tick_delay(ticks)
 long ticks;				/* number of ticks to wait */
 {
-    message m;
+/* This function uses the synchronous alarm to delay for a while. This works
+ * even if a previous synchronous alarm was scheduled, because the remaining
+ * tick of the previous alarm are returned so that it can be rescheduled.
+ * Note however that a long tick_delay (longer than the remaining time of the
+ * previous) alarm will also delay the previous alarm.
+ */
+    message m, m_alarm;
+    clock_t time_left;
     int s;
 
     if (ticks <= 0) return;		/* check for robustness */
@@ -16,10 +23,20 @@ long ticks;				/* number of ticks to wait */
     m.ALRM_EXP_TIME = ticks;		/* request message after ticks */
     m.ALRM_ABS_TIME = 0;		/* ticks are relative to now */
     s = _taskcall(SYSTASK, SYS_SYNCALRM, &m);
+    if (s != OK) return(s);
+
+    receive(HARDWARE,&m_alarm);		/* await synchronous alarm */
+
+    /* Check if we must reschedule the current alarm. */
+    if (m.ALRM_TIME_LEFT > 0) {
+    	printf("tick_delay: reschedule alarm\n");
+    	m.ALRM_EXP_TIME = m.ALRM_TIME_LEFT - ticks;
+    	if (m.ALRM_EXP_TIME <= 0) 
+    		m.ALRM_EXP_TIME = 1;
+    	s = _taskcall(SYSTASK, SYS_SYNCALRM, &m);
+    }
 
-    if (OK == s) receive(HARDWARE,&m);	/* await synchronous alarm */
     return(s);
-
 }
 
 
diff --git a/tools/Makefile b/tools/Makefile
index 31d3873bd..b6eb6c10c 100755
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -52,6 +52,7 @@ image: programs
 
 # rebuild the program or system libraries
 programs: 
+	cd ../include && $(MAKE) install
 	cd ../kernel && $(MAKE) 
 	cd ../servers && $(MAKE) install
 	cd ../drivers && $(MAKE) install