diff --git a/chan.c b/chan.c
index 2d11fca..68f0e00 100644
--- a/chan.c
+++ b/chan.c
@@ -10,32 +10,32 @@ struct hip_chan_t
 	int closed;
 
 	hip_oow_t unit_size;
-	hip_oow_t buf_size;
-
+	hip_oow_t unit_capa;
+	hip_oow_t unit_count;
+	hip_oow_t unit_rpos;
+	hip_oow_t unit_wpos;
 	hip_uint8_t* buf;
-	hip_uint8_t* endptr;
-	hip_uint8_t* readptr;
-	hip_uint8_t* writeptr;
 
 	hip_uctx_link_t sendq; // list of senders waiting on this channel
 	hip_uctx_link_t recvq; // list of receivers waiting on this channel
 };
 
-hip_chan_t* hip_chan_open(hip_t* hip, hip_oow_t buf_size)
+hip_chan_t* hip_chan_open(hip_t* hip, hip_oow_t unit_size, hip_oow_t unit_capa)
 {
 	hip_chan_t* c;
 
-	c = (hip_chan_t*)malloc(HIP_SIZEOF(*c) + buf_size);
+	c = (hip_chan_t*)malloc(HIP_SIZEOF(*c) + (unit_size * unit_capa));
 	if (HIP_UNLIKELY(!c)) return HIP_NULL;
 
 	memset(c, 0, HIP_SIZEOF(*c));
 	c->hip = hip;
 	c->closed = 0;
-	c->buf_size = buf_size;
+	c->unit_size = unit_size;
+	c->unit_capa = unit_capa;
+	c->unit_count = 0;
+	c->unit_rpos = 0;
+	c->unit_wpos = 0;
 	c->buf = (hip_uint8_t*)(c + 1);
-	c->endptr = 0;
-	c->readptr = 0;
-	c->writeptr = 0;
 
 	HIP_LIST_INIT(&c->recvq);
 	HIP_LIST_INIT(&c->sendq);
@@ -57,20 +57,35 @@ int hip_chan_send(hip_chan_t* c, const void* ptr, hip_oow_t len)
 	hip = c->hip;
 	caller = UCTX_FROM_LINK(hip->running);
 
-// TODO: IS BUFFER EMPTY
+	if (c->unit_count < c->unit_capa)
+	{
+		/* buffered */
+		hip_uint8_t* dptr;
+		if (len > c->unit_size) len = c->unit_size; /* can't buffer longer than the specified unit size */
+		dptr = &c->buf[c->unit_wpos * c->unit_size];
+		memcpy(dptr, ptr, len);
+		if (len < c->unit_size)
+		{
+			/* zero out the unfilled if the writing length is smaller than the unit size */
+			memset(dptr + len, 0, c->unit_size - len);
+		}
+		c->unit_wpos = (c->unit_wpos + 1) % c->unit_capa;
+		c->unit_count++;
+		return len;
+	}
 
 	if (!HIP_LIST_IS_EMPTY(&c->recvq)) /* there is a receving routine */
 	{
 		hip_uctx_link_t* x;
-		hip_uctx_t* xx;
+		hip_uctx_t* recver;
 
 		x = HIP_LIST_HEAD(&c->recvq);
 
-		xx = UCTX_FROM_LINK(x);
-		if (len > xx->chan_data_len) len = xx->chan_data_len;
-		memcpy(xx->chan_data_ptr, ptr, len);
-//printf ("USE SEND CHAT CALLER %p RECEIVER %p RET %p\n", caller, xx, xx->chan_ret_ptr);
-		*(xx->chan_ret_ptr) = len; /* manipulate the return value of the receiver */
+		recver = UCTX_FROM_LINK(x);
+		if (len > recver->chan_data_len) len = recver->chan_data_len;
+		memcpy(recver->chan_data_ptr, ptr, len);
+//printf ("USE SEND CHAT CALLER %p RECEIVER %p RET %p\n", caller, recver, recver->chan_ret_ptr);
+		*(recver->chan_ret_ptr) = len; /* set the return value of the receiver */
 
 		/* remove the receiving routine from the queue and make it runnable */
 		HIP_LIST_UNCHAIN(x);
@@ -100,22 +115,29 @@ int hip_chan_recv(hip_chan_t* c, void* ptr, hip_oow_t len)
 	hip = c->hip;
 	caller = UCTX_FROM_LINK(hip->running);
 
-	/* TODO: IS THERE DATA IN BUFFER ? */
+	if (c->unit_count > 0)
+	{
+		if (len > c->unit_size) len = c->unit_size;
+		memcpy(ptr, &c->buf[c->unit_rpos * c->unit_size], len);
+		c->unit_rpos = (c->unit_rpos + 1) % c->unit_capa;
+		c->unit_count--;
+		return len;
+	}
 
 	if (!HIP_LIST_IS_EMPTY(&c->sendq)) /* there is a sending routine */
 	{
 		hip_uctx_link_t* x;
-		hip_uctx_t* xx;
+		hip_uctx_t* sener;
 
 		/* remove the sending routine from the queue and make it runnable */
 		x = HIP_LIST_HEAD(&c->sendq);
 
 		/* copy the data from the sending routine's buffer */
-		xx = UCTX_FROM_LINK(x);
-		if (len > xx->chan_data_len) len = xx->chan_data_len; /* TODO: do something else instead of simple truncation */
-		memcpy(ptr, xx->chan_data_ptr, len);
-//printf ("USE RECV CHAT caller %p sender %p RET %p\n",caller, xx, xx->chan_ret_ptr);
-		*(xx->chan_ret_ptr) = len; /* manipulate the return value of the sender */
+		sener = UCTX_FROM_LINK(x);
+		if (len > sener->chan_data_len) len = sener->chan_data_len; /* TODO: do something else instead of simple truncation */
+		memcpy(ptr, sener->chan_data_ptr, len);
+//printf ("USE RECV CHAT caller %p sender %p RET %p\n",caller, sener, sener->chan_ret_ptr);
+		*(sener->chan_ret_ptr) = len; /* set the return value of the sender */
 
 		HIP_LIST_UNCHAIN(x);
 		HIP_LIST_ADD_BACK(x, &hip->runnables);
diff --git a/ctx.c b/ctx.c
index ce5da4d..873ffe0 100644
--- a/ctx.c
+++ b/ctx.c
@@ -36,13 +36,13 @@ static void invoke_uf(unsigned int a, unsigned int b)
 #else
 	uctx = (hip_uctx_t*)(((hip_oow_t)a << 32) | (hip_oow_t)b);
 #endif
-printf ("invoke_uf START ...%p\n", uctx);
+//printf ("invoke_uf START ...%p\n", uctx);
 	uctx->uf(uctx, uctx->ctx);
 
-printf ("invoke_uf DONE ...%p\n", uctx);
+//printf ("invoke_uf DONE ...%p\n", uctx);
 //TODO: This part must not be interrupted by the timer handler???
 	hip = uctx->hip;
-	if (uctx == hip->uctx_sched) /* if not the scheduler itcaller */
+	if (uctx == hip->uctx_sched) /* if not the scheduler itself */
 	{
 		/* back to where the schedule got activated for the first time */
 		setcontext(&hip->uc_main);
@@ -55,27 +55,17 @@ printf ("invoke_uf DONE ...%p\n", uctx);
 	else
 	{
 		/* switch to the scheduler */
-		HIP_LIST_UNCHAIN(&uctx->uctx);
+		assert (&uctx->uctx == hip->running);
 
-		if (uctx->flags & HIP_RTN_FLAG_AUTO_DESTROY)
-		{
-//printf (">>>>>>>>>> *********************** AUTHO DESTROYING UCTX %p\n", uctx);
-			hip_uctx_close(uctx);
-//printf (">>>>>>>>>> *********************** CLOSED TERMINATED %p\n", uctx);
-		}
-		else
-		{
-			HIP_LIST_ADD_BACK(&uctx->uctx, &hip->terminated);
-//printf (">>>>>>>>>> ************************ ADDED TO TERMINATED\n");
-		}
+		/* place the routine in the terminated routines list and switch to the scheduler */
+		hip_switch(hip, &hip->terminated);
 
-		setcontext(&hip->uctx_sched->uc); /* switch to the scheduler */
+		/* the control must never reach here for a terminated routine
+		 * as the scheduler never reschdule to this function */
 	}
 //TODO: This part must not be interrupted?
 
 	// TODO: schedule the runnable process?
-	// TODO: move to terminated list?
-	// TODO: destroy the object?
 }
 
 hip_uctx_t* hip_uctx_open(hip_t* hip, hip_oow_t stack_size, int flags, hip_ufun_t uf, void* ctx)
@@ -85,7 +75,7 @@ hip_uctx_t* hip_uctx_open(hip_t* hip, hip_oow_t stack_size, int flags, hip_ufun_
 
 	uctx = (hip_uctx_t*)malloc(HIP_SIZEOF(*uctx) + stack_size);
 	if (HIP_UNLIKELY(!uctx)) return HIP_NULL;
-printf ("MALLOC UCTX %p\n", uctx);
+//printf ("MALLOC UCTX %p\n", uctx);
 
 	sp = (void*)(uctx + 1);
 
@@ -115,7 +105,7 @@ printf ("MALLOC UCTX %p\n", uctx);
 	#endif
 	}
 
-printf("NEW UCTX %p\n", uctx);
+//printf("NEW UCTX %p\n", uctx);
 	return uctx;
 }
 
@@ -170,6 +160,15 @@ static void schedule(hip_uctx_t* uctx, void *ctx)
 		hip_uctx_link_t* h;
 		hip_uctx_t* u;
 
+		while (!HIP_LIST_IS_EMPTY(&hip->terminated))
+		{
+			// clean up terminated routines
+			h = HIP_LIST_HEAD(&hip->terminated);
+			HIP_LIST_UNCHAIN(h);
+			u = UCTX_FROM_LINK(h);
+			hip_uctx_close(u);
+		}
+
 		if (HIP_LIST_IS_EMPTY(&hip->runnables))
 		{
 /* TODO: check if there are sleeping ... */
@@ -323,7 +322,7 @@ hip_t* hip_open(int flags)
 
 	hip = (hip_t*)malloc(HIP_SIZEOF(*hip));
 	if (!hip) return HIP_NULL;
-printf ("MALLOC HIP %p\n", hip);
+//printf ("MALLOC HIP %p\n", hip);
 
 	memset(hip, 0, HIP_SIZEOF(*hip));
 	hip->flags = flags;
@@ -370,7 +369,7 @@ printf ("MALLOC HIP %p\n", hip);
 	if (hip->mux_id <= -1)
 	{
 		timer_delete(tid);
-printf("FREEING HIP %p\n", hip);
+//printf("FREEING HIP %p\n", hip);
 		free(hip);
 		return HIP_NULL;
 	}
@@ -441,7 +440,7 @@ void hip_close(hip_t* hip)
 
 	if (hip->uctx_mux) hip_uctx_close(hip->uctx_mux);
 	if (hip->uctx_sched) hip_uctx_close(hip->uctx_sched);
-printf("FREEING HIP2 %p\n", hip);
+//printf("FREEING HIP2 %p\n", hip);
 	free(hip);
 }
 
@@ -520,13 +519,6 @@ hip->uctx_sched->csi++;
 void hip_yield(hip_t* hip)
 {
 	hip_switch(hip, &hip->runnables);
-#if 0
-	hip_uctx_t* caller;
-	/* the caller must deal with hip->running before calling this function */
-	caller = UCTX_FROM_LINK(hip->running);
-	hip->running = HIP_NULL;
-	swapcontext(&caller->uc, &hip->uctx_sched->uc); /* switch to the scheduler */
-#endif
 }
 
 void hip_suspend(hip_t* hip)
@@ -738,12 +730,13 @@ printf (">> UF1 SEC [%d]\n", i);
 hip_sleep(uc->hip, 1000000000);
 }
 
+for (i = 0; i < 10; i++)
 	{
 		int n;
 		char buf[32];
 	printf (">> UF1 ALMOST DONE. WAITING FOR UF3\n");
 	n = hip_chan_recv(chan, buf, sizeof(buf));
-	printf (">> UF1 RECEIVED [%.*s]\n", (int)i, buf);
+	printf (">> UF1 RECEIVED [%.*s]\n", (int)n, buf);
 	n = hip_chan_send(chan, "holy cow", 8);
 	printf (">> UF1 SENT [%d]\n", (int)n);
 	}
@@ -774,7 +767,7 @@ static void uf3(hip_uctx_t* uc, void* ctx)
 	hip = uc->hip;
 	chan = (hip_chan_t*)ctx;
 
-#if 0
+#if 1
 	memset(&sa, 0, HIP_SIZEOF(sa));
 	sa.sin_family = AF_INET;
 	sa.sin_addr.s_addr = inet_addr("142.250.206.196");
@@ -813,10 +806,11 @@ hip_sleep(uc->hip, 1000000000);
 printf (">> UF3 SEC [%d]\n", i);
 		//hip_yield(uc->hip);
 hip_sleep(uc->hip, 1000000000);
-		if (i == 8) hip_newrtn(uc->hip, HIP_RTN_FLAG_AUTO_DESTROY, uf2, HIP_NULL);
+		if (i == 8) hip_newrtn(uc->hip, 0, uf2, HIP_NULL);
 	}
 printf (">> UF3 DONE DONE\n");
 
+for (i = 0; i < 10; i++)
 	{
 		int n;
 		char buf[64];
@@ -834,19 +828,20 @@ int main()
 
 setbuf(stdout, NULL);
 	hip = hip_open(HIP_FLAG_LAZY);
-	chan = hip_chan_open(hip, 100);
+	chan = hip_chan_open(hip, 100, 0);
 
-	hip_newrtn(hip, HIP_RTN_FLAG_AUTO_DESTROY, uf1, chan);
-	hip_newrtn(hip, HIP_RTN_FLAG_AUTO_DESTROY, uf2, HIP_NULL);
-	hip_newrtn(hip, HIP_RTN_FLAG_AUTO_DESTROY, uf3, chan);
+	hip_newrtn(hip, 0, uf1, chan);
+	hip_newrtn(hip, 0, uf2, HIP_NULL);
+	hip_newrtn(hip, 0, uf3, chan);
 
 	/* jump to the scheduler */
 	hip_schedule(hip, 0);
-printf("XXXXXXXXXXXXXXXXX ABOUT TO CLOSE ********************\n");
+printf("END OF SCHEDULE\n");
 
 	hip_chan_close(chan);
 /* TODO: close all uctxes ? */
 	hip_close(hip);
+printf("END OF APP\n");
 
 	return 0;
 
diff --git a/hip.h b/hip.h
index f55b648..7774fda 100644
--- a/hip.h
+++ b/hip.h
@@ -3,6 +3,8 @@
 
 #include <ucontext.h>
 
+#define HIP_DEBUG
+
 /* TODO: define these properly */
 #define HIP_LIKELY(x) x
 #define HIP_UNLIKELY(x) x
@@ -65,7 +67,7 @@ typedef enum hip_flag_t hip_flag_t;
 
 enum hip_rtn_flag_t
 {
-	HIP_RTN_FLAG_AUTO_DESTROY = (1 << 0)
+	HIP_RTN_FLAG_DUMMY = (1 << 0)
 };
 typedef enum hip_rtn_flag_t hip_rtn_flag_t;
 
@@ -83,10 +85,19 @@ typedef enum hip_rtn_flag_t hip_rtn_flag_t;
 	(_p)->next = _link; \
 } while(0)
 
+#if defined(HIP_DEBUG)
+#define HIP_LIST_UNCHAIN(_link) do { \
+	(_link)->next->prev = (_link)->prev; \
+	(_link)->prev->next = (_link)->next; \
+	(_link)->next = HIP_NULL; \
+	(_link)->prev = HIP_NULL; \
+} while(0)
+#else
 #define HIP_LIST_UNCHAIN(_link) do { \
 	(_link)->next->prev = (_link)->prev; \
 	(_link)->prev->next = (_link)->next; \
 } while(0)
+#endif
 
 #define HIP_LIST_HEAD(ll) ((ll)->next)
 #define HIP_LIST_TAIL(ll) ((ll)->prev)
@@ -118,7 +129,7 @@ void hip_switch(hip_t* hip, hip_uctx_link_t* list_to_deposit);
 void hip_suspend(hip_t* hip);
 
 
-hip_chan_t* hip_chan_open(hip_t* hip, hip_oow_t buf_size);
+hip_chan_t* hip_chan_open(hip_t* hip, hip_oow_t unit_size, hip_oow_t unit_capa);
 void hip_chan_close(hip_chan_t* c);
 int hip_chan_send(hip_chan_t* c, const void* ptr, hip_oow_t len);
 int hip_chan_recv(hip_chan_t* c, void* ptr, hip_oow_t len);