diff --git a/moo/kernel/Socket.moo b/moo/kernel/Socket.moo
index 77fdc75..d01f966 100644
--- a/moo/kernel/Socket.moo
+++ b/moo/kernel/Socket.moo
@@ -44,13 +44,13 @@ extend Socket
 		{
 			## this primitive method may return failure. 
 			## but ignore it here.
-			if (self.insem) 
+			if (self.insem notNil) 
 			{ 
 				System unsignal: self.insem.
 				System removeAsyncSemaphore: self.insem.
 				self.insem := nil.
 			}.
-			if (self.outsem)
+			if (self.outsem notNil)
 			{
 				System unsignal: self.outsem.
 				System removeAsyncSemaphore: self.outsem.
@@ -158,15 +158,18 @@ class MyObject(Object)
 			if (n == 0)
 			{
 				sck close.
+			}
+			else
+			{
+				(n asString & ' bytes read') dump.
+				data dump.
 			}.
-			(n asString & ' bytes read') dump.
-			data dump.
 		].
 
 		outact := [:sck :state |
 			if (state)
 			{
-				sck writeBytes: #[ $h, $e, $l, $l, $o ].
+				sck writeBytes: #[ $h, $e, $l, $l, $o, 10 ].
 				
 			}
 			else
@@ -178,7 +181,6 @@ class MyObject(Object)
 			if (state)
 			{
 				'CONNECTED NOW.............' dump.
-				##s onOutputDo: outact.
 				s writeBytes: #[ $h $e $l $l $o ].
 
 				s watchInput.
diff --git a/moo/kernel/generr.moo b/moo/kernel/generr.moo
index f881d14..3cf1fb0 100644
--- a/moo/kernel/generr.moo
+++ b/moo/kernel/generr.moo
@@ -29,7 +29,7 @@ class MyObject(Object)
 			'resource temporarily unavailable'
 			'bad system handle'
 
-			'data too large'
+			'*** undefined error ***'
 			'message receiver error'
 			'message sending error'
 			'wrong number of arguments'
@@ -37,8 +37,8 @@ class MyObject(Object)
 			'byte-code full'
 			'dictionary full'
 			'processor full'
-			'semaphore heap full'
-			'semaphore list full'
+			'too many semaphores'
+			'*** undefined error ***'
 			'divide by zero'
 			'I/O error'
 			'encoding conversion error'
diff --git a/moo/lib/err.c b/moo/lib/err.c
index b604b5f..2952413 100644
--- a/moo/lib/err.c
+++ b/moo/lib/err.c
@@ -57,7 +57,7 @@ static moo_ooch_t errstr_23[] = {'r','a','n','g','e',' ','e','r','r','o','r','\0
 static moo_ooch_t errstr_24[] = {'b','y','t','e','-','c','o','d','e',' ','f','u','l','l','\0'};
 static moo_ooch_t errstr_25[] = {'d','i','c','t','i','o','n','a','r','y',' ','f','u','l','l','\0'};
 static moo_ooch_t errstr_26[] = {'p','r','o','c','e','s','s','o','r',' ','f','u','l','l','\0'};
-static moo_ooch_t errstr_27[] = {'s','e','m','a','p','h','o','r','e',' ','h','e','a','p',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_27[] = {'t','o','o',' ','m','a','n','y',' ','s','e','m','a','p','h','o','r','e','s','\0'};
 static moo_ooch_t errstr_28[] = {'s','e','m','a','p','h','o','r','e',' ','l','i','s','t',' ','f','u','l','l','\0'};
 static moo_ooch_t errstr_29[] = {'d','i','v','i','d','e',' ','b','y',' ','z','e','r','o','\0'};
 static moo_ooch_t errstr_30[] = {'I','/','O',' ','e','r','r','o','r','\0'};
@@ -313,7 +313,7 @@ void moo_seterrwithsyserr (moo_t* moo, int syserr)
 }
 
 /* -------------------------------------------------------------------------- 
- * ASSERTION FAILURE HANDLER
+ * ASSERTION FAILURE HANDLERsemaphore heap full
  * -------------------------------------------------------------------------- */
 
 void moo_assertfailed (moo_t* moo, const moo_bch_t* expr, const moo_bch_t* file, moo_oow_t line)
diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index 7068f46..f93a778 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -57,6 +57,7 @@ static MOO_INLINE const char* proc_state_to_string (int state)
 #define SEM_LIST_MAX (SEM_LIST_INC * 1000)
 #define SEM_HEAP_MAX (SEM_HEAP_INC * 1000)
 #define SEM_IO_TUPLE_MAX (SEM_IO_TUPLE_INC * 1000)
+#define SEM_IO_MAP_ALIGN 1024 /* this must a power of 2 */
 
 #define SEM_HEAP_PARENT(x) (((x) - 1) / 2)
 #define SEM_HEAP_LEFT(x)   ((x) * 2 + 1)
@@ -740,7 +741,7 @@ static int async_signal_semaphore (moo_t* moo, moo_oop_semaphore_t sem)
 {
 	if (moo->sem_list_count >= SEM_LIST_MAX)
 	{
-		moo_seterrnum (moo, MOO_ESLFULL);
+		moo_seterrnum (moo, MOO_ESEMFLOOD, "too many semaphores in the semaphore list");
 		return -1;
 	}
 
@@ -1029,7 +1030,7 @@ static int add_to_sem_heap (moo_t* moo, moo_oop_semaphore_t sem)
 
 	if (moo->sem_heap_count >= SEM_HEAP_MAX)
 	{
-		moo_seterrnum (moo, MOO_ESHFULL);
+		moo_seterrbfmt(moo, MOO_ESEMFLOOD, "too many semaphores in the semaphore heap");
 		return -1;
 	}
 
@@ -1126,13 +1127,13 @@ static int add_to_sem_io (moo_t* moo, moo_oop_semaphore_t sem, moo_ooi_t io_hand
 
 /* TODO: specify the maximum io_handle supported and check it here instead of just relying on memory allocation success/failure? */
 
-		new_capa = MOO_ALIGN_POW2 (io_handle + 1, 1024);
+		new_capa = MOO_ALIGN_POW2(io_handle + 1, SEM_IO_MAP_ALIGN);
 
 		tmp = moo_reallocmem (moo, moo->sem_io_map, MOO_SIZEOF(*tmp) * new_capa);
 		if (!tmp) 
 		{
 			moo_copyoocstr (moo->errmsg.buf2, MOO_COUNTOF(moo->errmsg.buf2), moo->errmsg.buf);
-			moo_seterrbfmt (moo, MOO_EINVAL, "handle %zd out of supported range - %js", moo->errmsg.buf2);
+			moo_seterrbfmt (moo, moo->errnum, "handle %zd out of supported range - %js", moo->errmsg.buf2);
 			return -1;
 		}
 
@@ -1148,7 +1149,7 @@ static int add_to_sem_io (moo_t* moo, moo_oop_semaphore_t sem, moo_ooi_t io_hand
 		/* this handle is not in any tuples. add it to a new tuple */
 		if (moo->sem_io_tuple_count >= SEM_IO_TUPLE_MAX)
 		{
-			moo_seterrbfmt (moo, MOO_ESHFULL, "too many IO semaphore tuples");  /* TODO: change error code */
+			moo_seterrbfmt (moo, MOO_ESEMFLOOD, "too many IO semaphore tuples"); 
 			return -1;
 		}
 
diff --git a/moo/lib/main.c b/moo/lib/main.c
index 55b7336..e59982e 100644
--- a/moo/lib/main.c
+++ b/moo/lib/main.c
@@ -725,7 +725,8 @@ static void log_write (moo_t* moo, moo_oow_t mask, const moo_ooch_t* msg, moo_oo
 	xtn_t* xtn = moo_getxtn(moo);
 	int logfd;
 
-	if (!(xtn->logmask & mask)) return;
+	if (!(xtn->logmask & mask & ~MOO_LOG_ALL_LEVELS)) return; /* check log types */
+	if (!(xtn->logmask & mask & ~MOO_LOG_ALL_TYPES)) return; /* check log levels */
 
 	if (mask & MOO_LOG_STDOUT) logfd = 1;
 	else if (mask & MOO_LOG_STDERR) logfd = 2;
@@ -2029,10 +2030,23 @@ static int handle_logopt (moo_t* moo, const moo_bch_t* str)
 			else if (moo_compbcstr(flt, "ic") == 0) xtn->logmask |= MOO_LOG_IC;
 			else if (moo_compbcstr(flt, "primitive") == 0) xtn->logmask |= MOO_LOG_PRIMITIVE;
 
+			else if (moo_compbcstr(flt, "fatal") == 0) xtn->logmask |= MOO_LOG_FATAL;
+			else if (moo_compbcstr(flt, "error") == 0) xtn->logmask |= MOO_LOG_ERROR;
+			else if (moo_compbcstr(flt, "warn") == 0) xtn->logmask |= MOO_LOG_WARN;
+			else if (moo_compbcstr(flt, "info") == 0) xtn->logmask |= MOO_LOG_INFO;
+			else if (moo_compbcstr(flt, "debug") == 0) xtn->logmask |= MOO_LOG_DEBUG;
+
+			else if (moo_compbcstr(flt, "fatal+") == 0) xtn->logmask |= MOO_LOG_FATAL;
+			else if (moo_compbcstr(flt, "error+") == 0) xtn->logmask |= MOO_LOG_FATAL | MOO_LOG_ERROR;
+			else if (moo_compbcstr(flt, "warn+") == 0) xtn->logmask |= MOO_LOG_FATAL | MOO_LOG_ERROR | MOO_LOG_WARN;
+			else if (moo_compbcstr(flt, "info+") == 0) xtn->logmask |= MOO_LOG_FATAL | MOO_LOG_ERROR | MOO_LOG_WARN | MOO_LOG_INFO;
+			else if (moo_compbcstr(flt, "debug+") == 0) xtn->logmask |= MOO_LOG_FATAL | MOO_LOG_ERROR | MOO_LOG_WARN | MOO_LOG_INFO | MOO_LOG_DEBUG;
 		}
 		while (cm);
 
-		xtn->logmask |= MOO_LOG_ALL_LEVELS; /* TODO: parse levels also */
+
+		if (!(xtn->logmask & MOO_LOG_ALL_TYPES)) xtn->logmask |= MOO_LOG_ALL_TYPES;  /* no types specified. force to all types */
+		if (!(xtn->logmask & MOO_LOG_ALL_LEVELS)) xtn->logmask |= MOO_LOG_ALL_LEVELS;  /* no levels specified. force to all levels */
 	}
 	else
 	{
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 4bfc65d..eae5384 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -67,7 +67,7 @@ enum moo_errnum_t
 	MOO_EAGAIN,
 	MOO_EBADHND,
 
-	MOO_ENOAVAIL, /**< data not available*/
+	MOO_EXXXXX1,  /**< **** not used ****/
 	MOO_EMSGRCV,  /**< mesasge receiver error */
 	MOO_EMSGSND,  /**< message sending error. even doesNotUnderstand: is not found */
 	MOO_ENUMARGS, /**< wrong number of arguments */
@@ -75,8 +75,8 @@ enum moo_errnum_t
 	MOO_EBCFULL,  /**< byte-code full */
 	MOO_EDFULL,   /**< dictionary full */
 	MOO_EPFULL,   /**< processor full */
-	MOO_ESHFULL,  /**< semaphore heap full */
-	MOO_ESLFULL,  /**< semaphore list full */
+	MOO_ESEMFLOOD,/**< too many semaphores */
+	MOO_EXXXXX2,  /**< **** not used ***** */
 	MOO_EDIVBY0,  /**< divide by zero */
 	MOO_EIOERR,   /**< I/O error */
 	MOO_EECERR,   /**< encoding conversion error */
@@ -425,7 +425,7 @@ typedef enum moo_gcfin_t moo_gcfin_t;
 /* [NOTE] this macro doesn't include the size of the trailer */
 #define MOO_OBJ_BYTESOF(oop) ((MOO_OBJ_GET_SIZE(oop) + MOO_OBJ_GET_FLAGS_EXTRA(oop)) * MOO_OBJ_GET_FLAGS_UNIT(oop))
 
-#define MOO_OBJ_IS_OOP_POINTER(oop)     (MOO_OOP_IS_POINTER(oop) && (MOO_OBJ_GET_FLAGS_TYPE(oop) == MOO_OBJ_TYPE_OOP))
+#define MOO_OBJ_IS_OOP_POINTER(oop)      (MOO_OOP_IS_POINTER(oop) && (MOO_OBJ_GET_FLAGS_TYPE(oop) == MOO_OBJ_TYPE_OOP))
 #define MOO_OBJ_IS_CHAR_POINTER(oop)     (MOO_OOP_IS_POINTER(oop) && (MOO_OBJ_GET_FLAGS_TYPE(oop) == MOO_OBJ_TYPE_CHAR))
 #define MOO_OBJ_IS_BYTE_POINTER(oop)     (MOO_OOP_IS_POINTER(oop) && (MOO_OBJ_GET_FLAGS_TYPE(oop) == MOO_OBJ_TYPE_BYTE))
 #define MOO_OBJ_IS_HALFWORD_POINTER(oop) (MOO_OOP_IS_POINTER(oop) && (MOO_OBJ_GET_FLAGS_TYPE(oop) == MOO_OBJ_TYPE_HALFWORD))
@@ -990,11 +990,6 @@ struct moo_vmprim_t
 
 typedef struct moo_vmprim_t moo_vmprim_t;
 
-/* =========================================================================
- * IO MANIPULATION
- * ========================================================================= */
-
-/* TODO: MOVE moo_ioimpl_t HERE */
 
 /* =========================================================================
  * CALLBACK MANIPULATION