diff --git a/moo/kernel/Collect.moo b/moo/kernel/Collect.moo
index b4bb117..865384c 100644
--- a/moo/kernel/Collect.moo
+++ b/moo/kernel/Collect.moo
@@ -1382,13 +1382,12 @@ class SymbolTable(AssociativeCollection)
 class Dictionary(AssociativeCollection)
 {
 	/* [NOTE] 
-	 *  VM require Dictionary to implement new: and __put_assoc
+	 *  VM requires Dictionary to implement new: and __put_assoc
 	 *  for the dictionary expression notation - ##{ }
 	 */
 	
 	// TODO: implement Dictionary as a Hashed List/Table or Red-Black Tree
-	//       Do not inherit Set upon reimplementation
-	//
+
 	method(#class) new: capacity
 	{
 		^super new: (capacity + 10).
diff --git a/moo/kernel/System.moo b/moo/kernel/System.moo
index b33a36b..d611436 100644
--- a/moo/kernel/System.moo
+++ b/moo/kernel/System.moo
@@ -88,7 +88,9 @@ class System(Apex)
 			ret := class perform: method_name.
 		] 
 		ensure: [
-			self _setSig: 16rFF.
+			// signal end of the main process.
+			// __os_sig_handler will terminate all running subprocesses.
+			self _setSig: 16rFF. 
 		].
 
 		^ret.
@@ -198,7 +200,7 @@ class System(Apex)
 			/*
 			 0 -> startup  <--- this should also be stored in the 'caller' variable.
 			 1 -> __gc_finalizer
-			 2 -> __os_signal_handler 
+			 2 -> __os_sig_handler 
 			 3 ..  -> other processes started by application.
 			*/
 			proc := System _findProcessByIdGreaterThan: 2.
diff --git a/moo/kernel/generr.moo b/moo/kernel/generr.moo
index 86e00d9..9efe469 100644
--- a/moo/kernel/generr.moo
+++ b/moo/kernel/generr.moo
@@ -103,7 +103,7 @@ class MyObject(Object)
 			'inaccessible variable'
 			'ambiguous variable'
 			'too many instance/class variables'
-			'inaccessible self'
+			'inaccessible super'
 			'wrong expression primary'
 			'too many temporaries'
 			'too many arguments'
diff --git a/moo/lib/comp.c b/moo/lib/comp.c
index d6ec7b0..e7e7d80 100644
--- a/moo/lib/comp.c
+++ b/moo/lib/comp.c
@@ -5685,6 +5685,18 @@ static int compile_expression_primary (moo_t* moo, const moo_oocs_t* ident, cons
 				break;
 
 			case MOO_IOTOK_SUPER:
+				if (moo->c->cunit->cunit_type == MOO_CUNIT_INTERFACE)
+				{
+					/* i don't allow super in an interface method 
+					 * message sending to super requires the owning class
+					 * of an active method. a method taken by a class from
+					 * an interface points to the interface in the owner field.
+					 * for now, it's best not to allow it.
+					 * see moo_findmethod() in exec.c */
+					moo_setsynerrbfmt (moo, MOO_SYNERR_SUPERINACC, TOKEN_LOC(moo), TOKEN_NAME(moo), "super inaccessible in interface method");
+					return -1;
+				}
+
 				if (emit_byte_instruction(moo, BCODE_PUSH_RECEIVER, TOKEN_LOC(moo)) <= -1) return -1;
 				GET_TOKEN (moo);
 				*to_super = 1;
@@ -9058,7 +9070,6 @@ static int ciim_on_each_method (moo_t* moo, moo_oop_dic_t dic, moo_oop_associati
 	ciim_t* ciim = (ciim_t*)ctx;
 	moo_oocs_t name;
 	moo_oop_method_t mth;
-	moo_oop_methsig_t sig;
 
 	name.ptr = MOO_OBJ_GET_CHAR_SLOT(ass->key);
 	name.len = MOO_OBJ_GET_SIZE(ass->key);
@@ -9095,31 +9106,59 @@ static int ciim_on_each_method (moo_t* moo, moo_oop_dic_t dic, moo_oop_associati
 		 * the method. it's an error */
 	}
 
-	sig = (moo_oop_methsig_t)ass->value;
-	if (MOO_METHOD_GET_PREAMBLE_FLAGS(MOO_OOP_TO_SMOOI(mth->preamble)) != MOO_METHOD_GET_PREAMBLE_FLAGS(MOO_OOP_TO_SMOOI(sig->preamble)))
+	if (MOO_CLASSOF(moo, ass->value) == moo->_methsig)
 	{
-		moo_setsynerrbfmt (moo, MOO_SYNERR_CLASSNCIFCE, MOO_NULL, MOO_NULL, 
-			"%.*js>>%.*js modifiers conficting with %.*js>>%.*js",
-			MOO_OBJ_GET_SIZE(ciim->_class->name), MOO_OBJ_GET_CHAR_SLOT(ciim->_class->name),
-			name.len, name.ptr,
-			MOO_OBJ_GET_SIZE(ciim->ifce->name), MOO_OBJ_GET_CHAR_SLOT(ciim->ifce->name),
-			name.len, name.ptr
-		);
-		return -1;
+		/* it's a method signature without body */
+
+		moo_oop_methsig_t sig;
+
+		sig = (moo_oop_methsig_t)ass->value;
+		if (MOO_METHOD_GET_PREAMBLE_FLAGS(MOO_OOP_TO_SMOOI(mth->preamble)) != MOO_METHOD_GET_PREAMBLE_FLAGS(MOO_OOP_TO_SMOOI(sig->preamble)))
+		{
+		modifier_conflict:
+			moo_setsynerrbfmt (moo, MOO_SYNERR_CLASSNCIFCE, MOO_NULL, MOO_NULL, 
+				"%.*js>>%.*js modifiers conficting with %.*js>>%.*js",
+				MOO_OBJ_GET_SIZE(ciim->_class->name), MOO_OBJ_GET_CHAR_SLOT(ciim->_class->name),
+				name.len, name.ptr,
+				MOO_OBJ_GET_SIZE(ciim->ifce->name), MOO_OBJ_GET_CHAR_SLOT(ciim->ifce->name),
+				name.len, name.ptr
+			);
+			return -1;
+		}
+
+		if (mth->tmpr_nargs != sig->tmpr_nargs) /* don't need MOO_OOP_TO_SMOOI */
+		{
+		param_conflict:
+			moo_setsynerrbfmt (moo, MOO_SYNERR_CLASSNCIFCE, MOO_NULL, MOO_NULL, 
+				"%.*js>>%.*js parameters conflicting with %.*js>>%.*js",
+				MOO_OBJ_GET_SIZE(ciim->_class->name), MOO_OBJ_GET_CHAR_SLOT(ciim->_class->name),
+				name.len, name.ptr,
+				MOO_OBJ_GET_SIZE(ciim->ifce->name), MOO_OBJ_GET_CHAR_SLOT(ciim->ifce->name),
+				name.len, name.ptr
+			);
+			return -1;
+		}
 	}
-	
-	if (mth->tmpr_nargs != sig->tmpr_nargs) /* don't need MOO_OOP_TO_SMOOI */
+	else
 	{
-		moo_setsynerrbfmt (moo, MOO_SYNERR_CLASSNCIFCE, MOO_NULL, MOO_NULL, 
-			"%.*js>>%.*js parameters conflicting with %.*js>>%.*js",
-			MOO_OBJ_GET_SIZE(ciim->_class->name), MOO_OBJ_GET_CHAR_SLOT(ciim->_class->name),
-			name.len, name.ptr,
-			MOO_OBJ_GET_SIZE(ciim->ifce->name), MOO_OBJ_GET_CHAR_SLOT(ciim->ifce->name),
-			name.len, name.ptr
-		);
-		return -1;
+		/* it is a full interface method */
+
+		moo_oop_method_t sig;
+
+		MOO_ASSERT (moo, MOO_CLASSOF(moo, ass->value) == moo->_method);
+
+		sig = (moo_oop_method_t)ass->value;
+		if (MOO_METHOD_GET_PREAMBLE_FLAGS(MOO_OOP_TO_SMOOI(mth->preamble)) != MOO_METHOD_GET_PREAMBLE_FLAGS(MOO_OOP_TO_SMOOI(sig->preamble)))
+		{
+			goto modifier_conflict;
+		}
+
+		if (mth->tmpr_nargs != sig->tmpr_nargs) /* don't need MOO_OOP_TO_SMOOI */
+		{
+			goto param_conflict;
+		}
 	}
-	
+
 	return 0;
 }
 
diff --git a/moo/lib/err.c b/moo/lib/err.c
index e66c6ee..0099215 100644
--- a/moo/lib/err.c
+++ b/moo/lib/err.c
@@ -128,7 +128,7 @@ static moo_ooch_t synerrstr_52[] = {'u','n','u','s','a','b','l','e',' ','v','a',
 static moo_ooch_t synerrstr_53[] = {'i','n','a','c','c','e','s','s','i','b','l','e',' ','v','a','r','i','a','b','l','e','\0'};
 static moo_ooch_t synerrstr_54[] = {'a','m','b','i','g','u','o','u','s',' ','v','a','r','i','a','b','l','e','\0'};
 static moo_ooch_t synerrstr_55[] = {'t','o','o',' ','m','a','n','y',' ','i','n','s','t','a','n','c','e','/','c','l','a','s','s',' ','v','a','r','i','a','b','l','e','s','\0'};
-static moo_ooch_t synerrstr_56[] = {'i','n','a','c','c','e','s','s','i','b','l','e',' ','s','e','l','f','\0'};
+static moo_ooch_t synerrstr_56[] = {'i','n','a','c','c','e','s','s','i','b','l','e',' ','s','u','p','e','r','\0'};
 static moo_ooch_t synerrstr_57[] = {'w','r','o','n','g',' ','e','x','p','r','e','s','s','i','o','n',' ','p','r','i','m','a','r','y','\0'};
 static moo_ooch_t synerrstr_58[] = {'t','o','o',' ','m','a','n','y',' ','t','e','m','p','o','r','a','r','i','e','s','\0'};
 static moo_ooch_t synerrstr_59[] = {'t','o','o',' ','m','a','n','y',' ','a','r','g','u','m','e','n','t','s','\0'};
diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index f62f301..b30db19 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -1829,7 +1829,7 @@ moo_oop_method_t moo_findmethod (moo_t* moo, moo_oop_t receiver, moo_oop_char_t
 
 	message.ptr = MOO_OBJ_GET_CHAR_SLOT(selector);
 	message.len = MOO_OBJ_GET_SIZE(selector);
-	
+
 	_class = MOO_CLASSOF(moo, receiver);
 	if (_class == moo->_class)
 	{
@@ -1849,6 +1849,12 @@ moo_oop_method_t moo_findmethod (moo_t* moo, moo_oop_t receiver, moo_oop_char_t
 	{
 		MOO_ASSERT (moo, moo->active_method);
 		MOO_ASSERT (moo, moo->active_method->owner);
+
+		/* if 'super' is allowed in the interface method, the owner field
+		 * can be an interface. super must not be allowed  in the interface
+		 * method body. */
+		MOO_ASSERT (moo, MOO_CLASSOF(moo, moo->active_method->owner) == moo->_class);
+
 		c = (moo_oop_class_t)((moo_oop_class_t)moo->active_method->owner)->superclass;
 		if ((moo_oop_t)c == moo->_nil) goto not_found;
 		/* c is nil if it reached the top of the hierarchy.
@@ -1863,7 +1869,7 @@ moo_oop_method_t moo_findmethod (moo_t* moo, moo_oop_t receiver, moo_oop_char_t
 	mcidx = ((moo_oow_t)_class ^ (moo_oow_t)selector) & (MOO_METHOD_CACHE_SIZE - 1);
 	mcitm = &moo->method_cache[mth_type][mcidx];
 	
-	if (mcitm->receiver_class == c  && mcitm->selector == selector /*&& mcitm->method_type == mth_type*/)
+	if (mcitm->receiver_class == c && mcitm->selector == selector /*&& mcitm->method_type == mth_type*/)
 	{
 		/* cache hit */
 	#if defined(MOO_PROFILE_VM)
@@ -1871,7 +1877,7 @@ moo_oop_method_t moo_findmethod (moo_t* moo, moo_oop_t receiver, moo_oop_char_t
 	#endif
 		return mcitm->method;
 	}
-	
+
 	/* [IMPORT] the method lookup logic should be the same as ciim_on_each_method() in comp.c */
 	mth = find_method_in_class_chain(moo, c, mth_type, &message);
 	if (mth) 
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 24d86ba..cd9d1d1 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -1892,7 +1892,7 @@ enum moo_synerrnum_t
 	MOO_SYNERR_VARINACC,        /* inaccessible variable - e.g. accessing an instance variable from a class method is not allowed. */
 	MOO_SYNERR_VARAMBIG,        /* ambiguious variable - e.g. the variable is found in multiple pool dictionaries imported */
 	MOO_SYNERR_VARFLOOD,        /* too many instance/class variables */
-	MOO_SYNERR_SELFINACC,       /* inaccessible self */
+	MOO_SYNERR_SUPERINACC,      /* inaccessible super */
 	MOO_SYNERR_PRIMARYINVAL,    /* wrong expression primary */
 	MOO_SYNERR_TMPRFLOOD,       /* too many temporaries */
 	MOO_SYNERR_ARGFLOOD,        /* too many arguments */