Index: umc/python/computerroom/italc2.py
===================================================================
--- umc/python/computerroom/italc2.py	(Revision 42658)
+++ umc/python/computerroom/italc2.py	(Arbeitskopie)
@@ -347,6 +347,25 @@
 			notifier.timer_remove( self._timer )
 			self._timer = None
 
+	@property
+	def dict(self):
+		item = { 'id' : self.name,
+				 'name' : self.name,
+				 'user' : self.user.current,
+				 'teacher' : self.isTeacher,
+				 'connection' : self.state.current,
+				 'description' : self.description,
+				 'ip' : self.ipAddress,
+				 'mac' : self.macAddress,
+				 'objectType': self.objectType }
+		item.update(self.flagsDict)
+		return item
+
+	@property
+	def hasChanged(self):
+		states = (self.state, self.flags, self.user, self.teacher)
+		return any(state.hasChanged for state in states)
+
 	# UDM properties
 	@property
 	def name( self ):
Index: umc/python/computerroom/__init__.py
===================================================================
--- umc/python/computerroom/__init__.py	(Revision 42658)
+++ umc/python/computerroom/__init__.py	(Arbeitskopie)
@@ -363,19 +363,7 @@
 		if request.options.get('reload', False):
 			self._italc.room = self._italc.room # believe me that makes sense :)
 
-		result = []
-		for computer in self._italc.values():
-			item = { 'id' : computer.name,
-					 'name' : computer.name,
-					 'user' : computer.user.current,
-					 'teacher' : computer.isTeacher,
-					 'connection' : computer.state.current,
-					 'description' : computer.description,
-					 'ip' : computer.ipAddress,
-					 'mac' : computer.macAddress,
-					 'objectType': computer.objectType }
-			item.update(computer.flagsDict)
-			result.append(item)
+		result = [computer.dict for computer in self._italc.values()]
 
 		MODULE.info('computerroom.query: result: %s' % str(result))
 		self.finished(request.id, result)
@@ -394,24 +382,7 @@
 		if not self._italc.school or not self._italc.room:
 			raise UMC_CommandError('no room selected')
 
-		computers = []
-		for computer in self._italc.values():
-			item = dict(id = computer.name)
-			modified = False
-			if computer.state.hasChanged:
-				item['connection'] = str(computer.state.current)
-				modified = True
-			if computer.flags.hasChanged:
-				item.update(computer.flagsDict)
-				modified = True
-			if computer.user.hasChanged:
-				item['user'] = str(computer.user.current)
-				modified = True
-			if computer.teacher.hasChanged:
-				item['teacher'] = computer.teacher.current
-				modified = True
-			if modified:
-				computers.append(item)
+		computers = [computer.dict for computer in self._italc.values() if computer.hasChanged]
 		result = { 'computers' : computers }
 
 		userDN = _getRoomOwner(self._italc.roomDN)
@@ -511,9 +482,9 @@
 			self.finished(request.id, 'VNC is disabled')
 
 		try:
-			template = open('/usr/share/ucs-school-umc-computerroom/ultravnc.vnc')
-			content = template.read()
-		except:
+			with open('/usr/share/ucs-school-umc-computerroom/ultravnc.vnc') as fd:
+				content = fd.read()
+		except (IOError, OSError):
 			raise UMC_CommandError('VNC template file does not exists')
 
 		port = ucr.get('ucsschool/umc/computerroom/vnc/port', '11100')