diff --git a/src/backend/filedescriptor.c b/src/backend/filedescriptor.c
index 5f6bb4f13..d10fc9897 100644
--- a/src/backend/filedescriptor.c
+++ b/src/backend/filedescriptor.c
@@ -42,7 +42,7 @@ NOBUG_DEFINE_FLAG_PARENT (filedescriptor, file_all);
   This registry stores all acquired filedescriptors for lookup, they will be freed when not referenced anymore.
  */
 static PSplay registry = NULL;
-static lumiera_mutex registry_mutex = {PTHREAD_MUTEX_INITIALIZER NOBUG_RESOURCE_HANDLE_COMMA_INITIALIZER};
+static lumiera_mutex registry_mutex;
 
 
 static int
@@ -96,10 +96,7 @@ lumiera_filedescriptor_registry_init (void)
   if (!registry)
     LUMIERA_DIE (NO_MEMORY);
 
-  TODO ("LumieraMutex lumiera_mutex_init (LumieraMutex self, const char* purpose, struct nobug_flag* flag);");
-
-  //  RESOURCE_HANDLE_INIT (registry_mutex.rh);
-  RESOURCE_ANNOUNCE (filedescriptor, "mutex", "filedescriptor registry", &registry, registry_mutex.rh);
+  lumiera_mutex_init (&registry_mutex, "filedescriptor_registry", &NOBUG_FLAG (filedescriptor));
 }
 
 void
@@ -108,9 +105,7 @@ lumiera_filedescriptor_registry_destroy (void)
   TRACE (filedescriptor);
   REQUIRE (!psplay_nelements (registry));
 
-  RESOURCE_FORGET (filedescriptor, registry_mutex.rh);
-
-  TODO ("LumieraMutex lumiera_mutex_destroy (LumieraMutex self, struct nobug_flag* flag);");
+  lumiera_mutex_destroy (&registry_mutex, &NOBUG_FLAG (filedescriptor));
 
   if (registry)
     psplay_destroy (registry);
diff --git a/src/backend/mmap.h b/src/backend/mmap.h
index 1babab9b0..df2931694 100644
--- a/src/backend/mmap.h
+++ b/src/backend/mmap.h
@@ -62,20 +62,21 @@ struct lumiera_mmap_struct
 
   /** array with refcounters per page **/
   unsigned short* refmap;
-
-  //RESOURCE_HANDLE (rh);
 };
 
 
 LumieraMMap
 lumiera_mmap_init (LumieraMMap self, LumieraFile file, LList acquirer, off_t start, size_t size, size_t chunksize);
 
+
 LumieraMMap
 lumiera_mmap_new (LumieraFile file, LList acquirer, off_t start, size_t size, size_t chunksize);
 
+
 void
 lumiera_mmap_delete (LumieraMMap self);
 
+
 void*
 lumiera_mmap_destroy_node (LList node);
 
diff --git a/src/backend/mmapcache.h b/src/backend/mmapcache.h
index 4f8c29fdc..c6e4a9e86 100644
--- a/src/backend/mmapcache.h
+++ b/src/backend/mmapcache.h
@@ -47,7 +47,6 @@ struct lumiera_mmapcache_struct
   size_t total;
   size_t cached;
   lumiera_mutex lock;
-  RESOURCE_HANDLE (rh);
 };
 
 extern LumieraMMapcache lumiera_mcache;
diff --git a/src/backend/mmapings.h b/src/backend/mmapings.h
index 27069baff..26ed42ac2 100644
--- a/src/backend/mmapings.h
+++ b/src/backend/mmapings.h
@@ -36,7 +36,7 @@ typedef lumiera_mmapings* LumieraMMapings;
 
 /**
  * @file
- * Keeps all mmaped areas
+ * Manage the mmap objects of a file
  *
  */
 
@@ -54,7 +54,6 @@ struct lumiera_mmapings_struct
 
   LumieraFiledescriptor descriptor;
   lumiera_mutex lock;
-  RESOURCE_HANDLE (rh);
 };
 
 /**