diff --git a/src/tinySelf/vm/primitives/os/primitive_files.py b/src/tinySelf/vm/primitives/os/primitive_files.py
index 98ece65..7e6e41a 100644
--- a/src/tinySelf/vm/primitives/os/primitive_files.py
+++ b/src/tinySelf/vm/primitives/os/primitive_files.py
@@ -97,8 +97,8 @@ def __init__(self, value, obj_map=None, path=""):
         self.value = value
         self.path = path
 
-        if PrimitiveFileObject._OBJ_CACHE.map is not None:
-            self._slot_values = PrimitiveFileObject._OBJ_CACHE.slots
+        if PrimitiveFileObject._OBJ_CACHE.is_set:
+            PrimitiveFileObject._OBJ_CACHE.restore(self)
             return
 
         add_primitive_fn(self, "close", close_file, [])
@@ -110,8 +110,7 @@ def __init__(self, value, obj_map=None, path=""):
         add_primitive_fn(self, "seek:", seek_to, ["pos"])
         add_primitive_fn(self, "closed?", is_closed, [])
 
-        if PrimitiveFileObject._OBJ_CACHE.map is None:
-            PrimitiveFileObject._OBJ_CACHE.store(self)
+        PrimitiveFileObject._OBJ_CACHE.store(self)
 
     def __str__(self):
         status = ", closed" if self.value.closed else ""
diff --git a/src/tinySelf/vm/primitives/os/primitive_socket.py b/src/tinySelf/vm/primitives/os/primitive_socket.py
index 9dbcbb7..08043ac 100644
--- a/src/tinySelf/vm/primitives/os/primitive_socket.py
+++ b/src/tinySelf/vm/primitives/os/primitive_socket.py
@@ -50,16 +50,15 @@ def __init__(self, value, obj_map=None):
         assert isinstance(value, RSocket)
         self.value = value
 
-        if PrimitiveSocketObject._OBJ_CACHE.map is not None:
-            self._slot_values = PrimitiveSocketObject._OBJ_CACHE.slots
+        if PrimitiveSocketObject._OBJ_CACHE.is_set:
+            PrimitiveSocketObject._OBJ_CACHE.restore(self)
             return
 
         add_primitive_fn(self, "recv:", socket_recv, ["size"])
         add_primitive_fn(self, "sendAll:", socket_sendall, ["data"])
         add_primitive_fn(self, "close", socket_close, [])
 
-        if PrimitiveSocketObject._OBJ_CACHE.map is None:
-            PrimitiveSocketObject._OBJ_CACHE.store(self)
+        PrimitiveSocketObject._OBJ_CACHE.store(self)
 
     def __str__(self):
         return "PrimitiveSocket()"
diff --git a/src/tinySelf/vm/primitives/primitive_dict.py b/src/tinySelf/vm/primitives/primitive_dict.py
index 3a6123c..0ca19e4 100644
--- a/src/tinySelf/vm/primitives/primitive_dict.py
+++ b/src/tinySelf/vm/primitives/primitive_dict.py
@@ -140,8 +140,8 @@ def __init__(self, value, obj_map=None):
 
         self.value = value
 
-        if PrimitiveDictObject._OBJ_CACHE.map is not None:
-            self._slot_values = PrimitiveDictObject._OBJ_CACHE.slots
+        if PrimitiveDictObject._OBJ_CACHE.is_set:
+            PrimitiveDictObject._OBJ_CACHE.restore(self)
             return
 
         add_primitive_fn(self, "at:", dict_at, ["index"])
@@ -149,8 +149,7 @@ def __init__(self, value, obj_map=None):
         add_primitive_fn(self, "length", dict_length, [])
         add_primitive_fn(self, "at:Put:", dict_at_key_put_obj, ["key", "obj"])
 
-        if PrimitiveDictObject._OBJ_CACHE.map is None:
-            PrimitiveDictObject._OBJ_CACHE.store(self)
+        PrimitiveDictObject._OBJ_CACHE.store(self)
 
     def __str__(self):
         return "dict()"
diff --git a/src/tinySelf/vm/primitives/primitive_list.py b/src/tinySelf/vm/primitives/primitive_list.py
index 6100004..c5ae753 100644
--- a/src/tinySelf/vm/primitives/primitive_list.py
+++ b/src/tinySelf/vm/primitives/primitive_list.py
@@ -84,8 +84,8 @@ def __init__(self, value, obj_map=None):
         assert isinstance(value, list)
         self.value = value
 
-        if PrimitiveListObject._OBJ_CACHE.map is not None:
-            self._slot_values = PrimitiveListObject._OBJ_CACHE.slots
+        if PrimitiveListObject._OBJ_CACHE.is_set:
+            PrimitiveListObject._OBJ_CACHE.restore(self)
             return
 
         add_primitive_fn(self, "at:", list_at, ["index"])