diff --git a/src/lib/allocationcluster.cpp b/src/lib/allocationcluster.cpp
index 1f76fed72..306e4a659 100644
--- a/src/lib/allocationcluster.cpp
+++ b/src/lib/allocationcluster.cpp
@@ -1,5 +1,5 @@
 /*
-  AllocationCluster  -  allocating and owning a pile of objects 
+  AllocationCluster  -  allocating and owning a pile of objects
  
   Copyright (C)         Lumiera.org
     2008,               Hermann Vosseler <Ichthyostega@web.de>
@@ -25,9 +25,8 @@
 #include "common/error.hpp"
 #include "common/util.hpp"
 
-
 using util::isnil;
-//using util::cStr;
+
 
 namespace lib {
   
@@ -47,7 +46,7 @@ namespace lib {
    * the dtor without actually knowing the object's type.
    * 
    * @todo this is a preliminary or pseudo-implementation based on 
-   * a vector of smart pointers,  i.e. actually the objects are heap 
+   * a vector of raw pointers,  i.e. actually the objects are heap 
    * allocated. What actually should happen is for the MemoryManager to
    * allocate raw memory chunk wise, sub partition it and place the objects
    * into this private memory buffer. Further, possibly we could maintain
@@ -76,7 +75,7 @@ namespace lib {
     private:
       void clearStorage();
     };
-
+  
   
   
   void
@@ -98,7 +97,7 @@ namespace lib {
   AllocationCluster::MemoryManager::purge()
   {
     Thread::Lock<MemoryManager> guard   SIDEEFFECT;
-
+    
     REQUIRE (type_.killIt, "we need a deleter function");
     REQUIRE (0 < type_.allocSize, "allocation size unknown");
     REQUIRE (top_ == mem_.size() || (top_+1) == mem_.size());
@@ -116,7 +115,7 @@ namespace lib {
       delete[] mem_[--i];
     mem_.clear();
   }
-
+  
   
   inline void*
   AllocationCluster::MemoryManager::allocate()
@@ -125,10 +124,11 @@ namespace lib {
     
     REQUIRE (0 < type_.allocSize);
     REQUIRE (top_ <= mem_.size());
-
+    
     if (top_==mem_.size())
       mem_.resize(top_+1);
-    if (!mem_[top_])
+    
+    if (!mem_[top_]) // re-use existing allocation, if any
       mem_[top_] = new char[type_.allocSize];
     
     ENSURE (top_ < mem_.size());
@@ -141,7 +141,7 @@ namespace lib {
   AllocationCluster::MemoryManager::commit (void* pendingAlloc)
   {
     Thread::Lock<MemoryManager> guard   SIDEEFFECT;
-
+    
     REQUIRE (pendingAlloc);
     ASSERT (top_ < mem_.size());
     ASSERT (pendingAlloc == mem_[top_], "allocation protocol violated");
@@ -155,8 +155,8 @@ namespace lib {
   
   /** storage for static bookkeeping of type allocation slots */
   size_t AllocationCluster::maxTypeIDs;
-
-
+  
+  
   /** creating a new AllocationCluster prepares a table capable
    *  of holding the individual object families to come. Each of those
    *  is managed by a separate instance of the low-level memory manager.
@@ -224,7 +224,7 @@ namespace lib {
       }
     
     ASSERT (handler(slot));
-    return initiateAlloc(slot); 
+    return initiateAlloc(slot);
   }
   
   
diff --git a/src/lib/allocationcluster.hpp b/src/lib/allocationcluster.hpp
index 05226ef0a..a44151957 100644
--- a/src/lib/allocationcluster.hpp
+++ b/src/lib/allocationcluster.hpp
@@ -1,5 +1,5 @@
 /*
-  ALLOCATIONCLUSTER.hpp  -  allocating and owning a pile of objects 
+  ALLOCATIONCLUSTER.hpp  -  allocating and owning a pile of objects
  
   Copyright (C)         Lumiera.org
     2008,               Hermann Vosseler <Ichthyostega@web.de>
@@ -53,7 +53,6 @@
 
 #include "common/multithread.hpp"
 #include "common/error.hpp"
-//#include "common/util.hpp"
 #include "lib/scopedholder.hpp"
 #include "lib/scopedholdertransfer.hpp"
 
@@ -69,11 +68,14 @@ namespace lib {
    * Each of those contains a initially undetermined (but rather large)
    * number of individual objects, which can be expected to be allocated
    * within a short timespan and which are to be released cleanly on
-   * destruction of the AllocationCluster. There is a service creating
-   * individual objects with arbitrary ctor parameters and it is possible
-   * to control the oder in which the object families are to be discarded.
+   * destruction of the AllocationCluster. We provide a service creating
+   * individual objects with arbitrary ctor parameters.
    * @warning make sure the objects dtors aren't called and object references
    *          aren't used after shutting down a given AllocationCluster.
+   * @todo    implement a facility to control the oder in which
+   *          the object families are to be discarded. Currently
+   *          they are just purged in reverse order defined by
+   *          the first request for allocating a certain type.
    */
   class AllocationCluster
     : boost::noncopyable
@@ -83,6 +85,7 @@ namespace lib {
       AllocationCluster ();
       ~AllocationCluster ()  throw();
       
+      
       template<class TY>
       TY&
       create ()
@@ -122,7 +125,7 @@ namespace lib {
           TY* obj = new(allocation<TY>()) TY (p0,p1,p2,p3);
           return commit(obj);
         }
-
+      
       
     private:
       /** initiate an allocation for the given type */
@@ -160,7 +163,9 @@ namespace lib {
       typedef ScopedPtrHolder<MemoryManager> HMemManager;
       typedef Allocator_TransferNoncopyable<HMemManager> Allo; 
       typedef std::vector<HMemManager,Allo> ManagerTable;
-      ManagerTable typeHandlers_;
+      
+      ManagerTable typeHandlers_;  ///< table of active MemoryManager instances 
+      
       
       HMemManager& 
       handler (size_t slot)
@@ -174,7 +179,7 @@ namespace lib {
       void* initiateAlloc (size_t& slot);
       void* initiateAlloc (TypeInfo type, size_t& slot);
       
-      /** enrol the allocation after successful ctor call */ 
+      /** enrol the allocation after successful ctor call */
       void finishAlloc (size_t& slot, void*);
       
     };
@@ -188,7 +193,7 @@ namespace lib {
   struct AllocationCluster::TypeInfo
         {
           size_t allocSize;
-          void (*killIt)(void*);
+          void (*killIt)(void*);  ///< deleter function
           
           template<class TY>
           TypeInfo(TY*)
@@ -203,11 +208,11 @@ namespace lib {
         };
   
   
-
+  
   template<class TY>
   struct AllocationCluster::TypeSlot
     {
-      static size_t id_; ///< table pos of the memory manager in charge for type TY
+      static size_t id_; ///< table pos+1 of the memory manager in charge for type TY
       
       static size_t &
       get()
@@ -241,7 +246,7 @@ namespace lib {
   template<class TY>
   size_t AllocationCluster::TypeSlot<TY>::id_;
   
-
+  
   
   template<class TY>
   inline void*
@@ -253,7 +258,7 @@ namespace lib {
     ENSURE (mem);
     return mem;
   }
-    
+  
   template<class TY>
   inline TY&
   AllocationCluster::commit (TY* obj)
diff --git a/tests/50components.tests b/tests/50components.tests
index 71f4a5d51..4f505c5f6 100644
--- a/tests/50components.tests
+++ b/tests/50components.tests
@@ -10,6 +10,11 @@ return: 0
 END
 
 
+TEST "AllocationCluster_test" AllocationCluster_test <<END
+return: 0
+END
+
+
 TEST "Appconfig_test" Appconfig_test <<END
 return: 0
 END
@@ -274,7 +279,19 @@ END
 
 TEST "ScopedHolderTransfer_test" ScopedHolderTransfer_test <<END
 out: checking ScopedHolder<Dummy>...
+out: .
+out: ..install one element at index[0]
+out: .
+out: ..*** resize table to 16 elements
+out: .
+out: .throw some exceptions...
 out: checking ScopedPtrHolder<Dummy>...
+out: .
+out: ..install one element at index[0]
+out: .
+out: ..*** resize table to 16 elements
+out: .
+out: .throw some exceptions...
 END
 
 
diff --git a/tests/common/allocationclustertest.cpp b/tests/common/allocationclustertest.cpp
index 4b5d1f458..2d634ac37 100644
--- a/tests/common/allocationclustertest.cpp
+++ b/tests/common/allocationclustertest.cpp
@@ -40,6 +40,8 @@ using ::Test;
 using std::numeric_limits;
 using std::vector;
 
+
+
 namespace lib {
   namespace test {
     
@@ -49,7 +51,8 @@ namespace lib {
       uint NUM_OBJECTS  = 500;
       uint NUM_FAMILIES = 5;
       
-      long checksum = 0;
+      long checksum = 0; // validate proper pairing of ctor/dtor calls
+      bool randomFailures = false;
       
       template<uint i>
       class Dummy
@@ -67,7 +70,7 @@ namespace lib {
               char id = i1 + i2 + i3;
               content[0] = id;
               checksum += id;
-              if (0 == (rand() % 20))
+              if (randomFailures && 0 == (rand() % 20))
                 throw id;
             }
           
@@ -137,6 +140,7 @@ namespace lib {
     }
     
     
+    
     /*************************************************************************
      *  @test verify the proper workings of our custom allocation scheme
      *        managing families of interconnected objects for the segments
@@ -182,6 +186,7 @@ namespace lib {
             // all created objects dtors will be invoked.
           }
         
+        
         void
         checkAllocation()
           {
@@ -194,11 +199,14 @@ namespace lib {
             ASSERT (0==checksum);
           }
         
+        
         void
         checkErrorHandling()
           {
             ASSERT (0==checksum);
             {
+              randomFailures = true;
+              
               AllocationCluster clu;
               for (uint i=0; i<NUM_OBJECTS; ++i)
                 try
@@ -212,14 +220,14 @@ namespace lib {
                     checksum -= id;  // exception thrown from within constructor, 
                   }                 //  thus dtor won't be called. Repair the checksum!
             }
+            randomFailures = false;
             ASSERT (0==checksum);
           }
       };
     
       LAUNCHER (AllocationCluster_test, "unit common");
-
-
-  }// namespace test
     
-} // namespace lib
+    
+  }// namespace test
 
+} // namespace lib
diff --git a/tests/common/scopedholdertransfertest.cpp b/tests/common/scopedholdertransfertest.cpp
index 7507cfbdd..1c69e38bb 100644
--- a/tests/common/scopedholdertransfertest.cpp
+++ b/tests/common/scopedholdertransfertest.cpp
@@ -159,7 +159,7 @@ namespace lib {
               table.reserve(2);
               ASSERT (0==checksum);
               
-              cout << "\n..install one element at index[0]\n";
+              cout << ".\n..install one element at index[0]\n";
               table.push_back(HO());
               ASSERT (0==checksum);
               
@@ -167,7 +167,7 @@ namespace lib {
               ASSERT (0 < checksum);
               int theSum = checksum;
               
-              cout << "\n..*** resize table to 16 elements\n";
+              cout << ".\n..*** resize table to 16 elements\n";
               for (uint i=0; i<15; ++i)
                 table.push_back(HO());
               
@@ -194,7 +194,7 @@ namespace lib {
               ASSERT (0 < checksum);
               int theSum = checksum;
               
-              cout << "\n.throw some exceptions...\n";
+              cout << ".\n.throw some exceptions...\n";
               throw_in_ctor = true;
               try
                 {