diff --git a/src/db/dbCAC.h b/src/db/dbCAC.h
index cb8b9a3d7..23feb9c9d 100644
--- a/src/db/dbCAC.h
+++ b/src/db/dbCAC.h
@@ -55,6 +55,7 @@ public:
     dbSubscriptionIO ( dbChannelIO &chanIO, cacNotify &, unsigned type, unsigned long count );
     int begin ( struct dbAddr &addr, unsigned mask );
     void destroy ();
+    void show ( unsigned level ) const;
     static void * operator new ( size_t size );
     static void operator delete ( void *pCadaver, size_t size );
 private:
@@ -77,6 +78,7 @@ public:
     int initiatePutNotify (cacNotify &notify, struct dbAddr &addr, 
             unsigned type, unsigned long count, const void *pValue);
     void putNotifyDestroyNotify ();
+    void show ( unsigned level ) const;
     static void * operator new ( size_t size );
     static void operator delete ( void *pCadaver, size_t size );
 private:
@@ -98,7 +100,7 @@ public:
     void subscriptionUpdate ( unsigned type, unsigned long count, 
             const struct db_field_log *pfl, cacNotifyIO &notify );
     dbEventSubscription subscribe ( dbSubscriptionIO &subscr, unsigned mask );
-
+    void show ( unsigned level ) const;
     static void * operator new ( size_t size);
     static void operator delete ( void *pCadaver, size_t size );
 
@@ -107,7 +109,7 @@ private:
     char *pGetCallbackCache;
     dbPutNotifyBlocker *pBlocker;
     unsigned long getCallbackCacheSize;
-    tsDLList <dbSubscriptionIO> eventq;
+    tsDLList < dbSubscriptionIO > eventq;
     dbAddr addr;
 
     static tsFreeList < dbChannelIO > freeList;
@@ -143,6 +145,7 @@ public:
     void subscriptionUpdate ( struct dbAddr &addr, unsigned type, unsigned long count, 
             const struct db_field_log *pfl, cacNotifyIO &notify );
     dbEventSubscription subscribe ( struct dbAddr &addr, dbSubscriptionIO &subscr, unsigned mask );
+    void show ( unsigned level ) const;
 private:
     dbEventCtx ctx;
     char *pEventCallbackCache;
diff --git a/src/db/dbChannelIO.cpp b/src/db/dbChannelIO.cpp
index 4aec3a37c..006bf24df 100644
--- a/src/db/dbChannelIO.cpp
+++ b/src/db/dbChannelIO.cpp
@@ -186,3 +186,29 @@ void dbChannelIO::unlockOutstandingIO () const
 {
 }
 
+void dbChannelIO::show ( unsigned level ) const
+{
+    this->lock ();
+    printf ("channel at %p attached to local database record %s\n", 
+        this, this->addr.precord->name );
+
+    if ( level > 0u ) {
+        printf ( "\ttype %s, element count %li, field at %p\n",
+            dbf_type_to_text ( this->addr.dbr_field_type ), this->addr.no_elements,
+            this->addr.pfield );
+    }
+    if ( level > 1u ) {
+        this->serviceIO.show ( level - 2u );
+        printf ( "\tget callback cache at %p, with size %lu\n",
+            this->pGetCallbackCache, this->getCallbackCacheSize );
+        tsDLIterConstBD < dbSubscriptionIO > pItem = this->eventq.first ();
+        while ( pItem.valid () ) {
+            pItem->show ( level - 2u );
+            pItem++;
+        }
+        if ( this->pBlocker ) {
+            this->pBlocker->show ( level - 2u );
+        }
+    }
+    this->unlock ();
+}
diff --git a/src/db/dbPutNotifyBlocker.cpp b/src/db/dbPutNotifyBlocker.cpp
index 6c05ceb1f..53bc4a876 100644
--- a/src/db/dbPutNotifyBlocker.cpp
+++ b/src/db/dbPutNotifyBlocker.cpp
@@ -104,5 +104,17 @@ extern "C" void putNotifyCompletion ( putNotify *ppn )
     pBlocker->block.signal ();
 }
 
+void dbPutNotifyBlocker::show ( unsigned level ) const
+{
+    printf ( "put notify blocker at %p\n", this );
+    if ( level > 0u ) {
+        printf ( "\tdbPutNotifyIO at %p\n", this->pPN );
+        printf ( "\tdbChannelIO at %p\n", &this->chan );
+    }
+    if ( level > 1u ) {
+        this->block.show ( level - 2u );
+    }
+}
+
 
 
diff --git a/src/db/dbServiceIO.cpp b/src/db/dbServiceIO.cpp
index b6bff6a29..d20cf7078 100644
--- a/src/db/dbServiceIO.cpp
+++ b/src/db/dbServiceIO.cpp
@@ -156,3 +156,18 @@ dbEventSubscription dbServiceIO::subscribe ( struct dbAddr &addr, dbSubscription
 
     return es;
 }
+
+void dbServiceIO::show ( unsigned level ) const
+{
+    this->mutex.lock ();
+    printf ( "dbServiceIO at %p\n", this );
+    if (level > 0u ) {
+        printf ( "\tevent call back cache location %p, and its size %lu\n", 
+            this->pEventCallbackCache, this->eventCallbackCacheSize );
+    }
+    if ( level > 1u ) {
+        this->mutex.show ( level - 2u );
+    }
+    this->mutex.unlock ();
+}
+
diff --git a/src/db/dbSubscriptionIO.cpp b/src/db/dbSubscriptionIO.cpp
index 1225995ed..940e8c6a1 100644
--- a/src/db/dbSubscriptionIO.cpp
+++ b/src/db/dbSubscriptionIO.cpp
@@ -89,3 +89,19 @@ int dbSubscriptionIO::begin ( struct dbAddr &addr, unsigned mask )
     }
 }
 
+void dbSubscriptionIO::show ( unsigned level ) const
+{
+    printf ( "Data base subscription IO at %p\n", this );
+    if ( level > 0u ) {
+        short tmpType;
+        if ( this->type < SHRT_MAX ) {
+            tmpType = static_cast < short > ( this->type );
+            printf ( "\ttype %s, count %lu, channel at %p\n",
+                dbf_type_to_text ( tmpType ), this->count, &this->chan );
+        }
+        else {
+            printf ("strange type !, count %lu, channel at %p\n",
+                this->count, &this->chan );
+        }
+    }
+}
diff --git a/src/libCom/cxxTemplates/tsFreeList.h b/src/libCom/cxxTemplates/tsFreeList.h
index 952a8861c..8e12d9940 100644
--- a/src/libCom/cxxTemplates/tsFreeList.h
+++ b/src/libCom/cxxTemplates/tsFreeList.h
@@ -75,7 +75,7 @@ void * tsFreeList < T, N, DEBUG_LEVEL >::allocate (size_t size)
 {
     tsFreeListItem < T, DEBUG_LEVEL > *p;
 
-    if ( size != sizeof ( T ) ) {
+    if ( size != sizeof ( T ) || N == 0u ) {
         return ::operator new (size);
     }
 
@@ -115,14 +115,12 @@ void tsFreeList < T, N, DEBUG_LEVEL >::release (void *pCadaver, size_t size)
     if ( size != sizeof ( T ) ) {
         ::operator delete ( pCadaver );
     }
-    else {
-        if ( pCadaver ) {
-            this->lock ();
-            tsFreeListItem < T, DEBUG_LEVEL > *p = 
-                static_cast < tsFreeListItem < T, DEBUG_LEVEL > *> ( pCadaver );
-            p->pNext = this->pFreeList;
-            this->pFreeList = p;
-            this->unlock ();
-        }
+    else if ( pCadaver ) {
+        this->lock ();
+        tsFreeListItem < T, DEBUG_LEVEL > *p = 
+            static_cast < tsFreeListItem < T, DEBUG_LEVEL > *> ( pCadaver );
+        p->pNext = this->pFreeList;
+        this->pFreeList = p;
+        this->unlock ();
     }
 }
diff --git a/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp b/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp
index 347dbbee3..e9176eba9 100644
--- a/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp
+++ b/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp
@@ -90,6 +90,30 @@ void ipAddrToAsciiEngine::entryPoint ()
     this->threadExit.signal ();
 }
 
+void ipAddrToAsciiEngine::show ( unsigned level ) const
+{
+    this->mutex.lock ();
+    printf ( "ipAddrToAsciiEngine at %p with %u requests pendingh\n", 
+        this, this->labor.count () );
+    if ( level > 0u ) {
+        tsDLIterConstBD < ipAddrToAsciiAsynchronous > pItem = this->labor.first ();
+        while ( pItem.valid () ) {
+            pItem->show ( level - 1u );
+        }
+        printf ( "nextId = %u\n", this->nextId );
+    }
+    if ( level > 1u ) {
+        printf ( "mutex:\n" );
+        this->mutex.show ( level - 2u );
+        printf ( "event:\n" );
+        this->event.show ( level - 2u );
+        printf ( "exitFlag  boolean = %u\n", this->exitFlag );
+        printf ( "exit event:\n" );
+        this->threadExit.show ( level - 2u );
+    }
+    this->mutex.unlock ();
+}
+
 ipAddrToAsciiAsynchronous::ipAddrToAsciiAsynchronous 
     ( const osiSockAddr &addrIn ) :
     addr ( addrIn ), pEngine ( 0u )
@@ -128,3 +152,16 @@ epicsShareFunc bool ipAddrToAsciiAsynchronous::ioInitiate ( ipAddrToAsciiEngine
 
     return success;
 }
+
+void ipAddrToAsciiAsynchronous::show ( unsigned level ) const
+{
+    char ipAddr [64];
+
+    ipAddrToAsciiEngine::mutex.lock ();
+    sockAddrToA ( &this->addr.sa, ipAddr, sizeof ( ipAddr ) );
+    printf ( "ipAddrToAsciiAsynchronous for address %s\n", ipAddr );
+    if ( level > 0u ) {
+        printf ( "\tidentifier %u, engine %p\n", this->id, this->pEngine );
+    }
+    ipAddrToAsciiEngine::mutex.unlock ();
+}
diff --git a/src/libCom/misc/ipAddrToAsciiAsynchronous.h b/src/libCom/misc/ipAddrToAsciiAsynchronous.h
index 786120117..f05fabab8 100644
--- a/src/libCom/misc/ipAddrToAsciiAsynchronous.h
+++ b/src/libCom/misc/ipAddrToAsciiAsynchronous.h
@@ -30,6 +30,7 @@ class ipAddrToAsciiEngine : public osiThread {
 public:
     epicsShareFunc ipAddrToAsciiEngine ( const char *pName );
     epicsShareFunc ~ipAddrToAsciiEngine ();
+    epicsShareFunc void show ( unsigned level ) const;
 private:
     tsDLList < ipAddrToAsciiAsynchronous > labor;
     osiEvent event;
@@ -56,6 +57,7 @@ public:
     epicsShareFunc bool ioInitiate ( ipAddrToAsciiEngine &engine );
     epicsShareFunc bool identicalAddress ( const osiSockAddr &addr ) const;
     epicsShareFunc osiSockAddr address () const;
+    epicsShareFunc void show ( unsigned level ) const;
     virtual void ioCompletionNotify ( const char *pHostName ) = 0;
 private:
     osiSockAddr addr;
diff --git a/src/libCom/osi/osiEvent.h b/src/libCom/osi/osiEvent.h
index e28649420..bfd8eedba 100644
--- a/src/libCom/osi/osiEvent.h
+++ b/src/libCom/osi/osiEvent.h
@@ -20,9 +20,9 @@ public:
     ~osiEvent ();
     void signal ();
     void wait (); /* blocks until full */
-    bool wait (double timeOut); /* false if empty at time out */
+    bool wait ( double timeOut ); /* false if empty at time out */
     bool tryWait (); /* false if empty */
-    void show (unsigned level);
+    void show ( unsigned level ) const;
 
     class invalidSemaphore {}; /* exception */
     class noMemory {}; /* exception */
@@ -89,9 +89,9 @@ inline bool osiEvent::tryWait ()
     }
 }
 
-inline void osiEvent::show (unsigned level)
+inline void osiEvent::show ( unsigned level ) const
 {
-    semBinaryShow (this->id, level);
+    semBinaryShow ( this->id, level );
 }
 
 #endif /* osiEventh */
diff --git a/src/libCom/osi/osiMutex.h b/src/libCom/osi/osiMutex.h
index 737b9e4fb..7eda60ed3 100644
--- a/src/libCom/osi/osiMutex.h
+++ b/src/libCom/osi/osiMutex.h
@@ -19,10 +19,10 @@ public:
     osiMutex ();
     ~osiMutex ();
     void lock () const; /* blocks until success */
-    bool lock (double timeOut) const; /* true if successful */
+    bool lock ( double timeOut ) const; /* true if successful */
     bool tryLock () const; /* true if successful */
     void unlock () const;
-    void show (unsigned level) const;
+    void show ( unsigned level ) const;
 
     class invalidSemaphore {}; /* exception */
     class noMemory {}; /* exception */