diff --git a/Timeline/Disk_Stream.C b/Timeline/Disk_Stream.C
index 45cbbe9..b721d7c 100644
--- a/Timeline/Disk_Stream.C
+++ b/Timeline/Disk_Stream.C
@@ -96,7 +96,13 @@ void
 Disk_Stream::shutdown ( void )
 {
     _terminate = true;
-    pthread_join( _thread, NULL );
+
+    /* try to wake the thread so it'll see that it's time to die */
+    block_processed();
+
+    if ( _thread )
+        pthread_join( _thread, NULL );
+
     _terminate = false;
 }
 
diff --git a/Timeline/Disk_Stream.H b/Timeline/Disk_Stream.H
index 351bbb8..e1cc307 100644
--- a/Timeline/Disk_Stream.H
+++ b/Timeline/Disk_Stream.H
@@ -42,7 +42,7 @@ protected:
 
     pthread_t _thread;                                 /* io thread */
 
-    Track *_th;                 /* Track we belong to */
+    Track *_th;                               /* Track we belong to */
 
     nframes_t _nframes;                              /* buffer size */
 
diff --git a/Timeline/Mutex.H b/Timeline/Mutex.H
index f98f9eb..39b14e5 100644
--- a/Timeline/Mutex.H
+++ b/Timeline/Mutex.H
@@ -21,6 +21,8 @@
 
 #include <pthread.h>
 
+const pthread_mutex_t _mutex_initializer = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
+
 class Mutex
 {
 
@@ -30,7 +32,8 @@ public:
 
     Mutex ( )
         {
-            pthread_mutex_init( &_lock, NULL );
+//            pthread_mutex_init( &_lock, NULL );
+            _lock = _mutex_initializer;
         }
 
     virtual ~Mutex ( )
diff --git a/Timeline/Track.C b/Timeline/Track.C
index 2130324..e4d7353 100644
--- a/Timeline/Track.C
+++ b/Timeline/Track.C
@@ -423,6 +423,17 @@ Track::configure_outputs ( int n )
 {
     int on = output.size();
 
+    if ( n == on )
+        return true;
+
+//    engine->lock();
+
+    Playback_DS *ds = playback_ds;
+    playback_ds = NULL;
+
+    ds->shutdown();
+    delete ds;
+
     if ( n > on )
     {
         for ( int i = on; i < n; ++i )
@@ -444,6 +455,10 @@ Track::configure_outputs ( int n )
         }
     }
 
+
+    playback_ds = new Playback_DS( this, engine->frame_rate(), engine->nframes(), output.size() );
+
+//    engine->unlock();
     /* FIXME: bogus */
     return true;
 }
@@ -453,6 +468,17 @@ Track::configure_inputs ( int n )
 {
     int on = input.size();
 
+    if ( n == on )
+        return true;
+
+//    engine->lock();
+
+    Record_DS *ds = record_ds;
+    record_ds = NULL;
+
+    ds->shutdown();
+    delete ds;
+
     if ( n > on )
     {
         for ( int i = on; i < n; ++i )
@@ -474,6 +500,10 @@ Track::configure_inputs ( int n )
         }
     }
 
+    record_ds = new Record_DS( this, engine->frame_rate(), engine->nframes(), input.size() );
+
+//    engine->unlock();
+
     /* FIXME: bogus */
     return true;
 }