--- a/OSProcess.st	Tue Dec 27 14:02:12 2016 +0100
+++ b/OSProcess.st	Tue Dec 27 14:02:32 2016 +0100
@@ -436,10 +436,10 @@
      Answer true if the command could be started, false if not.
      Return immediately (do not wait until the command is finished)." 
 
-    |nullStream externalInStream externalAuxStream externalErrorStream externalOutStream|
+    |externalInStream externalAuxStream externalErrorStream externalOutStream|
 
-    shufflerProcesses := OrderedCollection new.
-    streamsToClose := OrderedCollection new:3.
+    shufflerProcesses := OrderedCollection new:4.
+    streamsToClose := OrderedCollection new:2.
 
     externalInStream := self setupShufflerForInput:inStream.
     externalAuxStream := self setupShufflerForInput:auxStream.
@@ -450,41 +450,21 @@
         externalOutStream := self setupShufflerForOutput:outStream.
     ].
 
-    "make sure, that the command gets a stdin, stdout and stderr"
-    externalInStream isNil ifTrue:[
-        externalInStream := nullStream := Filename nullDevice readWriteStream.
-        streamsToClose add:nullStream.
-    ].
-    externalOutStream isNil ifTrue:[
-        nullStream isNil ifTrue:[
-            nullStream := Filename nullDevice writeStream.
-            streamsToClose add:nullStream.
-        ].
-        externalOutStream := nullStream.
-    ].
-    externalErrorStream isNil ifTrue:[
-        nullStream isNil ifTrue:[
-            nullStream := Filename nullDevice writeStream.
-            streamsToClose add:nullStream.
-        ].
-        externalErrorStream := nullStream.
-    ].
-
     "start the command"
-    finishSema := Semaphore new.
+    finishSema := EventSemaphore new.
 
     Processor 
         monitor:[
             pid := OperatingSystem
-                    startProcess:command
-                    inputFrom:externalInStream
-                    outputTo:externalOutStream
-                    errorTo:externalErrorStream
-                    auxFrom:externalAuxStream
-                    environment:environment
-                    inDirectory:directory
-                    newPgrp:newPgrp
-                    showWindow:showWindow.
+                        startProcess:command
+                        inputFrom:externalInStream
+                        outputTo:externalOutStream
+                        errorTo:externalErrorStream
+                        auxFrom:externalAuxStream
+                        environment:environment
+                        inDirectory:directory
+                        newPgrp:newPgrp
+                        showWindow:showWindow.
         ] 
         action:[:status |
             status stillAlive ifFalse:[