--- a/ProcessorScheduler.st	Wed Mar 04 17:02:50 2020 +0100
+++ b/ProcessorScheduler.st	Wed Mar 04 17:04:26 2020 +0100
@@ -2596,10 +2596,20 @@
     "Modified: / 9.11.1998 / 20:39:06 / cg"
 !
 
-signal:aSemaphore after:aTimeDuration
+signal:aSemaphore after:secondsOrTimeDuration
     "arrange for a semaphore to be triggered after aTimeDuration"
 
-    self signal:aSemaphore afterMilliseconds:aTimeDuration getMilliseconds
+    |ms|
+
+    secondsOrTimeDuration isTimeDuration ifTrue:[
+        ms := secondsOrTimeDuration getMilliseconds.
+    ] ifFalse:[
+        ms := (secondsOrTimeDuration * 1000) rounded.
+    ].
+
+    self signal:aSemaphore afterMilliseconds:ms.
+
+    "Modified: / 04-03-2020 / 14:32:10 / Stefan Vogel"
 !
 
 signal:aSemaphore afterMilliseconds:millis
@@ -2721,7 +2731,7 @@
      If aBlock is nil, the semaphore is removed from the set of semaphores, after being signaled."
 
     |idx "{ Class: SmallInteger }"
-     wasBlocked slot|
+     wasBlocked slot readCheckEntry|
 
     wasBlocked := OperatingSystem blockInterrupts.
 
@@ -2729,6 +2739,10 @@
      aSemphore is never nil, but one of aFileDescriptor, aBlock may be nil"
 
     aFileDescriptor isNil ifTrue:[
+        aBlock isNil ifTrue:[
+            wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
+            self error:'Signalling requested for nil fd and nil block'.
+        ].    
         idx := readSemaphoreArray identityIndexOf:aSemaphore or:nil.
         idx == 0 ifTrue:[
             "aSemaphore is not registered yet, have to create a new slot"
@@ -2738,16 +2752,17 @@
         ] ifFalse:[
             slot := readSemaphoreArray at:idx.
             slot isNil ifTrue:[
+                "aSemaphore is not registered yet, found an empty slot"    
                 readSemaphoreArray at:idx put:aSemaphore.
                 readCheckArray at:idx put:aBlock
             ] ifFalse:[
                 "/ someone has already registered aSemaphore.
                 "/ Check if it is the block changes...
-                (readCheckArray at:idx) notNil ifTrue:[
-                    (readCheckArray at:idx) ~~ aBlock ifTrue:[
-                        'Processor [info]: checkblock changed for read-check' infoPrintCR.
-                        readCheckArray at:idx put:aBlock.
-                    ].
+                readCheckEntry := readCheckArray at:idx.
+                (readCheckEntry notNil 
+                 and:[readCheckEntry ~~ aBlock]) ifTrue:[
+                    Logger info:'Processor: checkblock changed for read-check'.
+                    readCheckArray at:idx put:aBlock.
                 ].
             ].
         ]
@@ -2761,6 +2776,7 @@
         ] ifFalse:[
             slot := readFdArray at:idx.
             slot isNil ifTrue:[
+                "aFileDescriptor is not registered yet, found an empty slot"
                 readFdArray at:idx put:aFileDescriptor.
                 readSemaphoreArray at:idx put:aSemaphore.
                 readCheckArray at:idx put:aBlock
@@ -2768,11 +2784,11 @@
                 "/ someone has already registered aFileDescriptor.
                 "/ Check if it is the semaphore or block changes...
                 (readSemaphoreArray at:idx) ~~ aSemaphore ifTrue:[
-                    'Processor [info]: sema changed for read-check' infoPrintCR.
+                    Logger info:'Processor: sema changed for read-check'.
                     readSemaphoreArray at:idx put:aSemaphore.
                 ].
                 (readCheckArray at:idx) ~~ aBlock ifTrue:[
-                    'Processor [info]: checkblock changed for read-check' infoPrintCR.
+                    Logger info:'Processor: checkblock changed for read-check'.
                     readCheckArray at:idx put:aBlock.
                 ].
             ].
@@ -2783,7 +2799,8 @@
     ].
     wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
 
-    "Modified: 4.8.1997 / 15:20:45 / cg"
+    "Modified: / 04-08-1997 / 15:20:45 / cg"
+    "Modified (format): / 04-03-2020 / 14:12:10 / Stefan Vogel"
 !
 
 signal:aSemaphore onInputStream:aStream
@@ -2791,15 +2808,23 @@
      This will do a select, if the OS supports selecting on that filedescriptor,
      otherwise, it will be polled every few milliseconds (MSDOS)."
 
+    |fd|
+
+    fd := aStream fileHandle.
+    fd isNil ifTrue:[
+        aSemaphore signal.
+    ].
+    
     aStream canBeSelected ifTrue:[
         "/ can this stream be selected on ?
-        self signal:aSemaphore onInput:aStream fileHandle orCheck:nil
+        self signal:aSemaphore onInput:fd orCheck:nil
     ] ifFalse:[
         "/ nope - must poll ...
         self signal:aSemaphore onInput:nil orCheck:[aStream canReadWithoutBlocking]
     ]
 
-    "Modified: / 14.12.1999 / 23:58:50 / cg"
+    "Modified: / 14-12-1999 / 23:58:50 / cg"
+    "Modified: / 04-03-2020 / 14:57:35 / Stefan Vogel"
 !
 
 signal:aSemaphore onOutput:aFileDescriptor
@@ -2892,15 +2917,23 @@
      This will do a select, if the OS supports selecting on that filedescriptor,
      otherwise, it will be polled every few milliseconds (MSDOS)."
 
+    |fd|
+
+    fd := aStream fileHandle.
+    fd isNil ifTrue:[
+        aSemaphore signal.
+    ].
+
     aStream canBeSelected ifTrue:[
         "/ can this stream be selected on ?
-        self signal:aSemaphore onOutput:aStream fileHandle orCheck:nil
+        self signal:aSemaphore onOutput:fd orCheck:nil
     ] ifFalse:[
         "/ nope - must poll ...
         self signal:aSemaphore onOutput:nil orCheck:[aStream canWriteWithoutBlocking]
     ]
 
-    "Modified: / 14.12.1999 / 23:59:19 / cg"
+    "Modified: / 14-12-1999 / 23:59:19 / cg"
+    "Modified: / 04-03-2020 / 14:58:05 / Stefan Vogel"
 ! !
 
 !ProcessorScheduler methodsFor:'special configuration'!