--- a/AbstractOperatingSystem.st	Thu Apr 28 06:55:15 2016 +0200
+++ b/AbstractOperatingSystem.st	Tue May 03 11:13:43 2016 +0200
@@ -2368,6 +2368,8 @@
 !
 
 createFileForReadWrite:pathName
+    "open a file for reading and writing, return an os specific fileHandle."
+
     self subclassResponsibility
 !
 
@@ -2415,10 +2417,14 @@
 !
 
 openFileForAppend:pathName
+    "open a file for appending, return an os specific fileHandle."
+
     self subclassResponsibility
 !
 
 openFileForRead:pathName
+    "open a file for reading, return an os specific fileHandle."
+
     self subclassResponsibility
 !
 
@@ -2427,10 +2433,14 @@
 !
 
 openFileForReadWrite:pathName
+    "open a file for reading and writing, return an os specific fileHandle."
+
     self subclassResponsibility
 !
 
 openFileForWrite:pathName
+    "open a file for writing, return an os specific fileHandle."
+
     self subclassResponsibility
 !