--- a/AbstractOperatingSystem.st	Mon Nov 28 23:10:41 2016 +0100
+++ b/AbstractOperatingSystem.st	Mon Nov 28 23:17:40 2016 +0100
@@ -771,6 +771,7 @@
 !
 
 errorHolderForNumber:anInteger
+    "return an osErrorHolder for the given error number (as returned by a system call)."
 
     ^ self subclassResponsibility
 !
@@ -3056,12 +3057,12 @@
 
 createHardLinkFrom:oldPath to:newPath
     "link the file 'oldPath' to 'newPath'. The link will be a hard link.
-     Return true if successful, false if not."
+     Return nil if successful, an OsErrorHolder if not."
 
     "/
     "/ assume that this OperatingSystem does not support links
     "/
-    ^ self unsupportedOperationSignal raise
+    ^ OSErrorHolder unsupportedOperation
 
     "Created: / 13.8.1998 / 21:37:12 / cg"
     "Modified: / 13.8.1998 / 21:38:39 / cg"
@@ -3070,12 +3071,12 @@
 createSymbolicLinkFrom:oldPath to:newPath
     "make a link from the file 'oldPath' to the file 'newPath'.
      The link will be a soft (symbolic) link.
-     Return true if successful, false if not."
+     Return nil if successful, an OsErrorHolder if not."
 
     "/
     "/ assume that this OperatingSystem does not support symbolic links
     "/
-    ^ self unsupportedOperationSignal raise
+    ^ OSErrorHolder unsupportedOperation
 
     "Created: / 13.8.1998 / 21:38:24 / cg"
     "Modified: / 13.8.1998 / 21:38:43 / cg"
@@ -3192,14 +3193,14 @@
 removeDirectory:fullPathName
     "remove the directory named 'fullPathName'.
      The directory must be empty and you must have appropriate access rights.
-     Return true if successful, false if directory is not empty or no permission.
+     return nil if successful, an OSErrorHolder if directory is not empty or no permission.
      This is a lowLevel entry - use Filename protocol for compatibility."
 
     self subclassResponsibility
 !
 
 removeFile:fullPathName
-    "remove the file named 'fullPathName'; return true if successful.
+    "remove the file named 'fullPathName'; return nil if successful, an OSErrorHolder on errror.
      This is a lowLevel entry - use Filename protocol for compatibility."
 
     self subclassResponsibility
@@ -3211,7 +3212,7 @@
      correct for the OS used - therefore, this should not be called
      directlt. Instead, use Filename protocol to rename; this cares for
      any invalid names.
-     Returns true if successful, false if not"
+     Returns nil if successful, an OsErrorHolder if not"
 
     self subclassResponsibility
 !