diff --git a/harbour/ChangeLog b/harbour/ChangeLog
index 3901f75c15..16f6a70f9a 100644
--- a/harbour/ChangeLog
+++ b/harbour/ChangeLog
@@ -1,3 +1,12 @@
+19991007-01:42 GMT+1 Victor Szel <info@szelvesz.hu>
+   * include/filesys.h
+     source/rtl/filesys.c
+     % Only use hb_fsReadLarge() and hb_fsWriteLarge() when the size of an
+       unsigned int is not the same as the size of an unsigned long.
+       (Same logic as for xmem*() functions)
+   * source/rtl/dummy.prg
+     - ReadKey() removed.
+
 19991007-01:16 GMT+1 Victor Szel <info@szelvesz.hu>
    + source/vm/main.c (added)
      source/vm/Makefile
diff --git a/harbour/include/filesys.h b/harbour/include/filesys.h
index 6a5b0ca48e..ad473289e0 100644
--- a/harbour/include/filesys.h
+++ b/harbour/include/filesys.h
@@ -88,7 +88,6 @@ extern BOOL     hb_fsLock       ( FHANDLE hFileHandle, ULONG ulStart,
 extern BOOL     hb_fsMkDir      ( BYTE * pDirName );
 extern FHANDLE  hb_fsOpen       ( BYTE * pFilename, USHORT uiFlags );
 extern USHORT   hb_fsRead       ( FHANDLE hFileHandle, BYTE * pBuff, USHORT ulCount );
-extern ULONG    hb_fsReadLarge  ( FHANDLE hFileHandle, BYTE * pBuff, ULONG ulCount );
 extern BOOL     hb_fsRmDir      ( BYTE * pDirName );
 extern int      hb_fsRename     ( BYTE * pOldName, BYTE * pNewName );
 extern ULONG    hb_fsSeek       ( FHANDLE hFileHandle, LONG lOffset, USHORT uiMode );
@@ -96,7 +95,17 @@ extern ULONG    hb_fsTell       ( FHANDLE hFileHandle );
 extern void     hb_fsSetDevMode ( FHANDLE hFileHandle, USHORT uiDevMode );
 extern void     hb_fsSetError   ( USHORT uiError );
 extern USHORT   hb_fsWrite      ( FHANDLE hFileHandle, BYTE * pBuff, USHORT ulCount );
+
+#if UINT_MAX == ULONG_MAX
+   /* NOTE: hb_fsRead/hb_fsWrite can work with ULONG data blocks */
+   #define hb_fsReadLarge   hb_fsRead
+   #define hb_fsWriteLarge  hb_fsWrite
+#else
+   /* NOTE: otherwise, the extended version of the functions
+            will be used to copy and/or set ULONG data blocks */
+extern ULONG    hb_fsReadLarge  ( FHANDLE hFileHandle, BYTE * pBuff, ULONG ulCount );
 extern ULONG    hb_fsWriteLarge ( FHANDLE hFileHandle, BYTE * pBuff, ULONG ulCount );
+#endif
 
 extern PHB_FNAME hb_fsFNameSplit ( char * szFilename ); /* Split given filename into path, name and extension */
 extern char *    hb_fsFNameMerge ( char * szFileName, PHB_FNAME pFileName ); /* This function joins path, name and extension into a string with a filename */
diff --git a/harbour/source/rtl/dummy.prg b/harbour/source/rtl/dummy.prg
index 2f2ecd8cfd..a8025f2685 100644
--- a/harbour/source/rtl/dummy.prg
+++ b/harbour/source/rtl/dummy.prg
@@ -80,17 +80,14 @@ FUNCTION __dbTotal()       ; RETURN NIL
 FUNCTION __dbUpdate()      ; RETURN NIL
 FUNCTION __dbZap()         ; RETURN NIL
 
-FUNCTION __LabelForm()     ; RETURN NIL
-FUNCTION __ReportForm()    ; RETURN NIL
-
-FUNCTION __SetFormat()     ; RETURN NIL
-FUNCTION __TypeFile()      ; RETURN NIL
-
 FUNCTION Browse()          ; RETURN .T.
 FUNCTION dbEdit()          ; RETURN NIL
 FUNCTION IsPrinter()       ; RETURN .T.
 FUNCTION NetName()         ; RETURN ""
-FUNCTION ReadKey()         ; RETURN 0
+FUNCTION __qqPub()         ; RETURN NIL
+FUNCTION __TypeFile()      ; RETURN NIL
+FUNCTION __LabelForm()     ; RETURN NIL
+FUNCTION __ReportForm()    ; RETURN NIL
 
 FUNCTION GetActive()       ; RETURN NIL
 FUNCTION GetApplyKey()     ; RETURN NIL
@@ -102,6 +99,5 @@ FUNCTION ReadFormat()      ; RETURN .F.
 FUNCTION ReadKill()        ; RETURN .F.
 FUNCTION ReadUpdated()     ; RETURN .T.
 FUNCTION Updated()         ; RETURN .T.
-
-FUNCTION __qqPub()         ; RETURN NIL
+FUNCTION __SetFormat()     ; RETURN NIL
 
diff --git a/harbour/source/rtl/filesys.c b/harbour/source/rtl/filesys.c
index a3483f59ea..3873955dda 100644
--- a/harbour/source/rtl/filesys.c
+++ b/harbour/source/rtl/filesys.c
@@ -519,6 +519,8 @@ USHORT  hb_fsWrite( FHANDLE hFileHandle, BYTE * pBuff, USHORT uiCount )
    return uiWritten;
 }
 
+#if UINT_MAX != ULONG_MAX
+
 ULONG   hb_fsReadLarge( FHANDLE hFileHandle, BYTE * pBuff, ULONG ulCount )
 {
    ULONG ulRead = 0L, ulLeftToRead = ulCount;
@@ -605,6 +607,8 @@ ULONG   hb_fsWriteLarge( FHANDLE hFileHandle, BYTE * pBuff, ULONG ulCount )
    return ulWritten;
 }
 
+#endif
+
 ULONG   hb_fsSeek( FHANDLE hFileHandle, LONG lOffset, USHORT uiFlags )
 {
    ULONG ulPos = -1;