diff --git a/.gitattributes b/.gitattributes
index 3681cc5a0e..ae15455037 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -8202,6 +8202,8 @@ rtl/morphos/videodata.inc svneol=native#text/plain
 rtl/msdos/Makefile svneol=native#text/plain
 rtl/msdos/Makefile.fpc svneol=native#text/plain
 rtl/msdos/prt0.asm svneol=native#text/plain
+rtl/msdos/sysfile.inc svneol=native#text/plain
+rtl/msdos/sysheap.inc svneol=native#text/plain
 rtl/msdos/sysos.inc svneol=native#text/plain
 rtl/msdos/sysosh.inc svneol=native#text/plain
 rtl/msdos/system.pp svneol=native#text/plain
diff --git a/rtl/msdos/sysfile.inc b/rtl/msdos/sysfile.inc
new file mode 100644
index 0000000000..023a1e7ed9
--- /dev/null
+++ b/rtl/msdos/sysfile.inc
@@ -0,0 +1,78 @@
+{
+    This file is part of the Free Pascal run time library.
+    Copyright (c) 2001 by Free Pascal development team
+
+    Low leve file functions
+
+    See the file COPYING.FPC, included in this distribution,
+    for details about the copyright.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+ **********************************************************************}
+
+{****************************************************************************
+                        Low level File Routines
+ ****************************************************************************}
+
+procedure do_close(handle : thandle);
+begin
+end;
+
+
+procedure do_erase(p : pchar);
+begin
+end;
+
+
+procedure do_rename(p1,p2 : pchar);
+begin
+end;
+
+
+function do_write(h:thandle;addr:pointer;len : longint) : longint;
+begin
+end;
+
+
+function do_read(h:thandle;addr:pointer;len : longint) : longint;
+begin
+end;
+
+
+function do_filepos(handle : thandle) : longint;
+begin
+end;
+
+
+procedure do_seek(handle:thandle;pos : longint);
+begin
+end;
+
+
+
+function do_seekend(handle:thandle):longint;
+begin
+end;
+
+
+function do_filesize(handle : thandle) : longint;
+begin
+end;
+
+
+{ truncate at a given position }
+procedure do_truncate (handle:thandle;pos:longint);
+begin
+end;
+
+procedure do_open(var f;p:pchar;flags:longint);
+begin
+end;
+
+
+function do_isdevice(handle:THandle):boolean;
+begin
+end;
diff --git a/rtl/msdos/sysheap.inc b/rtl/msdos/sysheap.inc
new file mode 100644
index 0000000000..a8e786e353
--- /dev/null
+++ b/rtl/msdos/sysheap.inc
@@ -0,0 +1,30 @@
+{
+    This file is part of the Free Pascal run time library.
+    Copyright (c) 2001 by Free Pascal development team
+
+    This file implements all the base types and limits required
+    for a minimal POSIX compliant subset required to port the compiler
+    to a new OS.
+
+    See the file COPYING.FPC, included in this distribution,
+    for details about the copyright.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+ **********************************************************************}
+
+
+{*****************************************************************************
+                              Heap Management
+*****************************************************************************}
+
+function SysOSAlloc (size: ptruint): pointer;
+begin
+  Result := nil;
+end;
+
+procedure SysOSFree(p: pointer; size: ptruint);
+begin
+end;