diff --git a/rtl/sinclairql/qdos.inc b/rtl/sinclairql/qdos.inc
index edbf925d71..fafcd78d66 100644
--- a/rtl/sinclairql/qdos.inc
+++ b/rtl/sinclairql/qdos.inc
@@ -98,6 +98,7 @@ end;
 const
   _IO_OPEN = $01;
   _IO_CLOSE = $02;
+  _IO_DELET = $04;
 
 function io_open_qlstr(name_qlstr: pointer; mode: longint): Tchanid; assembler; nostackframe; public name '_io_open_qlstr';
 asm
@@ -136,6 +137,32 @@ asm
   trap #2
 end;
 
+function io_delet_qlstr(name_qlstr: pointer): longint; assembler; nostackframe; public name '_io_delet_qlstr';
+asm
+  movem.l d2-d3,-(sp)
+  move.l name_qlstr,a0
+  moveq.l #-1,d1
+  moveq.l #_IO_DELET,d0
+  trap #2
+  tst.l d0
+@quit:
+  movem.l (sp)+,d2-d3
+end;
+
+function io_delet(name: pchar): Tchanid; public name '_io_delet';
+var
+  len: longint;
+  name_qlstr: array[0..63] of char;
+begin
+  len:=length(name);
+  if len > length(name_qlstr)-2 then
+    len:=length(name_qlstr)-2;
+
+  PWord(@name_qlstr)[0]:=len;
+  Move(name^,name_qlstr[2],len);
+
+  result:=io_delet_qlstr(@name_qlstr);
+end;
 
 const
   _IO_FBYTE = $01;
@@ -346,3 +373,15 @@ asm
 @quit:
   movem.l (sp)+,d2-d3/a2-a3
 end;
+
+const
+  _MT_RCLCK = $13;
+
+function mt_rclck: longint; assembler; nostackframe; public name '_mt_rclck';
+asm
+  move.l d2,-(sp)
+  moveq #_MT_RCLCK,d0
+  trap #1
+  move.l d1,d0
+  move.l (sp)+,d2
+end;
diff --git a/rtl/sinclairql/qdosfuncs.inc b/rtl/sinclairql/qdosfuncs.inc
index 118125e537..81b46dd7e3 100644
--- a/rtl/sinclairql/qdosfuncs.inc
+++ b/rtl/sinclairql/qdosfuncs.inc
@@ -26,6 +26,7 @@ procedure mt_rechp(area: pointer); external name '_mt_rechp';
 function io_open_qlstr(name_qlstr: pointer; mode: longint): Tchanid; external name '_io_open_qlstr';
 function io_open(name: pchar; mode: longint): Tchanid; external name '_io_open';
 function io_close(chan: Tchanid): longint; external name '_io_close';
+function io_delet(name: pchar): longint; external name '_io_delet';
 
 function io_fbyte(chan: Tchanid; timeout: Ttimeout): longint; external name '_io_fbyte';
 function io_fline(chan: Tchanid; timeout: Ttimeout; buf: pointer; len: word): longint; external name '_io_fline';
@@ -43,3 +44,5 @@ function sd_clear(chan: Tchanid; timeout: Ttimeout): longint; external name '_sd
 
 function ut_con(params: PWindowDef): Tchanid; external name '_ut_con';
 function ut_scr(params: PWindowDef): Tchanid; external name '_ut_scr';
+
+function mt_rclck: longint; external name '_mt_rclck';