diff --git a/hdr/VduExt b/hdr/VduExt
index 5177d6b061f7f6261567a48eb19bf86814a47440..6b53865f96a1ab22b44983a41bdbc7808ff52bfc 100644
--- a/hdr/VduExt
+++ b/hdr/VduExt
@@ -26,6 +26,7 @@ OldOpt  SETA    {OPT}
 ; 27-Oct-89  TMD   Added VIDCClockSpeed
 ; 05-Aug-91  DDV   Added Flag_FullPalette
 ; 15-Jul-93  TMD   Added NumModeVars
+; 21-Jul-98  NDT   Added PixelRate
 
 ; Sets up external symbols of the form VduExt_<var name>
 ; for use with SWI OS_ReadVDUVariables
@@ -103,6 +104,7 @@ NumModeVars * NotRVVTBarWobblyBitscounter
         NotRVVTBarWobblyBits    TCharSpaceY
         NotRVVTBarWobblyBits    GcolOraEorAddr
         NotRVVTBarWobblyBits    VIDCClockSpeed
+        NotRVVTBarWobblyBits    PixelRate
 
         NotRVVTBarWobblyBits    WindowWidth, &100
         NotRVVTBarWobblyBits    WindowHeight
diff --git a/s/Kernel b/s/Kernel
index cb8a2d16ddc4977a6502cdc70ca32e0b00c2f6a2..cd2474d38e8019906ebe918cf38f7b492be6ef6f 100644
--- a/s/Kernel
+++ b/s/Kernel
@@ -648,6 +648,10 @@ JTABLE  & SWIWriteC             ; this entry never gets used (see ^)
         & NoSuchSWI
         & NoSuchSWI
  ]
+	& NoSuchSWI	; SpecialControl
+	& NoSuchSWI	; EnterUSR32SWI
+	& NoSuchSWI	; EnterUSR26SWI
+	& NoSuchSWI	; VIDCDividerSWI
 
 
 MaxSwi * (.-JTABLE)/4
diff --git a/s/SWINaming b/s/SWINaming
index d116cc3b709592522f765da141b9a5881c2f7a19..c411b3b929e99470f651a1168ffc9f97771b30f6 100644
--- a/s/SWINaming
+++ b/s/SWINaming
@@ -194,6 +194,10 @@ System_Swi_Names
         AddSwiNameToDecodeTab CallASWI
         AddSwiNameToDecodeTab AMBControl
         AddSwiNameToDecodeTab CallASWIR12
+        AddSwiNameToDecodeTab SpecialControl
+        AddSwiNameToDecodeTab EnterUSR32
+        AddSwiNameToDecodeTab EnterUSR26
+        AddSwiNameToDecodeTab VIDCDivider
         = 0
 
  [ SwisInSystemTable+1 <> MaxSwi