diff --git a/PDP11/pdp11_cr.c b/PDP11/pdp11_cr.c
index 3482bcc0..bcc88ac5 100644
--- a/PDP11/pdp11_cr.c
+++ b/PDP11/pdp11_cr.c
@@ -181,7 +181,7 @@ extern int32 int_req[IPL_HLVL];
 #else                                                   /* PDP-11 version */
 #include "pdp11_defs.h"
 extern int32 int_req[IPL_HLVL];
-#define DFLT_DIS        (0)
+#define DFLT_DIS        (DEV_DIS)
 #define DFLT_CR11       (UNIT_CR11)
 #define DFLT_CPM        285
 #endif
diff --git a/PDP11/pdp11_io_lib.c b/PDP11/pdp11_io_lib.c
index 59af9a78..1d8a5d30 100644
--- a/PDP11/pdp11_io_lib.c
+++ b/PDP11/pdp11_io_lib.c
@@ -575,6 +575,11 @@ if (name) {                                             /* updating? */
                 autp->numc = nctrl;
             }
         }
+    dptr = find_dev (name);                             /* find ctrl */
+    if (dptr && !UNIBUS && !(dptr->flags & DEV_DIS) && !(dptr->flags & DEV_QBUS)) {
+        dptr->flags |= DEV_DIS;
+        return SCPE_ARG;
+        }
     }
 for (autp = auto_tab; autp->numc >= 0; autp++) {        /* loop thru table */
     if (autp->amod) {                                   /* floating csr? */
diff --git a/VAX/vax610_syslist.c b/VAX/vax610_syslist.c
index 09b81f5a..73ab1d1b 100644
--- a/VAX/vax610_syslist.c
+++ b/VAX/vax610_syslist.c
@@ -37,12 +37,10 @@ extern DEVICE tlb_dev;
 extern DEVICE sysd_dev;
 extern DEVICE qba_dev;
 extern DEVICE tti_dev, tto_dev;
-extern DEVICE cr_dev;
 extern DEVICE lpt_dev;
 extern DEVICE clk_dev;
 extern DEVICE rq_dev, rqb_dev, rqc_dev, rqd_dev;
 extern DEVICE rl_dev;
-extern DEVICE ry_dev;
 extern DEVICE ts_dev;
 extern DEVICE tq_dev;
 extern DEVICE dz_dev;
@@ -63,14 +61,12 @@ DEVICE *sim_devices[] = {
     &tto_dev,
     &dz_dev,
     &vh_dev,
-    &cr_dev,
     &lpt_dev,
     &rl_dev,
     &rq_dev,
     &rqb_dev,
     &rqc_dev,
     &rqd_dev,
-    &ry_dev,
     &ts_dev,
     &tq_dev,
     &xq_dev,
diff --git a/VAX/vax630_syslist.c b/VAX/vax630_syslist.c
index dfebea68..2226e53e 100644
--- a/VAX/vax630_syslist.c
+++ b/VAX/vax630_syslist.c
@@ -43,12 +43,10 @@ extern DEVICE wtc_dev;
 extern DEVICE sysd_dev;
 extern DEVICE qba_dev;
 extern DEVICE tti_dev, tto_dev;
-extern DEVICE cr_dev;
 extern DEVICE lpt_dev;
 extern DEVICE clk_dev;
 extern DEVICE rq_dev, rqb_dev, rqc_dev, rqd_dev;
 extern DEVICE rl_dev;
-extern DEVICE ry_dev;
 extern DEVICE ts_dev;
 extern DEVICE tq_dev;
 extern DEVICE dz_dev;
@@ -72,14 +70,12 @@ DEVICE *sim_devices[] = {
     &tto_dev,
     &dz_dev,
     &vh_dev,
-    &cr_dev,
     &lpt_dev,
     &rl_dev,
     &rq_dev,
     &rqb_dev,
     &rqc_dev,
     &rqd_dev,
-    &ry_dev,
     &ts_dev,
     &tq_dev,
     &xq_dev,
diff --git a/VAX/vax_syslist.c b/VAX/vax_syslist.c
index c367f29e..46985cff 100644
--- a/VAX/vax_syslist.c
+++ b/VAX/vax_syslist.c
@@ -39,12 +39,10 @@ extern DEVICE nvr_dev;
 extern DEVICE sysd_dev;
 extern DEVICE qba_dev;
 extern DEVICE tti_dev, tto_dev;
-extern DEVICE cr_dev;
 extern DEVICE lpt_dev;
 extern DEVICE clk_dev;
 extern DEVICE rq_dev, rqb_dev, rqc_dev, rqd_dev;
 extern DEVICE rl_dev;
-extern DEVICE ry_dev;
 extern DEVICE ts_dev;
 extern DEVICE tq_dev;
 extern DEVICE dz_dev;
@@ -70,14 +68,12 @@ DEVICE *sim_devices[] = {
     &cso_dev,
     &dz_dev,
     &vh_dev,
-    &cr_dev,
     &lpt_dev,
     &rl_dev,
     &rq_dev,
     &rqb_dev,
     &rqc_dev,
     &rqd_dev,
-    &ry_dev,
     &ts_dev,
     &tq_dev,
     &xq_dev,
diff --git a/Visual Studio Projects/VAX.vcproj b/Visual Studio Projects/VAX.vcproj
index e36825d6..ecee587d 100644
--- a/Visual Studio Projects/VAX.vcproj	
+++ b/Visual Studio Projects/VAX.vcproj	
@@ -203,10 +203,6 @@
 			Name="Source Files"
 			Filter="cpp;c;cxx;def;odl;idl;hpj;bat;asm"
 			>
-			<File
-				RelativePath="..\PDP11\pdp11_cr.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_dz.c"
 				>
@@ -227,10 +223,6 @@
 				RelativePath="..\PDP11\pdp11_rq.c"
 				>
 			</File>
-			<File
-				RelativePath="..\Pdp11\pdp11_ry.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_tq.c"
 				>
diff --git a/Visual Studio Projects/VAX610.vcproj b/Visual Studio Projects/VAX610.vcproj
index f403c7d3..9cc14590 100644
--- a/Visual Studio Projects/VAX610.vcproj	
+++ b/Visual Studio Projects/VAX610.vcproj	
@@ -203,10 +203,6 @@
 			Name="Source Files"
 			Filter="cpp;c;cxx;def;odl;idl;hpj;bat;asm"
 			>
-			<File
-				RelativePath="..\PDP11\pdp11_cr.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_dz.c"
 				>
@@ -227,10 +223,6 @@
 				RelativePath="..\PDP11\pdp11_rq.c"
 				>
 			</File>
-			<File
-				RelativePath="..\Pdp11\pdp11_ry.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_tq.c"
 				>
diff --git a/Visual Studio Projects/VAX620.vcproj b/Visual Studio Projects/VAX620.vcproj
index 3ec0ae1d..5875a3c8 100644
--- a/Visual Studio Projects/VAX620.vcproj	
+++ b/Visual Studio Projects/VAX620.vcproj	
@@ -203,10 +203,6 @@
 			Name="Source Files"
 			Filter="cpp;c;cxx;def;odl;idl;hpj;bat;asm"
 			>
-			<File
-				RelativePath="..\PDP11\pdp11_cr.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_dz.c"
 				>
@@ -227,10 +223,6 @@
 				RelativePath="..\PDP11\pdp11_rq.c"
 				>
 			</File>
-			<File
-				RelativePath="..\Pdp11\pdp11_ry.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_tq.c"
 				>
diff --git a/Visual Studio Projects/VAX630.vcproj b/Visual Studio Projects/VAX630.vcproj
index abe827ad..bdbd7797 100644
--- a/Visual Studio Projects/VAX630.vcproj	
+++ b/Visual Studio Projects/VAX630.vcproj	
@@ -203,10 +203,6 @@
 			Name="Source Files"
 			Filter="cpp;c;cxx;def;odl;idl;hpj;bat;asm"
 			>
-			<File
-				RelativePath="..\PDP11\pdp11_cr.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_dz.c"
 				>
@@ -227,10 +223,6 @@
 				RelativePath="..\PDP11\pdp11_rq.c"
 				>
 			</File>
-			<File
-				RelativePath="..\Pdp11\pdp11_ry.c"
-				>
-			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_tq.c"
 				>
diff --git a/descrip.mms b/descrip.mms
index 44440c9f..0618137e 100644
--- a/descrip.mms
+++ b/descrip.mms
@@ -624,8 +624,7 @@ VAX_SOURCE2 = $(PDP11_DIR)PDP11_IO_LIB.C,\
               $(PDP11_DIR)PDP11_RL.C,$(PDP11_DIR)PDP11_RQ.C,\
               $(PDP11_DIR)PDP11_TS.C,$(PDP11_DIR)PDP11_DZ.C,\
               $(PDP11_DIR)PDP11_LP.C,$(PDP11_DIR)PDP11_TQ.C,\
-              $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_CR.C,\
-              $(PDP11_DIR)PDP11_RY.C,$(PDP11_DIR)PDP11_VH.C
+              $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_VH.C
 .IFDEF ALPHA_OR_IA64
 VAX_OPTIONS = /INCL=($(SIMH_DIR),$(VAX_DIR),$(PDP11_DIR)$(PCAP_INC))\
                 /DEF=($(CC_DEFS),"VM_VAX=1","USE_ADDR64=1","USE_INT64=1"$(PCAP_DEFS))
@@ -652,8 +651,7 @@ VAX610_SOURCE2 = $(PDP11_DIR)PDP11_IO_LIB.C,\
                  $(PDP11_DIR)PDP11_RL.C,$(PDP11_DIR)PDP11_RQ.C,\
                  $(PDP11_DIR)PDP11_TS.C,$(PDP11_DIR)PDP11_DZ.C,\
                  $(PDP11_DIR)PDP11_LP.C,$(PDP11_DIR)PDP11_TQ.C,\
-                 $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_CR.C,\
-                 $(PDP11_DIR)PDP11_RY.C,$(PDP11_DIR)PDP11_VH.C
+                 $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_VH.C
 .IFDEF ALPHA_OR_IA64
 VAX610_OPTIONS = /INCL=($(SIMH_DIR),$(VAX610_DIR),$(PDP11_DIR)$(PCAP_INC))\
                  /DEF=($(CC_DEFS),"VM_VAX=1","USE_ADDR64=1","USE_INT64=1"$(PCAP_DEFS),"VAX_610=1")
@@ -680,8 +678,7 @@ VAX630_SOURCE2 = $(PDP11_DIR)PDP11_IO_LIB.C,\
                  $(PDP11_DIR)PDP11_RL.C,$(PDP11_DIR)PDP11_RQ.C,\
                  $(PDP11_DIR)PDP11_TS.C,$(PDP11_DIR)PDP11_DZ.C,\
                  $(PDP11_DIR)PDP11_LP.C,$(PDP11_DIR)PDP11_TQ.C,\
-                 $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_CR.C,\
-                 $(PDP11_DIR)PDP11_RY.C,$(PDP11_DIR)PDP11_VH.C
+                 $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_VH.C
 .IFDEF ALPHA_OR_IA64
 VAX630_OPTIONS = /INCL=($(SIMH_DIR),$(VAX630_DIR),$(PDP11_DIR)$(PCAP_INC))\
                  /DEF=($(CC_DEFS),"VM_VAX=1","USE_ADDR64=1","USE_INT64=1"$(PCAP_DEFS),"VAX_630=1")
@@ -708,8 +705,7 @@ VAX620_SOURCE2 = $(PDP11_DIR)PDP11_IO_LIB.C,\
                  $(PDP11_DIR)PDP11_RL.C,$(PDP11_DIR)PDP11_RQ.C,\
                  $(PDP11_DIR)PDP11_TS.C,$(PDP11_DIR)PDP11_DZ.C,\
                  $(PDP11_DIR)PDP11_LP.C,$(PDP11_DIR)PDP11_TQ.C,\
-                 $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_CR.C,\
-                 $(PDP11_DIR)PDP11_RY.C,$(PDP11_DIR)PDP11_VH.C
+                 $(PDP11_DIR)PDP11_XQ.C,$(PDP11_DIR)PDP11_VH.C
 .IFDEF ALPHA_OR_IA64
 VAX620_OPTIONS = /INCL=($(SIMH_DIR),$(VAX620_DIR),$(PDP11_DIR)$(PCAP_INC))\
                  /DEF=($(CC_DEFS),"VM_VAX=1","USE_ADDR64=1","USE_INT64=1"$(PCAP_DEFS),"VAX_620=1")
diff --git a/doc/pdp11_doc.doc b/doc/pdp11_doc.doc
index 8169ee7f..bd84a802 100644
Binary files a/doc/pdp11_doc.doc and b/doc/pdp11_doc.doc differ
diff --git a/doc/vax_doc.doc b/doc/vax_doc.doc
index 114b0083..27c85f0c 100644
Binary files a/doc/vax_doc.doc and b/doc/vax_doc.doc differ
diff --git a/makefile b/makefile
index 80d41010..d4404838 100644
--- a/makefile
+++ b/makefile
@@ -511,8 +511,7 @@ VAX = ${VAXD}/vax_cpu.c ${VAXD}/vax_cpu1.c ${VAXD}/vax_fpa.c ${VAXD}/vax_io.c \
 	${VAXD}/vax_sys.c  ${VAXD}/vax_syscm.c ${VAXD}/vax_syslist.c \
 	${PDP11D}/pdp11_rl.c ${PDP11D}/pdp11_rq.c ${PDP11D}/pdp11_ts.c \
 	${PDP11D}/pdp11_dz.c ${PDP11D}/pdp11_lp.c ${PDP11D}/pdp11_tq.c \
-	${PDP11D}/pdp11_xq.c ${PDP11D}/pdp11_ry.c ${PDP11D}/pdp11_vh.c \
-	${PDP11D}/pdp11_cr.c ${PDP11D}/pdp11_io_lib.c
+	${PDP11D}/pdp11_xq.c ${PDP11D}/pdp11_vh.c ${PDP11D}/pdp11_io_lib.c
 VAX_OPT = -DVM_VAX -DUSE_INT64 -DUSE_ADDR64 -I ${VAXD} -I ${PDP11D} ${NETWORK_OPT}
 
 
@@ -523,8 +522,7 @@ VAX610 = ${VAXD}/vax_cpu.c ${VAXD}/vax_cpu1.c ${VAXD}/vax_fpa.c \
 	${VAXD}/vax610_io.c ${VAXD}/vax610_syslist.c ${VAXD}/vax610_mem.c \
 	${PDP11D}/pdp11_rl.c ${PDP11D}/pdp11_rq.c ${PDP11D}/pdp11_ts.c \
 	${PDP11D}/pdp11_dz.c ${PDP11D}/pdp11_lp.c ${PDP11D}/pdp11_tq.c \
-	${PDP11D}/pdp11_xq.c ${PDP11D}/pdp11_ry.c ${PDP11D}/pdp11_vh.c \
-	${PDP11D}/pdp11_cr.c ${PDP11D}/pdp11_io_lib.c
+	${PDP11D}/pdp11_xq.c ${PDP11D}/pdp11_vh.c ${PDP11D}/pdp11_io_lib.c
 VAX610_OPT = -DVM_VAX -DVAX_610 -DUSE_INT64 -DUSE_ADDR64 -I ${VAXD} -I ${PDP11D} ${NETWORK_OPT}
 
 VAX630 = ${VAXD}/vax_cpu.c ${VAXD}/vax_cpu1.c ${VAXD}/vax_fpa.c \
@@ -534,8 +532,7 @@ VAX630 = ${VAXD}/vax_cpu.c ${VAXD}/vax_cpu1.c ${VAXD}/vax_fpa.c \
 	${VAXD}/vax630_io.c ${VAXD}/vax630_syslist.c \
 	${PDP11D}/pdp11_rl.c ${PDP11D}/pdp11_rq.c ${PDP11D}/pdp11_ts.c \
 	${PDP11D}/pdp11_dz.c ${PDP11D}/pdp11_lp.c ${PDP11D}/pdp11_tq.c \
-	${PDP11D}/pdp11_xq.c ${PDP11D}/pdp11_ry.c ${PDP11D}/pdp11_vh.c \
-	${PDP11D}/pdp11_cr.c ${PDP11D}/pdp11_io_lib.c
+	${PDP11D}/pdp11_xq.c ${PDP11D}/pdp11_vh.c ${PDP11D}/pdp11_io_lib.c
 VAX620_OPT = -DVM_VAX -DVAX_620 -DUSE_INT64 -DUSE_ADDR64 -I ${VAXD} -I ${PDP11D} ${NETWORK_OPT}
 VAX630_OPT = -DVM_VAX -DVAX_630 -DUSE_INT64 -DUSE_ADDR64 -I ${VAXD} -I ${PDP11D} ${NETWORK_OPT}