diff --git a/src/Makefile b/src/Makefile
index 5f5c6362b..39238a0d2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -411,7 +411,7 @@ endif
 ifeq ($(BUILD_SYS),kbuild)
 
 modules:
-	$(PYTHON) modsilent.py $(MAKE) KBUILD_EXTRA_SYMBOLS=$(moduledir)/Module.symvers -C $(KERNELDIR) SUBDIRS=`pwd` CC=$(CC) V=0 modules
+	$(PYTHON) modsilent.py $(MAKE) KBUILD_EXTRA_SYMBOLS=$(moduledir)/Module.symvers -C $(KERNELDIR) SUBDIRS=`pwd` CC=$(CC) V=1 modules
 	-cp Module.symvers *$(MODULE_EXT) ../rtlib/
 endif
 
@@ -669,7 +669,7 @@ EXTRA_CFLAGS = $(filter-out -ffast-math,$(RTFLAGS)) -D__MODULE__ -I$(BASEPWD) -I
 	-I$(BASEPWD)/libnml/os_intf -I$(BASEPWD)/libnml/nml -I$(BASEPWD)/libnml/buffer \
 	-I$(BASEPWD)/libnml/posemath -I$(BASEPWD)/rtapi -I$(BASEPWD)/hal \
 	-I$(BASEPWD)/emc/nml_intf -I$(BASEPWD)/emc/kinematics -I$(BASEPWD)/emc/motion \
-        -DSEQUENTIAL_SUPPORT -DHAL_SUPPORT -DDYNAMIC_PLCSIZE -DRT_SUPPORT -DOLD_TIMERS_MONOS_SUPPORT -DMODBUS_IO_MASTER \
+	-DSEQUENTIAL_SUPPORT -DHAL_SUPPORT -DDYNAMIC_PLCSIZE -DRT_SUPPORT -DOLD_TIMERS_MONOS_SUPPORT -DMODBUS_IO_MASTER \
 	-fno-fast-math $(call cc-option,-mieee-fp) -fno-unsafe-math-optimizations 
 	#not for sim: $(call cc-option,-Wframe-larger-than=2560)
 
@@ -684,7 +684,12 @@ endif
 # for libwou
 ifneq ($(WOU_VERSION),)
 EXTRA_CFLAGS += $(WOU_CFLAGS) -DMOTION_OVER_USB
+ifeq ($(BUILD_SYS),sim)
 LDFLAGS += $(WOU_LIBS)
+else
+# for kernel module build:
+EXTRA_CFLAGS += -I$(BASEPWD)/hal/drivers/ar-usb
+endif
 endif
 
 
@@ -949,7 +954,7 @@ modules: $(patsubst %.o,../rtlib/%.so,$(obj-m))
 	$(Q)ld -r -o objects/$*.tmp $^
 	@if ! $(IS_POWERPC); then objcopy -j .rtapi_export -O binary objects/$*.tmp objects/$*.exp; fi
 	@if ! $(IS_POWERPC); then objcopy -G __i686.get_pc_thunk.bx `xargs -r0n1 echo -G < objects/$*.exp | grep -ve '^-G $$' | sort -u` objects/$*.tmp; fi
-	$(Q)$(CC) -shared -Bsymbolic -o $@ objects/$*.tmp -lm $(LDFLAGS)
+	$(Q)$(CC) -shared -Bsymbolic $(LDFLAGS) -o $@ objects/$*.tmp -lm
 
 $(sort $(RTDEPS)): depends/rt%.d: %.c
 	@mkdir -p $(dir $@)
@@ -982,7 +987,7 @@ $(sort $(RTOBJS)) : objects/rt%.o : %.c
 
 ../rtlib/%.o:
 	$(ECHO) Linking $@
-	$(Q)ld -r -static -S -Os $(LDFLAGS) -o $@ $^ $(EXTRALINK) $(MATHLIB)
+	$(Q)ld -r -static -S $(OPT) $(LDFLAGS) -o $@ $^ $(EXTRALINK) $(MATHLIB)
 endif
 
 ifneq "$(filter normal sim,$(BUILD_SYS))" ""
diff --git a/src/emc/kinematics/align_gantry_kins.c b/src/emc/kinematics/align_gantry_kins.c
index ce41bde53..d2fbe1f98 100644
--- a/src/emc/kinematics/align_gantry_kins.c
+++ b/src/emc/kinematics/align_gantry_kins.c
@@ -12,8 +12,6 @@
 *
 ********************************************************************/
 
-#include "string.h"
-#include "assert.h"
 #include "rtapi_math.h"
 #include "kinematics.h"		/* these decls */
 
@@ -41,17 +39,6 @@ typedef struct {
 
 static align_pins_t *align_pins;
 
-// #define THETA           (*(align_pins->theta))
-// #define PREV_THETA      (align_pins->prev_theta)
-// #define PREV_X_OFFSET   (align_pins->prev_x_offset)
-// #define PREV_Y_OFFSET   (align_pins->prev_y_offset)
-// #define PREV_X_CENT     (align_pins->prev_y_cent)
-// #define PREV_Y_CENT     (align_pins->prev_x_cent)
-// #define X_OFFSET        (align_pins->x_offset)
-// #define Y_OFFSET        (align_pins->y_offset)
-// #define X_CENT          (align_pins->x_cent)
-// #define Y_CENT          (align_pins->y_cent)
-// #define TOUCH_OFF_CENT	 (*(align_pins->touch_off_cent))
 #define GANTRY_POLARITY (*(align_pins->gantry_polarity))
 #define YY_OFFSET       (*(align_pins->yy_offset))
 
@@ -63,48 +50,12 @@ EXPORT_SYMBOL(kinematicsForward);
 EXPORT_SYMBOL(kinematicsInverse);
 MODULE_LICENSE("GPL");
 
-// void cord_change_handler(EmcPose * pos, double  * joints) {
-//     // update XYZ position but keep joint position unchanged 
-//     if (TOUCH_OFF_CENT == 1) {
-//         X_CENT = joints[0];
-//         Y_CENT = joints[1];
-//     }
-//     if (THETA != PREV_THETA ||
-// 	TOUCH_OFF_CENT == 1) { 
-// 	if (joints[0] == 0 && joints[1] == 0) {
-// 	    return;
-// 	}
-//         // fprintf(stderr, "THETA(%f)\n", THETA);
-//         // fprintf(stderr, "x-cent(%f) y-cent(%f) x-offset(%f) y-offset(%f)\n", X_CENT, Y_CENT, X_OFFSET, Y_OFFSET);
-//         // fprintf(stderr, "1:x(%f) y(%f) \nj0(%f) j1(%f)\n", pos->tran.x, pos->tran.y,
-//         //                joints[0], joints[1]);
-//         pos->tran.x  = (joints[0] - X_CENT - X_OFFSET) * cos(THETA) +
-//                        (joints[1] - Y_CENT - Y_OFFSET) * sin(THETA) + X_OFFSET + X_CENT;
-//         pos->tran.y  = -(joints[0] - X_CENT - X_OFFSET)* sin(THETA) +
-//                         (joints[1] - Y_CENT - Y_OFFSET) * cos(THETA) + Y_OFFSET + Y_CENT;
-//         // fprintf(stderr, "2:x(%f) y(%f) \nj0(%f) j1(%f)\n", pos->tran.x, pos->tran.y,
-//         //         joints[0], joints[1]);
-//         PREV_THETA    = THETA;
-//         PREV_X_OFFSET = X_OFFSET; 
-//         PREV_Y_OFFSET = Y_OFFSET; 
-//         PREV_X_CENT   = X_CENT;   
-//         PREV_Y_CENT   = Y_CENT;   
-//     }
-//     TOUCH_OFF_CENT = 0;
-// }
-
 int kinematicsForward(const double *joints,
 		      EmcPose * pos,
 		      const KINEMATICS_FORWARD_FLAGS * fflags,
 		      KINEMATICS_INVERSE_FLAGS * iflags)
 {
 
-    // cord_change_handler((EmcPose *)pos, (double*)joints);
-    // pos->tran.x  = (joints[0] - X_CENT - X_OFFSET) * cos(THETA) +
-    //                (joints[1] - Y_CENT - Y_OFFSET) * sin(THETA) + X_OFFSET + X_CENT;
-    // pos->tran.y  = -(joints[0] - X_CENT - X_OFFSET)* sin(THETA) +
-    //                 (joints[1] - Y_CENT - Y_OFFSET) * cos(THETA) + Y_OFFSET + Y_CENT;
-
     pos->tran.x = joints[0];
     pos->tran.y = joints[1];
     pos->tran.z = joints[3];
@@ -125,31 +76,6 @@ int kinematicsInverse(const EmcPose * pos,
 		      const KINEMATICS_INVERSE_FLAGS * iflags,
 		      KINEMATICS_FORWARD_FLAGS * fflags)
 {
-    // double c_rad = pos->c*M_PI/180;
-    // double rad, x_cent, y_cent;
-    // fprintf(stderr,"kI j0(%f) j1(%f) THETA(%f) X_CENT(%f) Y_CENT(%f)\n",joints[0], joints[1],
-    // THETA, X_CENT, Y_CENT);
-    // fprintf(stderr,"KI x(%f) y(%f)\n", pos->tran.x, pos->tran.y);
-    // if (THETA == PREV_THETA) {
-    //     rad = THETA;
-    // } else {
-    //     rad = PREV_THETA;
-    // }
-    // if (X_CENT == PREV_X_CENT) {
-    //     x_cent = X_CENT;
-    // } else {
-    //     x_cent = PREV_X_CENT;
-    // }
-    // if (Y_CENT == PREV_Y_CENT) {
-    //     y_cent = Y_CENT;
-    // } else {
-    //     y_cent = PREV_Y_CENT;
-    // }
-    // joints[0] = (pos->tran.x - x_cent - X_OFFSET) * cos(rad) -
-    //             (pos->tran.y - y_cent - Y_OFFSET) * sin(rad) + X_OFFSET + x_cent;
-
-    // joints[1] = (pos->tran.x - x_cent - X_OFFSET) * sin(rad) +
-    //             (pos->tran.y - y_cent - Y_OFFSET) * cos(rad) + Y_OFFSET + y_cent;
     joints[0] = pos->tran.x;
     joints[1] = pos->tran.y;
     joints[2] = pos->tran.y - (YY_OFFSET * GANTRY_POLARITY);  // YY
@@ -161,7 +87,6 @@ int kinematicsInverse(const EmcPose * pos,
     // joints[6] = pos->u;
     // joints[7] = pos->v;
     // joints[8] = pos->w;
-    // fprintf(stderr,"kI j0(%f) j1(%f)\n",joints[0], joints[1]);
     DP("kINV: x(%f), y(%f), j0(%f), j1(%f), j2(%f), yy_offset(%f)\n",
        pos->tran.x, pos->tran.y, joints[0], joints[1], joints[2], YY_OFFSET);
     DP("kINV: s(%f), j5(%f)\n", pos->s, joints[5]);
diff --git a/src/emc/kinematics/alignmentkins.c b/src/emc/kinematics/alignmentkins.c
index 74d57c2d7..b5a90c929 100644
--- a/src/emc/kinematics/alignmentkins.c
+++ b/src/emc/kinematics/alignmentkins.c
@@ -60,15 +60,15 @@ void cord_change_handler(EmcPose * pos, double  * joints) {
         Y_OFFSET != PREV_Y_OFFSET ||
         X_CENT   != PREV_X_CENT   ||
         Y_CENT   != PREV_Y_CENT) {
-        fprintf(stderr, "THETA(%f)\n", THETA);
-        fprintf(stderr, "x-cent(%f) y-cent(%f) x-offset(%f) y-offset(%f)\n", X_CENT, Y_CENT, X_OFFSET, Y_OFFSET);
-        fprintf(stderr, "1:x(%f) y(%f) \nj0(%f) j1(%f)\n", pos->tran.x, pos->tran.y,
+        DP("THETA(%f)\n", THETA);
+        DP("x-cent(%f) y-cent(%f) x-offset(%f) y-offset(%f)\n", X_CENT, Y_CENT, X_OFFSET, Y_OFFSET);
+        DP("1:x(%f) y(%f) \nj0(%f) j1(%f)\n", pos->tran.x, pos->tran.y,
                         joints[0], joints[1]);
         pos->tran.x  = (joints[0] - X_CENT - X_OFFSET) * cos(THETA) +
                        (joints[1] - Y_CENT - Y_OFFSET) * sin(THETA) + X_OFFSET + X_CENT;
         pos->tran.y  = -(joints[0] - X_CENT - X_OFFSET)* sin(THETA) +
                         (joints[1] - Y_CENT - Y_OFFSET) * cos(THETA) + Y_OFFSET + Y_CENT;
-        fprintf(stderr, "2:x(%f) y(%f) \nj0(%f) j1(%f)\n", pos->tran.x, pos->tran.y,
+        DP("2:x(%f) y(%f) \nj0(%f) j1(%f)\n", pos->tran.x, pos->tran.y,
                 joints[0], joints[1]);
         PREV_THETA    = THETA;
         PREV_X_OFFSET = X_OFFSET; 
diff --git a/src/emc/kinematics/dptrace.h b/src/emc/kinematics/dptrace.h
index 454d1f929..483c52b51 100644
--- a/src/emc/kinematics/dptrace.h
+++ b/src/emc/kinematics/dptrace.h
@@ -1,6 +1,9 @@
 #ifndef _DPTRACE_H_
 #define _DPTRACE_H_
 
+#ifdef SIM
+
+// for simulation only:
 #include <stdio.h>
 
 #ifndef TRACE
@@ -27,4 +30,10 @@
 #define DPS(fmt, args...)    do {} while(0)
 #endif
 
+#else
+// NOT-SIM
+#define DP(fmt, args...)     do {} while(0)
+#define DPS(fmt, args...)    do {} while(0)
+#endif // SIM
+
 #endif  // _DPTRACE_H_
diff --git a/src/emc/kinematics/tc.c b/src/emc/kinematics/tc.c
index bb6bcd196..4a8a90888 100644
--- a/src/emc/kinematics/tc.c
+++ b/src/emc/kinematics/tc.c
@@ -16,9 +16,16 @@
   FIXME-- should include <stdlib.h> for sizeof(), but conflicts with
   a bunch of <linux> headers
   */
+#include "config.h"
+
+#ifdef RTAPI_SIM
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
+#else
+#define assert(args...)		do {} while(0)
+#endif
+
 #include "rtapi.h"		/* rtapi_print_msg */
 #include "posemath.h"
 #include "emcpos.h"
@@ -150,8 +157,14 @@ void nurbs_basisfun(int i, double u, int p,
   int j,r, id;
   double saved, temp, denom;
 
+#ifdef RTAPI_SIM
   double *left = (double*)malloc(sizeof(double)*(p+1));
   double *right = (double*)malloc(sizeof(double)*(p+1));
+#else
+  #warning "to implement rtai_kmalloc() or static memory chunk for left[] and right[]"
+  double left[4096];
+  double right[4096];
+#endif
 
   N[0] = 1.0;
   for (j = 1; j <= p; j++)
@@ -176,8 +189,12 @@ void nurbs_basisfun(int i, double u, int p,
       N[j] = saved;
 
     }
+#ifdef RTAPI_SIM
   free(left);
   free(right);
+#else
+  #warning "to implement rtai_kmalloc() or static memory chunk for left[] and right[]"
+#endif
 
 }
 
@@ -608,9 +625,10 @@ int tcqRemove(TC_QUEUE_STRUCT * tcq, int n)
 	(n > tcq->_len)) {	/* too many requested */
 	    return -1;
     }
-    /* if NURBS ?*/
-    for(i=tcq->start;i<(tcq->start+n);i++){
 
+#ifdef RTAPI_SIM
+    /* for NURBS only */
+    for(i=tcq->start;i<(tcq->start+n);i++){
         if(tcq->queue[i].motion_type == TC_NURBS) {
             //fprintf(stderr,"Remove TCNURBS PARAM\n");
             free(tcq->queue[i].nurbs_block.knots_ptr);
@@ -619,6 +637,8 @@ int tcqRemove(TC_QUEUE_STRUCT * tcq, int n)
 
         }
     }
+#endif
+
     /* update start ptr and reset allFull flag and len */
     tcq->start = (tcq->start + n) % tcq->size;
     tcq->allFull = 0;
diff --git a/src/emc/kinematics/tp.c b/src/emc/kinematics/tp.c
index d4eda1c0b..4e0208eb2 100644
--- a/src/emc/kinematics/tp.c
+++ b/src/emc/kinematics/tp.c
@@ -10,6 +10,17 @@
  *
  * Copyright (c) 2004 All rights reserved.
  ********************************************************************/
+#include "config.h"
+
+#ifdef RTAPI_SIM
+// SIM
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdint.h>
+#else
+#define assert(args...)		do {} while(0)
+#endif
 
 #include "rtapi.h"		/* rtapi_print_msg */
 #include "rtapi_string.h"       /* NULL */
@@ -21,16 +32,12 @@
 #include "hal.h"
 #include "../motion/mot_priv.h"
 #include "motion_debug.h"
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
 
 // #undef SMLBLND       // turn off seamless blending
 #define SMLBLND         // to evaluate seamless blending
 
 // to disable DP(): #define TRACE 0
 #define TRACE 0
-#include <stdint.h>
 #include "dptrace.h"
 #if (TRACE!=0)
 static FILE* dptrace = 0;
@@ -712,6 +719,12 @@ int tpAddCircle(TP_STRUCT * tp, EmcPose end, PmCartesian center,
 // allowed; we are guaranteed to have a move in xyz so target is
 // always the circle/arc/helical length.
 
+#ifndef RTAPI_SIM
+#warning "implement rtai_kmalloc() for nurbs"
+static CONTROL_POINT ctrl_pts_array[8192];
+static double knots_array[8192];
+static double N_array[8192];
+#endif
 
 int tpAddNURBS(TP_STRUCT *tp, int type, nurbs_block_t nurbs_block, EmcPose pos,
         unsigned char enables, double vel, double ini_maxvel,
@@ -742,15 +755,24 @@ int tpAddNURBS(TP_STRUCT *tp, int type, nurbs_block_t nurbs_block, EmcPose pos,
         nr_of_ctrl_pts = nurbs_block.nr_of_ctrl_pts;
         nr_of_knots = nurbs_block.nr_of_knots;
 
-
+#ifndef RTAPI_SIM
+#warning "implement rtai_kmalloc() for nurbs"
+	nurbs_to_tc->ctrl_pts_ptr = ctrl_pts_array;
+	nurbs_to_tc->knots_ptr = knots_array;
+	nurbs_to_tc->N = N_array;
+#else
+	// SIM
         nurbs_to_tc->ctrl_pts_ptr = (CONTROL_POINT*) malloc(
                 sizeof(CONTROL_POINT) * nurbs_block.nr_of_ctrl_pts);
         /* knots array: allocate 'order' of extra knots for THE-NURBS-BOOK-Algorithm */
         nurbs_to_tc->knots_ptr = (double*) malloc(sizeof(double)
                 * (nurbs_block.nr_of_knots + nurbs_block.order));
         nurbs_to_tc->N = (double*) malloc(sizeof(double) * (order + 1));
+#endif
         nurbs_to_tc->axis_mask = nurbs_block.axis_mask;
 
+
+
     }
 
     if (knots_todo > 0) {
diff --git a/src/emc/kinematics/yyzzkins.c b/src/emc/kinematics/yyzzkins.c
index 5acc4d3b9..2f8d47343 100644
--- a/src/emc/kinematics/yyzzkins.c
+++ b/src/emc/kinematics/yyzzkins.c
@@ -9,8 +9,16 @@
 * Copyright (c) 2012 All rights reserved.
 ********************************************************************/
 
+#ifdef RTAPI_SIM
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdint.h>
 #include "string.h"
-#include "assert.h"
+#else
+#define assert(args...)		do {} while(0)
+#endif
+
 #include "rtapi_math.h"
 #include "kinematics.h"		/* these decls */
 
diff --git a/src/emc/motion/control.c b/src/emc/motion/control.c
index 2fa83ddaf..09ca08843 100644
--- a/src/emc/motion/control.c
+++ b/src/emc/motion/control.c
@@ -12,7 +12,17 @@
  *
  * Copyright (c) 2004 All rights reserved.
  ********************************************************************/
+#include "config.h"
+
+#ifndef RTAPI_SIM
+#define assert(args...)		do {} while(0)
+#else
+// SIM
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
 #include <stdint.h>
+#endif
 
 #include "posemath.h"
 #include "rtapi.h"
@@ -25,9 +35,7 @@
 #include "tc.h"
 #include "simple_tp.h"
 #include "motion_debug.h"
-#include "config.h"
-#include "assert.h"
-#include <sync_cmd.h>
+#include "sync_cmd.h"
 
 // Mark strings for translation, but defer translation to userspace
 #define _(s) (s)
diff --git a/src/emc/motion/motion.c b/src/emc/motion/motion.c
index 9de425e4d..55eaafeae 100644
--- a/src/emc/motion/motion.c
+++ b/src/emc/motion/motion.c
@@ -20,7 +20,7 @@
 #include "motion_struct.h"
 #include "mot_priv.h"
 #include "rtapi_math.h"
-#include <sync_cmd.h>
+#include "sync_cmd.h"
 
 // Mark strings for translation, but defer translation to userspace
 #define _(s) (s)
diff --git a/src/emc/motion/motion.h b/src/emc/motion/motion.h
index 174f9da08..644bfc5a0 100644
--- a/src/emc/motion/motion.h
+++ b/src/emc/motion/motion.h
@@ -71,6 +71,7 @@ to another.
 #ifndef MOTION_H
 #define MOTION_H
 
+#include "config.h"
 #include "posemath.h"		/* PmCartesian, PmPose, pmCartMag() */
 #include "emcpos.h"		/* EmcPose */
 #include "cubic.h"		/* CUBIC_STRUCT, CUBIC_COEFF */
@@ -81,6 +82,12 @@ to another.
 #include "rtapi_limits.h"
 #include <stdarg.h>
 
+#ifdef RTAPI_SIM
+#include <stdint.h>
+#else
+#define uint32_t __u32
+#endif
+
 
 // define a special value to denote an invalid motion ID 
 // NB: do not ever generate a motion id of  MOTION_INVALID_ID
diff --git a/src/emc/motion/simple_tp.c b/src/emc/motion/simple_tp.c
index ec1d0a373..fb05030fa 100644
--- a/src/emc/motion/simple_tp.c
+++ b/src/emc/motion/simple_tp.c
@@ -10,12 +10,16 @@
 * Copyright (c) 2004 All rights reserved.
 ********************************************************************/
 
+#ifdef RTAPI_SIM
 #include <stdio.h>
-#include <stdint.h>
 #include <stdlib.h>
+#include <assert.h>
+#include <stdint.h>
 #include <string.h>
 #include <ctype.h>
-#include <assert.h>
+#else
+#define assert(args...)		do {} while(0)
+#endif
 
 #include "simple_tp.h"
 #include "rtapi_math.h"
diff --git a/src/emc/motion/usb_homing.c b/src/emc/motion/usb_homing.c
index 2bfb53c08..fcd643058 100644
--- a/src/emc/motion/usb_homing.c
+++ b/src/emc/motion/usb_homing.c
@@ -11,18 +11,23 @@
  * Copyright (c) 2004 All rights reserved.
  *
  ********************************************************************/
+#ifdef RTAPI_SIM
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdint.h>
+#else
+#define assert(args...)		do {} while(0)
+#endif
 
 #include "rtapi.h"
 #include "hal.h"
 #include "motion.h"
 #include "mot_priv.h"
 #include "rtapi_math.h"
-#include <stdio.h>
 #include <wou.h>
-#include <wb_regs.h>
 #include <mailtag.h>
-#include <sync_cmd.h>
-#include <assert.h>
+#include "sync_cmd.h"
 
 // Mark strings for translation, but defer translation to userspace
 #define _(s) (s)
diff --git a/src/emc/usr_intf/Submakefile b/src/emc/usr_intf/Submakefile
index 6990bdad0..ab3ef955a 100644
--- a/src/emc/usr_intf/Submakefile
+++ b/src/emc/usr_intf/Submakefile
@@ -2,7 +2,7 @@ EMCSHSRCS := emc/usr_intf/emcsh.cc \
              emc/usr_intf/shcom.cc
 EMCRSHSRCS := emc/usr_intf/emcrsh.cc \
               emc/usr_intf/shcom.cc
-LCOMSRCS := emc/usr_intf/linuxcnc_over_modbus.cc \
+# LCOMSRCS := emc/usr_intf/linuxcnc_over_modbus.cc \
               emc/usr_intf/shcom.cc
 EMCSCHEDSRCS := emc/usr_intf/schedrmt.cc \
               emc/usr_intf/emcsched.cc \
@@ -20,7 +20,8 @@ XEMCSRCS := emc/usr_intf/xemc.cc
 endif
 
 TCLSRCS := emc/usr_intf/emcsh.cc emc/usr_intf/iosh.cc
-USERSRCS += $(EMCSHSRCS) $(EMCRSHSRCS) $(LCOMSRCS) $(EMCSCHEDSRCS) $(EMCLCDSRCS) $(USRMOTSRCS) $(HALUISRCS) $(KEYSTICKSRCS)
+# USERSRCS += $(EMCSHSRCS) $(EMCRSHSRCS) $(LCOMSRCS) $(EMCSCHEDSRCS) $(EMCLCDSRCS) $(USRMOTSRCS) $(HALUISRCS) $(KEYSTICKSRCS)
+USERSRCS += $(EMCSHSRCS) $(EMCRSHSRCS) $(EMCSCHEDSRCS) $(EMCLCDSRCS) $(USRMOTSRCS) $(HALUISRCS) $(KEYSTICKSRCS)
 
 ifeq "$(HAVE_NCURSES)" "yes"
 USERSRCS += $(KEYSTICKSRCS)
@@ -32,7 +33,7 @@ endif
 
 $(call TOOBJSDEPS, $(TCLSRCS)) : EXTRAFLAGS = $(ULFLAGS) $(TCL_CFLAGS)
 $(call TOOBJSDEPS, $(EMCSHSRCS)) : EXTRAFLAGS = $(ULFLAGS) $(TCL_CFLAGS) -fPIC
-$(call TOOBJSDEPS, $(LCOMSRCS)) : EXTRAFLAGS = $(LIBMODBUS_CFLAGS)
+# $(call TOOBJSDEPS, $(LCOMSRCS)) : EXTRAFLAGS = $(LIBMODBUS_CFLAGS)
 
 ../bin/tooledit: emc/usr_intf/tooledit.tcl
 	cp $< $@
@@ -49,10 +50,10 @@ TARGETS += ../tcl/linuxcnc.so
 	$(Q)$(CXX) $(LDFLAGS) -o $@ $(ULFLAGS) $^ -lpthread
 TARGETS += ../bin/linuxcncrsh
 
-../bin/linuxcnc_over_modbus: $(call TOOBJS, $(LCOMSRCS)) ../lib/liblinuxcnc.a ../lib/libnml.so.0 ../lib/liblinuxcncini.so.0
-	$(ECHO) Linking $(notdir $@)
-	$(Q)$(CXX) $(LDFLAGS) -o $@ $(ULFLAGS) $^ -lpthread $(LIBMODBUS_LIBS) -lrt
-TARGETS += ../bin/linuxcnc_over_modbus
+# ../bin/linuxcnc_over_modbus: $(call TOOBJS, $(LCOMSRCS)) ../lib/liblinuxcnc.a ../lib/libnml.so.0 ../lib/liblinuxcncini.so.0
+# 	$(ECHO) Linking $(notdir $@)
+# 	$(Q)$(CXX) $(LDFLAGS) -o $@ $(ULFLAGS) $^ -lpthread $(LIBMODBUS_LIBS) -lrt
+# TARGETS += ../bin/linuxcnc_over_modbus
 
 ../bin/schedrmt: $(call TOOBJS, $(EMCSCHEDSRCS)) ../lib/liblinuxcnc.a ../lib/libnml.so.0 ../lib/liblinuxcncini.so.0
 	$(ECHO) Linking $(notdir $@)
diff --git a/src/hal/classicladder/module_hal.c b/src/hal/classicladder/module_hal.c
index 74e6cbb96..05ae7e71e 100644
--- a/src/hal/classicladder/module_hal.c
+++ b/src/hal/classicladder/module_hal.c
@@ -23,9 +23,7 @@
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
-#include "unistd.h"
-#include "stdio.h"
-#include "stdlib.h"
+
 #include "rtapi.h"
 #include "rtapi_app.h"
 #include "rtapi_errno.h"
@@ -81,7 +79,6 @@ extern StrGeneralParams GeneralParamsMirror;
 
 #define TIME_REFRESH_RUNG_NS (1000 * 1000 * (TIME_REFRESH_RUNG_MS))
 
-
 void HalReadPhysicalInputs(void) {
 	int i;
 	for( i=0; i<InfosGene->GeneralParams.SizesInfos.nbr_phys_inputs; i++) {
@@ -134,14 +131,14 @@ void HalWriteFloatOutputs(void) {
 // your timer are using multiples of 100 microseconds they might not be accurate.
 // t0 and t1 are for keeping track of how long the refresh of sections, 
 // and HAL pins take (it is displayed in the 'section display' GUI (in microseconds). 
-static long last_period;
+
 static void hal_task(void *arg, long period) {
 	unsigned long t0, t1,milliseconds;
 	static unsigned long leftover=0;
 	leftover += period;
 	milliseconds= leftover / 1000000;
 	leftover %= 1000000;
-        last_period = period;
+
 	if (milliseconds >= 1) {
 		InfosGene->GeneralParams.PeriodicRefreshMilliSecs=milliseconds;
 		*hal_state = InfosGene->LadderState;
diff --git a/src/hal/drivers/ar-usb/wou_stepgen.c b/src/hal/drivers/ar-usb/wou_stepgen.c
index 501ca6f5a..a27c4ba9f 100644
--- a/src/hal/drivers/ar-usb/wou_stepgen.c
+++ b/src/hal/drivers/ar-usb/wou_stepgen.c
@@ -10,10 +10,20 @@
  *
  * Last change:
  ********************************************************************/
+#include "config.h"
 
-#ifndef RTAPI
-#error This is a realtime component only!
-#endif
+#ifndef RTAPI_SIM
+#error "this module for user space simulator only"
+#else
+// SIM
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+#include <ctype.h>
+#include <time.h>
+#include <unistd.h>
 
 #include "rtapi.h"		/* RTAPI realtime OS API */
 #include "rtapi_app.h"		/* RTAPI realtime module decls */
@@ -22,16 +32,8 @@
 #include <math.h>
 #include <string.h>
 #include <float.h>
-#include <assert.h>
-#include <stdio.h>
 #include "rtapi_math.h"
 #include "motion.h"
-#include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-#include <ctype.h>
-#include <time.h>
-#include <unistd.h>
 
 #include <wou.h>
 #include <wb_regs.h>
@@ -2423,4 +2425,6 @@ static int export_machine_control(machine_control_t * machine_control)
     return 0;
 }
 
+#endif	// RTAPI_SIM
+
 // vim:sw=4:sts=4:et: