diff --git a/C/amasm.c b/C/amasm.c
index 366a05972..19764850b 100644
--- a/C/amasm.c
+++ b/C/amasm.c
@@ -2079,6 +2079,7 @@ do_pass(void)
     } else {
       /* static clause */
       if (pass_no) {
+	cl_u->sc.Id = FunctorDBRef;
 	cl_u->sc.ClFlags = 0;
 	cl_u->sc.Owner = Yap_ConsultingFile();
 	if (clause_has_blobs) {
@@ -2441,7 +2442,7 @@ do_pass(void)
 	  longjmp(Yap_CompilerBotch, 3);	  
 	}
 	
-	if ( (char *)(label_offset+cpc->rnd1) > freep)
+	if ( (char *)(label_offset+cpc->rnd1) >= freep)
 	  freep = (char *)(label_offset+(cpc->rnd1+1));
 	label_offset[cpc->rnd1] = (CELL) code_p;
       }
@@ -2650,15 +2651,44 @@ Yap_assemble(int mode, Term t, PredEntry *ap, int is_fact)
       !is_fact) {
     DBTerm *x;
     LogUpdClause *cl;
+    CELL *h0 = H;
+
+    H = (CELL *)freep;
     while ((x = Yap_StoreTermInDBPlusExtraSpace(t, size)) == NULL) {
+      H = h0;
       if (!Yap_growheap(TRUE, size)) {
 	Yap_Error_TYPE = SYSTEM_ERROR;
 	return NULL;
       }
+      h0 = H;
+      H = (CELL *)freep;
     }
+    H = h0;
     cl = (LogUpdClause *)((CODEADDR)x-(UInt)size);
     cl->ClSource = x;
     code_addr = (yamop *)cl;
+  } else if (mode == ASSEMBLING_CLAUSE && 
+      (ap->PredFlags & SourcePredFlag ||
+       (!ap->cs.p_code.NOfClauses && yap_flags[SOURCE_MODE_FLAG])) &&
+      !is_fact) {
+    DBTerm *x;
+    StaticClause *cl;
+    CELL *h0 = H;
+
+    H = (CELL *)freep;
+    while ((x = Yap_StoreTermInDBPlusExtraSpace(t, size)) == NULL) {
+      H = h0;
+      if (!Yap_growheap(TRUE, size)) {
+	Yap_Error_TYPE = SYSTEM_ERROR;
+	return NULL;
+      }
+      h0 = H;
+      H = (CELL *)freep;
+    }
+    H = h0;
+    cl = (StaticClause *)((CODEADDR)x-(UInt)size);
+    cl->ClSource = x;
+    code_addr = (yamop *)cl;
   } else {
     while ((code_addr = (yamop *) Yap_AllocCodeSpace(size)) == NULL) {
       if (!Yap_growheap(TRUE, size)) {
@@ -2667,7 +2697,6 @@ Yap_assemble(int mode, Term t, PredEntry *ap, int is_fact)
       }
     }
   }
-  //  fprintf(stderr,"vsc: asking for %p\n",code_addr);
   entry_code = do_pass();
   YAPLeaveCriticalSection();
 #ifdef LOW_PROF
diff --git a/C/c_interface.c b/C/c_interface.c
index b6d094ec4..d25a0b45a 100644
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -843,7 +843,7 @@ YAP_CompileClause(Term t)
 
   Yap_ErrorMessage = NULL;
   ARG1 = t;
-  codeaddr = Yap_cclause (t,0, mod);
+  codeaddr = Yap_cclause (t,0, mod, t);
   if (codeaddr != NULL) {
     t = Deref(ARG1); /* just in case there was an heap overflow */
     Yap_addclause (t, codeaddr, TRUE, mod);
diff --git a/C/cdmgr.c b/C/cdmgr.c
index 6b3a23e26..7c55c6b22 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -1133,7 +1133,7 @@ addcl_permission_error(AtomEntry *ap, Int Arity, int in_use)
 
 
 static Term
-addclause(Term t, yamop *cp, int mode, int mod, Term src)
+addclause(Term t, yamop *cp, int mode, int mod)
 /*
  *
  mode
@@ -1201,8 +1201,10 @@ addclause(Term t, yamop *cp, int mode, int mod, Term src)
       StaticClause     *clp = ClauseCodeToStaticClause(cp);
       clp->ClFlags |= StaticMask;
       if (IsAtomTerm(t) ||
-	  FunctorOfTerm(t) != FunctorAssert)
+	  FunctorOfTerm(t) != FunctorAssert) {
 	clp->ClFlags |= FactMask;
+	clp->ClSource = NULL;
+      }
     }
     if (compile_mode)
       p->PredFlags = pflags | CompiledPredFlag | FastPredFlag;
@@ -1246,7 +1248,7 @@ addclause(Term t, yamop *cp, int mode, int mod, Term src)
 
 void
 Yap_addclause(Term t, yamop *cp, int mode, int mod) {
-  addclause(t, cp, mode, mod, t);
+  addclause(t, cp, mode, mod);
 }
 
 void
@@ -1408,11 +1410,11 @@ p_compile(void)
   if (IsVarTerm(t3) || !IsAtomTerm(t3))
     return (FALSE);
   mod = Yap_LookupModule(t3);
-  codeadr = Yap_cclause(t, 2, mod); /* vsc: give the number of arguments
+  codeadr = Yap_cclause(t, 2, mod, Deref(ARG3)); /* vsc: give the number of arguments
 			      to cclause in case there is overflow */
   t = Deref(ARG1);        /* just in case there was an heap overflow */
   if (!Yap_ErrorMessage)
-    addclause(t, codeadr, (int) (IntOfTerm(t1) & 3), mod, Deref(ARG3));
+    addclause(t, codeadr, (int) (IntOfTerm(t1) & 3), mod);
   if (Yap_ErrorMessage) {
     if (IntOfTerm(t1) & 4) {
       Yap_Error(Yap_Error_TYPE, Yap_Error_Term,
@@ -1441,13 +1443,13 @@ p_compile_dynamic(void)
   old_optimize = optimizer_on;
   optimizer_on = FALSE;
   mod = Yap_LookupModule(t3);
-  code_adr = Yap_cclause(t, 3, mod); /* vsc: give the number of arguments to
+  code_adr = Yap_cclause(t, 3, mod, Deref(ARG3)); /* vsc: give the number of arguments to
 			       cclause() in case there is a overflow */
   t = Deref(ARG1);        /* just in case there was an heap overflow */
   if (!Yap_ErrorMessage) {
     
     optimizer_on = old_optimize;
-    t = addclause(t, code_adr, (int) (IntOfTerm(t1) & 3), mod, Deref(ARG3));
+    t = addclause(t, code_adr, (int) (IntOfTerm(t1) & 3), mod);
   } else {
     if (IntOfTerm(t1) & 4) {
       Yap_Error(Yap_Error_TYPE, Yap_Error_Term, "line %d, %s", Yap_FirstLineInParse(), Yap_ErrorMessage);
@@ -1902,6 +1904,33 @@ p_is_log_updatable(void)
   return(out);
 }
 
+static Int 
+p_is_source(void)
+{				/* '$is_dynamic'(+P)	 */
+  PredEntry      *pe;
+  Term            t = Deref(ARG1);
+  Term            t2 = Deref(ARG2);
+  Int             out;
+  SMALLUNSGN      mod = Yap_LookupModule(t2);
+
+  if (IsVarTerm(t)) {
+    return (FALSE);
+  } else if (IsAtomTerm(t)) {
+    Atom at = AtomOfTerm(t);
+    pe = RepPredProp(PredPropByAtom(at, mod));
+  } else if (IsApplTerm(t)) {
+    Functor         fun = FunctorOfTerm(t);
+    pe = RepPredProp(PredPropByFunc(fun, mod));
+  } else
+    return (FALSE);
+  if (pe == NIL)
+    return (FALSE);
+  READ_LOCK(pe->PRWLock);
+  out = (pe->PredFlags & SourcePredFlag);
+  READ_UNLOCK(pe->PRWLock);
+  return(out);
+}
+
 static Int 
 p_is_dynamic(void)
 {				/* '$is_dynamic'(+P)	 */
@@ -2980,7 +3009,7 @@ get_pred(Term t1, Term tmod, char *command)
 static Int
 fetch_next_lu_clause(PredEntry *pe, yamop *i_code, Term th, Term tb, Term tr, yamop *cp_ptr, int first_time)
 {
-  LogUpdClause *cl = Yap_follow_lu_indexing_code(pe, i_code, th, tb, tr, NextClause(PredLogUpdClause->cs.p_code.FirstClause), cp_ptr);
+  LogUpdClause *cl = Yap_follow_indexing_code(pe, i_code, th, tb, tr, NextClause(PredLogUpdClause->cs.p_code.FirstClause), cp_ptr);
   Term rtn;
 
   if (cl == NULL)
@@ -2998,24 +3027,26 @@ fetch_next_lu_clause(PredEntry *pe, yamop *i_code, Term th, Term tb, Term tr, ya
   }
 #endif
   if (cl->ClFlags & FactMask) {
-    Functor f = FunctorOfTerm(th);
-    UInt arity = ArityOfFunctor(f), i;
-    CELL *pt = RepAppl(th)+1;
-
     if (!Yap_unify(tb, MkAtomTerm(AtomTrue)) ||
 	!Yap_unify(tr, rtn))
       return FALSE;
-    for (i=0; i<arity; i++) {
-      XREGS[i+1] = pt[i];
+    if (pe->ArityOfPE) {
+      Functor f = FunctorOfTerm(th);
+      UInt arity = ArityOfFunctor(f), i;
+      CELL *pt = RepAppl(th)+1;
+
+      for (i=0; i<arity; i++) {
+	XREGS[i+1] = pt[i];
+      }
+      /* don't need no ENV */
+      if (first_time) {
+	CP = P;
+	ENV = YENV;
+	YENV = ASP;
+	YENV[E_CB] = (CELL) B;
+      }
+      P = cl->ClCode;
     }
-    /* don't need no ENV */
-    if (first_time) {
-      CP = P;
-      ENV = YENV;
-      YENV = ASP;
-      YENV[E_CB] = (CELL) B;
-    }
-    P = cl->ClCode;
     return TRUE;
   } else {
     Term t;
@@ -3048,6 +3079,9 @@ p_log_update_clause(void)
   pe = get_pred(t1, Deref(ARG2), "clause/3");
   if (pe == NULL || EndOfPAEntr(pe))
     return FALSE;
+  if(pe->OpcodeOfPred == INDEX_OPCODE) {
+    IPred(pe);
+  }
   return fetch_next_lu_clause(pe, pe->cs.p_code.TrueCodeOfPred, t1, ARG3, ARG4, P, TRUE);
 }
 
@@ -3063,28 +3097,30 @@ p_continue_log_update_clause(void)
 static Int
 fetch_next_lu_clause0(PredEntry *pe, yamop *i_code, Term th, Term tb, yamop *cp_ptr, int first_time)
 {
-  LogUpdClause *cl = Yap_follow_lu_indexing_code(pe, i_code, th, tb, TermNil, NextClause(PredLogUpdClause0->cs.p_code.FirstClause), cp_ptr);
+  LogUpdClause *cl = Yap_follow_indexing_code(pe, i_code, th, tb, TermNil, NextClause(PredLogUpdClause0->cs.p_code.FirstClause), cp_ptr);
 
   if (cl == NULL)
     return FALSE;
   if (cl->ClFlags & FactMask) {
-    Functor f = FunctorOfTerm(th);
-    UInt arity = ArityOfFunctor(f), i;
-    CELL *pt = RepAppl(th)+1;
-
     if (!Yap_unify(tb, MkAtomTerm(AtomTrue)))
       return FALSE;
-    for (i=0; i<arity; i++) {
-      XREGS[i+1] = pt[i];
+    if (pe->ArityOfPE) {
+      Functor f = FunctorOfTerm(th);
+      UInt arity = ArityOfFunctor(f), i;
+      CELL *pt = RepAppl(th)+1;
+
+      for (i=0; i<arity; i++) {
+	XREGS[i+1] = pt[i];
+      }
+      /* don't need no ENV */
+      if (first_time) {
+	CP = P;
+	ENV = YENV;
+	YENV = ASP;
+	YENV[E_CB] = (CELL) B;
+      }
+      P = cl->ClCode;
     }
-    /* don't need no ENV */
-    if (first_time) {
-      CP = P;
-      ENV = YENV;
-      YENV = ASP;
-      YENV[E_CB] = (CELL) B;
-    }
-    P = cl->ClCode;
     return TRUE;
   } else {
     Term t;
@@ -3116,6 +3152,9 @@ p_log_update_clause0(void)
   pe = get_pred(t1, Deref(ARG2), "clause/3");
   if (pe == NULL || EndOfPAEntr(pe))
     return FALSE;
+  if(pe->OpcodeOfPred == INDEX_OPCODE) {
+    IPred(pe);
+  }
   return fetch_next_lu_clause0(pe, pe->cs.p_code.TrueCodeOfPred, t1, ARG3, P, TRUE);
 }
 
@@ -3128,6 +3167,84 @@ p_continue_log_update_clause0(void)
   return fetch_next_lu_clause0(pe, ipc, Deref(ARG3), ARG4, B->cp_ap, FALSE);
 }
 
+static Int
+fetch_next_static_clause(PredEntry *pe, yamop *i_code, Term th, Term tb, Term tr, yamop *cp_ptr, int first_time)
+{
+  StaticClause *cl = (StaticClause *)Yap_follow_indexing_code(pe, i_code, th, tb, tr, NextClause(PredStaticClause->cs.p_code.FirstClause), cp_ptr);
+  Term rtn;
+
+  if (cl == NULL)
+    return FALSE;
+  rtn = MkDBRefTerm((DBRef)cl);
+  if (cl->ClFlags & FactMask) {
+    if (!Yap_unify(tb, MkAtomTerm(AtomTrue)) ||
+	!Yap_unify(tr, rtn))
+      return FALSE;
+
+    if (pe->ArityOfPE) {
+      Functor f = FunctorOfTerm(th);
+      UInt arity = ArityOfFunctor(f), i;
+      CELL *pt = RepAppl(th)+1;
+
+      for (i=0; i<arity; i++) {
+	XREGS[i+1] = pt[i];
+      }
+      /* don't need no ENV */
+      if (first_time) {
+	CP = P;
+	ENV = YENV;
+	YENV = ASP;
+	YENV[E_CB] = (CELL) B;
+      }
+      P = NEXTOP(cl->ClCode,ld);
+    }
+    return TRUE;
+  } else {
+    Term t;
+
+    while ((t = Yap_FetchTermFromDB(cl->ClSource)) == 0L) {
+      if (first_time) {
+	if (!Yap_gc(4, YENV, P)) {
+	  Yap_Error(OUT_OF_STACK_ERROR, TermNil, Yap_ErrorMessage);
+	  return FALSE;
+	}
+      } else {
+	if (!Yap_gc(5, ENV, CP)) {
+	  Yap_Error(OUT_OF_STACK_ERROR, TermNil, Yap_ErrorMessage);
+	  return FALSE;
+	}
+      }
+    }
+    return(Yap_unify(th, ArgOfTerm(1,t)) &&
+	   Yap_unify(tb, ArgOfTerm(2,t)) &&
+	   Yap_unify(tr, rtn));
+  }
+}
+
+static Int			/* $hidden_predicate(P) */
+p_static_clause(void)
+{
+  PredEntry      *pe;
+  Term t1 = Deref(ARG1);
+
+  pe = get_pred(t1, Deref(ARG2), "clause/3");
+  if (pe == NULL || EndOfPAEntr(pe))
+    return FALSE;
+  if(pe->OpcodeOfPred == INDEX_OPCODE) {
+    IPred(pe);
+  }
+  return fetch_next_static_clause(pe, pe->cs.p_code.TrueCodeOfPred, t1, ARG3, ARG4, P, TRUE);
+}
+
+static Int			/* $hidden_predicate(P) */
+p_continue_static_clause(void)
+{
+  PredEntry *pe = (PredEntry *)IntegerOfTerm(Deref(ARG1));
+  yamop *ipc = (yamop *)IntegerOfTerm(ARG2);
+
+  return fetch_next_static_clause(pe, ipc, Deref(ARG3), ARG4, ARG5, B->cp_ap, FALSE);
+}
+
 #ifdef LOW_PROF
 
 static void
@@ -3302,6 +3419,7 @@ Yap_InitCdMgr(void)
   Yap_InitCPred("$in_use", 2, p_in_use, TestPredFlag | SafePredFlag|SyncPredFlag);
   Yap_InitCPred("$is_dynamic", 2, p_is_dynamic, TestPredFlag | SafePredFlag);
   Yap_InitCPred("$is_log_updatable", 2, p_is_log_updatable, TestPredFlag | SafePredFlag);
+  Yap_InitCPred("$is_source", 2, p_is_source, TestPredFlag | SafePredFlag);
   Yap_InitCPred("$pred_exists", 2, p_pred_exists, TestPredFlag | SafePredFlag);
   Yap_InitCPred("$number_of_clauses", 3, p_number_of_clauses, SafePredFlag|SyncPredFlag);
   Yap_InitCPred("$undefined", 2, p_undefined, SafePredFlag|TestPredFlag);
@@ -3333,7 +3451,8 @@ Yap_InitCdMgr(void)
   Yap_InitCPred("$continue_log_update_clause", 5, p_continue_log_update_clause, SafePredFlag|SyncPredFlag);
   Yap_InitCPred("$log_update_clause", 3, p_log_update_clause0, SyncPredFlag);
   Yap_InitCPred("$continue_log_update_clause", 4, p_continue_log_update_clause0, SafePredFlag|SyncPredFlag);
-  Yap_InitCPred("$continue_log_update_clause", 4, p_continue_log_update_clause0, SafePredFlag|SyncPredFlag);
+  Yap_InitCPred("$static_clause", 4, p_static_clause, SyncPredFlag);
+  Yap_InitCPred("$continue_static_clause", 5, p_continue_static_clause, SafePredFlag|SyncPredFlag);
   Yap_InitCPred("$static_pred_statistics", 5, p_static_pred_statistics, SyncPredFlag);
 }
 
diff --git a/C/compiler.c b/C/compiler.c
index dae9fe051..5811e41c1 100644
--- a/C/compiler.c
+++ b/C/compiler.c
@@ -2703,7 +2703,7 @@ c_optimize(PInstr *pc)
 }
 
 yamop *
-Yap_cclause(Term inp_clause, int NOfArgs, int mod)
+Yap_cclause(Term inp_clause, int NOfArgs, int mod, Term src)
 {				/* compile a prolog clause, copy of clause myst be in ARG1 */
   /* returns address of code for clause */
   Term head, body;
@@ -2868,7 +2868,7 @@ Yap_cclause(Term inp_clause, int NOfArgs, int mod)
     Yap_ShowCode();
 #endif
   /* phase 3: assemble code                                                */
-  acode = Yap_assemble(ASSEMBLING_CLAUSE, inp_clause, CurrentPred, body == MkAtomTerm(AtomTrue));
+  acode = Yap_assemble(ASSEMBLING_CLAUSE, src, CurrentPred, body == MkAtomTerm(AtomTrue));
 
 
   /* check first if there was space for us */
diff --git a/C/index.c b/C/index.c
index baac300d8..26e89a362 100644
--- a/C/index.c
+++ b/C/index.c
@@ -6010,6 +6010,21 @@ lu_clause(yamop *ipc)
   return c;
 }
 
+static LogUpdClause *
+static_clause(yamop *ipc)
+{
+  StaticClause *c;
+  CELL *p = (CELL *)ipc;
+
+  if (ipc == FAILCODE)
+    return NULL;
+  while ((c = ClauseCodeToStaticClause(p))->Id != FunctorDBRef ||
+	 (c->ClFlags & (LogUpdMask|IndexMask|DynamicMask|SwitchTableMask|SwitchRootMask))) {
+    p--;
+  }
+  return (LogUpdClause *)c;
+}
+
 static void
 store_clause_choice_point(Term t1, Term tb, Term tr, yamop *ipc, PredEntry *pe, yamop *ap_pc, yamop *cp_pc)
 {
@@ -6052,7 +6067,7 @@ update_clause_choice_point(yamop *ipc, yamop *ap_pc)
 }
 
 LogUpdClause *
-Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr, yamop *ap_pc, yamop *cp_pc)
+Yap_follow_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr, yamop *ap_pc, yamop *cp_pc)
 {
   CELL *tar = RepAppl(t1);
   UInt i;
@@ -6061,6 +6076,7 @@ Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr
   yamop *start_pc = ipc;
   choiceptr b0 = NULL;
   yamop **jlbl = NULL;
+  int lu_pred = ap->PredFlags & LogUpdatePredFlag;
 
   if (ap->ModuleOfPred != 2) {
     /* makes no sense for IDB, as ArityOfPE means nothing */
@@ -6068,7 +6084,7 @@ Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr
       XREGS[i] = tar[i];
     }
   }
-    /* try to refine the interval using the indexing code */
+  /* try to refine the interval using the indexing code */
   while (ipc != NULL) {
     op_numbers op = Yap_op_from_opcode(ipc->opc);
 
@@ -6082,7 +6098,10 @@ Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr
 	store_clause_choice_point(t1, tb, tr, NEXTOP(ipc,ld), ap, ap_pc, cp_pc);
       else
 	update_clause_choice_point(NEXTOP(ipc,ld), ap_pc);
-      return lu_clause(ipc->u.ld.d);
+      if (lu_pred)
+	return lu_clause(ipc->u.ld.d);
+      else
+	return static_clause(ipc->u.ld.d);
     case _try_me:
     case _try_me1:
     case _try_me2:
@@ -6099,7 +6118,10 @@ Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr
     case _retry_profiled:
     case _count_retry:
       update_clause_choice_point(NEXTOP(ipc,ld),ap_pc);
-      return lu_clause(ipc->u.ld.d);
+      if (lu_pred)
+	return lu_clause(ipc->u.ld.d);
+      else
+	return static_clause(ipc->u.ld.d);
     case _retry_me:
     case _retry_me1:
     case _retry_me2:
@@ -6119,7 +6141,10 @@ Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr
       abolish_incomplete_subgoals(B);
 #endif /* TABLING */
       b0 = B;
-      return lu_clause(ipc->u.ld.d);
+      if (lu_pred)
+	return lu_clause(ipc->u.ld.d);
+      else
+	return static_clause(ipc->u.ld.d);
     case _profiled_trust_me:
     case _trust_me:
     case _count_trust_me:
@@ -6363,7 +6388,10 @@ Yap_follow_lu_indexing_code(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr
 #endif /* TABLING */
 	/* I did a trust */
       }
-      return lu_clause(ipc);
+      if (lu_pred)
+	return lu_clause(ipc);
+      else
+	return static_clause(ipc);
     }
   }
   if (b0) {
diff --git a/C/init.c b/C/init.c
index bd44e8710..114e33242 100644
--- a/C/init.c
+++ b/C/init.c
@@ -979,7 +979,7 @@ InitCodes(void)
   heap_regs->pred_recorded_with_key = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("$recorded_with_key"),3),0));
   heap_regs->pred_log_upd_clause = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("$do_log_upd_clause"),5),0));
   heap_regs->pred_log_upd_clause0 = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("$do_log_upd_clause"),4),0));
-  heap_regs->pred_log_upd_retract = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("$do_log_upd_retract"),4),0));
+  heap_regs->pred_static_clause = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("$do_static_clause"),5),0));
   heap_regs->pred_throw = RepPredProp(PredPropByFunc(FunctorThrow,0));
   heap_regs->pred_handle_throw = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("$handle_throw"),3),0));
   heap_regs->pred_goal_expansion = RepPredProp(PredPropByFunc(Yap_MkFunctor(Yap_LookupAtom("goal_expansion"),3),1));
diff --git a/C/tracer.c b/C/tracer.c
index 4d18a711c..70dd3917b 100644
--- a/C/tracer.c
+++ b/C/tracer.c
@@ -115,6 +115,10 @@ low_level_trace(yap_low_level_port port, PredEntry *pred, CELL *args)
   /*  extern int gc_calls; */
 
   vsc_count++;
+  if (vsc_count == 121085) 
+    vsc_xstop = 1;
+  if (vsc_count < 121000LL)
+    return;
 #ifdef COMMENTED
   if (port != enter_pred ||
       !pred ||
diff --git a/H/Heap.h b/H/Heap.h
index 178f07eed..393d8bdb3 100644
--- a/H/Heap.h
+++ b/H/Heap.h
@@ -10,7 +10,7 @@
 * File:		Heap.h         						 *
 * mods:									 *
 * comments:	Heap Init Structure					 *
-* version:      $Id: Heap.h,v 1.47 2003-11-12 12:33:31 vsc Exp $	 *
+* version:      $Id: Heap.h,v 1.48 2003-11-21 16:56:20 vsc Exp $	 *
 *************************************************************************/
 
 /* information that can be stored in Code Space */
@@ -293,7 +293,7 @@ typedef struct various_codes {
   struct pred_entry *pred_recorded_with_key;
   struct pred_entry *pred_log_upd_clause;
   struct pred_entry *pred_log_upd_clause0;
-  struct pred_entry *pred_log_upd_retract;
+  struct pred_entry *pred_static_clause;
   struct pred_entry *pred_throw;
   struct pred_entry *pred_handle_throw;
   struct array_entry *dyn_array_list;
@@ -533,7 +533,7 @@ typedef struct various_codes {
 #define  PredRecordedWithKey      heap_regs->pred_recorded_with_key
 #define  PredLogUpdClause         heap_regs->pred_log_upd_clause
 #define  PredLogUpdClause0        heap_regs->pred_log_upd_clause0
-#define  PredLogUpdRetract        heap_regs->pred_log_upd_retract
+#define  PredStaticClause         heap_regs->pred_static_clause
 #define  PredThrow                heap_regs->pred_throw
 #define  PredHandleThrow          heap_regs->pred_handle_throw
 #define  DynArrayList             heap_regs->dyn_array_list
diff --git a/H/Yapproto.h b/H/Yapproto.h
index 533664e08..c9c85c193 100644
--- a/H/Yapproto.h
+++ b/H/Yapproto.h
@@ -10,7 +10,7 @@
 * File:		Yap.proto						 *
 * mods:									 *
 * comments:	Function declarations for YAP				 *
-* version:      $Id: Yapproto.h,v 1.40 2003-11-12 12:33:31 vsc Exp $	 *
+* version:      $Id: Yapproto.h,v 1.41 2003-11-21 16:56:20 vsc Exp $	 *
 *************************************************************************/
 
 /* prototype file for Yap */
@@ -118,7 +118,7 @@ int	STD_PROTO(Yap_compare_terms,(Term,Term));
 void	STD_PROTO(Yap_InitCmpPreds,(void));
 
 /* compiler.c */
-yamop  *STD_PROTO(Yap_cclause,(Term, int, int));
+yamop  *STD_PROTO(Yap_cclause,(Term, int, int, Term));
 
 /* computils.c */
 
diff --git a/H/clause.h b/H/clause.h
index ef16db6da..e3bf8a04d 100644
--- a/H/clause.h
+++ b/H/clause.h
@@ -106,7 +106,9 @@ typedef struct static_index {
 
 typedef struct static_clause {
   /* A set of flags describing info on the clause */
+  Functor         Id;
   CELL            ClFlags;
+  DBTerm          *ClSource;
   Atom Owner;
   /* The instructions, at least one of the form sl */
   yamop            ClCode[MIN_ARRAY];
@@ -185,7 +187,7 @@ yamop   *STD_PROTO(Yap_ExpandIndex,(PredEntry *));
 yamop   *STD_PROTO(Yap_CleanUpIndex,(struct logic_upd_index *));
 void     STD_PROTO(Yap_AddClauseToIndex,(PredEntry *,yamop *,int));
 void     STD_PROTO(Yap_RemoveClauseFromIndex,(PredEntry *,yamop *));
-LogUpdClause  *STD_PROTO(Yap_follow_lu_indexing_code,(PredEntry *,yamop *,Term,Term,Term, yamop *,yamop *));
+LogUpdClause  *STD_PROTO(Yap_follow_indexing_code,(PredEntry *,yamop *,Term,Term,Term, yamop *,yamop *));
 
 #if LOW_PROF
 /* profiling */
diff --git a/H/rheap.h b/H/rheap.h
index d6c7c6a5b..a6e3e9eeb 100644
--- a/H/rheap.h
+++ b/H/rheap.h
@@ -309,6 +309,10 @@ restore_codes(void)
     (PredEntry *)AddrAdjust((ADDR)heap_regs->pred_recorded_with_key);
   heap_regs->pred_log_upd_clause =
     (PredEntry *)AddrAdjust((ADDR)heap_regs->pred_log_upd_clause);
+  heap_regs->pred_log_upd_clause0 =
+    (PredEntry *)AddrAdjust((ADDR)heap_regs->pred_log_upd_clause0);
+  heap_regs->pred_static_clause =
+    (PredEntry *)AddrAdjust((ADDR)heap_regs->pred_static_clause);
   heap_regs->pred_throw =
     (PredEntry *)AddrAdjust((ADDR)heap_regs->pred_throw);
   heap_regs->pred_handle_throw =
diff --git a/pl/boot.yap b/pl/boot.yap
index cf423211e..d0fc0dae9 100644
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -380,13 +380,6 @@ repeat :- '$repeat'.
 	    ( Fl /\ 16'040000 =\= 0 -> '$check_multifile_pred'(H,Mod,Fl) ; true )
         ;
             true
-      ),	    
-      ( Fl /\ 16'400000 =:= 0 ->       % is this procedure in source mode?
-        % no, just ignore
-        true
-      ;
-	% and store our clause
-	'$store_stat_clause'(G0, H, L, Mod)
       ).
 
 '$store_stat_clause'(G0, H, L, M) :-
@@ -404,7 +397,6 @@ repeat :- '$repeat'.
 	'$is_multifile'(G, M), !,
 	functor(G, Na, Ar),
 	'$erase_mf_source'(Na, Ar, M).
-'$erase_source'(G, M) :- '$recordedp'(M:G,_,R), erase(R), fail.
 '$erase_source'(_, _).
 
 '$erase_mf_source'(Na, Ar, M) :-
diff --git a/pl/debug.yap b/pl/debug.yap
index c756bd4e1..1a1054388 100644
--- a/pl/debug.yap
+++ b/pl/debug.yap
@@ -393,16 +393,11 @@ debugging :-
 	'$execute0'(G, M).
 '$spycall'(G,M) :-
 	'$flags'(G,M,F,F),
-	F /\ 16'2008 =\= 0, !, % dynamic procedure, or logical semantics
+	F /\ 16'402008 =\= 0, !, % dynamic procedure, logical semantics, or source
 	% use the interpreter
 	'$clause'(G, M, Cl),
 	CP is '$last_choice_pt',
 	'$do_spy'(Cl, M, CP).
-'$spycall'(G,M) :-
-	'$some_recordedp'(M:G), !,
-	'$clause'(G, M, Cl),
-	CP is '$last_choice_pt',
-	'$do_spy'(Cl, M, CP).
 '$spycall'(G,M) :-
 	'$continue_debugging',
 	'$execute0'(G, M).
diff --git a/pl/errors.yap b/pl/errors.yap
index 95d7de6af..bd52803ff 100644
--- a/pl/errors.yap
+++ b/pl/errors.yap
@@ -177,8 +177,6 @@ print_message(Level, Mss) :-
 	'$preprocess_stack'(Gs, I, NGs).
 '$beautify_hidden_goal'('$ensure_loaded',_,prolog,ClNo,Gs,I,NGs) :- !,
 	'$preprocess_stack'(Gs, I, NGs).
-'$beautify_hidden_goal'('$recordedp',_,prolog,ClNo,Gs,I,NGs) :- !,
-	'$preprocess_stack'(Gs, I, NGs).
 '$beautify_hidden_goal'('$continue_with_command',_,prolog,ClNo,Gs,I,NGs) :- !,
 	'$preprocess_stack'(Gs, I, NGs).
 '$beautify_hidden_goal'('$spycall_stdpred',_,prolog,ClNo,Gs,I,NGs) :- !,
diff --git a/pl/listing.yap b/pl/listing.yap
index 61f3ed9f7..d377e1690 100644
--- a/pl/listing.yap
+++ b/pl/listing.yap
@@ -55,16 +55,8 @@ listing(V) :-
 '$funcspec'(Name,_,_) :-
 	'$do_error'(domain_error(predicate_spec,Name),listing(Name)).
 
-'$list_clauses'(Stream, Mod, Pred) :-
-	'$is_log_updatable'(Pred, Mod), !,
-	'$log_update_clause'(Pred,Mod,Body),
-	'$portray_clause'(Stream,(Pred:-Body)),
-	fail.
 '$list_clauses'(Stream, M, Pred) :-
-	( '$recordedp'(M:Pred,_,_) -> nl(Stream) ),
-	fail.
-'$list_clauses'(Stream, M, Pred) :-
-        '$recordedp'(M:Pred,(Pred:-Body),_),
+	'$clause'(Pred, M, Body),
 	'$portray_clause'(Stream,(Pred:-Body)),
         fail.
 
diff --git a/pl/preds.yap b/pl/preds.yap
index 0501918de..5f857543a 100644
--- a/pl/preds.yap
+++ b/pl/preds.yap
@@ -314,6 +314,9 @@ clause(V,Q,R) :-
 	'$do_error'(type_error(callable,R),M:clause(R,Q)).
 '$clause'(M:P,_,Q,R) :- !,
 	'$clause'(P,M,Q,R).
+'$clause'(P,M,Q,R) :-
+	'$is_source'(P, M), !,
+	'$static_clause'(P,M,Q,R).
 '$clause'(P,M,Q,R) :-
 	'$is_log_updatable'(P, M), !,
 	'$log_update_clause'(P,M,Q,R).
@@ -339,10 +342,10 @@ clause(V,Q,R) :-
 	'$continue_log_update_clause'(A,B,C,D).
 '$do_log_upd_clause'(A,B,C,D).
 
-'$do_log_upd_retract'(_,_,_,_).
-'$do_log_upd_retract'(A,B,C,D) :-
-	'$continue_log_update_retract'(A,B,C,D).
-'$do_log_upd_retract'(A,B,C,D).
+'$do_static_clause'(_,_,_,_,_).
+'$do_static_clause'(A,B,C,D,E) :-
+	'$continue_static_clause'(A,B,C,D,E).
+'$do_static_clause'(A,B,C,D,E).
 
 nth_clause(P,I,R) :- nonvar(R), !,
 	'$nth_instancep'(P,I,R).
@@ -625,8 +628,7 @@ abolish(X) :-
         functor(G,A,N),
 	'$do_error'(permission_error(modify,static_procedure,A/N),abolish(Module:G)).
 '$abolishs'(G, M) :-
-	'$purge_clauses'(G, M),
-	'$recordedp'(M:G,_,R), erase(R), fail.
+	'$purge_clauses'(G, M), fail.
 '$abolishs'(_, _).
 
 %
@@ -776,7 +778,8 @@ predicate_property(Pred,Prop) :-
 '$predicate_property'(P,M,_,built_in) :- 
 	'$system_predicate'(P,M), !.
 '$predicate_property'(P,M,_,source) :- 
-	( '$recordedp'(M:P,_,_) -> true ; false).
+	'$flags'(G,M,F,F),
+	( F /\ 16'400000 =\= 0 -> true ; false).
 '$predicate_property'(P,M,_,dynamic) :-
 	'$is_dynamic'(P,M).
 '$predicate_property'(P,M,_,static) :-