diff --git a/C/adtdefs.c b/C/adtdefs.c
index 3f083a211..894278c06 100644
--- a/C/adtdefs.c
+++ b/C/adtdefs.c
@@ -518,7 +518,7 @@ Yap_NewThreadPred(PredEntry *ap)
   p->ArityOfPE = ap->ArityOfPE;
   p->cs.p_code.FirstClause = p->cs.p_code.LastClause = NULL;
   p->cs.p_code.NOfClauses = 0;
-  p->PredFlags = 0L;
+  p->PredFlags = (ThreadLocalPredFlag|LogUpdatePredFlag);
   p->src.OwnerFile = ap->src.OwnerFile;
   p->OpcodeOfPred = UNDEF_OPCODE;
   p->CodeOfPred = p->cs.p_code.TrueCodeOfPred = (yamop *)(&(p->OpcodeOfPred)); 
@@ -577,6 +577,50 @@ Yap_NewPredPropByAtom(AtomEntry *ae, SMALLUNSGN cur_mod)
   return (p0);
 }
 
+Prop
+Yap_PredPropByFunctorNonThreadLocal(Functor f, SMALLUNSGN cur_mod)
+/* get predicate entry for ap/arity; create it if neccessary.              */
+{
+  Prop p0;
+  FunctorEntry *fe = (FunctorEntry *)f;
+
+  WRITE_LOCK(fe->FRWLock);
+  p0 = fe->PropsOfFE;
+  while (p0) {
+    PredEntry *p = RepPredProp(p0);
+    if (/* p->KindOfPE != 0 || only props */
+	(p->ModuleOfPred == cur_mod || !(p->ModuleOfPred))) {
+      WRITE_UNLOCK(fe->FRWLock);
+      return (p0);
+    }
+    p0 = p->NextOfPE;
+  }
+  return Yap_NewPredPropByFunctor(fe,cur_mod);
+}
+
+Prop
+Yap_PredPropByAtomNonThreadLocal(Atom at, SMALLUNSGN cur_mod)
+/* get predicate entry for ap/arity; create it if neccessary.              */
+{
+  Prop p0;
+  AtomEntry *ae = RepAtom(at);
+
+  WRITE_LOCK(ae->ARWLock);
+  p0 = ae->PropsOfAE;
+  while (p0) {
+    PredEntry *pe = RepPredProp(p0);
+    if ( pe->KindOfPE == PEProp && 
+	 (pe->ModuleOfPred == cur_mod || !pe->ModuleOfPred)) {
+      WRITE_UNLOCK(ae->ARWLock);
+      return(p0);
+    }
+    p0 = pe->NextOfPE;
+  }
+  return Yap_NewPredPropByAtom(ae,cur_mod);
+}
+
+
+
 Term
 Yap_GetValue(Atom a)
 {
diff --git a/C/alloc.c b/C/alloc.c
index cc2840811..46065e802 100644
--- a/C/alloc.c
+++ b/C/alloc.c
@@ -12,7 +12,7 @@
 * Last rev:								 *
 * mods:									 *
 * comments:	allocating space					 *
-* version:$Id: alloc.c,v 1.44 2004-02-05 16:56:58 vsc Exp $		 *
+* version:$Id: alloc.c,v 1.45 2004-02-11 01:20:56 vsc Exp $		 *
 *************************************************************************/
 #ifdef SCCS
 static char SccsId[] = "%W% %G%";
@@ -163,6 +163,8 @@ InitExStacks(int Trail, int Stack)
   Yap_LocalBase = Yap_GlobalBase + sa;
   Yap_TrailBase = Yap_LocalBase + sizeof(CELL);
 
+  ScratchPad.ptr = NULL;
+  ScratchPad.sz = ScratchPad.msz = SCRATCH_START_SIZE;
   AuxSp = NULL;
 
 #ifdef DEBUG
diff --git a/C/cdmgr.c b/C/cdmgr.c
index 4b2ac61c2..41ed22888 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -1525,37 +1525,12 @@ p_endconsult(void)
   return (TRUE);
 }
 
-static Int 
-p_purge_clauses(void)
-{				/* '$purge_clauses'(+Func) */
-  PredEntry      *pred;
-  Term            t = Deref(ARG1);
-  Term            t2 = Deref(ARG2);
+static void
+purge_clauses(PredEntry *pred)
+{
   yamop          *q;
-  SMALLUNSGN      mod;
   int		  in_use;
 
-  Yap_PutValue(AtomAbol, MkAtomTerm(AtomNil));
-  if (IsVarTerm(t))
-    return (FALSE);
-  if (IsVarTerm(t2) || !IsAtomTerm(t2)) {
-    return (FALSE);
-  }
-  mod = Yap_LookupModule(t2);
-  if (IsAtomTerm(t)) {
-    Atom at = AtomOfTerm(t);
-    pred = RepPredProp(PredPropByAtom(at, mod));
-  } else if (IsApplTerm(t)) {
-    Functor         fun = FunctorOfTerm(t);
-    pred = RepPredProp(PredPropByFunc(fun, mod));
-  } else
-    return (FALSE);
-  WRITE_LOCK(pred->PRWLock);
-  if (pred->PredFlags & StandardPredFlag) {
-    WRITE_UNLOCK(pred->PRWLock);
-    Yap_Error(PERMISSION_ERROR_MODIFY_STATIC_PROCEDURE, t, "assert/1");
-    return (FALSE);
-  }
   if (pred->PredFlags & IndexedPredFlag)
     RemoveIndexation(pred);
   Yap_PutValue(AtomAbol, MkAtomTerm(AtomTrue));
@@ -1598,6 +1573,44 @@ p_purge_clauses(void)
   pred->src.OwnerFile = AtomNil;
   if (pred->PredFlags & MultiFileFlag)
     pred->PredFlags ^= MultiFileFlag;
+}
+
+void
+Yap_Abolish(PredEntry *pred)
+{
+  purge_clauses(pred);
+}
+
+static Int 
+p_purge_clauses(void)
+{				/* '$purge_clauses'(+Func) */
+  PredEntry      *pred;
+  Term            t = Deref(ARG1);
+  Term            t2 = Deref(ARG2);
+  SMALLUNSGN      mod;
+
+  Yap_PutValue(AtomAbol, MkAtomTerm(AtomNil));
+  if (IsVarTerm(t))
+    return (FALSE);
+  if (IsVarTerm(t2) || !IsAtomTerm(t2)) {
+    return (FALSE);
+  }
+  mod = Yap_LookupModule(t2);
+  if (IsAtomTerm(t)) {
+    Atom at = AtomOfTerm(t);
+    pred = RepPredProp(PredPropByAtom(at, mod));
+  } else if (IsApplTerm(t)) {
+    Functor         fun = FunctorOfTerm(t);
+    pred = RepPredProp(PredPropByFunc(fun, mod));
+  } else
+    return (FALSE);
+  WRITE_LOCK(pred->PRWLock);
+  if (pred->PredFlags & StandardPredFlag) {
+    WRITE_UNLOCK(pred->PRWLock);
+    Yap_Error(PERMISSION_ERROR_MODIFY_STATIC_PROCEDURE, t, "assert/1");
+    return (FALSE);
+  }
+  purge_clauses(pred);
   WRITE_UNLOCK(pred->PRWLock);
   return (TRUE);
 }
diff --git a/C/compiler.c b/C/compiler.c
index cc454e1df..b602c74e5 100644
--- a/C/compiler.c
+++ b/C/compiler.c
@@ -1251,7 +1251,7 @@ c_goal(Term Goal, int mod, compiler_struct *cglobs)
       return;
     }
 #endif /* YAPOR */
-    p = RepPredProp(p0 = PredPropByAtom(atom, mod));
+    p = RepPredProp(p0 = Yap_PredPropByAtomNonThreadLocal(atom, mod));
     /* if we are profiling, make sure we register we entered this predicate */
     if (profiling)
       Yap_emit(enter_profiling_op, (CELL)p, Zero, &cglobs->cint);
@@ -1260,7 +1260,7 @@ c_goal(Term Goal, int mod, compiler_struct *cglobs)
   }
   else {
     f = FunctorOfTerm(Goal);
-    p = RepPredProp(p0 = PredPropByFunc(f, mod));
+    p = RepPredProp(p0 = Yap_PredPropByFunctorNonThreadLocal(f, mod));
     if (f == FunctorOr) {
       CELL l = ++cglobs->labelno;
       CELL m = ++cglobs->labelno;
diff --git a/C/index.c b/C/index.c
index e5f84133f..357e0b232 100644
--- a/C/index.c
+++ b/C/index.c
@@ -6556,10 +6556,12 @@ Yap_FollowIndexingCode(PredEntry *ap, yamop *ipc, Term t1, Term tb, Term tr, yam
     case _unlock_lu:
       ipc = NEXTOP(ipc,e);
       break;
-#if THREADS
     case _thread_local:
-      break;
+#if THREADS
+      ap = Yap_GetThreadPred(ap);
+      ipc = ap->CodeOfPred;
 #endif
+      break;
     case _index_pred:
     case _spy_pred:
       Yap_IPred(ap);
diff --git a/C/init.c b/C/init.c
index 007ae12fc..826f5584c 100644
--- a/C/init.c
+++ b/C/init.c
@@ -962,7 +962,7 @@ InitCodes(void)
   heap_regs->functor_stream = Yap_MkFunctor (AtomStream, 1);
   heap_regs->functor_stream_pos = Yap_MkFunctor (AtomStreamPos, 3);
   heap_regs->functor_stream_eOS = Yap_MkFunctor (Yap_LookupAtom("end_of_stream"), 1);
-  heap_regs->functor_thread_run = Yap_MkFunctor (Yap_FullLookupAtom("$top_thread_goal"), 1);
+  heap_regs->functor_thread_run = Yap_MkFunctor (Yap_FullLookupAtom("$top_thread_goal"), 2);
   heap_regs->functor_change_module = Yap_MkFunctor (Yap_FullLookupAtom("$change_module"), 1);
   heap_regs->functor_current_module = Yap_MkFunctor (Yap_FullLookupAtom("$current_module"), 1);
   FunctorThrow = Yap_MkFunctor( Yap_FullLookupAtom("throw"), 1);
diff --git a/C/threads.c b/C/threads.c
index edd52afec..1c87affd1 100644
--- a/C/threads.c
+++ b/C/threads.c
@@ -52,22 +52,39 @@ allocate_new_tid(void)
 }
 
 static void
-store_specs(int new_worker_id, UInt ssize, UInt tsize, Term tgoal)
+store_specs(int new_worker_id, UInt ssize, UInt tsize, Term tgoal, Term tdetach)
 {
   ThreadHandle[new_worker_id].ssize = ssize;
   ThreadHandle[new_worker_id].tsize = tsize;
   ThreadHandle[new_worker_id].tgoal =
     Yap_StoreTermInDB(tgoal,4);
+  ThreadHandle[new_worker_id].cmod =
+    CurrentModule;
+  if (IsVarTerm(tdetach))
+    tdetach = MkAtomTerm(AtomFalse);
+  ThreadHandle[new_worker_id].tdetach =
+    tdetach;
 }
 
 
 static void
 thread_die(void)
 {
+  Prop p0 = AbsPredProp(heap_regs->thread_handle[worker_id].local_preds);
+
+  /* kill all thread local preds */
+  while(p0) {
+    PredEntry *ap = RepPredProp(p0);
+    p0 = ap->NextOfPE;
+    Yap_Abolish(ap);
+    Yap_FreeCodeSpace((char *)ap);
+  }
   Yap_KillStacks();
   LOCK(ThreadHandlesLock);
+  ActiveSignals = 0L;
+  free(ScratchPad.ptr);
+  free(ThreadHandle[worker_id].default_yaam_regs);
   ThreadHandle[worker_id].in_use = FALSE;
-  free((void *)ThreadHandle[worker_id].default_yaam_regs);
   UNLOCK(ThreadHandlesLock);
 }
 
@@ -75,7 +92,7 @@ static void *
 thread_run(void *widp)
 {
   Term tgoal;
-  Term tgs[1];
+  Term tgs[2];
   int out;
   REGSTORE *standard_regs = (REGSTORE *)malloc(sizeof(REGSTORE));
   int myworker_id = *((int *)widp); 
@@ -85,17 +102,25 @@ thread_run(void *widp)
   pthread_setspecific(Yap_yaamregs_key, (void *)standard_regs);
   worker_id = myworker_id;
   Yap_InitExStacks(ThreadHandle[myworker_id].ssize, ThreadHandle[myworker_id].tsize);
+  CurrentModule = ThreadHandle[myworker_id].cmod;
   Yap_InitYaamRegs();
   {
     Yap_ReleasePreAllocCodeSpace(Yap_PreAllocCodeSpace());
   }
   tgs[0] = Yap_FetchTermFromDB(ThreadHandle[worker_id].tgoal);
-  tgoal = Yap_MkApplTerm(FunctorThreadRun, 1, tgs);
+  tgs[1] = ThreadHandle[worker_id].tdetach;
+  tgoal = Yap_MkApplTerm(FunctorThreadRun, 2, tgs);
   out = Yap_RunTopGoal(tgoal);
   thread_die();
   return NULL;
 }
 
+static Int
+p_thread_new_tid(void)
+{
+  return Yap_unify(MkIntegerTerm(allocate_new_tid()), ARG1);
+}
+
 static Int
 p_create_thread(void)
 {
@@ -103,16 +128,17 @@ p_create_thread(void)
   UInt tsize = IntegerOfTerm(Deref(ARG3));
   /*  UInt systemsize = IntegerOfTerm(Deref(ARG4)); */
   Term tgoal = Deref(ARG1);
-  int new_worker_id = allocate_new_tid();
+  Term tdetach = Deref(ARG5);
+  int new_worker_id = IntegerOfTerm(Deref(ARG6));
   if (new_worker_id == -1) {
     /* YAP ERROR */
     return FALSE;
   }    
   ThreadHandle[new_worker_id].id = new_worker_id;
-  store_specs(new_worker_id, ssize, tsize, tgoal);
-  if ((ThreadHandle[new_worker_id].ret = pthread_create(&(ThreadHandle[new_worker_id].handle), NULL, thread_run, (void *)(&(ThreadHandle[new_worker_id].id)))) == 0)
-    return Yap_unify(MkIntegerTerm(new_worker_id), ARG5);
-  thread_die();
+  store_specs(new_worker_id, ssize, tsize, tgoal, tdetach);
+  if ((ThreadHandle[new_worker_id].ret = pthread_create(&(ThreadHandle[new_worker_id].handle), NULL, thread_run, (void *)(&(ThreadHandle[new_worker_id].id)))) == 0) {
+    return TRUE;
+  }
   /* YAP ERROR */
   return FALSE;
 }
@@ -148,15 +174,9 @@ p_thread_detach(void)
 
 static Int
 p_thread_exit(void)
-{
-  pthread_exit(NULL);
-  return TRUE;
-}
-
-static Int
-p_thread_die(void)
 {
   thread_die();
+  pthread_exit(NULL);
   return TRUE;
 }
 
@@ -223,7 +243,7 @@ p_new_mutex(void)
 static Int
 p_destroy_mutex(void)
 {
-  SWIMutex *mut = (SWIMutex*)Deref(ARG1);
+  SWIMutex *mut = (SWIMutex*)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_mutex_destroy(&mut->m) < 0)
     return FALSE;
@@ -234,7 +254,7 @@ p_destroy_mutex(void)
 static Int
 p_lock_mutex(void)
 {
-  SWIMutex *mut = (SWIMutex*)Deref(ARG1);
+  SWIMutex *mut = (SWIMutex*)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_mutex_lock(&mut->m) < 0)
     return FALSE;
@@ -246,7 +266,7 @@ p_lock_mutex(void)
 static Int
 p_trylock_mutex(void)
 {
-  SWIMutex *mut = (SWIMutex*)Deref(ARG1);
+  SWIMutex *mut = (SWIMutex*)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_mutex_trylock(&mut->m) == EBUSY)
     return FALSE;
@@ -258,7 +278,7 @@ p_trylock_mutex(void)
 static Int
 p_unlock_mutex(void)
 {
-  SWIMutex *mut = (SWIMutex*)Deref(ARG1);
+  SWIMutex *mut = (SWIMutex*)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_mutex_unlock(&mut->m) < 0)
     return FALSE;
@@ -269,7 +289,7 @@ p_unlock_mutex(void)
 static Int
 p_info_mutex(void)
 {
-  SWIMutex *mut = (SWIMutex*)Deref(ARG1);
+  SWIMutex *mut = (SWIMutex*)IntegerOfTerm(Deref(ARG1));
 
   return Yap_unify(ARG2, MkIntegerTerm(mut->owners)) &&
     Yap_unify(ARG2, MkIntegerTerm(mut->tid_own));
@@ -292,7 +312,7 @@ p_cond_create(void)
 static Int
 p_cond_destroy(void)
 {
-  pthread_cond_t *condp = (pthread_cond_t *)Deref(ARG1);
+  pthread_cond_t *condp = (pthread_cond_t *)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_cond_destroy(condp) < 0)
     return FALSE;
@@ -303,7 +323,7 @@ p_cond_destroy(void)
 static Int
 p_cond_signal(void)
 {
-  pthread_cond_t *condp = (pthread_cond_t *)Deref(ARG1);
+  pthread_cond_t *condp = (pthread_cond_t *)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_cond_signal(condp) < 0)
     return FALSE;
@@ -313,7 +333,7 @@ p_cond_signal(void)
 static Int
 p_cond_broadcast(void)
 {
-  pthread_cond_t *condp = (pthread_cond_t *)Deref(ARG1);
+  pthread_cond_t *condp = (pthread_cond_t *)IntegerOfTerm(Deref(ARG1));
 
   if (pthread_cond_broadcast(condp) < 0)
     return FALSE;
@@ -323,11 +343,10 @@ p_cond_broadcast(void)
 static Int
 p_cond_wait(void)
 {
-  pthread_cond_t *condp = (pthread_cond_t *)Deref(ARG1);
-  SWIMutex *mut = (SWIMutex*)Deref(ARG2);
+  pthread_cond_t *condp = (pthread_cond_t *)IntegerOfTerm(Deref(ARG1));
+  SWIMutex *mut = (SWIMutex*)IntegerOfTerm(Deref(ARG2));
 
-  if (pthread_cond_wait(condp, &mut->m) < 0)
-    return FALSE;
+  pthread_cond_wait(condp, &mut->m);
   return TRUE;
 }
 
@@ -353,7 +372,7 @@ p_install_thread_local(void)
   if (pe->PredFlags & (UserCPredFlag|HiddenPredFlag|CArgsPredFlag|SourcePredFlag|SyncPredFlag|TestPredFlag|AsmPredFlag|StandardPredFlag|DynamicPredFlag|CPredFlag|SafePredFlag|IndexedPredFlag|BinaryTestPredFlag|SpiedPredFlag)) {
     return FALSE;
   }
-  pe->PredFlags |= ThreadLocalPredFlag;
+  pe->PredFlags |= (ThreadLocalPredFlag|LogUpdatePredFlag);
   pe->OpcodeOfPred = Yap_opcode(_thread_local);
   pe->CodeOfPred = (yamop *)&pe->OpcodeOfPred;
   WRITE_UNLOCK(pe->PRWLock);
@@ -371,14 +390,21 @@ p_thread_signal(void)
   return TRUE;
 }
 
+static Int 
+p_no_threads(void)
+{				/* '$thread_signal'(+P)	 */
+  return FALSE;
+}
+
 void Yap_InitThreadPreds(void)
 {
-  Yap_InitCPred("$create_thread", 5, p_create_thread, 0);
+  Yap_InitCPred("$no_threads", 0, p_no_threads, 0);
+  Yap_InitCPred("$thread_new_tid", 1, p_thread_new_tid, 0);
+  Yap_InitCPred("$create_thread", 6, p_create_thread, 0);
   Yap_InitCPred("$thread_self", 1, p_thread_self, SafePredFlag);
   Yap_InitCPred("$thread_join", 1, p_thread_join, 0);
   Yap_InitCPred("$detach_thread", 1, p_thread_detach, 0);
   Yap_InitCPred("$thread_exit", 0, p_thread_exit, 0);
-  Yap_InitCPred("$thread_die", 0, p_thread_die, 0);
   Yap_InitCPred("thread_set_concurrency", 2, p_thread_set_concurrency, 0);
   Yap_InitCPred("$valid_thread", 1, p_valid_thread, 0);
   Yap_InitCPred("$new_mutex", 1, p_new_mutex, SafePredFlag);
@@ -393,7 +419,21 @@ void Yap_InitThreadPreds(void)
   Yap_InitCPred("$cond_broadcast", 1, p_cond_broadcast, SafePredFlag);
   Yap_InitCPred("$cond_wait", 2, p_cond_wait, SafePredFlag);
   Yap_InitCPred("$install_thread_local", 2, p_install_thread_local, SafePredFlag);
-  Yap_InitCPred("$thread_signal", 2, p_thread_signal, SafePredFlag);
+  Yap_InitCPred("$signal_thread", 1, p_thread_signal, SafePredFlag);
+}
+
+#else
+
+
+static Int 
+p_no_threads(void)
+{				/* '$thread_signal'(+P)	 */
+  return TRUE;
+}
+
+void Yap_InitThreadPreds(void)
+{
+  Yap_InitCPred("$no_threads", 0, p_create_thread, 0);
 }
 
 
diff --git a/H/Heap.h b/H/Heap.h
index e153b1055..d9a51d106 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 1.53 2004-02-09 14:19:04 vsc Exp $	 *
+* version:      $Id: Heap.h,v 1.54 2004-02-11 01:20:56 vsc Exp $	 *
 *************************************************************************/
 
 /* information that can be stored in Code Space */
@@ -65,6 +65,8 @@ typedef struct thandle {
   int in_use;
   UInt ssize;
   UInt tsize;
+  Term tdetach;
+  SMALLUNSGN cmod;
   struct DB_TERM *tgoal;
   int id;
   int ret;
diff --git a/H/Yapproto.h b/H/Yapproto.h
index cd7ceb38b..daebd1472 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 1.44 2004-02-06 02:26:23 vsc Exp $	 *
+* version:      $Id: Yapproto.h,v 1.45 2004-02-11 01:20:56 vsc Exp $	 *
 *************************************************************************/
 
 /* prototype file for Yap */
@@ -31,6 +31,8 @@ Atom	STD_PROTO(Yap_FullLookupAtom,(char *));
 void	STD_PROTO(Yap_LookupAtomWithAddress,(char *,AtomEntry *));
 Prop	STD_PROTO(Yap_NewPredPropByFunctor,(struct FunctorEntryStruct *, SMALLUNSGN));
 Prop	STD_PROTO(Yap_NewPredPropByAtom,(struct AtomEntryStruct *, SMALLUNSGN));
+Prop	STD_PROTO(Yap_PredPropByFunctorNonThreadLocal,(struct FunctorEntryStruct *, SMALLUNSGN));
+Prop	STD_PROTO(Yap_PredPropByAtomNonThreadLocal,(struct AtomEntryStruct *, SMALLUNSGN));
 Functor	STD_PROTO(Yap_UnlockedMkFunctor,(AtomEntry *,unsigned int));
 Functor	STD_PROTO(Yap_MkFunctor,(Atom,unsigned int));
 void	STD_PROTO(Yap_MkFunctorWithAddress,(Atom,unsigned int,FunctorEntry *));
@@ -112,6 +114,7 @@ int     STD_PROTO(where_new_clause, (Prop, int));
 #endif
 void	STD_PROTO(Yap_init_consult,(int, char *));
 void	STD_PROTO(Yap_end_consult,(void));
+void	STD_PROTO(Yap_Abolish,(struct pred_entry *));
 
 
 /* cmppreds.c */
diff --git a/console/yap.c b/console/yap.c
index 92b54a249..fef3a6e19 100644
--- a/console/yap.c
+++ b/console/yap.c
@@ -496,7 +496,7 @@ exec_top_level(int BootMode, YAP_init_args *iap)
 	char init_file[256];
 	YAP_Atom atfile;
 	YAP_Functor fgoal;
-	YAP_Term goal, as[1];
+	YAP_Term goal, as[2];
 
 #if HAVE_STRNCAT
 	strncpy(init_file, PL_SRC_DIR, 256);
@@ -511,8 +511,9 @@ exec_top_level(int BootMode, YAP_init_args *iap)
 	/* consult init file */
 	atfile = YAP_LookupAtom(init_file);
 	as[0] = YAP_MkAtomTerm(atfile);
-	fgoal = YAP_MkFunctor(YAP_FullLookupAtom("$consult"), 1);
-	goal = YAP_MkApplTerm(fgoal, 1, as);
+	as[1] = YAP_MkAtomTerm(YAP_LookupAtom("prolog"));
+	fgoal = YAP_MkFunctor(YAP_FullLookupAtom("$consult"), 2);
+	goal = YAP_MkApplTerm(fgoal, 2, as);
 	/* launch consult */
 	YAP_RunGoal(goal);
 	/* set default module to user */
diff --git a/pl/errors.yap b/pl/errors.yap
index 18abb9661..a63db925b 100644
--- a/pl/errors.yap
+++ b/pl/errors.yap
@@ -387,6 +387,9 @@ print_message(Level, Mss) :-
 '$output_error_message'(domain_error(syntax_error_handler,What), Where) :-
 	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a syntax error handler ]~n",
 	[Where,What]).
+'$output_error_message'(domain_error(thread_create_option,Option+Opts), Where) :-
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not in ~w ]~n",
+	[Where,Option, Opts]).
 '$output_error_message'(domain_error(time_out_spec,What), Where) :-
 	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a valid specification for a time out ]~n",
 	[Where,What]).
diff --git a/pl/threads.yap b/pl/threads.yap
index bcdf86c76..4b98f9893 100644
--- a/pl/threads.yap
+++ b/pl/threads.yap
@@ -20,7 +20,17 @@
 	thread_at_exit(:),
 	thread_signal(+,:).
 
-'$top_thread_goal'(G) :-
+:- initialization('$init_thread0').
+
+'$init_thread0' :-
+	no_threads, !.
+'$init_thread0' :-
+	'$create_mq'(0).
+	
+
+'$top_thread_goal'(G, Detached) :-
+	'$thread_self'(Id),
+	(Detached == true -> '$detach_thread'(Id) ; true),
 	'$current_module'(Module),
 	'$system_catch'((G,'$close_thread'),Module,Exception,'$thread_exception'(Exception)).
 
@@ -43,14 +53,14 @@ thread_create(Goal, Id, Options) :-
 	G0 = thread_create(Goal, Id, Options),
 	'$check_callable'(Goal,G0),
 	'$thread_options'(Options, Aliases, Stack, Trail, System, Detached, G0),
-	'$create_thread'(Goal, Stack, Trail, System, Id),
+	'$thread_new_tid'(Id),
+	'$add_thread_aliases'(Aliases, Id),
 	'$clean_db_on_id'(Id),
-	(Detached == true -> '$detach_thread'(Id) ; true),
-	'$create_mq'(Id),
-	'$add_thread_aliases'(Aliases, Id).
+	'$create_mq'(Id),	
+	'$create_thread'(Goal, Stack, Trail, System, Detached, Id).
 
 '$clean_db_on_id'(Id) :-
-	recorda('$thread_exit_status', [Id|_], R),
+	recorded('$thread_exit_status', [Id|_], R),
 	erase(R),
 	fail.
 '$clean_db_on_id'(Id) :-
@@ -70,10 +80,12 @@ thread_create(Goal, Id, Options) :-
 	'$thread_ground_stacks'(Stack),
 	'$thread_ground_stacks'(Trail),
 	'$thread_ground_stacks'(System).	
-'$thread_options'([Opt|OPts], Aliases, Stack, Trail, System, Detached, G0) :-
-	'$thread_option'(OPt, Aliases, Stack, Trail, System, Detached, G0, Aliases0),
+'$thread_options'([Opt|Opts], Aliases, Stack, Trail, System, Detached, G0) :-
+	'$thread_option'(Opt, Aliases, Stack, Trail, System, Detached, G0, Aliases0),
 	'$thread_options'(Opts, Aliases0, Stack, Trail, System, Detached, G0).
 
+'$thread_option'(Option, Aliases, _, _, _, _, G0, Aliases) :- var(Option), !,
+	'$do_error'(instantiation_error,G0).
 '$thread_option'(stacks(Stack), Aliases, Stack, _, _, _, G0, Aliases) :- !,
 	( \+ integer(Stack) -> '$do_error'(type_error(integer,Stack),G0) ; true ).
 '$thread_option'(trail(Trail), Aliases, _, Trail, _, _, G0, Aliases) :- !,
@@ -85,7 +97,7 @@ thread_create(Goal, Id, Options) :-
 '$thread_option'(detached(B), Aliases, _, _, _, B, G0, Aliases) :- !,
 	( B \== true, B \== false  -> '$do_error'(domain_error(flag_value,B+[true,false]),G0) ; true ).
 '$thread_option'(Option, Aliases, _, _, _, _, G0, Aliases) :-
-	'$do_error'(domain_error(thread_option,Option+[stacks(_),trail(_),system(_),alias(_),detached(_)]),G0).
+	'$do_error'(domain_error(thread_create_option,Option+[stacks(_),trail(_),system(_),alias(_),detached(_)]),G0).
 
 '$thread_ground_stacks'(0) :- !.
 '$thread_ground_stacks'(_).
@@ -170,8 +182,8 @@ current_thread(Tid, Status) :-
 
 mutex_create(V) :-
 	var(V), !,
-	'$new_mutex'(Id),
-	recorda('$mutex'(Id,Id),_).
+	'$new_mutex'(V),
+	recorda('$mutex',[V|V],_).
 mutex_create(A) :-
 	atom(A),
 	recorded('$mutex',[A|_],_), !,
@@ -179,7 +191,7 @@ mutex_create(A) :-
 mutex_create(A) :-
 	atom(A), !,
 	'$new_mutex'(Id),
-	recorda('$mutex'(A,Id),_).
+	recorda('$mutex',[A|Id],_).
 mutex_create(V) :-
 	'$do_error'(type_error(atom,V),mutex_create(V)).
 	
@@ -187,8 +199,8 @@ mutex_destroy(V) :-
 	var(V), !,
 	'$do_error'(instantiation_error,mutex_destroy(A)).
 mutex_destroy(A) :-
-	recorded('$mutex',[A|Id],R),
-	'$kill_mutex'(Id),
+	recorded('$mutex',[A|Id],R), !,
+	'$destroy_mutex'(Id),
 	erase(R).
 mutex_destroy(A) :-
 	atom(A), !,
@@ -200,7 +212,7 @@ mutex_lock(V) :-
 	var(V), !,
 	'$do_error'(instantiation_error,mutex_lock(A)).
 mutex_lock(A) :-
-	recorded('$mutex',[A|Id],_),
+	recorded('$mutex',[A|Id],_), !,
 	'$lock_mutex'(Id).
 mutex_lock(A) :-
 	atom(A), !,
@@ -213,7 +225,7 @@ mutex_trylock(V) :-
 	var(V), !,
 	'$do_error'(instantiation_error,mutex_trylock(A)).
 mutex_trylock(A) :-
-	recorded('$mutex',[A|Id],_),
+	recorded('$mutex',[A|Id],_), !,
 	'$trylock_mutex'(Id).
 mutex_trylock(A) :-
 	atom(A), !,
@@ -226,7 +238,7 @@ mutex_unlock(V) :-
 	var(V), !,
 	'$do_error'(instantiation_error,mutex_unlock(A)).
 mutex_unlock(A) :-
-	recorded('$mutex',[A|Id],_),
+	recorded('$mutex',[A|Id],_), !,
 	( '$unlock_mutex'(Id) ->
 	    true
 	;
@@ -263,14 +275,14 @@ message_queue_create(Cond) :-
 	'$cond_create'(Cond),
 	recorda('$queue',q(Cond,Mutex,Cond), _).
 message_queue_create(Name) :-
-	atom(Name), !,
-	recorded('$thread_alias',[Name|_],_),
-	'$do_error'(permission_error(create,queue,Name),thread_queue_create(Name)).
+	atom(Name),
+	recorded('$thread_alias',[Name|_],_), !,
+	'$do_error'(permission_error(create,queue,Name),message_queue_create(Name)).
 message_queue_create(Name) :-
 	atom(Name), !,
 	'$create_mq'(Name).
 message_queue_create(Name) :-
-	'$do_error'(type_error(atom,Name),thread_queue_create(Name)).
+	'$do_error'(type_error(atom,Name),message_queue_create(Name)).
 
 '$create_mq'(Name) :-
 	mutex_create(Mutex),
@@ -280,7 +292,7 @@ message_queue_create(Name) :-
 	
 message_queue_destroy(Name) :-
 	var(Name), !,
-	'$do_error'(instantiation_error,thread_queue_destroy(Name)).
+	'$do_error'(instantiation_error,message_queue_destroy(Name)).
 message_queue_destroy(Queue) :-
 	recorded('$queue',q(Queue,Mutex,Cond),R), !,
 	erase(R),
@@ -289,9 +301,9 @@ message_queue_destroy(Queue) :-
 	'$clean_mqueue'(Queue).
 message_queue_destroy(Queue) :-
 	atom(Queue), !,
-	'$do_error'(existence_error(queue,Queue),thread_queue_destroy(Name)).
+	'$do_error'(existence_error(queue,Queue),message_queue_destroy(Name)).
 message_queue_destroy(Name) :-
-	'$do_error'(type_error(atom,Name),thread_queue_destroy(Name)).
+	'$do_error'(type_error(atom,Name),message_queue_destroy(Name)).
 
 '$clean_mqueue'(Q) :-
 	recorded('$msg_queue',q(Queue,_),R),
@@ -300,7 +312,7 @@ message_queue_destroy(Name) :-
 '$clean_mqueue'(_).
 	
 thread_send_message(Queue, Term) :-
-	recorded('$thread_alias',[Queue|Id],_),
+	recorded('$thread_alias',[Queue|Id],_), !,
 	thread_send_message(Id, Term).
 thread_send_message(Queue, Term) :-
 	recorded('$queue',q(Queue,Mutex,Cond),_),
@@ -320,8 +332,8 @@ thread_get_message(Queue, Term) :-
 
 '$thread_get_message_loop'(Queue, Term, Mutex, Cond) :-
 	recorded('$msg_queue',q(Queue,Term),R), !,
-	mutex_unlock(Mutex),
-	erase(R).
+	erase(R),
+	mutex_unlock(Mutex).
 '$thread_get_message_loop'(Queue, Term, Mutex, Cond) :-
 	'$cond_wait'(Cond, Mutex),
 	'$thread_get_message_loop'(Queue, Term, Mutex, Cond).
@@ -335,13 +347,17 @@ thread_peek_message(Queue, Term) :-
 	mutex_lock(Mutex),
 	'$thread_peek_message2'(Queue, Term, Mutex).
 
-'$thread_get_message_loop'(Queue, Term, Mutex) :-
+'$thread_peek_message2'(Queue, Term, Mutex) :-
 	recorded('$msg_queue',q(Queue,Term),_), !,
 	mutex_unlock(Mutex).
-'$thread_get_message_loop'(Queue, Term, Mutex) :-
+'$thread_peek_message2'(Queue, Term, Mutex) :-
 	mutex_unlock(Mutex),
 	fail.
 
+thread_local(X) :-
+	'$current_module'(M),
+	'$thread_local'(X,M).
+
 '$thread_local'(X,M) :- var(X), !,
 	'$do_error'(instantiation_error,thread_local(M:X)).
 '$thread_local'(Mod:Spec,_) :- !,
@@ -376,11 +392,9 @@ thread_signal(Thread, Goal) :-
 	'$do_error'(type_error(integer,Thread),thread_signal(Thread, Goal)).
 
 '$thread_signal'(Thread, Goal) :-
-	mutex_lock(Thread),
 	( recorded('$thread_signal',[Thread|_],R), erase(R), fail ; true ),
 	recorda('$thread_signal',[Thread|Goal],_),
 	'$signal_thread'(Thread).
-	mutex_unlock(Thread).
 
 '$thread_gfetch'(G) :-
 	'$thread_self'(Id),