diff --git a/C/iopreds.c b/C/iopreds.c
index f13cce949..7f1236d39 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -6594,36 +6594,6 @@ Yap_StringToTerm(char *s,Term *tp)
   return t;
 }
 
-static Int
-p_file_base_name (void)
-{				/* file_base_name(Stream,N)                      */
-  Term t = Deref(ARG1);
-  Atom at;
-  if (IsVarTerm(t)) {
-    Yap_Error(INSTANTIATION_ERROR, t, "file_base_name/2");
-    return FALSE;    
-  }
-  if (!IsAtomTerm(t)) {
-    Yap_Error(TYPE_ERROR_ATOM, t, "file_base_name/2");
-    return FALSE;    
-  }
-  at = AtomOfTerm(t);
-  if (IsWideAtom(at)) {
-      wchar_t *c = RepAtom(at)->WStrOfAE;
-      Int i = wcslen(c);
-      while (i && !Yap_dir_separator((int)c[--i]));
-      return Yap_unify(ARG2, MkAtomTerm(Yap_LookupWideAtom(c+i)));
-  } else {
-      char *c = RepAtom(at)->StrOfAE;
-      Int i = strlen(c);
-      while (i && !Yap_dir_separator((int)c[--i]));
-      if (Yap_dir_separator((int)c[i])) {
-	i++;
-      }
-      return Yap_unify(ARG2, MkAtomTerm(Yap_LookupAtom(c+i)));
-  }
-}
-
 Term
 Yap_TermToString(Term t, char *s, unsigned int sz, int flags)
 {
@@ -6756,7 +6726,6 @@ Yap_InitIOPreds(void)
   Yap_InitCPred ("$has_readline", 0, p_has_readline, SafePredFlag|HiddenPredFlag);
   Yap_InitCPred ("$toupper", 2, p_toupper, SafePredFlag|HiddenPredFlag);
   Yap_InitCPred ("$tolower", 2, p_tolower, SafePredFlag|HiddenPredFlag);
-  Yap_InitCPred ("file_base_name", 2, p_file_base_name, SafePredFlag|HiddenPredFlag);
 
   CurrentModule = SYSTEM_MODULE;
   Yap_InitCPred ("swi_format", 3, p_swi_format, SyncPredFlag);
diff --git a/C/sysbits.c b/C/sysbits.c
index bf2233932..98a646ee8 100755
--- a/C/sysbits.c
+++ b/C/sysbits.c
@@ -2325,31 +2325,6 @@ p_mv (void)
 }
 
 
-/* find the directory info from a file name */
-static Int
-p_file_directory_name (void)
-{
-  Term t1 = Deref(ARG1);
-  char *chp;
-
-  if (IsVarTerm(t1)) {
-    Yap_Error(INSTANTIATION_ERROR, t1, "first arg of file_directory_name/2");
-    return FALSE;
-  }
-  if (!IsAtomTerm(t1)) {
-    Yap_Error(TYPE_ERROR_ATOM, t1,  "first arg of file_directory_name/2");
-    return FALSE;
-  }
-  TrueFileName (RepAtom(AtomOfTerm(t1))->StrOfAE,  NULL, Yap_FileNameBuf, FALSE);
-  chp = Yap_FileNameBuf+strlen(Yap_FileNameBuf);
-  while (!dir_separator(*--chp) && chp != Yap_FileNameBuf);
-  if (chp == Yap_FileNameBuf) {
-    return Yap_unify(MkAtomTerm(AtomDot),ARG2);
-  }
-  *chp = '\0';
-  return Yap_unify(MkAtomTerm(Yap_LookupAtom(Yap_FileNameBuf)),ARG2);
-}
-
 /* Change the working directory */
 static Int
 p_cd (void)
@@ -3324,7 +3299,6 @@ Yap_InitSysPreds(void)
   Yap_InitCPred ("$first_signal", 1, p_first_signal, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("$host_type", 1, p_host_type, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("$continue_signals", 0, p_continue_signals, SafePredFlag|SyncPredFlag|HiddenPredFlag);
-  Yap_InitCPred ("file_directory_name", 2, p_file_directory_name, SafePredFlag);
   Yap_InitCPred ("$env_separator", 1, p_env_separator, SafePredFlag);
   Yap_InitCPred ("$unix", 0, p_unix, SafePredFlag);
   Yap_InitCPred ("$win32", 0, p_win32, SafePredFlag);
diff --git a/pl/boot.yap b/pl/boot.yap
index c992efd00..5c1ad9afa 100755
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -1359,6 +1359,20 @@ b_getval(GlobalVariable, Val) :-
 	 '$do_error'(existence_error(variable, GlobalVariable),b_getval(GlobalVariable, Val))
 	).
 		    
-access_file(File, Mode) :- swi_access_file(File, Mode).
-time_file(File, Time) :- swi_time_file(File, Time).
+access_file(File, Mode) :-
+	swi_access_file(File, Mode).
+expand_file_name(Exp, Matches) :-
+	swi_expand_file_name(Exp, Matches).
+file_base_name(File, Base) :-
+	swi_file_base_name(File, Base).
+file_directory_name(File, Dir) :-
+	swi_file_directory_name(File, Dir).
+file_name_extension(File, Name, Extension) :-
+	swi_file_name_extension(File, Name, Extension).
+prolog_to_os_filename(Prolog, OS) :-
+	swi_prolog_to_os_filename(Prolog, OS).
+time_file(File, Time) :-
+	swi_time_file(File, Time).
+working_directory(OLD, NEW) :-
+	swi_working_directory(OLD, NEW).
 
diff --git a/pl/consult.yap b/pl/consult.yap
index 7ac6e14ca..f176e55e6 100755
--- a/pl/consult.yap
+++ b/pl/consult.yap
@@ -1030,43 +1030,3 @@ make :-
 	fail.
 make.
 
-file_name_extension(A1,A2,F) :-
-	var(F),
-	nonvar(A1), nonvar(A2), !,
-	atom_codes(A2, S2),
-	(
-	 S2 = [0'.|_] %'
-	;
-	 A2 = ''
-	->
-	 atom_concat(A1, A2, F)
-	;
-	 atom_concat([A1, '.', A2], F)
-	).
-file_name_extension(A1,A2,F) :-
-	var(F), !,
-	'$do_error'(instantiation_error,file_name_extension(A1,A2,F)).
-file_name_extension(A1,A2,F) :-
-	nonvar(A2), !,
-	atom_codes(F, S),
-	atom_codes(A2, S2),
-	'$file_name_extension'(S, S1, E2),
-	(
-	 S2 = [0'.|E2] %'
-	->
-	 true 
-	;
-	 S2 = E2
-	),
-	atom_codes(A1, S1).
-file_name_extension(A1,A2,F) :-
-	atom_codes(F, S),
-	'$file_name_extension'(S, S1, S2),
-	atom_codes(A2, S2),
-	atom_codes(A1, S1).
-
-'$file_name_extension'(S, S1, S2) :-
-	lists:append(S1, [0'.|S2], S),
-	\+ lists:append(_, [0'.|_], S2), !.
-'$file_name_extension'(S, S, []).
-
diff --git a/pl/yio.yap b/pl/yio.yap
index 2a2ac6d30..bec79d50f 100644
--- a/pl/yio.yap
+++ b/pl/yio.yap
@@ -1181,25 +1181,6 @@ with_output_to(Output, Command) :-
 	atom_codes(Char, [Code]),
 	'$codes_to_chars'(String0, String, Chars).
 
-prolog_to_os_filename(Prolog, OS) :-
-	'$undefined'(swi_prolog_to_os_filename(Prolog, OS), system),
-	'$current_module'(Old, system),
-	load_foreign_files([libplstream], [], initIO),
-	'$current_module'(system, Old),
-	fail.
-prolog_to_os_filename(Prolog, OS) :-
-	system:swi_prolog_to_os_filename(Prolog, OS).
-
-
-expand_file_name(Exp, Matches) :-
-	'$undefined'(swi_expand_file_name(Exp, Matches), system),
-	'$current_module'(Old, system),
-	load_foreign_files([libplstream], [], initIO),
-	'$current_module'(system, Old),
-	fail.
-expand_file_name(Exp, Matches) :-
-	system:swi_expand_file_name(Exp, Matches).
-