diff --git a/Make.inc.in b/Make.inc.in
index 39cc4a0d..d1f110cd 100755
--- a/Make.inc.in
+++ b/Make.inc.in
@@ -49,6 +49,9 @@ INSTALL_LIBDIR=@INSTALL_LIBDIR@
 INSTALL_INCLUDEDIR=@INSTALL_INCLUDEDIR@
 INSTALL_DOCSDIR=@INSTALL_DOCSDIR@
 
+# the following is the flag for /bin/cp which shall copy the file only for updating (timestamp based)--on GNU Linux, '-u'
+CPUPDFLAG=
+
 LIBDIR=@LIBDIR@
 RSB_LIBS=@RSB_LIBS@
 BASELIBNAME=@BASELIBNAME@
diff --git a/base/Makefile b/base/Makefile
index 484c89e2..639035b9 100644
--- a/base/Makefile
+++ b/base/Makefile
@@ -4,9 +4,13 @@ HERE=.
 LIBDIR=../lib
 LIBNAME=$(BASELIBNAME)
 LIBMOD=psb_base_mod$(.mod)
-lib: mods sr cm in pb tl
-	/bin/cp -p $(HERE)/$(LIBNAME) $(LIBDIR)
-	/bin/cp -p $(LIBMOD) *$(.mod) $(LIBDIR)
+lib: $(LIBDIR)/$(LIBNAME) $(LIBDIR)/$(LIBMOD) mods sr cm in pb tl
+
+$(LIBDIR)/$(LIBNAME): $(HERE)/$(LIBNAME)
+	/bin/cp -p $(CPUPDFLAG) $(HERE)/$(LIBNAME) $(LIBDIR)
+
+$(LIBDIR)/$(LIBMOD):
+	/bin/cp -p $(CPUPDFLAG) $(LIBMOD) *$(.mod) $(LIBDIR)
 
 sr cm in pb tl: mods
 
diff --git a/base/comm/Makefile b/base/comm/Makefile
index fe2a96ec..95edf220 100644
--- a/base/comm/Makefile
+++ b/base/comm/Makefile
@@ -13,7 +13,9 @@ LIBDIR=..
 MODDIR=../modules
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG)$(MODDIR) $(FMFLAG).
 
-lib: mpfobjs $(OBJS)
+lib: mpfobjs $(OBJS) $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(MPFOBJS) $(OBJS)
 	$(AR) $(LIBDIR)/$(LIBNAME) $(MPFOBJS) $(OBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
diff --git a/base/internals/Makefile b/base/internals/Makefile
index a1554429..5f1d5dc7 100644
--- a/base/internals/Makefile
+++ b/base/internals/Makefile
@@ -22,9 +22,11 @@ MODDIR=../modules
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG)$(MODDIR) $(FMFLAG).
 CINCLUDES=-I. 
 
-lib: mpfobjs $(FOBJS) $(FOBJS2) $(COBJS) $(MPFOBJS2)
-	$(AR) $(LIBDIR)/$(LIBNAME) $(MPFOBJS) $(MPFOBJS2) $(FOBJS) $(FOBJS2) \
-             $(COBJS)
+lib: mpfobjs $(FOBJS) $(FOBJS2) $(COBJS) $(MPFOBJS2) $(LIBDIR)/$(LIBNAME) 
+
+
+$(LIBDIR)/$(LIBNAME): $(MPFOBJS) $(MPFOBJS2) $(FOBJS) $(FOBJS2)
+	$(AR) $(LIBDIR)/$(LIBNAME) $(MPFOBJS) $(MPFOBJS2) $(FOBJS) $(FOBJS2) $(COBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
 $(FOBJS) $(FBOJS2): $(MODDIR)/psi_mod$(.mod)
diff --git a/base/modules/Makefile b/base/modules/Makefile
index c5dae3ac..d5ad4304 100644
--- a/base/modules/Makefile
+++ b/base/modules/Makefile
@@ -32,12 +32,13 @@ CINCLUDES=-I.
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG). $(FIFLAG).
 
 
-lib:  penvmod  $(UTIL_MODS)  $(OBJS)  
-	$(AR) $(LIBDIR)/$(LIBNAME) $(MODULES) $(OBJS) $(MPFOBJS)
-	$(RANLIB) $(LIBDIR)/$(LIBNAME)
+lib:  penvmod  $(UTIL_MODS)  $(OBJS)  $(LIBDIR)/$(LIBNAME) 
 	/bin/cp -p $(CPUPDFLAG) $(LIBMOD) $(LIBDIR)
 	/bin/cp -p $(CPUPDFLAG) *$(.mod) $(LIBDIR)
 
+$(LIBDIR)/$(LIBNAME): $(MODULES) $(OBJS) $(MPFOBJS)
+	$(AR) $(LIBDIR)/$(LIBNAME) $(MODULES) $(OBJS) $(MPFOBJS)
+	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
 psi_comm_buffers_mod.o: psb_const_mod.o 
 psi_penv_mod.o: psi_comm_buffers_mod.o psb_const_mod.o psb_realloc_mod.o 
diff --git a/base/psblas/Makefile b/base/psblas/Makefile
index fbb06a8b..a6c419ca 100644
--- a/base/psblas/Makefile
+++ b/base/psblas/Makefile
@@ -17,7 +17,9 @@ MODDIR=../modules
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG)$(MODDIR) $(FMFLAG).
 
 
-lib: $(OBJS) 
+lib: $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(OBJS) 
 	$(AR) $(LIBDIR)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
diff --git a/base/serial/Makefile b/base/serial/Makefile
index 684d7baa..2fa7224c 100644
--- a/base/serial/Makefile
+++ b/base/serial/Makefile
@@ -12,7 +12,9 @@ LIBDIR=..
 MODDIR=../modules
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG)$(MODDIR) $(FMFLAG).
 
-lib: auxd  f77d impld lib1
+lib: auxd  f77d impld lib1 $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(FOBJS)
 	$(AR) $(LIBDIR)/$(LIBNAME) $(FOBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
diff --git a/base/serial/aux/Makefile b/base/serial/aux/Makefile
index 05f83793..c8880a9e 100644
--- a/base/serial/aux/Makefile
+++ b/base/serial/aux/Makefile
@@ -31,9 +31,12 @@ FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG)$(MODDIR) $(FMFLAG)$(SPARKERDIR)  $(FMFLAG
 
 default: lib
 
-lib: $(OBJS)
+lib: $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(OBJS)
 	$(AR) $(LIBDIR)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
+
 zlsr.o  zlsrx.o:  zlcmp_mod.o
 zalsr.o zalsrx.o: zalcmp_mod.o
 zasr.o  zasrx.o:  zacmp_mod.o
diff --git a/base/serial/f77/Makefile b/base/serial/f77/Makefile
index 52a024a3..68312db2 100644
--- a/base/serial/f77/Makefile
+++ b/base/serial/f77/Makefile
@@ -26,7 +26,9 @@ LIBFILE=$(LIBDIR)/$(LIBNAME)
 
 default: lib
 
-lib: $(OBJS)
+lib: $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(OBJS)
 	$(AR) $(LIBDIR)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
diff --git a/base/serial/impl/Makefile b/base/serial/impl/Makefile
index 9e1e2260..cde0dfbc 100644
--- a/base/serial/impl/Makefile
+++ b/base/serial/impl/Makefile
@@ -28,7 +28,9 @@ LIBFILE=$(LIBDIR)/$(LIBNAME)
 
 default: lib
 
-lib: $(OBJS)
+lib: $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(OBJS)
 	$(AR) $(LIBDIR)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
diff --git a/base/tools/Makefile b/base/tools/Makefile
index 2af4b6b6..298fc67f 100644
--- a/base/tools/Makefile
+++ b/base/tools/Makefile
@@ -27,7 +27,9 @@ LIBDIR=..
 MODDIR=../modules
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG)$(MODDIR) $(FMFLAG). $(FIFLAG)$(MODDIR)
 
-lib: mpfobjs $(FOBJS)
+lib: mpfobjs $(FOBJS) $(LIBDIR)/$(LIBNAME)
+
+$(LIBDIR)/$(LIBNAME): $(MPFOBJS) $(FOBJS)
 	$(AR) $(LIBDIR)/$(LIBNAME) $(MPFOBJS) $(FOBJS)
 	$(RANLIB) $(LIBDIR)/$(LIBNAME)
 
diff --git a/krylov/Makefile b/krylov/Makefile
index b1a82f81..78b1e054 100644
--- a/krylov/Makefile
+++ b/krylov/Makefile
@@ -24,11 +24,17 @@ LIBNAME=$(METHDLIBNAME)
 
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG).
 
-lib:  $(OBJS) 
+lib:  $(LIBDIR)/$(LIBNAME) $(LIBDIR)/$(LIBMOD)
+
+$(LIBDIR)/$(LIBNAME): $(HERE)/$(LIBNAME)
+	/bin/cp -p $(CPUPDFLAG) $(HERE)/$(LIBNAME) $(LIBDIR)
+
+$(LIBDIR)/$(LIBMOD):
+	/bin/cp -p $(CPUPDFLAG) $(LIBMOD) $(LIBDIR)
+
+$(HERE)/$(LIBNAME): $(OBJS) 
 	$(AR) $(HERE)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(HERE)/$(LIBNAME)
-	/bin/cp -p $(HERE)/$(LIBNAME) $(LIBDIR)
-	/bin/cp -p $(LIBMOD) $(LIBDIR)
 
 psb_s_inner_krylov_mod.o psb_c_inner_krylov_mod.o psb_d_inner_krylov_mod.o psb_z_inner_krylov_mod.o:  psb_base_inner_krylov_mod.o
 psb_inner_krylov_mod.o: psb_s_inner_krylov_mod.o psb_c_inner_krylov_mod.o psb_d_inner_krylov_mod.o psb_z_inner_krylov_mod.o 
diff --git a/opt/Makefile b/opt/Makefile
index e84f46c0..3aaba616 100644
--- a/opt/Makefile
+++ b/opt/Makefile
@@ -22,12 +22,13 @@ OBJS=psb_d_ell_impl.o psb_d_ell_mat_mod.o rsb_mod.o psb_d_rsb_mat_mod.o
 
 LIBNAME=libpsb_opt.a
 
-lib: $(LIBNAME)
+lib: $(HERE)/$(LIBNAME)
+	/bin/cp -p $(CPUPDFLAG) $(HERE)/$(LIBNAME) $(LIBDIR)
+	/bin/cp -p $(CPUPDFLAG) $(LIBMOD) $(LIBDIR)
+
+$(HERE)/$(LIBNAME): $(OBJS)
 	$(AR) $(HERE)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(HERE)/$(LIBNAME)
-	/bin/cp -p $(HERE)/$(LIBNAME) $(LIBDIR)
-	/bin/cp -p $(LIBMOD) $(LIBDIR)
-
 
 libpsb_opt.a: $(OBJS)
 	ar cur libpsb_opt.a $(OBJS)
diff --git a/prec/Makefile b/prec/Makefile
index fd35d982..72a7c3c3 100644
--- a/prec/Makefile
+++ b/prec/Makefile
@@ -27,11 +27,19 @@ COBJS=
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG).
 OBJS=$(F90OBJS) $(COBJS) $(MPFOBJS) $(MODOBJS)
 
-lib:  $(OBJS) 
+lib:  $(LIBDIR)/$(LIBNAME) $(LIBDIR)/$(LIBMOD)
+
+$(HERE)/$(LIBNAME):
 	$(AR) $(HERE)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(HERE)/$(LIBNAME)
-	/bin/cp -p $(HERE)/$(LIBNAME) $(LIBDIR)
-	/bin/cp -p $(LIBMOD) $(LOCAL_MODS) $(LIBDIR)
+
+$(LIBDIR)/$(LIBNAME): $(HERE)/$(LIBNAME)
+	/bin/cp -p $(CPUPDFLAG) $(HERE)/$(LIBNAME) $(LIBDIR)
+
+$(LIBDIR)/$(LIBMOD):
+	/bin/cp -p $(CPUPDFLAG) $(LIBMOD) $(LOCAL_MODS) $(LIBDIR)
+
+
 
 $(OBJS): $(LIBDIR)/psb_base_mod$(.mod)
 
diff --git a/test/serial/Makefile b/test/serial/Makefile
index af34b563..964b3726 100644
--- a/test/serial/Makefile
+++ b/test/serial/Makefile
@@ -22,14 +22,17 @@ RSB_EXTRA=-lgomp
 all: d_coo_matgen d_matgen 
 d_coo_matgen: d_coo_matgen.o 
 	$(F90LINK) $(LINKOPT) d_coo_matgen.o  -o d_coo_matgen  $(PSBLAS_LIB) $(LDLIBS)
-	/bin/mv d_coo_matgen $(EXEDIR)	
+	/bin/cp -p $(CPUPDFLAG) d_coo_matgen $(EXEDIR)	
+	#/bin/mv d_coo_matgen $(EXEDIR)	
+
 psb_d_cxx_impl.o d_matgen.o: psb_d_cxx_mat_mod.o 
 psb_d_cyy_impl.o d_matgen.o: psb_d_cyy_mat_mod.o 
 d_matgen.o: psb_d_czz_mat_mod.o 
 d_matgen: d_matgen.o psb_d_cxx_mat_mod.o psb_d_cxx_impl.o psb_d_cyy_mat_mod.o psb_d_cyy_impl.o  psb_d_czz_mat_mod.o 
 	$(F90LINK) $(LINKOPT) d_matgen.o psb_d_cxx_mat_mod.o psb_d_cxx_impl.o psb_d_cyy_mat_mod.o\
 	 psb_d_cyy_impl.o  psb_d_czz_mat_mod.o  -o d_matgen  $(PSBLAS_LIB) $(LDLIBS) $(RSB_EXTRA)
-	/bin/mv d_matgen $(EXEDIR)	
+	/bin/cp -p $(CPUPDFLAG) d_matgen $(EXEDIR)	
+#	/bin/mv d_matgen $(EXEDIR)	
 
 check: all
 	cd runs && echo 5 | ./d_matgen
diff --git a/util/Makefile b/util/Makefile
index 1d3227f5..de4f9a15 100644
--- a/util/Makefile
+++ b/util/Makefile
@@ -16,11 +16,17 @@ LIBNAME=$(UTILLIBNAME)
 FINCLUDES=$(FMFLAG)$(LIBDIR) $(FMFLAG).
 
 
-lib:  $(OBJS) 
+lib:  $(LIBDIR)/$(LIBNAME) $(LIBDIR)/$(LIBMOD)
+
+$(LIBDIR)/$(LIBNAME): $(HERE)/$(LIBNAME)
+	/bin/cp -p $(CPUPDFLAG) $(HERE)/$(LIBNAME) $(LIBDIR)
+
+$(LIBDIR)/$(LIBMOD):
+	/bin/cp -p $(CPUPDFLAG) $(LIBMOD) $(LOCAL_MODS) $(LIBDIR)
+
+$(HERE)/$(LIBNAME):
 	$(AR) $(HERE)/$(LIBNAME) $(OBJS)
 	$(RANLIB) $(HERE)/$(LIBNAME)
-	/bin/cp -p $(HERE)/$(LIBNAME) $(LIBDIR)
-	/bin/cp -p $(LIBMOD) $(LOCAL_MODS) $(LIBDIR)
 
 
 psb_util_mod.o: $(BASEOBJS)