diff --git a/sw/logalizer/Makefile b/sw/logalizer/Makefile
index 3e15ef13a5..c14ab8f4bd 100644
--- a/sw/logalizer/Makefile
+++ b/sw/logalizer/Makefile
@@ -29,9 +29,13 @@ INCLUDES= -I +xml-light -I +lablgtk2 -I ../lib/ocaml
 
 all: play plotter plot
 
-play : log_file.ml play.ml
+play : log_file.ml play_core.ml play.ml
 	@echo OL $@
-	$(Q)$(OCAMLC) $(INCLUDES) -custom -o $@ unix.cma str.cma xml-light.cma glibivy-ocaml.cma -I +lablgtk2 -I ../lib/ocaml lablgtk.cma lib-pprz.cma gtkInit.cmo  $^
+	$(Q)$(OCAMLC) $(INCLUDES) -custom -o $@ unix.cma str.cma xml-light.cma glibivy-ocaml.cma -I +lablgtk2 -I ../lib/ocaml lablgtk.cma lib-pprz.cma gtkInit.cmo $^
+
+play-nox : play_core.ml play-nox.ml
+	@echo OL $@
+	$(Q)$(OCAMLC) $(INCLUDES) -custom -o $@ unix.cma str.cma xml-light.cma glibivy-ocaml.cma -I +lablgtk2 -I ../lib/ocaml lablgtk.cma lib-pprz.cma  $^
 
 plotter : plotter.cmo
 	@echo OL $@
diff --git a/sw/logalizer/play-nox.ml b/sw/logalizer/play-nox.ml
new file mode 100644
index 0000000000..2a38c3d42f
--- /dev/null
+++ b/sw/logalizer/play-nox.ml
@@ -0,0 +1,32 @@
+(*
+ * $Id$
+ *
+ * Log player
+ *  
+ * Copyright (C) 2004-2009 ENAC, Pascal Brisset, Antoine Drouin
+ *
+ * This file is part of paparazzi.
+ *
+ * paparazzi is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * paparazzi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with paparazzi; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA. 
+ *
+ *)
+
+let () =
+  let (serial_port, adj, speed) = Play_core.init () in
+      
+  Play_core.play ~no_gui:true serial_port adj speed;
+
+  Play_core.main ()
diff --git a/sw/logalizer/play.ml b/sw/logalizer/play.ml
index ec5cd6466b..d59539079b 100644
--- a/sw/logalizer/play.ml
+++ b/sw/logalizer/play.ml
@@ -3,7 +3,7 @@
  *
  * Log player
  *  
- * Copyright (C) 2004 CENA/ENAC, Pascal Brisset, Antoine Drouin
+ * Copyright (C) 2004-2009 ENAC, Pascal Brisset, Antoine Drouin
  *
  * This file is part of paparazzi.
  *
@@ -26,179 +26,26 @@
 
 open Printf
 
-module Ground_Pprz = Pprz.Messages(struct let name = "ground" end)
-module Tm_Pprz = Pprz.Messages(struct let name = "telemetry" end)
-
-let (//) = Filename.concat
-let replay_dir = Env.paparazzi_home // "var" // "replay"
-let dump_fp = Env.paparazzi_src // "sw" // "tools" // "gen_flight_plan.out -dump"
-
-let log = ref [||]
-
-let write_xml = fun f xml ->
-  let d = Filename.dirname f in
-  ignore (Sys.command (sprintf "mkdir -p %s" d));
-  let m = open_out f in
-  fprintf m "%s" (Xml.to_string_fmt xml);
-  close_out m
-
-
-let store_conf = fun conf acs ->
-  let l = 
-    List.fold_right (fun x r ->
-      if ExtXml.tag_is x "aircraft" then
-	if List.mem (ExtXml.attrib x "ac_id") acs then
-	  let ac_name = ExtXml.attrib x "name" in
-	  let ac_dir = replay_dir // "var" // ac_name in
-
-	  let w = fun s ->
-	    (* Histotical: still useful ? *)
-	    let f = replay_dir // "conf" // ExtXml.attrib x s in
-	    write_xml f (ExtXml.child x s);
-	    (* Write in the conf/ directory of the A/C *)
-	    let f = ac_dir // "conf" // ExtXml.attrib x s in
-	    write_xml f (ExtXml.child x s);
-	    f in
-	  ignore (w "airframe");
-	  ignore (w "radio");
-	  let fp = w "flight_plan" in
-	  (** We must "dump" the flight plan from the original one *)
-	  ignore (Sys.command (sprintf "mkdir -p %s" ac_dir));
-	  let dump = ac_dir // "flight_plan.xml" in
-	  let c = sprintf "%s %s > %s" dump_fp fp dump in
-	  if Sys.command c <> 0 then
-	    failwith c;
-	  Xml.Element ("aircraft", Xml.attribs x, [])::r
-	else r
-      else (** Keep ground section *)
-	x::r)
-      (Xml.children conf) [] in
-  let orig_conf = Xml.Element ("conf", [], l) in
-  write_xml (replay_dir // "conf" // "conf.xml") orig_conf
-
-let store_messages = fun protocol ->
-  write_xml (replay_dir // "conf" // "messages.xml") protocol
-
-let time_of = fun (t, _, _) -> t
-
-let load_log = fun window (adj:GData.adjustment) xml_file ->
-  let xml = Xml.parse_file xml_file in
-  let data_file =  ExtXml.attrib xml "data_file" in
-
-  let f = Ocaml_tools.find_file [Filename.dirname xml_file] data_file in
-  let f = Ocaml_tools.open_compress f in
-  let lines = ref [] in
-  let acs = ref [] in
-  try
-    while true do
-      let l = input_line f in
-      try
-	Scanf.sscanf l "%f %s %[^\n]"
-	  (fun t ac m -> 
-	    lines := (t,ac,m):: !lines;
-	    if not (List.mem ac !acs) then acs := ac :: !acs
-	  )
-      with
-	_ -> ()
-    done
-  with
-    End_of_file ->
-      close_in f;
-      log := Array.of_list (List.rev !lines);
-      let start = time_of !log.(0) in
-      let end_ = time_of !log.(Array.length !log - 1) in
-      adj#set_bounds ~lower:start ~upper:end_ ();
-      adj#set_value start;
-      window#set_title (Filename.basename xml_file);
-
-      store_conf (ExtXml.child xml "conf") !acs;
-      store_messages (ExtXml.child xml "protocol")
-      
-
-
-let timer = ref None
-let was_running = ref false
-let no_gui = ref false
-
-let stop = fun () ->
-  match !timer with
-    None -> ()
-  | Some t -> GMain.Timeout.remove t; timer := None
-
 
+let set_title_and_bounds = fun window (adj:GData.adjustment) xml_file ->
+  let (start, end_) = Play_core.get_log_bounds () in
+  adj#set_bounds ~lower:start ~upper:end_ ();
+  adj#set_value start;
+  window#set_title (Filename.basename xml_file)
 
 let open_log = fun window adj () ->
-  stop ();
-  ignore (Log_file.chooser ~callback:(fun name -> load_log window adj name) ())
+  Play_core.stop ();
+  ignore (Log_file.chooser ~callback:(fun name -> Play_core.load_log name; set_title_and_bounds window adj name) ())
 
-let index_of_time = fun log t ->
-  let rec loop = fun a b ->
-    if a >= b then a else
-    let c = (a+b)/ 2 in
-    if t <= time_of log.(c) then loop a c else loop (c+1) b in
-  loop 0 (Array.length log - 1)
 
-let rec run = fun serial_port timescale log adj i speed ->
-  let (t, ac, m) = log.(i) in
-  Ivy.send (Printf.sprintf "replay%s %s" ac m);
-  begin
-    match serial_port with
-      None -> ()
-    | Some channel ->
-	try
-	  let msg_id, vs = Tm_Pprz.values_of_string m in
-	  let payload = Tm_Pprz.payload_of_values msg_id (int_of_string ac) vs in
-	  let buf = Pprz.Transport.packet payload in
-	  Debug.call 'o' (fun f -> fprintf f "%s\n" (Debug.xprint buf));
-	  fprintf channel "%s%!" buf
-	with
-	  _ -> ()
-  end;
-  adj#set_value t;
-  if i + 1 < Array.length log then
-    let dt = time_of log.(i+1) -. t in
-    timer := Some (GMain.Timeout.add (truncate (1000. *. dt /. speed#value)) (fun () -> run serial_port timescale log adj (i+1) speed; false))
-  else
-    if !no_gui then
-      exit 0
-    else
-      timescale#misc#set_sensitive true
-      
-let play = fun serial_port timescale adj speed ->
-  stop ();
-  if Array.length !log > 1 then
-    run serial_port timescale !log adj (index_of_time !log adj#value) speed
-  
-  
+let () =
+  let (serial_port, adj, speed) = Play_core.init () in
 
-let _ =
   let icon = GdkPixbuf.from_file Env.icon_file in
   let window = GWindow.dialog ~icon ~title:"Replay" ~width:300 () in
   let quit = fun () -> GMain.Main.quit (); exit 0 in
   ignore (window#connect#destroy ~callback:quit);
-
-  let adj = GData.adjustment 
-      ~value:0. ~lower:0. ~upper:1000. 
-    ~step_incr:0.5 ~page_incr:1.0 ~page_size:1.0 () in
-
-  let speed = object
-    val mutable v = 1. method value = v method set_value x = v <- x
-  end in
-
-  let bus = ref "127.255.255.255:2010" in
-  let port = ref "/dev/ttyUSB0"
-  and baudrate = ref "9600"
-  and output_on_serial = ref false in
-  Arg.parse 
-    [ "-b", Arg.String (fun x -> bus := x), "Bus\tDefault is 127.255.255.25:2010";
-      "-d", Arg.Set_string port, (sprintf "<port> Default is %s" !port);
-      "-no_gui", Arg.Set no_gui, "Disable graphical interface";
-      "-o", Arg.Set output_on_serial, "Output binary messages on serial port";
-      "-s", Arg.Set_string baudrate, (sprintf "<baudrate>  Default is %s" !baudrate)]
-    (fun x -> load_log window adj x)
-    "Usage: ";
-      
-
+  
   let menubar = GMenu.menu_bar ~packing:window#vbox#pack () in
   let factory = new GMenu.factory menubar in
   let accel_group = factory#accel_group in
@@ -206,33 +53,18 @@ let _ =
   let file_menu_fact = new GMenu.factory file_menu ~accel_group in
 
   let timescale = GRange.scale `HORIZONTAL ~adjustment:adj ~packing:window#vbox#pack () in
-
-  let serial_port = 
-    if !output_on_serial then
-      Some (Unix.out_channel_of_descr (Serial.opendev !port (Serial.speed_of_baudrate !baudrate)))
-    else 
-      None
-  in
   
   ignore (file_menu_fact#add_item "Open Log" ~key:GdkKeysyms._O ~callback:(open_log window adj));  
-  ignore (file_menu_fact#add_item "Play" ~key:GdkKeysyms._X ~callback:(fun () -> timescale#misc#set_sensitive false; play serial_port timescale adj speed));  
-  ignore (file_menu_fact#add_item "Stop" ~key:GdkKeysyms._S ~callback:(fun () -> timescale#misc#set_sensitive true; stop ()));  
+  ignore (file_menu_fact#add_item "Play" ~key:GdkKeysyms._X ~callback:(fun () -> timescale#misc#set_sensitive false; Play_core.play serial_port adj speed));  
+  ignore (file_menu_fact#add_item "Stop" ~key:GdkKeysyms._S ~callback:(fun () -> timescale#misc#set_sensitive true; Play_core.stop ()));  
   ignore (file_menu_fact#add_item "Quit" ~key:GdkKeysyms._Q ~callback:quit);  
+  
+  window#add_accel_group accel_group;
+  window#show ();
 
-  if !no_gui then
-    play serial_port timescale adj speed
-  else begin
-    window#add_accel_group accel_group;
-    window#show ()
+  if !Play_core.file_to_load <> "" then begin
+    set_title_and_bounds window adj !Play_core.file_to_load;
+    Play_core.play serial_port adj speed
   end;
 
-  Ivy.init "Paparazzi replay" "READY" (fun _ _ -> ());
-  Ivy.start !bus;
-
-  let world_update_time = fun _ vs ->
-      speed#set_value (Pprz.float_assoc "time_scale" vs)
-    in
-
-    ignore (Ground_Pprz.message_bind "WORLD_ENV" world_update_time);
-
-  GMain.Main.main ()
+  Play_core.main ()
diff --git a/sw/logalizer/play_core.ml b/sw/logalizer/play_core.ml
new file mode 100644
index 0000000000..749901e3ab
--- /dev/null
+++ b/sw/logalizer/play_core.ml
@@ -0,0 +1,216 @@
+(*
+ * $Id$
+ *
+ * Log player
+ *  
+ * Copyright (C) 2004 CENA/ENAC, Pascal Brisset, Antoine Drouin
+ *
+ * This file is part of paparazzi.
+ *
+ * paparazzi is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * paparazzi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with paparazzi; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA. 
+ *
+ *)
+
+open Printf
+
+module Ground_Pprz = Pprz.Messages(struct let name = "ground" end)
+module Tm_Pprz = Pprz.Messages(struct let name = "telemetry" end)
+
+let (//) = Filename.concat
+let replay_dir = Env.paparazzi_home // "var" // "replay"
+let dump_fp = Env.paparazzi_src // "sw" // "tools" // "gen_flight_plan.out -dump"
+
+let log = ref [||]
+
+let write_xml = fun f xml ->
+  let d = Filename.dirname f in
+  ignore (Sys.command (sprintf "mkdir -p %s" d));
+  let m = open_out f in
+  fprintf m "%s" (Xml.to_string_fmt xml);
+  close_out m
+
+
+let store_conf = fun conf acs ->
+  let l = 
+    List.fold_right (fun x r ->
+      if ExtXml.tag_is x "aircraft" then
+	if List.mem (ExtXml.attrib x "ac_id") acs then
+	  let ac_name = ExtXml.attrib x "name" in
+	  let ac_dir = replay_dir // "var" // ac_name in
+
+	  let w = fun s ->
+	    (* Histotical: still useful ? *)
+	    let f = replay_dir // "conf" // ExtXml.attrib x s in
+	    write_xml f (ExtXml.child x s);
+	    (* Write in the conf/ directory of the A/C *)
+	    let f = ac_dir // "conf" // ExtXml.attrib x s in
+	    write_xml f (ExtXml.child x s);
+	    f in
+	  ignore (w "airframe");
+	  ignore (w "radio");
+	  let fp = w "flight_plan" in
+	  (** We must "dump" the flight plan from the original one *)
+	  ignore (Sys.command (sprintf "mkdir -p %s" ac_dir));
+	  let dump = ac_dir // "flight_plan.xml" in
+	  let c = sprintf "%s %s > %s" dump_fp fp dump in
+	  if Sys.command c <> 0 then
+	    failwith c;
+	  Xml.Element ("aircraft", Xml.attribs x, [])::r
+	else r
+      else (** Keep ground section *)
+	x::r)
+      (Xml.children conf) [] in
+  let orig_conf = Xml.Element ("conf", [], l) in
+  write_xml (replay_dir // "conf" // "conf.xml") orig_conf
+
+let store_messages = fun protocol ->
+  write_xml (replay_dir // "conf" // "messages.xml") protocol
+
+let time_of = fun (t, _, _) -> t
+
+let get_log_bounds = fun () ->
+  let start = time_of !log.(0) in
+  let end_ = time_of !log.(Array.length !log - 1) in
+  (start, end_)
+
+
+
+let load_log = fun xml_file ->
+  let xml = Xml.parse_file xml_file in
+  let data_file =  ExtXml.attrib xml "data_file" in
+
+  let f = Ocaml_tools.find_file [Filename.dirname xml_file] data_file in
+  let f = Ocaml_tools.open_compress f in
+  let lines = ref [] in
+  let acs = ref [] in
+  try
+    while true do
+      let l = input_line f in
+      try
+	Scanf.sscanf l "%f %s %[^\n]"
+	  (fun t ac m -> 
+	    lines := (t,ac,m):: !lines;
+	    if not (List.mem ac !acs) then acs := ac :: !acs
+	  )
+      with
+	_ -> ()
+    done
+  with
+    End_of_file ->
+      close_in f;
+      log := Array.of_list (List.rev !lines);
+      store_conf (ExtXml.child xml "conf") !acs;
+      store_messages (ExtXml.child xml "protocol")
+
+
+let timer = ref None
+let was_running = ref false
+let bus = ref "127.255.255.255:2010"
+let port = ref "/dev/ttyUSB0"
+let baudrate = ref "9600"
+let file_to_load = ref ""
+let output_on_serial = ref false
+
+
+let stop = fun () ->
+  match !timer with
+    None -> ()
+  | Some t -> GMain.Timeout.remove t; timer := None
+
+
+let index_of_time = fun log t ->
+  let rec loop = fun a b ->
+    if a >= b then a else
+    let c = (a+b)/ 2 in
+    if t <= time_of log.(c) then loop a c else loop (c+1) b in
+  loop 0 (Array.length log - 1)
+
+let run = fun serial_port log adj i0 speed no_gui ->
+  let rec loop = fun i ->
+    let (t, ac, m) = log.(i) in
+    Ivy.send (Printf.sprintf "replay%s %s" ac m);
+    begin
+      match serial_port with
+	None -> ()
+      | Some channel ->
+	  try
+	  let msg_id, vs = Tm_Pprz.values_of_string m in
+	  let payload = Tm_Pprz.payload_of_values msg_id (int_of_string ac) vs in
+	  let buf = Pprz.Transport.packet payload in
+	  Debug.call 'o' (fun f -> fprintf f "%s\n" (Debug.xprint buf));
+	  fprintf channel "%s%!" buf
+	  with
+	    _ -> ()
+    end;
+    adj#set_value t;
+    if i + 1 < Array.length log then begin
+      let dt = time_of log.(i+1) -. t in
+      timer := Some (GMain.Timeout.add (truncate (1000. *. dt /. speed#value)) (fun () -> loop (i+1);false))
+    end else if no_gui then
+      exit 0
+  in
+  loop i0
+
+      
+let play = fun ?(no_gui=false) serial_port adj speed ->
+  stop ();
+  if Array.length !log > 1 then
+    run serial_port !log adj (index_of_time !log adj#value) speed no_gui
+
+
+let init = fun () ->
+  Arg.parse 
+    [ "-b", Arg.String (fun x -> bus := x), "Bus\tDefault is 127.255.255.25:2010";
+      "-d", Arg.Set_string port, (sprintf "<port> Default is %s" !port);
+      "-o", Arg.Set output_on_serial, "Output binary messages on serial port";
+      "-s", Arg.Set_string baudrate, (sprintf "<baudrate>  Default is %s" !baudrate)]
+    (fun x -> file_to_load := x)
+    "Usage: ";
+
+  if !file_to_load <> "" then
+    load_log !file_to_load;
+
+
+  let serial_port = 
+    if !output_on_serial then
+      Some (Unix.out_channel_of_descr (Serial.opendev !port (Serial.speed_of_baudrate !baudrate)))
+    else 
+      None in
+
+  let adj = GData.adjustment 
+      ~value:0. ~lower:0. ~upper:1000. 
+      ~step_incr:0.5 ~page_incr:1.0 ~page_size:1.0 () in
+
+  let speed = object
+    val mutable v = 1. method value = v method set_value x = v <- x
+  end in
+
+  let world_update_time = fun _ vs ->
+    speed#set_value (Pprz.float_assoc "time_scale" vs)
+  in
+
+  ignore (Ground_Pprz.message_bind "WORLD_ENV" world_update_time);
+  
+  (serial_port, adj, speed)
+
+
+
+
+let main = fun () ->
+  Ivy.init "Paparazzi replay" "READY" (fun _ _ -> ());
+  Ivy.start !bus;
+
+  GMain.Main.main ()