anchor.diff:  
   %% @doc Get history of a xnest.
   -spec history(pid(), number())-> {ok, list()} | {error, binary()}.
  -history(_XNestPid, _Count) ->
  +history(XNestPid, Count) ->
       %%可能直接调用hisotry模块的函数
  -    FadeHistory = [[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}] 
  -		  ,[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}]
  -		  ],
  -    %%gen_server:call(XNestPid, {history, Count}).
  -    {ok, FadeHistory}.
  +    %%FadeHistory = [[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}] 
  +    %%    	  ,[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}]
  +    %%    	  ],
  +    %%{ok, FadeHistory}.
  +    gen_server:call(XNestPid, {history, Count}).
   
   
   %% gen_server.
   init([]) ->
  +    History = [],
       Clients = ets:new(xnest, [set]),
       erlang:send_after(?TTL, self(), {tick}),
  -	{ok, #state{clients=Clients, idel_time=0}}.
  +    {ok, #state{history=History, clients=Clients, idel_time=0}}.
   
   %handle_call
   handle_call({join, ClientPid}, _From, State) ->
  
positive.code:     catch _:_ ->
          {{error, <<"Error occured when deploy message!">>}, State}
      end,
  	{noreply, NewState};
  
  handle_cast(_Msg, State) ->
  	{noreply, State}.
  
negative.code: 
  %handle_cast
  handle_cast({From, text, Message}, State) ->
      History = State#state.history,
      SubHistory = case length(History) =:= ?HISTORY_LEN of
          true ->
              [ _H|T ] = History,
              T;
          false ->
              History
      end,
      {Y, M, D} = date(),
      Date = list_to_binary(io_lib:format("~4..0B-~2..0B-~2..0B", [Y, M, D])),
      NewHistory = lists:append(SubHistory, [[{<<"from">>, From}, {<<"payload">>, Message}, {<<"send_time">>, Date}]]),
  
      %%TBD, use lists:foldr for deploy message is not effective, we should think about another way.
      Clients = State#state.clients,
      DeployFun = fun({Client, _ClientInfo}, AccIn) ->
  