anchor.diff:  handle_call({start, Host, Directory}, _From, State) ->
       State1 = handle_start(Host, Directory, State),
       {reply, ok, State1};
  +handle_call(get_master_node, _From, #state{master = Master} = State) ->
  +    {reply, Master, State};
   handle_call({monitor_master, Master}, _From, State) ->
       true = erlang:monitor_node(Master, true),
       {reply, ok, State#state{master = Master}};
  
positive.code: start(Host, Directory) ->
      gen_server:call(?SERVER, {start, Host, Directory}).
  
  -spec monitor_master(node()) -> ok.
  monitor_master(Node) ->
      gen_server:call({?SERVER, Node}, {monitor_master, node()}).
  
negative.code:          start/2,
           monitor_master/1,
           ping/1,
           node_name/1,
           get_master_node/0]).
  
  %% ------------------------------------------------------------------
  %% gen_server Function Exports
  