anchor.diff:               end,
       NewData = rrd:add_nonexisting_timeslots(MyData, OldValue),
       ets:insert(Table, {TableIndex, NewData}),
  +    Table;
  +
  +on({report_single, Process, Key, NewValue_or_UpdateFun}, Table) ->
  +    proc_set_value(Process, Key, NewValue_or_UpdateFun),
       Table;
   
   on({web_debug_info, Requestor}, Table) ->
  
positive.code:             end
      end.
  
  %% @doc Sets the value at Key. Either specify a new value or an update function
  %%      which generates the new value from the old one.
  -spec proc_set_value(Process::atom(), Key::key(),
                       NewValue_or_UpdateFun::term() | fun((Old::Value | undefined) -> New::Value)) -> ok.
  proc_set_value(Process, Key, UpdateFun) when is_function(UpdateFun, 1)->
      InternalKey = to_internal_key(Key),
      OldValue = erlang:get(InternalKey),
      NewValue = UpdateFun(OldValue),
  
negative.code:     % note: it may happen that the new value created a new slot which already
      % discarded all logged data from the previous (unreported) time slot
      % -> send OldValue, too
      comm:send_local(MyMonitor, {report_rrd, Process, Key, OldValue, Value}).
  
  %% @doc Message handler when the rm_loop module is fully initialized.
  -spec on(message(), state()) -> state().
  on({report_rrd, Process, Key, OldValue, _NewValue}, Table) ->
      % note: reporting is always done when a new time slot is created
      % -> use the values from the old value
      TableIndex = {Process, Key},
      MyData = case ets:lookup(Table, TableIndex) of
                   [{TableIndex, X}] -> X;
                   []      ->
  