anchor.diff:  
     ok = file:write(File, ChunkMap),
     {ok, Size}.
  +
  +read_chunk_map(#dbstate{} = State) ->
  +  ChunkMap = lists:map(fun({_Number, Offset}) ->
  +        {md, Timestamp, _Bid, _Ask} = read_full_md_at_offset(Offset, State),
  +        {Timestamp, Offset}
  +    end, nonzero_chunks(State)),
  +  State#dbstate{chunk_map = ChunkMap}.
   
   
   nonzero_chunks(#dbstate{file = File, chunk_size = ChunkSize, chunk_map_offset = ChunkMapOffset}) ->
  
positive.code:   lists:reverse(ReversedResult).
  
  
  start_chunk(Timestamp, #dbstate{daystart = undefined, date = Date} = State) ->
    DaystartSeconds = calendar:datetime_to_gregorian_seconds({Date, {0,0,0}}) - calendar:datetime_to_gregorian_seconds({{1970,1,1}, {0,0,0}}),
    Daystart = DaystartSeconds * 1000,
    ?D({daystart, Daystart}),
    start_chunk(Timestamp, State#dbstate{daystart = Daystart});
  
  start_chunk(Timestamp, State) ->
    #dbstate{
  
negative.code:   StockDBOpts = update_db_options(SavedDBOpts, GivenStockDBOpts),
    State0 = parse_opts(StockDBOpts, #dbstate{}),
  
    StateFileOpen = State0#dbstate{
      file = File,
      chunk_map_offset = ChunkMapOffset},
  
    StateChunkRead = read_chunk_map(StateFileOpen),
    ?D({last_chunk, lists:last(StateChunkRead#dbstate.chunk_map)}),
  
    StateReady = fast_forward(StateChunkRead),
  
    ?D({last_packet, StateReady#dbstate.last_timestamp}),
    {ok, StateReady}.
  
  
  update_db_options(OldOptions, _NewOptions) ->
  