anchor.diff:  
   -define(SIZE_TYPE, unsigned-integer).
   
  --define(VERSION, 3).
  +-define(VERSION, 4).
   -define(OPTS, [raw, binary]).
   -define(MFILE_VER, 1).
   
  
positive.code: 
  new(Dir, Opts) when (is_list(Dir) orelse is_binary(Dir)) , is_list(Opts) ->
      {file_size, FileSize} = proplists:lookup(file_size, Opts),
      DataSize = proplists:get_value(data_size, Opts, ?DATA_SIZE),
      case new(FileSize, DataSize, Dir) of
          {ok, M} ->
              {ok, apply_opts(M, Opts)};
          E ->
              E
      end.
  
  new(FileSize, DataSize, Dir) when
        is_integer(FileSize), FileSize > 0,
        is_binary(Dir) ->
      new(FileSize, DataSize, binary_to_list(Dir));
  
  new(FileSize, DataSize, Dir) ->
      IdxFile = filename:join([Dir, "mstore"]),
      case open_mfile(IdxFile) of
          {ok, F, _IS, _Metrics} when F =/= FileSize ->
              {error, filesize_missmatch};
          {ok, _F, IS, _Metrics} when IS =/= DataSize ->
              {error, itemsize_missmatch};
          {ok, F, IS,  Metrics} ->
              {ok, #mstore{size=F, dir=Dir, metrics=Metrics, data_size=IS}};
          _ ->
              file:make_dir(Dir),
              MStore = #mstore{size=FileSize, dir=Dir,
                               data_size=DataSize},
              ok = file:write_file(IdxFile, index_header(MStore)),
              {ok, MStore}
      end.
  
negative.code:                        _ ->
                             Acc1
                     end,
              do_get(S, FS, Dir, Metric, R, Acc2);
          {error,not_found} ->
              Acc1 = <<Acc/binary, (mmath_bin:empty(Count))/binary>>,
              do_get(S, FS, Dir, Metric, R, Acc1);
          eof ->
              Acc1 = <<Acc/binary, (mmath_bin:empty(Count))/binary>>,
              do_get(S, FS, Dir, Metric, R, Acc1);
          E ->
              E
      end;
  
  do_get(S,
         [_, {FileBase, F}] = FS,
         Dir, Metric, [{Time, Count} | R], Acc)
    when ((Time div S)*S) =:= FileBase ->
      case mfile:read(F, Metric, Time, Count) of
          {ok, D} ->
  