anchor.diff:          {ok, _} ->
               {error, bad_index};
           _E ->
  -            case file:open(File++".mstore", [read, write | ?OPTS]) of
  +            case file:open([File |".mstore"], [read, write | ?OPTS]) of
                   {ok, F} ->
                       M = #mstore{name=File, file=F, offset=Offset,
                                   size=Size, next=0},
  
positive.code: -spec open(Dir :: string()) -> {ok, #mset{}} | {error, not_found}.
  
  open(Dir) ->
      case file:consult(Dir++"/mstore") of
          {ok, [{FileSize, NumFiles, Seed}]} ->
              {ok, #mset{size=FileSize, chash=chash:fresh(NumFiles, []), dir=Dir, seed=Seed}};
          _ ->
  
negative.code: 
  do_get(S, Dir, Metric, [{Time, Count} | R], Acc) ->
      FileBase = (Time div S)*S,
      Base = [Dir, "/", integer_to_list(FileBase)],
      {ok, F} = open(Base, FileBase, S),
      case read(F, Metric, Time, Count) of
          {ok, D} ->
  