anchor.diff:  make_filename_mgr_name(FluName) when is_atom(FluName) ->
       list_to_atom(atom_to_list(FluName) ++ "_filename_mgr").
   
  -handle_find_file(Tid, {coc,CoC_Namespace,CoC_Locator}=CoC_NL, Prefix, DataDir) ->
  -    N = machi_util:read_max_filenum(DataDir, CoC_Namespace, CoC_Locator, Prefix),
  -    {File, Cleanup} = case find_file(DataDir, CoC_NL, Prefix, N) of
  -        [] ->
  -            {find_or_make_filename(Tid, DataDir, CoC_Namespace, CoC_Locator, Prefix, N), false};
  -        [H] -> {H, true};
  -        [Fn | _ ] = L ->
  -            lager:debug(
  -              "Searching for a matching file to prefix ~p and sequence number ~p gave multiples: ~p",
  -              [Prefix, N, L]),
  -            {Fn, true}
  -    end,
  -    maybe_cleanup(Tid, {CoC_Namespace, CoC_Locator, Prefix, N}, Cleanup),
  -    filename:basename(File).
  -
  -find_or_make_filename(Tid, DataDir, CoC_Namespace, CoC_Locator, Prefix, N) ->
  -    case ets:lookup(Tid, {CoC_Namespace, CoC_Locator, Prefix, N}) of
  +handle_find_file(_FluName, Tid, {coc,CoC_Namespace,CoC_Locator}, Prefix, DataDir) ->
  +    case ets:lookup(Tid, {CoC_Namespace, CoC_Locator, Prefix}) of
            [] ->
  +            N = machi_util:read_max_filenum(DataDir, CoC_Namespace, CoC_Locator, Prefix),
               F = generate_filename(DataDir, CoC_Namespace, CoC_Locator, Prefix, N),
  -            true = ets:insert_new(Tid, {{CoC_Namespace, CoC_Locator, Prefix, N}, F}),
  +            true = ets:insert(Tid, {{CoC_Namespace, CoC_Locator, Prefix}, F}),
               F;
           [{_Key, File}] ->
               File
  
positive.code:                                   {coc, _CoC_Ns, _CoC_Loc}=CoC_NL)
    when is_atom(FluName) ->
      N = make_filename_mgr_name(FluName),
      gen_server:call(N, {find_filename, EpochId, CoC_NL, Prefix}, ?TIMEOUT);
  find_or_make_filename_from_prefix(_FluName, _EpochId, Other, Other2) ->
      lager:error("~p is not a valid prefix/CoC ~p", [Other, Other2]),
      error(badarg).
  
negative.code:     io_lib:format("~8.16.0b-~4.16.0b-4~3.16.0b-~4.16.0b-~12.16.0b",
                          [A, B, C band 16#0fff, D band 16#3fff bor 16#8000, E]).
  
  list_files(DataDir, Prefix) ->
      {F_bin, Path} = machi_util:make_data_filename(DataDir, "*^" ++ Prefix ++ "^*"),
      filelib:wildcard(binary_to_list(F_bin), filename:dirname(Path)).
  