anchor.diff:      runthru(ets:tab2list(T), 0, Pos).
   
   -spec any_trimmed(table(),
  -                  machi_dt:chunk_pos(),
  +                  pos_integer(),
                     machi_dt:chunk_size()) -> boolean().
   any_trimmed(CsumT, Offset, Size) ->
       Chunks = find(CsumT, Offset, Size),
  
positive.code: 
  -spec open(string(), proplists:proplist()) ->
                    {ok, table()} | {error, file:posix()}.
  open(CSumFilename, _Opts) ->
      T = ets:new(?MODULE, [private, ordered_set]),
      CSum = machi_util:make_tagged_csum(none),
      %% Dummy entry for headers
      true = ets:insert_new(T, {0, ?MINIMUM_OFFSET, CSum}),
      C0 = #machi_csum_table{
             file=CSumFilename,
             table=T},
      case file:read_file(CSumFilename) of
          %% , [read, raw, binary]) of
          {ok, Bin} ->
              List = case split_checksum_list_blob_decode(Bin) of
                         {List0, <<>>} ->
  
negative.code:                                end, Chunks),
                   true = ets:insert(T, {Offset, Size, CsumOrTrimmed})
               end
               || {Offset, Size, CsumOrTrimmed} <- List],
              ok;
          {error, enoent} ->
              ok;
          Error ->
  