On Sun, 2007-04-22 at 18:37 +0930, Tim wrote: > Tim: > >> I think you missed the beginning (or middle?) of the thread where it was > >> discussed that it'd be better if files identified themselves, rather > >> than having to work it out, after the fact. Saving a file with > >> appropriate descriptions, rather than having to determine the content > >> analytically, has its advantages. > > Arthur Pemberton: > > And you're still going to need a `file` type program to read those > > descriptions. > > True enough, but if all files had an unabiguous descriptor right at the > start, it'd be an improvement. As it stands, some file managers spend a > rather annoying amount of time working out what the files are, when you > load up a directory. They have to plough through a file, and look for > markers in various places, and make guesses. That assessment is much > more work than, say, reading the first few bytes of a file that actually > said "image/jpeg", for example. > > > -- > (This box runs FC6, my others run FC4 & FC5, in case that's > important to the thread.) > > Don't send private replies to my address, the mailbox is ignored. > I read messages from the public lists. > Don't forget the revision number. When compression algorithms change, they are never backwards compatible directly, but often can read the earlier files if the correct revision is known. Date of the compression or utility might also be important. Maybe (to use your example) "image/jpeg_10.05.02b/20070422" might give enough information. Then the decoders would have to have a list of all applicable revisions and dates that they could decode. And then what happens when one such file cannot be decoded. Maybe the date reads 20080422. Remember that the date is the release date of the creating algorithm. Also each utility would have to include code to put this information in the file. And what do you do with existing files that do not have this kind of information, how should they be handled? It is not quite that simple, although we would all like it to be. Regards, Les H
