Re: Magic is useless!

[James Henstridge <james daa com au>]

Maciej Stachowiak wrote:

> On 07Jan2002 11:13PM (+0800), James Henstridge wrote:
>
> > Is it just me, or do file extensions and mime types stored in the 
> > filesystem as metadata seem equivalent?  Both move with the file in the 
> > filesystem (provided the app/user doesn't decide to change them), and 
> > won't be available if just reading from a bytestream (in which case you 
> > will need to get the information some other way, such as file magic).
> >
> > The benefit of file extensions is that they are maintained over almost 
> > every file system type.
>
> The disadvantage of file extensions is that they limit what the user
> can name the file, and break if the user renames the file in an
> unapproved way. There are certainly tradeoffs here.
Of course, if the file manager doesn't display the file extensions (such 
as explorer on Windows, and I believe finder on MacOS also (for UFS 
partitions)), then the user won't change them.  In windows, if you turn 
on file extension display, it will still warn you if you try to change a 
file extension.

You could argue that a mime type metadata would be just as fragile as 
extensions.  What happens when a user attempts to change their GIF files 
to PNG format by simply changing the mime type metadata?  They would be 
just as screwed as if they just changed the file extensions and that was 
used to determine file type.

James.

--
Email: james daa com au
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