Re: About metadata (long!)

[Ian Wells <I Wells tarragon-et co uk>]

[Article chopped - it's massive, and the reference is in this mail's header]

My arguments:

- if a file format has nowehere to put an 'attribute' such as a
copyright message, a thumbnail, or whatever, it's not appropriate to
put the attribute in the file.  Word 97 files allow thumbnails and
summary information, so feel free to use them.  JPEGs don't have space
for a thumbnail, so you either translate them to a different file
format which has a thumbnail (permanently or on-the-fly) or you do
without.

- you can encapsulate any file in another container file (tar, ar,
multipart MIME) or whatever) if you really feel the need to add attributes.
You can use AVFS to get hold of the data and the attributes for
applications which are (relatively) thick and can't work out the file
format for themselves.

- if you're really that bothered about all of this, you can make
directories and treat them as files (Acorn RISCOS does this, at least
for applications).  That way, there's a file in there which represents 
the data and a number of other files which represent the metadata, and 
your filer treats it as one large lump.  But this is a bit horrible
and it has issues with 'mv' under Unix.

- if your idea doesn't work in the bounds of a normal Unix filesystem, 
it's not good enough.  Adding anything to a Unix filesystem structure
which doesn't need to be there is completely inappropriate.

- if your file is on an NFS disk and modified/copied/renamed by
someone else on another non-GNOME machine, it's still got to be right.
This means that any additional database is no good, any
filesystem-changing things aren't going to work, and anything which
requires a GNOME-specific file format had better be simple enough to
deal with (translate to and from) on non-GNOME systems.  In the case
of the last point here, I'd suggest we're talking shell-script simple
to separate; we don't want to go inventing file formats willy-nilly.
Hence the suggestions listed above.

I hope this covers all the bases...

-- 
Ian.