Ned,
Other applications use groups of files. (... markup languages,
for example.) In this case it may make a lot of sense to put each of the
components inside of a multipart/related object.
SGML is a good example of "groups of files". In the I-D on sgml the
proposal is to use Multipart/SGML, have the first part be the main
document, use a Content-reference: header to match body parts to
internally referenced file names. It is not clear to me that
headerset or references is a simplification.
Most ... don't provide a way to package up all their
components in a single bundle. (The only format I know of ...
is DDIF and its DOTS packages.)
SGML has a packaging scheme too, SDIF. Don't know if anyone uses it.
Ed
And then there are things that lie in between the two extremes. Appledouble,
for example, is the way it is because Macintosh files are multipart entities,
and the data part is meaningful by itself on non-Mac platforms. (I suspect th
at
Windows NT will give rise to some interesting variations eventually, since it
s
files can contain an arbitrary number of separate "forks".)
In the final analysis it is all a matter of thinking through the engineering
tradeoffs. Monolithic object formats have their place, as do sophisticated us
es
of MIME multipart objects.
Ned