[ogsa-wg] use case template

[Donal K. Fellows]

Geoffrey Fox wrote:
> As you gather requirements, I would suggest looking at several mashups 
> and the new generation of (workflow) tools they are supported by such as 
> http://www.protosw.com/ (which offer an ipod a day in their mashup 
> building contest) and Yahoo pipes http://pipes.yahoo.com/pipes/. A 
> trivial discussion of mashups versus workflow is at 
> http://grids.ucs.indiana.edu/ptliupages/presentations/Web20Mar04-07.ppt
> 
> I am known for following fads too much but I think the rather complex 
> web service workflow will face increasing competition from Mashup 
> technology with its naturally larger customer and developer base.

While some mashups do show the power of ad-hoc programming, there are
areas where workflows have a distinct set of benefits. Firstly, I've
been discovering over the past months how workflows are key to many
business processes and planning (e.g. airports aren't mashups, even if
they look like it superficially to travellers). Secondly, every mashup
I've ever heard of relies on having the end user as a computation locus;
the mashup is in their browser. The problem is that this requires the
end user to be present and using a (full featured) browser. In turn,
that restricts the applicability quite strongly, especially in relation
to small devices and part-time networks. It's also not clear to me just
how well mashups tackle security; I've certainly read in the past that
this is a distinct problem from a privacy perspective. It's usually much
clearer what is going on with a workflow, and that clarity is important
in many application domains (especially ones with non-trivial legal
requirements).

In short, workflows (especially not service-oriented ones) can go places
where mashups can't; the mashup advantage is in the presentation layer
and not the business-logic layer. Maybe some businesses will try to keep
the business-logic layer largely transparent so as to better support
mashups, but many (most?) won't and there are many known problems with
the approach of putting lots of critical code in the presentation layer.

Donal.