xml-dev - Re: Microsoft's DISCO proposal and XML packaging

["Simon St.Laurent" <simonstl@simonstl.com>]

At 06:16 PM 7/12/00 +0800, Rick JELLIFFE wrote:
>Edd Dumbill wrote:
>> 
>> I've just read http://msdn.microsoft.com/xml/general/disco.asp
>> "Draft: Discovery of Web Services (DISCO)"

>I wonder if Simon and Sean might care to compare Disco with their
>approaches?

I'm still recovering from the mild shock of only finding three pages at my
printer.  At first, as a supporter of simpler Web standards, I was pleased,
but on reading them, I'm not finding much meat.

The real meat appears to be in SOAP Contract Language (SCL), marked as an
early draft but available from:
http://msdn.microsoft.com/net/scl.zip

It seems to me like DISCO - and SCL in particular - are much more about
point-to-point SOAP-style communication setup than about XML packaging per
se.  While schemas and stylesheets are described, so are things like
schedules, rules, and contexts for flows.

This is very different from XPDL and some of its competitors, which I tend
to see describing document classes rather that flows.  The two needn't be
incompatible, and I think document type description can be an important
part of flow description, but neither are they identical.

Moving forward, I'd strongly recommend that packaging be implemented using
XLink or (less happily) RDF.  When I started XPDL, I planned that it would
work out to be an XLink (or set of XLinks), though the disappearance of the
remapping attributes left me high-and-dry and I haven't gone back to that
task - yet. 

Some sort of discovery mechanism, possibly though not necessarily using
HTTP, seems very much in order, however, and I hope this proposal moves
discussion forward.

Simon St.Laurent
XML Elements of Style / XML: A Primer, 2nd Ed.
http://www.simonstl.com - XML essays and books