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> -----Original Message-----
> From: Gavin Thomas Nicol [mailto:gtn@rbii.com]
> Sent: Friday, December 28, 2001 10:50 AM
> To: xml-dev@lists.xml.org
> Subject: Re: [xml-dev] XML "tuple spaces" alpha technology
> demonstrated
>
> We've had XML repositories for years that are roughly akin
> (in terms of functionality) to a Ruple space.. but the kind of
> applications that can leverage this, and the programmers that can program
very
> loosely coupled distributed systems, are somewhat uncommon
Right, but maybe it's like saying we've had FTP and SGML for years that are
roughly akin to HTTP and XML, so HTTP+XML=SOAP is no big deal. There just
wasn't that convergence of established but complementary technologies that
produced web services as an "emergent property." Likewise, maybe, just
maybe, the "XML spaces" concept is much greater than the sum of its parts
(Linda, XML, SOAP, XML repositories) ... perhaps there was a bit too much
brandy in the Christmas fruitcake, but I can envision the possibility that
XML and NXDB's will do for Linda what HTTP/HTML did for hypertext theory.
It's true that loosely coupled distributed systems have traditionally been
hard to work with. I don't have enough knowledge of the details, but
consider the SOAP analogy: CORBA and DCOM systems are hard to configure,
make secure but useable, and a real pain to make them play nicely with one
another. By combining the HTTP infrastructure with XML's platform
neutrality and universal data representation capabilities, SOAP makes a lot
of the traditional problems just go away. Similarly, the
Linda/JavaSpaces/TSpaces folks have been trying to figure out how to make it
possible for ordinary programmers to work with loosely coupled distributed
systems for years. My hope is that by combining the Linda-esque loosely
coupled distributed systems architecture with the XML physical
infrastructure, Ruple, JXTA-spaces, etc. will achieve a similar
transcendence.
> Cool technology, perhaps, but where's the real killer app?
Sheesh, if I knew how to answer the "what's the next killer app" question,
I'd be rich enough to put Dare Obasanjo's "what to do when I am an evil
overlord" suggestions into practice in my daily life :~)
I may not have my facts right (Al Snell set me straight on some technical
aspects of RPC over unreliable connections that I think he meant to post to
the list), but my guess is that wireless web services are the "killer app"
for XML spaces. The RPC paradigm says "let's pretend the wireless internet
is fast and reliable, and hope that some lower layer preserves the
illusion." The "spaces" paradigm says "the wireless internet is
unpredictable, let's design around that fact." My highly non-expert guess
is that while humans can deal with 404 errors just fine, that's going to
throw the two-way XML web for a much bigger loop; the Linda-esque approach
of connecting processes that are disconnected in space and/or time via
"spaces" seems like a more solid foundation on which to build.
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