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Bob,
I post to this forum only infrequently, so please forgive me for butting
in. I think some reactions to the entire thread bubbled over when I read
your recent post.
Despite your protests, and my not knowing a thing about you or about most
other participants in the discussion, I think there may be more in common
between you and Walter Perry than you've admitted to so far. Both of you
are mediators -- maybe even arbitrageurs, to borrow from Walter -- who seek
to fill a niche (and perhaps make a living in return) by concentrating a
body of knowledge at a point, leveraging what you know to provide for
others something that is too costly, or too difficult, for them to obtain
for themselves unaided. From what you've said, yours is knowledge about the
feeds -- about where they are, and how they work -- which you aggregate and
analyze for your customers. Your product is valuable to them because to get
a combination of broad access (maintenance of which is a chore) with
breakdowns and breakouts (the indexing you provide), would otherwise
require both hours of labor, and considerable expertise -- to say nothing
of will or drive. Very valuable.
But difficult -- not least because of the "ownership" issue that troubles
you. Who owns the feeds, who is responsible for them? How much
responsibility do you take, as an intermediary? In fact, I think you have
put your finger on the exact nub of the matter. This is a matter of
Aristotelian warrants. Postel's Law is being invoked on the one hand, out
of context -- as if by saying "be liberal" Postel were arguing that users
of the protocol he is defining can go ahead and break the rules, what the
heck, because being liberal and forgiving in what you accept is the rule.
But Postel (as has been pointed out) doesn't fairly warrant this: his
assumption is that users will be following the explicit rules. Only where
the rules fail to be perfectly clear, he adds (in a metastatement that is
not, after all, a specification of a protocol but rather -- in the
"Philosophy" section -- a hopeful instruction to his readers about how to
behave), they should be "conservative ... and liberal". Note *both*
conservative and liberal. To suggest that he's therefore licensing
rule-breaking (whatever the rule may be) is to miss how he's simultaneously
insisting on conformity ("be conservative in what you do"). The Law is a
paradox.
To be fair, in its larger context -- that is, *if* you assume all parties
are scrupulously and respectfully following the rules given (to whatever
extent those rules are clear -- maybe "Postel's Law" is a hedge to cover
those cases where it is the rulegiver who has failed?) -- it isn't a
paradox at all, but rather a simple restatement of the Golden Rule. Yeah --
be nice, guys. If you can't agree with the other party on what the rule is,
then maybe *both* should step up, make allowances, since that's what you'd
want from the other guy. As an ethical principle this is both ancient and
sound. If we all followed it, the world would be a better place. "Our
discipline is strict, so that life will be easy" (a Sufi saying, IIRC).
Yet as you know, it's a more difficult rule to practice than it is to
pronounce; and even when everybody tries to follow it, there can be
missteps: such is the nature of human (and hence machine) imperfection.
(Let's not fall into the trap of imagining that machines are perfect and
pristine, that because some routine is formalized and automated through
code, it is therefore above failing and beyond fixing -- no, this is more
like the Sorcerer's Apprentice. We are not talking about software
applications as they exist in the conception of their designer's brains,
where they can do no wrong. Software in the real world is both buggy, and
plain wrongheaded; is expressive of learning processes -- *human* learning
processes -- that are often young, halting or bone-headed, or choosing hard
ways over easy ones.)
Hence the need for mediators, steppers-between, arbitrageurs. An honorable
profession, if a shady one. But however much they know about rule-breaking
or exploiting the in-between spaces, the good mediators know the boundaries
are there for a reason, and the rules are a good thing.
As it applies to XML, ironically, Postel's Law would be difficult, even
impossible, to observe if it were not exactly for the relatively stark
clarity afforded by the definition of XML well-formedness. (That allegation
that XML's creators "broke Postel's Law" misses the point that Postel was
writing a *specification*, after all.) Imagine if XML were woolier and
wafflier than it is, that its corner cases had not been fully explored and
discoverable in the archives of this list. What would being liberal or
conservative mean then? Among the endless debates over what was in and what
was out, the horn would be sounded for being liberal in what you accept
from others, and for all to play, we would have to accept more and more.
Soon enough we would have bloatware and vendor lock-in (hey, where have we
seen that?). Far from a wise counsel that we should work together, Postel's
Law would be a recipe for disaster, if the hawks could not keep insisting
that "if it's not well-formed, it's not XML". Well-formedness, however
bizarre or arbitrary it may seem in some respects (no unescaped less-than
signs in attribute values! no slashes in tag names!) is not just a
religion, it is the placing of a boundary. If it parses as XML, well good,
go ahead and move on. If it doesn't, all bets are off. Not a threat, but
simply a statement of fact, that stuff that doesn't lie about what
character encoding it uses (to use an example actually cited), is going to
be more predictable and less troublesome in general than stuff that does.
There may well be a role for mediating even these clear boundaries, as
Michael Champion suggests: help out by making not-quite-XML into XML. To be
successful (assuming there is enough busted XML around that people couldn't
be bothered to fix), this service would not have to be right or perfect
(this is the work of human interpreters, and is necessarily tricky --
Hermes not Apollo), merely earnest enough, and skilled enough, to sustain a
stream of work from those who know it to be worth their pile of
micropayments. A kind of benign arbitrage. Most of the time, Mike (a newly
minted millionaire) just fixes up XML declarations and replaces errant
ampersands. It doesn't cost him much, because his software is so smart. But
once in a while, something like Tim's anti-XML comes his way. What will he
do then? Hopefully, follow the Golden Rule (including being conservative in
what you do). Hopefully, go out of band and raise a question on a different
channel, make an effort to resolve the problem properly in its real-world
context, not just guess or flip a coin.
Just so, in your role as mediator between the feed-reading masses and the
net's flora and fauna -- a virtual supermarket for online tasties -- you do
not simply have to take the bad stuff and pass it along silently, as if you
were guiltily putting mislabelled snacks on the shelves. You can speak up.
Others have already suggested how it could be done -- a red X on a GUI
makes a statement -- and if there's any means of feedback, all the players
will be motivated to come into line with each other, over time, first
making your job easy, then eventually making it perhaps unnecessary, at
which point you can go on to make your further millions doing something
else. In the meantime, whether you want that red X on not-quite-XML,
coddling your users of the moment at the cost of further interoperation
down the line (or worse when the anti-XML comes along) -- or whether you
want it only on stuff that's well-formed, if invalid (perhaps passing the
non-XML back to its Postel's Law-breaking producer), is a business and
social decision, not a technical one.
Nor do I see any reason to think Walter is doing much different.
Interested readers might want to take a look at Michael Sperberg-McQueen's
keynote at Extreme 2002:
http://www.mulberrytech.com/Extreme/Proceedings/html/2002/CMSMcQ02/EML2002CMSMcQ02.html
"if network effects are the best predictor, then we must infer that the
people who actually are responsible for making a good decision are the
early adopters. In IT, that means you. You have a responsibility to judge
what matters not by network effects but by technical merit."
Regards,
Wendell
At 06:03 PM 1/15/2004, you wrote:
> It may work for Walter to claim that the data is his and not
>someone else's but it isn't ok for at pubsub.com . The function we're
>providing is content-based routing -- we're not doing re-publishing,
>data mining, or other stuff (yet). Thus, when we pass data to you,
>we're claiming that it *is* someone else's data -- it just got to you
>by flowing through our content-based PubSub routers. We don't claim
>the data and we take no responsibility for it (within the limits of
>applicable law...)
======================================================================
Wendell Piez mailto:wapiez@mulberrytech.com
Mulberry Technologies, Inc. http://www.mulberrytech.com
17 West Jefferson Street Direct Phone: 301/315-9635
Suite 207 Phone: 301/315-9631
Rockville, MD 20850 Fax: 301/315-8285
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Mulberry Technologies: A Consultancy Specializing in SGML and XML
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