Re: Stab in the dark

Peter Deutsch <>
Date: Tue, 22 Mar 1994 05:04:46 --100
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From: Peter Deutsch <>
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Subject: Re: Stab in the dark
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[ Larry wrote: ]
.  .  . 
> If URNs are allowed to refer to multiple formats of documents, or
> multiple versions of updating documents, or online streams of
> information that you might telnet to, then no, you can't easily
> include the MD5 signature of the document.

Getting metainfo is a problem, and we have to solve it,
but do we have to solve it here with URNs and URLs?
It seems to me like we're wandering into the relm of the
underlying transport protocols. IF the protocol supports a
"meta-info" operation you could query for the associated
checksum, etc. If it doesn't you can't.  This seems like
the kind of functionality that would drive "buyer choices"
in selecting the next generation of services.

As a sign of things to come, both Gopher and WWW are able
to provide you with basic meta info now and work continues
to extend these, for example by finding new ways to access
interactive services. I'm not sure that it's really needed
to incorporate metainfo directly into URN or URL format
itself (I may be misunderstanding your comments here).

> What you're saying is that you don't have to trust the URN -> URL
> resolution process, because you will verify the entire URN ->
> <resource> resolution?
> I'm not sure I can live with that, although I'd like to think about it
> a bit more.

The way I see it, we can build a system with a single URN
encoding strategy (eg. mandate MD5 and be done), or
provide a more general architecture which is used to
support multiple URN strategies (implicit in our
assumptions about leaving decisions about versioning to
URN assignors, etc). My money is on the bet that the later
is what we'll end up with, since it is the only way to
provide for grand-fathering and the rough consensus thing
we have to have.

Now, if we allow multiple URN schemes, you will simply
have no choice but to accept that there will be some
schemes "you can't live with". They will have
characteristics you don't find acceptable but they're out
there anyways. The best you can do is recognize the
general scheme and alert your users with appropriate

I don't actually see this as a serious problem. Darwinian
selection will determine the most appropriate URN schemes
in practice. 

					- peterd

  My proposal for funding the Internet is pretty simple. I vote we institute
  an "Information Superhighway" tax, the proceeds of which will be used to
  fund network infrastructure. The way this would work is simple - every time
  someone uses the words "Information Superhighway" or any of its derivatives
  we strike them with a sharp object and make them pay a $10 fee (of course,
  the sharp object is not actually needed to make this scheme work, it's just
  in there because it seems an appropriate thing to do...)