home *** CD-ROM | disk | FTP | other *** search
- [Admin: If anyone is missing documents from this discussion which I
- have, they are all in a mailbox
- file://info.cern.ch/pub/www/doc/udi/discussion.mbox. Some of the
- messages were sent to only some of the lists. Also, I mis-spelled
- the name of cni-arch.uccvma in my original posting, so some replies
- have not gone there. I will not repost them. The orginal udi paper
- is slightly updated now. Same UDI -- no versioning ;-)]
-
- Now, about these USDNs:
-
- > Date: Thu, 5 Mar 92 07:32:50 EST
- > From: ses@cmns.think.com
-
- There have been several messages now with a common theme: That what I
- called in the udi1 paper a "lasting registered name" is better than
- an "address".
-
- Peter Deutsch argues the point at length in
- <9203042206.AA12411@expresso.cc.mcgill.ca>, using the term USDN by
- analogy with ISBN.
-
- John Curran on <Thu, 27 Feb 92 19:45:42 -0500> argues the same, and
- also suggests quoting both registered name and address (which I
- wasn't so sure about in case they get out of sync).
-
- I completely agree with Peter and Simon's point of view, and I have
- modified the paper to put more emphasis on this. What I obvioulsy
- didn't make clear enough is my feeling that:-
-
- 1.There may be more than one USDN scheme, just as there are many
- physical addres schemes.
-
- 2. There may be more than two stages: it is an oversimplifiaction to
- talk of only a USDN and an address: For example, an ISO standard may
- dereference (or as Ed says, "swizzle") to a document produced by the
- IETF which may dereference down to a prospero name which may be a
- pointer to an FTP file.
-
- 3. We can't use USDNs now because they aren't there. We need a
- transision strategy.
-
- Therefore, UDis were supposed to be able to hold _either_ a USDN _or_
- a physical address. They weren't intended to get involved with the
- discussion of which USDN/ISBN/ISSN/ISDN (?!) scheme is better. So, I
- say, by all means define an USDN scheme, then register it as a
- possible UDI. If is good and everybody uses it, everything will end
- up with a USDN, and the context will always be USDN documents, so the
- usdn: prefix (or whatever) will not in practice be used. I'm all for
- the market deciding between protocols.
-
- Simon:
-
- > I'm strongly in favour of the two stage lookup process; X.500 is
- obvious
- > technology, although it is rather heavyweight for personal
- computers. An
-
- > alternative might be some sort of DNS/archie-like service. These
- could return
- > Tim's UDIs, which could then deliver the good themselves.
-
- I would say "a server takes x500 UDIs and returns physical UDIs which
- deleiver the goods themselves.", meaning the same thing. (I would
- allow it the option of delivering a set of addresses, not just one.)
- Yes, x500 is heavyweight so one can have a lighter protocol which
- accesses a real x500 engine via a gateway with a large cache.
-
- > Of course, invdidual information sources should still use local
- document
-
- > numbers where possible, but should provide a way of mapping from
- local-id
- > to universal-id when needed.
-
- Yes.
-
- > One little question: What should be done about document versions?
- > Obviously, different versions of a document should have different
- > UDSNs, but should there be a simple way to compare USDNs modulo
- > versions?
-
-
- Good point. What about versions which split? A great spin-off of
- having versions available is that you can refer to a line number in
- them. A line number in a document which is not frozen is useless.
- [This solves a recurring problem in hypertext systems, when one wants
- to link to part of a document to which one has no write access, and
- which may change].
-
- > Here are some suggestions.. Eat hot ASN, Cultural Cringer.
- > [...]
-
- We must be careful not to reinvent the wheel: if the USDN problem is
- the same as the phone book problem (which it seems to be) then we
- should pick up on x500.
-
- An important thing about x.500 is that it was designed to scale (I
- hope!). By contrast as Ed says:
-
- | Date: Wed, 04 Mar 92 23:52:05 -0500
- | From: Edward Vielmetti <emv@msen.com>
- | [...]
- | ISBN is hierarchical so you can stamp out your own
- | unique ID's; ISSN (international standard serial number) has
- | a central cataloging authority.
-
- and i doubt whether either of those will scale to allow document
- publishing on the net by every kindergarten child etc etc twice a
- minute. That's why I assume x500 is best in theory at least. But tell
- me I'm wrong.
-
- Ed also mentions message-ids which are after all unique. The trouble
- is, there's no way of looking up where to find them.
-
- Tim
-
- __________________________________________________________
- Tim Berners-Lee timbl@info.cern.ch
- World Wide Web initiative (NeXTMail is ok)
- CERN Tel: +41(22)767 3755
- 1211 Geneva 23, Switzerland Fax: +41(22)767 7155
-
-
-
-
-
-
-