Re: DNS and Directory Services

[David Collier-Brown <davecb@Canada.Sun.COM>]

Paul A Vixie and Michael Dillon have been debating directory
service, and I fear they're in **violent** agreement.

  Alas. ``terminological inexactitude'' raises its ugly head oncer
more.

  If I defined
	lookup service ::= send one string, get 0 or 1 string back
	search service ::= send a pattern, get 0, 1 or many strings 		
			   back

then it would be fair to claim:
  DNS is only a lookup service
  The white pages and a string matcher is a lookup service
  The white pages and a pattern matcher (or a human!) is a search
service

  I claim that ``directory service'' is far too ambiguous for
this discussion, and should be restricted to discussions of
ls, X.500 and LDAP.

   Specifically,I claim that directory services fit somewhere 
**between** lookup and search services, such that:
i) search can be built on repeated access to a directory or lookup
   service and a pattern-matcher   
ii) directory can be built on repeated access to a lookup services and a
   string matcher

   And I speculate that DNS isn't really what I want to access
repeatedly without **significant** caching for any search service.
Search is a <UNPRINTABLE EPITHED DELETED> load for most database
systems.  I think I'd want enough disk to hold .com, and half the
country domains, and about a gig of main memory for the dns cache
of my search engine.

--dave
-- 
David Collier-Brown,  | Always do right. This will gratify some people
185 Ellerslie Ave.,   | astonish the rest.        -- Mark Twain
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