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Re: use of LDAP for query

From: Dan Brickley <Daniel.Brickley@Bristol.ac.uk>
Date: Wed, 9 Dec 1998 19:48:00 +0000 (GMT)
To: www-webdav-dasl@w3.org
Message-ID: <Pine.GHP.4.02A.9812091936290.5874-100000@mail.ilrt.bris.ac.uk>
On Wed, 9 Dec 1998, Jim Davis wrote:

> At 06:29 AM 12/9/98 PST, LeVan,Ralph wrote:
> >> From: Jim Davis [mailto:jdavis@parc.xerox.com]
> >> I think it's also reasonable to consider, from the library 
> >> point of view,
> >> whether LDAP might work as well as DASL.  Do you have any 
> >> thoughts on that?
> >
> >I can't really believe you made that suggestion.  The objections that the
> >Web community has consistently expressed about Z39.50 are it's statefulness,
> >binary encoding and transmission over raw tcp/ip.  LDAP has all those
> >deficiencies.  In addition, it has a really weak searching mechanism.
> 
> Thanks.  It's good to get input from a librarian's perspective. 
> 
> FWIW, the Isaac project
> (http://scout.cs.wisc.edu/scout/research/rfp/IssacCall.html) is using LDAP
> for metadata search.  I don't know why they picked LDAP, (except that
> probably they started before DASL was proposed, and they have working code
> now), but it seemd to me possible that to a librarian there might be other
> factors I had not considered.

My understanding from talking to the Scout folks was that they wanted a
protocol simpler and easier to implement than Z39.50, but 
less doomed looking than WHOIS++, the protocol used by many of the
other subject-based metadata repositories doing similar work. WHOIS++ is
attractive in that it has inbuilt facilities for query routing /
referrals (ie. the centroids /CIP mechanism for sharing database
indexes), but is not widely expected to set the world on fire anytime
soon. LDAP is intriguing as a halfway house between the simplicity of
WHOIS++ (eg. see [1]) and the richness of Z39.50. There is also work
(within DESIRE, Scout and elsewhere) on integrating richer query-routing
/ index sharing mechanisms into LDAP (eg. searching one server might
elicit a referral to a more likely target elsewhere).

Dan






[1] Jon Knight's referral following 6 line WHOIS++ client:
	http://www.roads.lut.ac.uk/People/jon.html
Received on Wednesday, 9 December 1998 14:48:04 GMT

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