Re: Z39.50 and URI

Michael Mealling (ccoprmm@oit.gatech.edu)
Tue, 23 Aug 1994 12:10:08 -0400 (EDT)

From: ccoprmm@oit.gatech.edu (Michael Mealling)
Message-Id: <199408231610.AA09133@oit.gatech.edu>
Subject: Re: Z39.50 and URI
To: hoymand@gate.net (Dirk Herr-Hoyman)
Date: Tue, 23 Aug 1994 12:10:08 -0400 (EDT)
In-Reply-To: <199408231304.JAA65161@inca.gate.net> from "Dirk Herr-Hoyman" at Aug 23, 94 09:04:57 am

Dirk Herr-Hoyman said this:
> 1) Connectionless vs. connection-oriented. The work so far in URI has a
> connectionless orientation. Z39.50, on the other hand, is connection
> oriented. It is meant to be run in a session, with results from a request
> being used later. This doesn't map very well to a URL, and is a large
> reason why there is no Z39.50 URL yet.
>
> It occurs to me that this has broader architectural implications for URI.
> Are we going to work within this connectionless paradigm only? We have
> been able to shoehorn FTP into a URL, but this is tame compared to what
> happens in Z39.50.

I don't really think 'shoehorn' is completely accurate. The purpose of
a URL is to retrieve a given object, not to implement a meta-protocol. This
is why some folx see the nntp URL as limited because they want to
be able to put all the NNTP command set into a URL. The questions is
really can I specify a Z39.50 URL that will just give me the object
in question. If I want to use the additional browsing and searching power
of Z39.50 then I should be using a much more capable Z39.50 browser.

> 2) URC and Variant sets. Z39.50 was developed by the library community.
> While not the only use for Z39.50 by any means, most databases at this
> point are library catalogs. Clearly this contains the type of information
> that we are proposing would go into a URC. One aspect of this is the
> Variant set. While syntactically (and protocol wise) different, I think
> the goal is the same, to provide information on choices for retrieval.
>
> Are there two sets of railroad tracks being built on this mountain? Will
> they fit together when they meet?

I don't think so. There is enough cross pollenation of the two groups that
there will be good interoperability twixt the two systems. We'll use
bits of Z39.50 and you can use bits of the URI stuff....

Kevin? Jim?

-MM

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