Re: URC proposal for Davenport Group

Daniel W. Connolly (connolly@hal.com)
Sun, 22 Jan 1995 18:09:39 -0600


Message-Id: <9501230009.AA22780@austin2.hal.com>
To: Terry Allen <terry@ora.com>
Cc: davenport@ora.com, uri@bunyip.com, hackers@ora.com
Subject: Re: URC proposal for Davenport Group 
In-Reply-To: Your message of "Sun, 22 Jan 1995 12:41:10 PST."
             <199501222041.MAA02978@rock> 
Date: Sun, 22 Jan 1995 18:09:39 -0600
From: "Daniel W. Connolly" <connolly@hal.com>


Before you get too far into the details of data formats,
components, and system design, could you give a brief
description of the features you need that are not
available though currently deployed technology?

For example:

In message <199501222041.MAA02978@rock>, Terry Allen writes:
>
>Then it has to be wrapped up and made to work so that I can write a link
>in my Docbook document (Docbook has a Ulink element to hold
>URLs) like this, for a URN:
>   ... blarty foo <ulink url="the.urn.goes.here">Windows 3.1
>	User's Guide</ulink> blarts more blarts
>
>or this, for a URC title query:
>
>   ... blarty foo <ulink url="the.urc.for.title.goes.here">Windows 3.1
>	User's Guide</ulink> blarts more blarts
>
>and when the user clicks on the hot spot, the intended document
>is fetched and displayed from the local installation or from the
>Internet, assuming the user is connected to it.  It may be
>desirable to extend <ulink> with attributes additional to 
>the present URL attribute.
>
>The browser has to transmit the URN or URC to the local URC 
>resolution service, then if need be to the publisher's URC
>resolution service site, and upon receipt of the response,
>to invoke the "some machinery" to pick a URL and fetch it.

I see no features in the above scenario that are not
currently available. Just write:

	<ulink uri="http://www.microsoft.com/windows3.1/userguide.html">
	Windows 3.1 User's Guide</ulink>

and run a chaching HTTP server. The client will consult the cache, and
if it's not available, the caching server will go to microsoft.com and
get userguide.html, which is a "cover page" (URC, surrogate record,
header, card catalog, abstract, call it what you like) encoded in HTML
for universal access. The "cover page" has the Title, author, perhaps
an abstract, and links to the document in, say, postscript, PDF, and
RTF format, along with ordering information for hardcopy (or alink to
such ordering info). The user chooses which URL to follow manually --
I haven't seen any successful techniques for automating this step.

As an excellent example of this sort of thing in action, see:

	http://www.research.digital.com/SRC/publications/src-rr.html
	(a bunch of citations leading to abstract pages which
	lead to postscript reprints)

	http://www.cs.indiana.edu/cstr/
	(a searchable index of abstracts etc.)

	http://www.cs.indiana.edu/cstr/?Distributed+Authentication
	(an example search result -- a list of "urc"s in a way)

Some folks _are_ going beyond HTML, HTTP and forms:

	http://rd.cs.colorado.edu/harvest/
	Harvest. They propose a new protocol for bulk distribution
	of "SOIF" records -- structured object information format;
	There's lots of neat technology here. Have a look if you
	want to do resource discovery on a large scale.

Dan