Re: URC proposal for Davenport Group

Dirk Herr-Hoyman (hoymand@gate.net)
Mon, 23 Jan 1995 14:21:38 -0500


Date: Mon, 23 Jan 1995 14:21:38 -0500
Message-Id: <ab4a11c40d0210045e62@[199.227.1.142]>
To: "Daniel W. Connolly" <connolly@hal.com>, Terry Allen <terry@ora.com>
From: hoymand@gate.net (Dirk Herr-Hoyman)
Subject: Re: URC proposal for Davenport Group
Cc: davenport@ora.com, uri@bunyip.com, hackers@ora.com

At 5:54 PM 1/23/95, Daniel W. Connolly wrote:
>In message <199501230109.RAA07091@rock>, Terry Allen writes:
>I like the concrete example...
>
>>| 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
>>
>
>I think I'm missing something. You want it so:
>
>        * the user to selects a ULINK
>        * the browser uses info from the ULINK to find another document
>        * that document is displayed
>
>Where does the URC and the bibliographic database come in? As far as I
>can tell, the browser just takes a URL from the ULINK, decodes it into
>a server and path as usual, and sends the path to the server. The
>server looks up the path (ok... this could be some sort of database
>lookup: is this the piece you want to explore?) and returns an SGML
>entity.
>
I believe what is missing here in Terry's example is a URN or Uniform
Resource Name.  The URC is meant to be the "glue" that holds together URNs
and URLs.  Instead of using URLs as the ulink, one would use a URN, which
is a location (and maybe format, language, ...) independent name.  Then, a
URN resolution server is queried, much like a DNS server, and returns a
URC.  The URC holds 0 or more URLs, as well as select other meta-data.

So, a URC comes together with a bibliographic database because they both
hold meta-data.

I'll rephrase Terry's example now as:

<ulink uri="urn:microsoft:doc/windows3.1/userguide">
 Windows 3.1 User's Guide</ulink>

And the associated URC could be

<urc>
<publisher>
Microsoft
</publisher>
<locationGroup>
<item>
<url>http://www.microsoft.com/windows3.1/userguide.ps</url>
<format>text/html</format>
</item>
<item>
<url>ftp://ftp.microsoft.com/pub/windows/windows3.1/userguide.ps</url>
<format>application/postscript</format>
</locationGroup>
</urc>

You may or may not care for the syntax of this URC, but I hope the intent
is clear.

There are many practical considerations here, such has just how does the
URN resolution server work, what protocol does it use.  But, the main point
we are exploring at the moment is whether it makes sense to use SGML to
encode the URCs.  If we are to live in an increasing SGML oriented document
world, then this would be a nice touch, since the URC could be contained
within the document itself, as well as on a URN server.  Makes harvesting
the URCs a conceivable task.

--
Dirk Herr-Hoyman <hoymand@gate.net> |          I tried to contain myself
CyberBeach Publishing               |                                but
   * Internet publishing services   |                          I got out
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