Re: URC spec

Michael Shapiro (
Mon, 12 Jun 1995 23:03:36 -0500 (CDT)

From: (Michael Shapiro)
Message-Id: <>
Subject: Re: URC spec
Date: Mon, 12 Jun 1995 23:03:36 -0500 (CDT)

   There  is  an  implied  assumption  in  the   SGML-based   URC
specifiction  that  URNs  resolve to URCs. I think that this is a
fundamental mistake.  URNs should not be required to  resolve  to
URCs. They should be allowed to resolve to any resource.

   In section 3 "Attribute Sets", the specification states

     "A ... complication arises as a result of using  a  URN  for
     the AID .... We resolve AID-1, which is a URN, and ge back a
     URC (URC-2) ....  What is the AID in URC-2? How do we  avoid
     infinite regress?"

   The proposed solution is to convert the  AID  from  a  URN  to
something which is not a URN, but has all the properties of a URN
in that it is a persistent name for a resource that  happens  not
to be a URC.

   This  infinite  regression  could  also  be  solved   if   the
requirement  that  all  URNs resolve to URCs be relaxed. Here, it
seems to me, is a perfect example of the need  for  a  URN  which
does NOT resolve to a URC.

Michael Shapiro         
NCSA                              (217) 244-6642
605 E Springfield Ave. RM 152CAB  fax: (217) 333-5973
Champaign, IL 61820