# Re: The <URL: Wrapper take 2

Steven D. Majewski (sdm7g@virginia.edu)
Thu, 15 Sep 1994 19:27:19 -0400 (EDT)

- Messages sorted by: [ date ][ thread ][ subject ][ author ]
- Next message: Steven D. Majewski: "Re: The <URL: Wrapper take 2"
- Previous message: Mark P. McCahill: "Re: The <URL: Wrapper take 2"
- Next in thread: Roy T. Fielding: "Re: The <URL: Wrapper take 2"
- Reply: Roy T. Fielding: "Re: The <URL: Wrapper take 2"

    Date: Thu, 15 Sep 1994 19:27:19 -0400 (EDT)

    From: "Steven D. Majewski" <sdm7g@virginia.edu>

    To: Michael Mealling <Michael.Mealling@oit.gatech.edu>

    Subject: Re: The <URL: Wrapper take 2

    In-Reply-To: <199409152156.RAA08878@oit.gatech.edu>

    Message-Id: <Pine.A32.3.90.940915181316.23173B-100000@elvis.med.Virginia.EDU>

On Thu, 15 Sep 1994, Michael Mealling wrote:

> Steven D. Majewski said this:
> > What about URI's that aren't really locators: "URL:urn:..." for
> > example, and are message-id's and news: or nntp: really *locators*,
> > or a non-location-specific indicator.
>
> AH!!... I think I see the confusion. In the case of a URIs that aren't
> locators it would NOT be 'URL:urn' but 'URN:'. For example, we now have
> signigicant work being done with LIFNs (Location Independent File Names)
> that aren't URNs nor are they URLs but they LOOK like URNs as far as
> syntax is concerned. Therefore we have to have something to differentiate
> twixt the two: LIFN:<value> and URN:<value>. This is why we need to be
> able to know without funky regular expressions that everything after
> the colon is a URL or a URN or a LIFN or <insert your favorite UR* here>.
>

URN: is part of the described syntax for URN's (in the last draft I
looked at ), and according to rfc1630 is also the "scheme" part of
a URI that is a URN ( The URN draft says "URN:" , rfc1630 says "urn" )

rfc1630's BNF says a "prefixedurl" is "u r l : url"

In the current draft, URL: is not described as part of the syntax, nor
is it in the BNF or the syntax.

I assume LIFN: ( or is it "lifn:" ? ;-) would also be a URI scheme.

Does there need to be an additional scheme to say that LIFN: is not
a locator, but a logical indicator of some sort.

If you are going to get picky about sorting out Locators from other
indicators, then mid: and cid: are not Locators - they don't give
sufficient access information - but are Indicators. So if URL is
really needed to distinguish Locators from other Indicators,
<URN:mid:message-id> is wrong and misleading. If it's *not*
misleading, then there is clearly no need to distinguish Locators.

There *IS* a need to distinguish URN's , but URN is the "scheme"
that tells you what type or URI it is. (You don't need URN:urn:...
URL:some-url-scheme: is similarly redundant. )

If scheme is an unknown one, then does it make much difference to know
if it is a Locator or some more logical indicator ? ( If I don't
know what to do with a LIFN:, I don't see that it makes much difference
whether it denotes a Locator - i.e. an Indicator with protocol and
access information, or is a logical indicator. Knowing that doesn't
give me anything else to do with it. URN's on the other hand are
distinguished because there is a next step - contact a "name broker"
to resolve it into a URL ( or list of URL's or URC's )

- Steve Majewski (804-982-0831) <sdm7g@Virginia.EDU>
- UVA Department of Molecular Physiology and Biological Physics

- Next message: Steven D. Majewski: "Re: The <URL: Wrapper take 2"
- Previous message: Mark P. McCahill: "Re: The <URL: Wrapper take 2"
- Next in thread: Roy T. Fielding: "Re: The <URL: Wrapper take 2"
- Reply: Roy T. Fielding: "Re: The <URL: Wrapper take 2"