Re: Explaining the benefits of http-range14 (was Re: [HTTP-range-14] Hyperthing: Semantic Web URI Validator (303, 301, 302, 307 and hash URIs) )

On 10/20/11 7:40 AM, Nathan wrote:
> Kingsley Idehen wrote:
>> On 10/20/11 2:38 AM, Michael Smethurst wrote:
>>> name = generic information resource urblah
>>>
>> You assign names to data objects. A data object is an encapsulation 
>> of data that can be simple of complex. In all cases data objects are 
>> accessible via addresses. In all cases, you access a data object via  
>> act of de-reference (irrespective of levels of indirection).
>>>
>>> address = specific representation url (exposed in content location 
>>> headers and rel="alternate" < forgot that bit earlier)
>>>
>> address (a URL) = how you get at the data, basically, data object 
>> access is the prime function. That isn't necessarily the case if you 
>> use a URL as a generic name i.e., one doesn't assume data object 
>> access, you can only assume data object identification.
>>
>> The intuition challenge here is that URLs are being perceived as 
>> being indistinguishable from URIs at both the functional and 
>> conceptual levels. A URL being a kind of URI implies they are related 
>> but not identical. Thus, using URLs as data object names is quite 
>> *unintuitive* but extremely *ingenious*, especially in the context of 
>> the World Wide Web.
>
> Trying to follow, can you confirm:
>
>   URL = Absolute / non-frag URI?
>   URI = URI-with-frag?
>
> And you're suggesting that we do not name things, rather we name data 
> objects (each data object "represents"/"describes" a thing), and since 
> they are data objects we can name them with either a URL or a URI, the 
> only distinction being that when naming with a URL (and no redirect) 
> you can only provide a serialization of one data object in response to 
> a lookup on an address (URL), whereas with a URI you can can provide a 
> serialization of several data objects (since URI contains a URL).
>
> Or are you saying that a URL = an address and a URI = a name, and a 
> single URI is not (or cannot be both) a name and an address?

I would say, use *names* to identify data objects. Use *location names* 
(purpose/functions specific) to identity their location/address. Use a 
*location naming mechanism" that is abstracts the data access process. 
Use indirection (de-reference) such that access to the same data object 
works whether you reference it by generic name or data access address. 
Use content negotiation to determine what actual representation of a 
data object gets delivered from server to client as part of a 
client-server message exchange.
>
> Or, are you saying that we can use a single URL/URI as both a name and 
> an address (which afaict, everybody already does).

Correct! Everybody already does exactly what you describe, but this all 
happens in the Web's information space dimension, so name and address 
disambiguation doesn't matter.


When you enter the Web's data space dimension, name and address 
disambiguation matters since without said disambiguation we can't 
effectively handle the fidelity of *object equivalence* :-)

"...two notions of object equivalence exist: two objects can be 
identical (they are the same object) or they can be equal (they have the 
same value)." -- excerpted [1]

Linked Data is a nifty tweak of what got lost a while back re. Object 
technology. Last time around programming language vendors ransacked this 
powerful concept. My fundamental hope and mission, this time around, is 
to not let Web architecture misunderstanding repeat the problem from the 
past. There isn't a shortage of literature (I've posted many links) 
demonstrating that the Web was always conceived as an object based system.

I hope I answered your questions.

Link:

1. 
http://www.cs.cmu.edu/afs/cs.cmu.edu/user/clamen/OODBMS/Manifesto/htManifesto/node4.html 
<http://www.cs.cmu.edu/afs/cs.cmu.edu/user/clamen/OODBMS/Manifesto/htManifesto/node4.html>

2.http://www.w3.org/Addressing/rfc1630.txt

3.http://www.w3.org/People/Connolly/9703-web-apps-essay.html 
<http://www.w3.org/People/Connolly/9703-web-apps-essay.html>


Kingsley
>
> Best,
>
> Nathan
>
>


-- 

Regards,

Kingsley Idehen	
President&  CEO
OpenLink Software
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen