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Re: Prelim. DAV spec.

From: Daniel W. Connolly <connolly@beach.w3.org>
Date: Thu, 31 Oct 1996 17:48:47 -0400
Message-Id: <199610312148.VAA26592@beach.w3.org>
To: Larry Masinter <masinter@parc.xerox.com>
cc: yarong@microsoft.com, ejw@rome.ics.uci.edu, w3c-dist-auth@w3.org
In message <96Oct31.115252pdt."415911"@mule.parc.xerox.com>, Larry Masinter wri
tes:
>> A representation (or entity -- same thing) is immutable, the way
>> integers and URLs are immutable. How many versions of the number
>> 2 or the string "http://www.w3.org/" are there?
>
>Well, a 'representation' isn't exactly the 'same thing' as an entity.
>We're working in an area where there aren't enough precise terms.
>
>It's very risky to try to make a 'plain logic' argument where we're
>primarily having difficulty with definitions of terms.

Fair enough. Let me make my context, or world-view clear. I've been
working on this issue of terminology for years, and in my world-view,
representation and entity mean exactly the same thing. I've written
down their defintion, plus a whole lot of other definitions, at:

http://www.w3.org/pub/WWW/Architecture/Terms

The document isn't in a completely consistent state, but many
of the definitions there are relavent and could be useful.

Because the terms 'representation' and 'entity' are somewhat
overloaded and confused, I consider them synonyms of my preferred
term, 'digital artifact':

digital artifact 
	some information represented as a sequence of octets (bytes) with
	an associated data format. aka document, entity, entity body,
	body part, representation

In contrast, consider:


document 

       1.a collection of resources that form a unit of information
	 that can be visited. A
         document has an address. The document consists of the object
	 at that address, plus
         some other objects connected to that object.

         aka Node in hypertext research literature. Also known as a
	 frame (KMS), card (Hypercard, Notecards). Used with this
	 special meaning in hypertext circles: do not confuse with
	 "node" meaning "network host".
       2.The object type with methods GET, PUT, POST, and DELETE. 
       3.see: digital artifact (c.f. HTML spec, SGML spec) 
       4.see: resource 

resource 
	an addressable unit of information or service in the
	Web. Examples include files, images,
	documents, programs, query results, etc. 

     aka object. 

object 


By the way, as requested by Yaron, here's a definition for 'principal'.

principal 
     the source of some messages; for example: persons, computers, and
	programs. See: authentic

authentic 
     An authentic message is one that has been received as the sending
	principal intended.
     Related failures include: 
         Corruption -- machine malfunction 
         Forgery -- intentional modification 
         Version skew (see also: replica) 

Dan
Received on Thursday, 31 October 1996 16:43:40 GMT

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