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RE: WebArch introduction, sort of

From: Larry Masinter <LMM@acm.org>
Date: Sat, 17 Jan 2009 07:25:15 -0800
To: <noah_mendelsohn@us.ibm.com>, "'Henry S. Thompson'" <ht@inf.ed.ac.uk>
Cc: <www-tag@w3.org>
Message-ID: <000c01c978b7$cd182630$67487290$@org>

I'm not sure it's worth getting into making up a theory
of MIME here, but a couple of things are probably
worth a footnote:

Content-type can also have parameters, and 

text/plain;charset="iso-8859-1" v.s.
 text/plain;charset="iso-8859-5"

can't easily be auto-detected. Many systems either ignore
the parameters or don't even allow them, which causes
difficulties.

It may be useful to distinguish between a "message"
which may have additional transfer encodings and
metadata properties (HTTP or other MIME headers) from
the pure "representation". I don't think it's entirely
clear whether all of the additional header/meta information
is completely transport independent or whether it also
is part of the "representation". So the octet-stream
which is actually transported might be encrypted or
compressed or whatever, and the process for transforming
from the received octet-stream within the message,
into a local embodiment (e.g., pixels on the screen 
as displayed by a web browser) might never instantiate
the actual "representation" as defined here.

Larry








-----Original Message-----
From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] On Behalf Of
noah_mendelsohn@us.ibm.com
Sent: Friday, January 16, 2009 2:24 PM
To: Henry S. Thompson
Cc: www-tag@w3.org
Subject: Re: WebArch introduction, sort of


Reading your excellent document again, I see:

"Representation' names a pair: a character sequence and a media type. The 
media type specifies how the character string should be interpreted. For 
example JPG or HTML or MP3 would be likely media types for representations 
of an image of an apple, a news report about an orchard or a recording of 
a Beatles song, respectively."

I don't think that's quite write.  I think the pair is {media-type, 
octet-sequence}.  For some important media types, characters aren't 
involved, I think.  Since you're trying to appeal to a broader audience, 
you might approximate that as {media-type, byte-stream}, or some such, on 
the theory that readers of a document like this are somewhat more likely 
to have the right associations with the term byte stream and/or be 
confused by references to octets.

Noah

--------------------------------------
Noah Mendelsohn 
IBM Corporation
One Rogers Street
Cambridge, MA 02142
1-617-693-4036
--------------------------------------








ht@inf.ed.ac.uk (Henry S. Thompson)
Sent by: www-tag-request@w3.org
12/04/2008 07:52 AM
 
        To:     www-tag@w3.org
        cc:     (bcc: Noah Mendelsohn/Cambridge/IBM)
        Subject:        WebArch introduction, sort of



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I've written what is intended to be an introduction to URIs for the
non-specialist.  People who need to teach WebArch might find it a
useful starting point.

   _What's a URI and why does it matter?_

     http://www.ltg.ed.ac.uk/~ht/WhatAreURIs/

Feedback welcome,

ht
- -- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
                         Half-time member of W3C Team
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 651-1426, e-mail: ht@inf.ed.ac.uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged 
spam]
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Received on Saturday, 17 January 2009 16:15:22 GMT

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