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Re: Major errors in Caching and Cache-Control

From: Ted Hardie <hardie@merlot.arc.nasa.gov>
Date: Wed, 5 Jun 1996 13:00:24 -0700 (PDT)
Message-Id: <199606052000.NAA08084@merlot.arc.nasa.gov>
To: jg@w3.org
Cc: fielding@liege.ICS.UCI.EDU, mogul@pa.dec.com, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Jim writes:
> Now, independent of whether HTTP/1.1 does or does not forbid the
> transformation of objects being transferred, or storage of such objects
> in caches, content authors have valid reasons (for example, the datatype
> may be being used for mission critical, health or scientific use) where such
> transformations MUST be forbidden; and the transformations may not be
> taking place in the context of HTTP at all (some cooperative cache systems
> may very well not use HTTP.
> 
> I personally think that forbidding transformations in the context
> of HTTP is probably a mistake, but well see what consensus, if any, there
> may be in the WG.
> 
> It seems to me that the sooner we get "no-transform" into the hands of
> content authors the ability to say that this data better not be messed
> with between me and the end user, the better.  I'd sure not want my
> medical images so messed with.  People will (already are) experimenting
> with such data transformation in research contexts; wouldn't surprise me
> (might even take bets on) people doing it for product.
> 


I can give a real-world example of this.  One of the programs we work
with, GLOBE, uses the WWW to allow teachers and students to work with
environmental data; each school enters data which is relate to all the
other schools' data and used to create visualizations for use in the
classroom.  One of the requirements for participation in the program
is that a school have access to the web; many schools tried to meet
that requirement by getting AOL accounts.  

AOL, however, transfers images to its end users in its own format; it
translates GIF or JPEG to that format in order to reduce download time
for its users.  Unfortunately, that proprietary format eliminated
quite a bit of the actual content for some types of maps.  These had
to be changed to fit the color tables and other characteristics of the
AOL system.  

Had AOL obeyed a "no transform" directive, this could have been
avoided.
				regards,
					Ted Hardie

Note:  This problem was addressed some time ago; AOL may have since
reformed.
Received on Wednesday, 5 June 1996 13:03:59 EDT

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