Re: [apps-discuss] seeking pragmatic guidelines for content-type 'structure': when to go top-level?

"Martin J. Dürst" <> Thu, 10 November 2011 10:53 UTC

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Subject: Re: [apps-discuss] seeking pragmatic guidelines for content-type 'structure': when to go top-level?
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On 2011/11/10 18:28, t.petch wrote:
> ----- Original Message -----
> From: "Dave CROCKER"<>
> To: "Apps Discuss"<>
> Sent: Thursday, November 10, 2011 7:59 AM
>> Folks,
>> On 11/10/2011 2:02 PM, Barry Leiba wrote:
>>>> But the fact is that we have a major/minor type system. We can as well make
>>>> reasonable use of it.
>>> As I said in the other thread (on font/*), we already have the concept
>>> of saying "This is text," "This is an image," and "This is audio," and
>>> I see only negative points in insisting that everything other than the
>>> few TLMTs that we're already defined have to be "application".  We
>>> should do some filtering and apply some judgment, of course, but
>>> making everything the equivalent to "application/image-jpeg" is silly
>>> and non-useful.
>> That states a basic direction/goal: To have a lower hurdle than perhaps was
>> there before.
>> Does it have any basic downsides?
>> My sense from the latest round of postings, including Ned's, is that there is
> no
>> current reason to impose a high hurdle on TLCTs.
>>        Consensus check
>>        ===============
>>        Is there anyone out there who believes that it is extremely expensive or
>> dangerous to introduce new, top-level Content-Type and that, therefore, the
>> barrier to new TLCTs should be (kept) high?
> Yes.  Based on FUD rather than concrete information,

It's nice for you to admit that your argument is based on FUD. But I 
think its a bad idea to use that for standards development.

Ned has given some very good arguments for why most if not all software 
uses the full (i.e. major/minor) type for dispatching,... All the 
experience I have (which I have to admit is way less than Ned) points in 
the same direction.

> but what will all the
> deployed software do when face with a new top-level Content-Type?  And how long
> will it take for the makers of commercial software to incorporate this in their
> products (1-2years) and how long will it take for that software to be widely
> deployed(3-5 years)?

If it will have taken the IETF more than 10 years to get around to 
finally approve the font/ top level type, we can't blame developers when 
it takes them 3-5 years to deploy that.

And the deployment time is the same if we register new types under 

Regards,   Martin.

> I just received an (antisocial) e-mail with .gif's attached, so I edited the
> Content-Type to be font/various things, and my MUA took no notice, just
> processed them as .gif.
> I modified the Content-Description in the same way, same result.
> Only when I modified the filename (eg to .ttf) did the MUA take any notice and
> complain that the attachment was not a font, pdf etc.
> I think we need to know this for commonly deployed platforms before we can say
> it is not dangerous.
> Tom Petch