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Re: Quality factors

From: Koen Holtman <koen@win.tue.nl>
Date: Thu, 9 Oct 1997 20:48:54 +0200 (MET DST)
Message-Id: <199710091848.UAA08127@wsooti08.win.tue.nl>
To: Graham Klyne <GK@acm.org>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Graham Klyne:
>
>The following thoughts emerged from an off-line discussion about the use of
>quality factors in content negiatiation.
>
>The premise for what follows is the assertion that the only practical use
>for a quality factor is to rank some set of alternatives according to
>preference.

I don't agree with this premise, but we have discussed this before.  I
do want to comment on the reasoning below however:

>Simple sequencing of of alternatives (e.g. per Multipart/Alternative) may
>not be possible because the sender may not be able to locate (hence
>present) the alternatives in order of quality.  Therefore some separate
>ranking mechanism is required.
> 
>I suggest that in this case a 3-digit (max) number is insufficient, as with
>a significant number of alternatives an implementation will soon run out of
>space within which to slot further entries between existing entries.  I
>estimate that a perverse presentation would run out ranking space after
>about 10 entries (log2(1001)).

Your reasoning assumes that the sender has to send out the source
quality value of a variant as soon as the variant itself is sent.  If
you wait sending source quality values until all variants have been
sent, the problem does not exist anymore.  And I see no logical reason
why you could not wait: the recipient can't do anything until the last
source quality value is received anyway.

>GK.

Koen.
Received on Thursday, 9 October 1997 11:54:13 EDT

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