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Re: reiser4 (was Re: [PATCH] Revised extended attributesinterface)

To: curtis@xxxxxxxxxxxxxx
Subject: Re: reiser4 (was Re: [PATCH] Revised extended attributesinterface)
From: Hans Reiser <reiser@xxxxxxxxxxx>
Date: Wed, 12 Dec 2001 00:34:41 +0300
Cc: Anton Altaparmakov <aia21@xxxxxxxxx>, Nathan Scott <nathans@xxxxxxx>, Andreas Gruenbacher <ag@xxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx, linux-xfs@xxxxxxxxxxx
References: <20011205143209.C44610@wobbly.melbourne.sgi.com> <20011207202036.J2274@redhat.com> <20011208155841.A56289@wobbly.melbourne.sgi.com> <3C127551.90305@namesys.com> <20011211134213.G70201@wobbly.melbourne.sgi.com> <5.1.0.14.2.20011211184721.04adc9d0@pop.cus.cam.ac.uk> <3C166920.77F644F@integratus.com>
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Extended attributes differ from files in N ways (forgive me for not specifying N exactly, it would distract us).

What I am saying is that each of the N permutations required to transform a file into an extended attribute should be separately selectable. Theory guys would call this orthogonalizing the primitives. (I am a theory guy.;-) ).

It is very important to decompose one's primitives into separately specifiable primitives. It makes for a much more expressive abstract model. This is a very standard policy among mathematicians, that they strive to decompose primitives into a more orthogonal toolkit because they know from hundreds of years of experience that it inevitably leads to more expressive power. Let us learn from these mathematicians who are so much older and wiser than we.

Hans

curtis@xxxxxxxxxxxxxx wrote:

I know I'm stepping into a minefield, but I just can't help putting in
my 2 pennies.  :-)

Anton Altaparmakov wrote:

At 12:02 11/12/01, Hans Reiser wrote:

What would have happened if set theory had not just sets and elements, but
sets, elements, extended-attributes, and streams, and you could not use
the same operators on streams that you use on elements?  It would have
been crap as a theoretical model.  It does real damage when you add things
that require different operators to the set of primitives. Closure is
extremely important to design.  Don't do this.

Since we are going into analogies: You don't use a hammer to affix a screw
and neither do you use a screwdriver to affix a nail...at least I don't. I
think you are trying to use a large sledge hammer to put together things
which do not fit together thus breaking them in the process. To use your
own words: Don't do this. (-; Each is distinct and should be treated as
such. </me ducks>


I agree with Anton. Files have certain characteristics that we all know and love, stream-style attributes have pretty-much those same characteristics. IMHO, we would like EAs to have a different set of characteristics so that the application programmer has different tools in her toolbox. To continue the analogy: "if all you have is a hammer, everything looks like a nail". Give someone that _already has_ a hammer a screwdriver and they will be confused for a while but will end up happier than if you gave them a "better hammer".

Thanks,

        Curtis





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