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Date: Wed, 17 Oct 2007 13:32:05 -0700
From: Julian Elischer <julian@elischer.org>
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To: Poul-Henning Kamp <phk@phk.freebsd.dk>
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Cc: arch@freebsd.org, "Constantine A. Murenin" <cnst@freebsd.org>
Subject: Re: sensors fun..
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Poul-Henning Kamp wrote:
> In message <47166BA5.1000100@elischer.org>, Julian Elischer writes:
> 
>>> Having a userland 
>>> interface also makes it easier to have backends that are entirely in 
>>> userland.
>>>
>> maybe a loopback filesystem
> 
> Just what is it that is so enticing about the kernel ?  Why not simply
> pass it to a daemon ?

Becuause you can not open and do a directory listing on a process but you can 
on something that is presented as a file system.

The advantage is that all the heavy lifting is done in user space
and the kernel only supplies a convenient delivery mechanism.
Pipes are also a kernel supplied delivery mechanism but they are not
random access, where a file system is. Otherwise they are similar.

>