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Date:      Fri, 17 Feb 2012 09:54:37 -0800
From:      Marcel Moolenaar <marcel@xcllnt.net>
To:        Bruce Evans <brde@optusnet.com.au>
Cc:        marcel@FreeBSD.org, Eitan Adler <eadler@FreeBSD.org>, svn-src-all@FreeBSD.org, "Kenneth D. Merry" <ken@FreeBSD.org>, Andriy Gapon <avg@FreeBSD.org>, src-committers@FreeBSD.org, svn-src-head@FreeBSD.org, Julian Elischer <julian@FreeBSD.org>
Subject:   Re: svn commit: r231814 - in head/sys: kern sys
Message-ID:  <2CDFAEC9-D57A-4513-96D1-8A78D27E8696@xcllnt.net>
In-Reply-To: <20120217191017.U1871@besplex.bde.org>
References:  <201202160511.q1G5BZNk099785@svn.freebsd.org> <20120216181210.K1423@besplex.bde.org> <4F3CC40D.4000307@freebsd.org> <4F3CC5C4.7020501@FreeBSD.org> <4F3CC8A5.3030107@FreeBSD.org> <20120216174758.GA64180@nargothrond.kdm.org> <20120217053341.R1256@besplex.bde.org> <20120217000846.GA7641@nargothrond.kdm.org> <4F3D9D03.6020507@FreeBSD.org> <9CB7ECE8-FF10-43BE-9EBD-16953BE3B193@xcllnt.net> <20120217191017.U1871@besplex.bde.org>

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On Feb 17, 2012, at 4:13 AM, Bruce Evans wrote:

> On Thu, 16 Feb 2012, Marcel Moolenaar wrote:
> 
>> I think we should lift above the immediate problem and allow for
>> single- and multi-line messages that are atomically appended to
>> the message buffer. Console output and propagation of messages
>> outside of the kernel should all come out of the message buffer
>> and preserving the atomicity of the messages.
> 
> This is just wrong for (low-level) console messages.

I think it actually is the right approach in that the low-level
console stops being this pivotal component that introduces
limitations for no good reason. We need "quiet" boots, but we
also want to have boot messages available somewhere for post
mortems. Decoupling the generation and holding/storage of
messages from what you can subsequently do with them, like
displaying them, is a good thing. The decoupling allows us
to generate and store messages in the most stringent cases,
and it allows us to filter based on preference or condition.
It's not that hard to print messages that relates to errors
only when you have priorities or facilities or other kinds
of augmentation that help us raise awareness of the things
FreeBSD users/operators need to be aware of.

I belief the notion of a low-level console is arcane and
antiquated. Every "output" channel that can be monitored by
humans should have the possibility of being human friendly,
where human friendly is defined, for the most part, by the
the human monitoring the channel and not by us.

For example: I dislike our boot messages, because it's noise
to me 99.99% of the time. If I'm waiting for FreeBSD to boot
and monitor the console, I'd rather stare at the logo and a
twiddle. If I see a lot of messages scrolling by fast, I look
away (preferably at a photo of a white tropical beach, the
sea and a few palm trees).

-- 
Marcel Moolenaar
marcel@xcllnt.net





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