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Date:      Fri, 27 Jun 2014 23:04:54 +0200
From:      Polytropon <freebsd@edvax.de>
To:        paul beard <paulbeard@gmail.com>
Cc:        "questions@freebsd.org" <questions@freebsd.org>, Lowell Gilbert <freebsd-questions-local@be-well.ilk.org>
Subject:   Re: what should uname -v be telling me here?
Message-ID:  <20140627230454.041c1baa.freebsd@edvax.de>
In-Reply-To: <CAMtcK2rh3tSF6brU_JxA1%2Btzzuv8SsEoHf_oxAhcW95NRRpKjQ@mail.gmail.com>
References:  <CAMtcK2rBDWwu1=4DbKGB_4kDdi5Fz9Mq3%2Bzf_Ph9jTmrCLZpSg@mail.gmail.com> <44lhsi5ugm.fsf@be-well.ilk.org> <CAMtcK2rZzJPaWBnuZ6s2iZyg4_XjE62JBFTo=iUd%2BT_r4_zoew@mail.gmail.com> <20140627223650.25210a53.freebsd@edvax.de> <CAMtcK2rh3tSF6brU_JxA1%2Btzzuv8SsEoHf_oxAhcW95NRRpKjQ@mail.gmail.com>

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On Fri, 27 Jun 2014 13:57:06 -0700, paul beard wrote:
> On Fri, Jun 27, 2014 at 1:36 PM, Polytropon <freebsd@edvax.de> wrote:
> > You need to find out where /boot resides (in my case,
> > it's on ad4s1a, which is mounted at /) to identify the boot
> > device (or to be precise, the device the kernel has been read
> > from).
> 
> 
> I keep thinking this should be something you ought to be able to
> discover without being on console. I realize the BIOS can't be
> interrogated but if I knew that the active kernel was ad3:/boot/kernel
> or ad2:/boot/kernel, it would be useful. Kind of surprised that
> doesn't appear anywhere in dmesg or that it can't be read out of
> somewhere.

There is an entry in /var/log/messages and dmesg:

	% dmesg | grep "mount root"
	Trying to mount root from ufs:/dev/ad4s1a

But as I said, this is where the root file system has been
mounted from. It doesn't _have to be_ the same file system
the kernel has been read from (or where the system has been
booted from).

It's possible to construct a boot chain where the BIOS starts
booting from ad2, which reads the kernel from a partition
on ad4, and which continues to mount root from ad6 (which
is called ada0). Those disks could be identified as disk0,
disk1 and disk2 to the BIOS...




-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...



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