Date: Sun, 25 Jul 2010 17:07:03 +0200 From: Polytropon <freebsd@edvax.de> To: claudiu vasadi <claudiu.vasadi@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: how does freebsd know which kernel to boot ? Message-ID: <20100725170703.2ca935d9.freebsd@edvax.de> In-Reply-To: <AANLkTindiTejP4e-Rt0rPXmX-7gMsJ8x%2BwJoUjPkdQGb@mail.gmail.com> References: <AANLkTindiTejP4e-Rt0rPXmX-7gMsJ8x%2BwJoUjPkdQGb@mail.gmail.com>
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On Sun, 25 Jul 2010 16:21:38 +0200, claudiu vasadi <claudiu.vasadi@gmail.com> wrote: > hello ppl, > > > I was wondering about the following: > > After I do "make build|install kernel" and reboot, the new kernel is > automatically booted but the old one is still on the disk. Therefore, how > does FreeBSD know which one to boot ? > > I'm guessing it's writing this info somewhere but I do not know where or > how. > > > > Can anyone give me some short description ? The kernel is booted by the kernel loader. Its configuration is in /boot/loader.conf and /boot/default/loader.conf. It will default to "kernel" (the name of the kernel to boot) by default, but you can specify another name, too. You can also interrupt the boot and request a different than the default kernel; using the "nextboot" can achieve similar results. Upon kernel installation by "make installkernel", the existing kernel will be moved to kernel.old; the newly installed kernel will then be kernel, and the loader will load exactly this name as before. Interesting man pages are: % man loader % man loader.conf % man nextboot % man boot % less /boot/defaults/loader.conf -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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