docs/84154: Handbook somewhat off in use of /boot/kernel.old

[Gary W. Swearingen]

The following reply was made to PR docs/84154; it has been noted by GNATS.

From: garys at opusnet.com (Gary W. Swearingen)
To: John Baldwin <jhb at FreeBSD.org>
Cc: freebsd-doc at FreeBSD.org, FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: docs/84154: Handbook somewhat off in use of /boot/kernel.old
Date: Thu, 28 Jul 2005 06:52:06 -0700

 John Baldwin <jhb at FreeBSD.org> writes:
 
 > How about:
 >
 > The new kernel and modules will be copied to the /boot/kernel directory.  If 
 > the currently running kernel came from "/boot/kernel", then the old kernel 
 > and modules will be moved to the /boot/kernel.old directory.
 
 Change "will be" to "will first be". As-is, it doesn't sound right
 because one wonders how the old kernel can be moved "then", when the
 old kernel is gone.
 
 > I haven't read the full doc for context, but it looks like the replacement 
 > text doesn't actually replace the same meaning.  The reason for kernel.old 
 > only getting updated if the kernel being installed is running is to try to 
 > make kernel.old more reliable as in theory it should always be a kernel that 
 > was running well enough to do an installkernel now.  Probably the surrounding 
 > section here needs more updating to reflect that larger change.
 
 I'm not sure about that reason.  I think the reason is that if you're
 not booting from /boot/kernel, it's probably bad, so there's no reason
 to save it.  (It shouldn't try to be that smart, failing some of the
 time.  I'd always do the backup like my editor does, assuming I'll
 have saved the old one if I wanted to.) If users follow the handbook,
 they won't be booting out of /boot/kernel.old anyway as they'll be
 booting out of /boot/kernel.GENERIC (like I always have).
 
 Anyway, here's the whole old para
 
    Note: If you are having trouble building a kernel, make sure to
    keep a GENERIC, or some other kernel that is known to work on hand
    as a different name that will not get erased on the next build. You
    cannot rely on kernel.old because when installing a new kernel,
    kernel.old is overwritten with the last installed kernel which may
    be non-functional. Also, as soon as possible, move the working
    kernel to the proper /boot/kernel location or commands such as
    ps(1) may not work properly. To do this, simply rename the
    directory containing the good kernel:
 
 maybe replace with
 
    Note: If you are having trouble building a kernel, keep on hand a
    GENERIC, or some other kernel that is known to work, as a different
    name than "/boot/kernel.old".  That directory will get removed by
    standard "make" scripts when installing a new kernel if the running
    kernel came from "/boot/kernel".  Also, as soon as possible, move
    the working kernel to the proper /boot/kernel location or commands
    such as ps(1) may not work properly. To do this, simply rename the
    directory containing the good kernel: