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Re: what upgrades require reboot?

On Tue, Jun 06, 2000 at 08:36:26AM -0700, Paulo Henrique Baptista de Oliveira wrote:
> 	Are there any O.S. that did not want to reboot when a new kernel is
> installed? 
> 	I remember hearing that FreeBSD doesnt need this...

well strictly speaking you don't usually have to reboot *immediatly*
when you install a new kernel, unless your replacing it with the same
version and have modules autoloaded (in which case they may not match
the running kernel)  but rebooting to make the new kernel active is
almost universaly neccessary.

i do remember hearing about (i want to say solaris) having the ability
to actually load a new kernel into memory replacing the old one
without rebooting.  it sounded like a horrid hack, and it was "very
highly" reccommended that the system be brought down to single user
mode before attempting it.  really i don't see the point there, all
you save is your uptime (which is really dubious given the entire
kernel structures are replaced) since you need to go single user you
still have downtime (as far as any users are concerned).

i don't know about FreeBSD's kernel upgrade procedure, but OpenBSD
does need a reboot to activate a new kernel, but AFAICT that reboot
does not have to be immediate, no real ill effects appear to happen by
replacing /bsd and waiting a bit before rebooting.  BSD's don't
require you to reinstall the boot loader whenever you touch the kernel
though ;-)  (to be fair linux does not either if you use grub instead
of lilo, non-x86 archs also generally have smarter boot loaders too,
yaboot, silo etc) 

Ethan Benson

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