Re: what upgrades require reboot?

[Pat Mahoney <pat7@gmx.net>]

On Tue, Jun 06, 2000 at 06:40:34PM -0800, Ethan Benson wrote:
> 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
> http://www.alaska.net/~erbenson/

AFAIK, Hurd doesn't require reboots.  Of course, it is a modular
kernel.  I suppose upgrading the microkernel would require a reboot.

-- 
Pat Mahoney  <pat7@gmx.net>


"If people are good only because they fear punishment, and hope for
reward, then we are a sorry lot indeed."
                -- Albert Einstein