On Mon, 29 Jan 2018 08:18:35 -0500 rhkra...@gmail.com wrote:
> > I regularly download "security" upgrades for Wheezy. I assume that > most of those don't take effect until I restart the application. For > instance, a Firefox upgrade does not take effect until I shutdown > Firefox and restart it. > > Correspondingly, I assume that a Linux kernel upgrade does not take > effect until I reboot the machine. Yes, but it's a little more complicated. The modules used by the kernel (and the kernel file itself) *are* replaced during the process of upgrading the kernel, but the running code is not. There is a tiny chance of some kind of mismatch if new modules are loaded, so rebooting is recommended soon, and in the past I used to see a message to that effect, displayed during the upgrade. Generally, user applications (e.g. Firefox) will not be restarted automatically, but most daemons will be e.g. mysql, exim4. Some important daemons may request your input as to whether to restart or not e.g. during a major upheaval such as a libc upgrade. Pretty much all software on a server is in the form of daemons, and generally rebooting a server is only necessary after a change of kernel. -- Joe
