From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267185AbUBSOEY (ORCPT ); Thu, 19 Feb 2004 09:04:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267215AbUBSOEY (ORCPT ); Thu, 19 Feb 2004 09:04:24 -0500 Received: from chaos.analogic.com ([204.178.40.224]:25473 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S267185AbUBSOEW (ORCPT ); Thu, 19 Feb 2004 09:04:22 -0500 Date: Thu, 19 Feb 2004 09:05:25 -0500 (EST) From: "Richard B. Johnson" X-X-Sender: root@chaos Reply-To: root@chaos.analogic.com To: Carlos Silva cc: linux-kernel@vger.kernel.org Subject: Re: Hot kernel change In-Reply-To: <12608.62.229.71.110.1077197623.squirrel@webmail.r3pek.homelinux.org> Message-ID: References: <12608.62.229.71.110.1077197623.squirrel@webmail.r3pek.homelinux.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Feb 2004, Carlos Silva wrote: > hi, > > i would like to know if isn't it possible to implement a hot kernel > change, i mean, without reboot. i would do it myself if i had the knoledge > to do it but i'm starting with kernel-level programing now. i think it > would be possible if we make something like M$'s OS do when it hibernates, > copy all the memory, registers, etc to the disc and then put all back > again. > > am i dreaming or this is possible? :) > > Greetings, > > Carlos "r3pek" Silva Sure it's possible. However, you can't change to a new kernel this way because the addresses of the hardware devices like the PCI bus devices may change with a new kernel. Since the displacements of the kernel's internal workings will change with a new version, there would need to be considerable work done in re-designing the kernel so that it wouldn't matter. The best you can do, right now, is reload the same kernel. It will take about as much time as a reboot, so why bother? Oh, you intend to keep the same processes running, do you? You expect to be writing a letter in X-windows and hit the reset switch, magically returning to the same state after the machine has a new kernel installed? Well, well-written software is indistinguishable from magic, but first you need to find out how to make time run back- wards because, at the very least, the new kernel will be installed in the future which means many things will have changed (like network IP addresses, dynamic routes, remote file discriptors, etc.) Sounds like a neat project for a College Student who wants to learn to solve problems they haven't even dreamed of yet. Cheers, Dick Johnson Penguin : Linux version 2.4.24 on an Intel Pentium III machine (797.90 BogoMips). Note 96.31% of all statistics are fiction.