From owner-freebsd-hackers@FreeBSD.ORG Tue Jan 25 22:40:00 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 77C2A16A4CE for ; Tue, 25 Jan 2005 22:40:00 +0000 (GMT) Received: from mail24.sea5.speakeasy.net (mail24.sea5.speakeasy.net [69.17.117.26]) by mx1.FreeBSD.org (Postfix) with ESMTP id 37FC143D1D for ; Tue, 25 Jan 2005 22:40:00 +0000 (GMT) (envelope-from ayerkes@speakeasy.net) Received: (qmail 4978 invoked from network); 25 Jan 2005 22:40:00 -0000 Received: from dsl081-145-152.chi1.dsl.speakeasy.net (HELO firebird) ([64.81.145.152]) (envelope-sender ) by mail16.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 25 Jan 2005 22:39:59 -0000 Date: Tue, 25 Jan 2005 17:13:50 -0600 From: art yerkes To: hackers@freebsd.org Message-Id: <20050125171350.574f4750.ayerkes@speakeasy.net> In-Reply-To: <20050125214543.GA1113@archibold> References: <86pszu639o.fsf@borg.borderworlds.dk> <86brbe6052.fsf@borg.borderworlds.dk> <200501242240.j0OMeIXP043763@apollo.backplane.com> <41F59242.7090900@jonny.eng.br> <200501251948.j0PJmpYG048845@apollo.backplane.com> <20050125214543.GA1113@archibold> X-Mailer: Sylpheed version 0.9.10 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: Resuming from a crashdump X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Jan 2005 22:40:00 -0000 On Tue, 25 Jan 2005 21:45:43 +0000 Steven Smith wrote: > If you just send pages to disk rather than to another machine on the > network, then you should be able to suspend-to-disk an entire > operating system with minimal user-perceived downtime. One > possibility here would be to e.g. live suspend the machine every five > minutes or so, and guarantee the user never loses more than five > minutes of work. You're assuming that the filesystem doesn't change in the 5 minutes. Loading a dirty kernel state about a filesystem that changed later is asking for trouble. Also, the kernel doesn't know the whole story about the display state, because X does its own acceleration, and manages the font cache by itself. Some hardware registers are write only (VGA palette registers), which means that the application or driver which set them needs to assist in remembering how to put them back together. -- Here's a simple experiment. Stand on a train track between two locomotives which are pushing on you with equal force in opposite directions. You will exhibit no net motion. None the less, you may soon begin to notice that something important is happening. -- Robert Stirniman