From owner-freebsd-questions Thu May 10 13: 7:26 2001 Delivered-To: freebsd-questions@freebsd.org Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by hub.freebsd.org (Postfix) with ESMTP id D261437B423 for ; Thu, 10 May 2001 13:07:22 -0700 (PDT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.11.3/8.11.3) id f4AK7E514759; Thu, 10 May 2001 15:07:14 -0500 (CDT) (envelope-from dan) Date: Thu, 10 May 2001 15:07:13 -0500 From: Dan Nelson To: Mikko Tyolajarvi Cc: sudakov@sibptus.tomsk.ru, questions@FreeBSD.ORG Subject: Re: dmesg buffer between reboots Message-ID: <20010510150713.C18228@dan.emsphone.com> References: <3AFA39FA.6EC0F4EA@DougBarton.net>; <20010510155907.A51971@sibptus.tomsk.ru> <200105101812.f4AICGv90535@explorer.rsa.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.17i In-Reply-To: <200105101812.f4AICGv90535@explorer.rsa.com>; from "Mikko Tyolajarvi" on Thu May 10 11:12:16 GMT 2001 X-OS: FreeBSD 5.0-CURRENT Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In the last episode (May 10), Mikko Tyolajarvi said: > Hmm... on several of my machines, this already happens. I haven't > done anything special. Thus: > > mikko% dmesg > [...] > panic: page fault > > syncing disks... 1 > done > Uptime: 13d10h9m50s > /dev/vmmon: Mkdule vmmon: unloaded > Automatic reboot in 15 seconds - press a key on the console to abort > Rebooting... > Copyright (c) 1992-2000 Tha FreeBSD Project. It all depends on the motherboard/BIOS. Some zero out the RAM between reboots, some don't. I believe this trick also only works if you always boot the same kernel (different sized kernels will store the dmesg buffer in different places in memory). I seem to remeber idle speculations on somehow stuffing the dmesg buffer in video RAM somewhere, since it stands a better change of surviving warm boots (the BIOS doesn't touch it). -- Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message