From owner-freebsd-questions Tue Nov 5 13:13:54 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B466737B411 for ; Tue, 5 Nov 2002 13:13:49 -0800 (PST) Received: from mx1.millerzell.com (mx1.millerzell.com [204.183.156.252]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5686E43E3B for ; Tue, 5 Nov 2002 13:13:49 -0800 (PST) (envelope-from andrew.boring@MillerZell.com) Received: from ATLS201.millerzell.com (exchsrvr1.millerzell.com [10.10.1.45]) by mx1.millerzell.com (Postfix) with ESMTP id 065EA4A29B for ; Tue, 5 Nov 2002 21:13:49 -0500 (EST) Received: by atlexch1.millerzell.com with Internet Mail Service (5.5.2653.19) id ; Tue, 5 Nov 2002 16:03:09 -0500 Message-ID: <91D2FF62456123469A70489F28B331F9021927A7@atlexch1.millerzell.com> From: andrew.boring@MillerZell.com To: daleco@daleco.biz, zopewiz@yahoo.com, freebsd-questions@FreeBSD.ORG Subject: RE: Junior hacker assignment :o Date: Tue, 5 Nov 2002 16:03:08 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: text/plain; charset="iso-8859-1" Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > -----Original Message----- > From: DaleCo Help Desk [mailto:daleco@daleco.biz] > If the OS is shut down, then the kernel's shut down, > right, and how's it gonna count seconds 'til Resurrection Day? I'm going out on a limb here, but there is an article in SysAdmin magazine that discusses the idea of a "halted firewall" on Linux: http://www.samag.com/documents/s=1824/sam0201d/0201d.htm The idea is that even when you issue a "shutdown -h" command and it says the system is halted the kernel, scheduler and memory manager are still running, but interactive processes that could possibly cause it do start doing stuff like writing to disk are not. A quote: "When the machine is halted, the kernel still resides in memory, even when the machine runs through the shutdown process. [...] However, the kernel is still running as a scheduler and memory manager at that point. [...] Because the kernel is still running, any kernel-based tasks that we can run in normal use can be run while halted." You just need some form of input/output to/from the kernel and seriel port for your UPS. I don't know enough about kernel hacking on Linux or FreeBSD and the article only messed around with the shutdown scripts, but this might be a useful starting point. -- Andrew Boring, Senior Network Engineer Miller Zell 404-526-1440 andrew.boring@millerzell.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message