From owner-freebsd-hackers Wed Aug 6 02:06:05 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id CAA10289 for hackers-outgoing; Wed, 6 Aug 1997 02:06:05 -0700 (PDT) Received: from nico.telstra.net (nico.telstra.net [139.130.204.16]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id CAA10284 for ; Wed, 6 Aug 1997 02:06:01 -0700 (PDT) Received: from freebie.lemis.com (gregl1.lnk.telstra.net [139.130.136.133]) by nico.telstra.net (8.6.10/8.6.10) with ESMTP id TAA05092; Wed, 6 Aug 1997 19:06:22 +1000 From: Greg Lehey Received: (grog@localhost) by freebie.lemis.com (8.8.7/8.6.12) id SAA05837; Wed, 6 Aug 1997 18:35:27 +0930 (CST) Message-Id: <199708060905.SAA05837@freebie.lemis.com> Subject: Re: Hot Swappable Kernels In-Reply-To: from "Jamil J. Weatherbee" at "Aug 6, 97 00:56:38 am" To: jamil@counterintelligence.ml.org (Jamil J. Weatherbee) Date: Wed, 6 Aug 1997 18:35:27 +0930 (CST) Cc: hackers@freebsd.org (FreeBSD Hackers) Organisation: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8250 Fax: +61-8-8388-8250 Mobile: +61-41-739-7062 WWW-Home-Page: http://www.lemis.com/~grog X-Mailer: ELM [version 2.4ME+ PL32 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Jamil J. Weatherbee writes: > > I know this may sound kind of lame: > > I was thinking last night of what would be required to have a hot > swappable kernel.. i.e. being able to compile the kernel binary (probably) > modules and then insert it into a running system while maintaining its > running status --- to my knowledge kernel recompiles are the only reason a > perfectly rebooting system needs to come down every once in a while. I suspect people are going to shoot you down in flames, and they're probably justified. But I suppose you'd like to know that I've done just that in the past, at Tandem. The operating system is a loosely coupled network, so we were able to boot one machine at a time. Despite the obvious interest of such a scheme for Tandem, and despite my extensive lobbying, it never came to anything. I can't imagine how you would start to do such a thing with UNIX. The closest you could come to it would be to split most of the kernel into LKMs, and change them. But there's a basic conflict of concept between keeping a kernel running (even if it's no longer the same kernel) and booting a kernel. Greg