From owner-freebsd-hackers Wed Aug 6 17:05:14 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id RAA29359 for hackers-outgoing; Wed, 6 Aug 1997 17:05:14 -0700 (PDT) Received: from argus.tfs.net (tc1-p22.tfs.net [139.146.197.22]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id RAA29346 for ; Wed, 6 Aug 1997 17:05:00 -0700 (PDT) Received: (from jbryant@localhost) by argus.tfs.net (8.8.5/8.8.5) id TAA00279; Wed, 6 Aug 1997 19:04:17 -0500 (CDT) From: Jim Bryant Message-Id: <199708070004.TAA00279@argus.tfs.net> Subject: Re: Hot Swappable Kernels In-Reply-To: <199708060905.SAA05837@freebie.lemis.com> from Greg Lehey at "Aug 6, 97 06:35:27 pm" To: grog@lemis.com (Greg Lehey) Date: Wed, 6 Aug 1997 19:04:16 -0500 (CDT) Cc: freebsd-hackers@freebsd.org Reply-to: jbryant@tfs.net X-Windows: R00LZ!@# MS-Winbl0wz DR00LZ!@# X-Mailer: ELM [version 2.4ME+ PL31H (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 In reply: > 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, Keep in mind that even for Guardian-90, you still have to boot... Let's see, what changes if i simply change MAXUSERS... This is one of the simpler scenarios... Changing other things can be really hairy... Unix on a PC is not Guardian-90 on a Non-Stop. An occassional reboot is not a bad thing. Prediction: Three years, tops. Compaq will run Tandem into the ground. A shame too... jim -- All opinions expressed are mine, if you | "I will not be pushed, stamped, think otherwise, then go jump into turbid | briefed, debriefed, indexed, or radioactive waters and yell WAHOO !!! | numbered!" - #1, "The Prisoner" ------------------------------------------------------------------------------ Internet: jbryant@tfs.net AX.25 Packet: kc5vdj@wv0t.#neks.ks.usa.noam voice: KC5VDJ - 6 Meters AM/FM/SSB, 2 Meters AM/FM/SSB, 70cm FM. grid: EM28PW ------------------------------------------------------------------------------ HF/6M/2M: IC-706-MkII, 2M: HTX-212, 2M: HTX-202, 70cm: HTX-404, Packet: KPC-3+