Date: Mon, 25 Nov 2002 15:50:24 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Marcin Dalecki <mdcki@gmx.net> Cc: Kris Kennaway <kris@obsecurity.org>, Robert Watson <rwatson@FreeBSD.ORG>, Mikhail Teterin <mi+mx@aldan.algebra.com>, current@FreeBSD.ORG Subject: Re: -current unusable after a crash Message-ID: <3DE2B740.4206206E@mindspring.com> References: <200211250959.39594.mi%2Bmx@aldan.algebra.com> <Pine.NEB.3.96L.1021125102358.33619A-100000@fledge.watson.org> <20021125172445.GA8953@rot13.obsecurity.org> <3DE29DE6.CDD96F3F@mindspring.com> <3DE2AF65.9000502@gmx.net>
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Marcin Dalecki wrote: > > I don't think this is really possible. > > > > I went looking for a generic "application use" CMOS are for this > > sort of thing a while back, and I was unable to find one. > > Well you should please take a look at the "fast boot" option > of moderately modern BIOS-es. Somthing along those lines went right now > in to the linux kernel. Seems pretty adequate to me, since you would > be even able to controll it through the BIOS setup... Is there documentation available for this anywhere? The BIOS vendor documentation, not the Linux source code. My gut feeling is that this isn't going to be too helpful, without AC failure notification with a DC holdup time. The problem is that the best case is power failure, and the worst case is a corrupted GDT and a double panic off a trap 12 in the trap 12 handler (such that you would get a trap 12 when you tried to write back to the CMOS that this was the worst case, not the best case). Basically, you are still stuck needing power failure notification, so you can write the cause of the failure back. At startup, you have to set the saved state to "worst possible failure: no way to update cause of failure in CMOS", and then back off to softer failure modes from there. I think this "Fast boot" stuff is useful, but the way it's useful is if your main memory is reflected to a seperate area of the disk, so that you can bring up the system image very quickly. Basically, it means that it's not at all useful for the problem at hand, unless it provides for power fail notification. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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