Date: Mon, 31 Jan 2005 09:38:29 -0600 From: Billy Newsom <billy@nlcc.us> To: freebsd-questions@freebsd.org Subject: Re: How do I do a COLD Reboot on FreeBSD? Message-ID: <41FE50F5.9000705@nlcc.us> In-Reply-To: <200501311502.j0VF29A28199@clunix.cl.msu.edu> References: <200501311502.j0VF29A28199@clunix.cl.msu.edu>
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Jerry McAllister wrote: >>I need to do a cold restart. I've looked through a lot of docs, and I >>can't >>seem to find this out. The computer I am working with seems to no longer >>enjoy a warm reboot (like "shutdown -r now" or "reboot") but I'm pretty >>sure >>it will do cold reboots fine. Is there a port, or is the shutdown command >>hackable for this, or what? >> >>I remember many computers in bygone years which had this problem. It was >>pretty common back in the 90's it seems like. Computers would reboot and >>act >>weird using CTRL-ALT-DELETE, but work fine when powered off and on. > > > FreeBSD is pretty good about doing a very clean reboot as far as the OS > is concerned. But, it is possible that some devices don't clean up well > in ways that are out of FreeBSD control. So, a "cold boot" can be a > good idea in some circumstances. > > To do this, do a 'shutdown -h now' or a 'shutdown -p now' if your > hardware supports the -p and you have it set up. Choose your own > time of delay for 'now' if you have other people on the machine. > > If you did the '-h' or the '-p' didn't turn off the power, then > at the "press any key to reboot" prompt, turn off the power. > Then, unplug the power source and let it set for a few minutes to let > any charge dissipate. This can be important because the capacitance > in some of the devices including the power supply can provide just > enough charge to keep them from reloading if that is their inclination > and you lose the effect you are looking for. You should also unplug > the network connection and any external devices that have their own > power supply. I know that this is all very good advice and information from the shutdown man page and good stuff about the nature of capacitors, but all of this is known to myself and unfortunately not useful... The shutdown -p does essentially a different thing (and one time it caused the freeze problem to disappear.) but this also does not work. I don't want to shut the computer off, anyway, I want it to reboot back to FreeBSD remotely if need be. And so far, the halt command (or its shutdown -h equivalent) is not what I want, either. If I press a key to reboot, I get the same issue anyway. There's a remote possibility that the halt code is causing the freeze up, because FreeBSD 4.7 did not have this problem. I'm not confident whether the machine broke or the new 5.3 code broke, so I won't speculate which. I just need the reboot code. ... > After a sufficient time drain capacitance - I usually go to the bathroom > or go get something to drink to kill a few minutes - , then just plug > it all back in. Plug in the network cable and any external devices first > and then the power cord and turn it on and let it boot. It's not the capacitors, but perhaps some strange bug in the BIOS or something, I guess. The issue that I'm highlighting is that when a floppy program does a cold reset of this machine, the system (re)boots normally. As a side note, I have run this machine through the ringer trying to discover any hardware errors. The memory is now EDO ECC (it had been something else) and the problem persists. I have run diagnostics, memtest86, etc. Futile. The cold reset code exists somewhere. Anybody? Billy > > Voila, you have gone from warm to cold to warm again. > > ////jerry > > >>The computer I've got actually fails a memory test during the warm reboot. >>This freezes it. I have to power cycle the machine. And then, the computer >>performs a warm restart, bypassing its memory checks! One more power cycle >>laster, it will boot normally. If I don't do this last reboot, the FreeBSD >>boot loader or the beginning of the kernel boot crashes very early. It's >>stable otherwise on a cold reboot. >> >>Thanks, >>Billy
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