Re: How do I do a COLD Reboot on FreeBSD?

From: Jerry McAllister (jerrymc_at_clunix.cl.msu.edu)
Date: 01/31/05

  • Next message: Billy Newsom: "Re: How do I do a COLD Reboot on FreeBSD?" 
    To: smartweb@leadhill.net (Billy Newsom)
Date: Mon, 31 Jan 2005 10:02:08 -0500 (EST)

    >
    > 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.

    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.

    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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  • Next message: Billy Newsom: "Re: How do I do a COLD Reboot on FreeBSD?"

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