Date: Sun, 17 Jul 2011 08:32:06 +0200 From: Polytropon <freebsd@edvax.de> To: Aryeh Friedman <aryeh.friedman@gmail.com> Cc: FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: how to force a hard reboot remotely Message-ID: <20110717083206.db111314.freebsd@edvax.de> In-Reply-To: <CAGBxaXnz3cD6ZKaDiDW_YEWpdhwjkAUBLM07T0_2NkpGc5QfmA@mail.gmail.com> References: <CAGBxaXnz3cD6ZKaDiDW_YEWpdhwjkAUBLM07T0_2NkpGc5QfmA@mail.gmail.com>
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On Sat, 16 Jul 2011 22:40:19 -0400, Aryeh Friedman wrote: > Is there any way to force a complete power down and then reset of a > i386 without physically being present? I'm not fully sure what you mean by "reset" in terms that it happens _after_ powering down. When a machine is powered down (i. e. switched off), it's "implicitely" a reset - compare to pressing the RESET button which will keep the system powered on, but will perform a (very hard) reset. Allow me to point you to the following manpages: man shutdown man reboot man init A problem will be: How to power a machine back on that has been powered off? I assume you don't want the hard reset, you want to perform a clean shutdown first, followed by a powering down, and THEN power the machine back up. That's quite easy, although you need something more than just onboard means. I may introduce a (quite stupid) solution I "invented" many years ago: Prior to performing the "shutdown -p <time>" command, you access one of the parallel port's lines in order to start a timer (a quite basic transistor + relay is sufficient). This timer runs at least as long as the shutdown needs in average. Let's assume the shutdown needs (including all timeouts and wait states) 5 minutes. After those 5 minutes, the timer generates a "pressing" of the machine's power button, which means it will power on again. It's comparable to C. E. Shannon's "Ultimate Machine" in some regards. :-) Of couse, this approach can be used even to switch on AT systems which (unlike ATX) have a real power switch. This switch is then replaced by a self-supporting relay system that can be externally triggered (as those systems can't reflect the -p option of shutdown, just -h is possible). I hope this is a little inspiration about what's possible if you're willing to get your hands dirty. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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