Return to BSD News archive
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!news.Hawaii.Edu!ames!hookup!news.kei.com!MathWorks.Com!europa.eng.gtefsd.com!howland.reston.ans.net!gatech!purdue!haven.umd.edu!umd5.umd.edu!jjarray.umd.edu!fcawth From: fcawth@jjarray.umd.edu (Fred Cawthorne) Newsgroups: comp.os.386bsd.development Subject: Re: UPS driver/daemon/utils Date: 1 Sep 1994 13:33:38 GMT Organization: Center for Superconductivity Research - Univ. of Maryland Lines: 31 Message-ID: <344l7i$lld@umd5.umd.edu> References: <hm.777584469@hcswork> NNTP-Posting-Host: jjarray.umd.edu X-Newsreader: Tin 1.1 PL4 hm@hcswork.hcs.de (Hellmuth Michaelis) writes: : What follows is a package to handle a uninterruptible power supply : built into a PC running FreeBSD 1.1R. : [stuff deleted] : : If someone has a better idea, i'd like to hear about it! Well, I don't know about better, but different anyway... I use a serial port to monitor the UPS, as is commonly done. A process sits and watches CD, sleeping most of the time. When the power fails, the process waits for a minute to make sure it wasn't just intermittant. Then, it begins the reboot process. I hacked the reboot code in the kernel to assert DTR and wait a few seconds right before it reboots the machine. My UPS has a signal that lets it shut off if the main power is down, conserving battery life. Thus, FreeBSD will shut down, and then turn the computer off. When the power comes back up, it reboots and the UPS has enough battery life left to go through a few more reboot cycles. I didn't want to run the UPS batteries down, since if the power comes back on for a short period of time, then dies again, the system might not be in a state where it can shut down easily. (i.e. if it is booting...) Anyway, I think this type of scheme is commonly used on file servers and the like.. Some UPS's don't have this power shut-off input, so I guess then you just have to hope the power doesn't do wierd things. Maybe somene could add an "OPTIONS DTRBOOT" or something like that to the kernel config??? Fred.