Date: Thu, 5 Oct 1995 22:15:00 +0100 (MET) From: hm@altona.hamburg.com (Hellmuth Michaelis) To: owensc@enc.edu (Charles Owens) Cc: hackers@freefall.freebsd.org, msmith@atrad.adelaide.edu.au Subject: Re: Fiskars UPS support... Message-ID: <m0t0xd6-00001AC@ernie.altona.hamburg.com> In-Reply-To: <Pine.BSF.3.91.951005090952.16423G-100000@itsdsv1.enc.edu> from "Charles Owens" at Oct 5, 95 09:18:28 am
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> Mark Smith said:
>
> > The crucial issue in this case is, once the UPS has sounded its death knell,
> > ie. power's out, and battery holdout is down to a few minutes, what should
> > one do?
> >
> > If you decide to shutdown, and then power comes back, you're stuck
> > shutdown, waiting for the power failure to reboot you.
> > If you go single-user, can you arrange to have the daemon survive the
> > shutdown and send an appropriate signal to the root shell when the power
> > comes back?
> >
> > Or would it be better to reboot and then as part of the boot process wait
> > for the UPS to give the all-clear?
Some time ago i did such a thing for FreeBSD, the current version can be
found on ftp.freefall.org in pub/FreeBSD/incoming/freebsd205ups.tar.gz.
The thing consists of a device driver with which the status of the AC line
is accessible, a daemon constantly monitors it and in case of a power fail
it shuts the system down after a specified amount of time, leaving a file
"/powerfail" and reboots. When the system comes up again, one of the very
first things which is done in /etc/rc is to check whether there exists a
file "/powerfail", if so, it enters a tight loop waiting for either AC
power coming back or the battery becoming empty. I had to do it this way
because the UPS is built-in into the machine and there are only 2 flags
available: AC fail and battery OK at power up, nothing else.
It works.
hellmuth
--
Hellmuth Michaelis hm@altona.hamburg.com Hamburg, Europe
(A)bort, (R)etry, (I)nstall BSD ?
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