Newsgroups: alt.sources.d
Path: utzoo!telly!eci386!woods
From: woods@eci386.uucp (Greg A. Woods)
Subject: Re: UPS monitor daemon part 1 of 1
Message-ID: <1991Apr25.181844.22772@eci386.uucp>
Reply-To: woods@eci386.UUCP (Greg A. Woods)
Organization: Elegant Communications Inc.
References: <1991Apr03.095011.9609@pilikia.pegasus.com> <1991Apr11.155416.28426@eci386.uucp> <958@fnx.UUCP>
Date: Thu, 25 Apr 1991 18:18:44 GMT

In article <958@fnx.UUCP> del@fnx.UUCP (Dag Erik Lindberg) writes:
> In article <1991Apr11.155416.28426@eci386.uucp> woods@eci386.UUCP (that's me!) wrote:
> >A more elegant solution for System V is to just sent a SIGPWR to init,
> >i.e. kill(1, SIGPWR); and have your inittab configured correctly to
> >"do the right thing" with powerfail (and/or powerwait) entries.  Why
> >waste all that code which was put there for just this feature?
> 
> WRONG!!!  This may be good enough for a single user workstation, but
> any multi-user system *MUST* warn users of impending doom to allow 
> them to save their work, shut down whatever they are doing, and exit
> in a way that will allow them to resume work as quickly as possible
> when power is restored.  Don't assume that everyone will be aware
> power went out on the system, they could be in a different building,
> or even another city.

Uh, I said "do the right thing"....  On my 3b2, which is certainly not
a workstation(!), when init receives a SIGPWR, such as when the
"power" switch is flicked to off, the system is gracefully shut down,
giving the users a one-minute warning to log off....  I never assume
anything!  :-)

> >/etc/shutdown scripts are for human users, and can vary widely -- some
> >even ask for confirmation!  Not something the average daemon can answer!
> 
> So don't use the supplied shutdown script.  Modify it, or write another.

No, I'd change the deamon to do a 'kill(1, SIGPWR)', then make sure my
inittab and related scripts did the right thing (i.e. the same way my
3b2 works).

On the other hand, with my 3b2, a directly connecting the UPS to the
powerfail line on the "power" switch into the motherboard eliminates
the need for the daemon in the first place!
-- 
							Greg A. Woods
woods@{eci386,gate,robohack,ontmoh,tmsoft}.UUCP		ECI and UniForum Canada
+1-416-443-1734 [h]  +1-416-595-5425 [w]  VE3TCP	Toronto, Ontario CANADA
Political speech and writing are largely the defense of the indefensible-ORWELL