Xref: utzoo comp.unix.sysv386:7819 comp.unix.wizards:25430 comp.unix.internals:2710
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!rsi!prcrs!paul
From: paul@prcrs.prc.com (Paul Hite)
Newsgroups: comp.unix.sysv386,comp.unix.wizards,comp.unix.internals
Subject: Re: SIGPWR signal in system v
Message-ID: <1910@prcrs.prc.com>
Date: 6 May 91 16:23:01 GMT
References: <1991May6.112253.5344@cs.tcd.ie>
Followup-To: comp.unix.sysv386
Organization: PRC Realty Systems, McLean, VA
Lines: 18

In article <1991May6.112253.5344@cs.tcd.ie>, ohurley@cs.tcd.ie (Oisin Hurley) writes:
> 
> Does anybody out there have information on the SYS V SIGPWR signal? The man
> says that this signal occurs if there's a power failure. 

Well, I have only seen one system, the HP 9000/800, that uses this.  The 800's
have a battery back-up that keeps main memory (only) alive while power is out.
(The battery is optional on some models.)  If power is restored before the 
battery dies, the system will recover.  First, some special entries in 
inittab get executed:
	pf::powerwait:/etc/powerfail >/dev/console 2>&1 #power fail routines

This reloads software into smart cards on our system.  After this is done,
SIGPWR is sent to every process, but the default on SIGPWR is to ignore it.
vi (for one) will catch the signal and repaint the screen.

Paul Hite   PRC Realty Systems  McLean,Va   paul@prcrs.prc.com    (703) 556-2243
        You can't tell which way the train went by studying its tracks.