Date: Fri, 6 Feb 1998 14:14:06 -0500 (EST) From: "Bruce M. Walter" <walter@fortean.com> To: Tom <tom@sdf.com> Cc: Terry Lambert <tlambert@primenet.com>, John Fieber <jfieber@indiana.edu>, calin@ibd.dbio.ro, freebsd-hackers@FreeBSD.ORG Subject: Re: Powering off the system/UPS Message-ID: <Pine.BSF.3.95q.980206140354.365A-100000@callisto.fortean.com> In-Reply-To: <Pine.BSF.3.95q.980206102658.7371A-100000@misery.sdf.com>
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> Not even an issue. You want to start the shutdown well in advance > anyhow, because battery life is a bit variable. > > The biggest problem is that a usermode program loses control as soon as > it halts the system. What happens if power is resumed? The system is > limbo with "Press any key to reboot" on the screen. A smarter UPS can > help, but adding intelligence to the OS is easier. This is true. What we've been looking at is a combination of a userland monitor daemon and a device driver which is customizable for different cables and UPS capabilities. The driver handles the low-level communication with the UPS and provides status information to the user daemon. It also installs a poweroff callback to shutdown the UPS inverter if: 1) the kernel calls the poweroff callback with the RB_POWEROFF flag set in howto -and- 2) the UPS is in line fail mode If the power is restored after the reboot begins, the kernel will fallthrough to the RB_AUTOBOOT code (as long as we remove the silly logic from reboot(8) which sets RB_HALT if RB_POWEROFF is set by the -p option... RB_HALT should be set if reboot(8) is called as halt(8) ONLY. They're the same program, after all ;) A -p (poweroff) options should also probably be added to shutdown (I'm working on most of this). If the system reboots and the line is in failure mode, the driver can go into a loop: 'Give me power or give me death' before the filesystems are mounted. - Bruce ======================================================================== || Bruce M. Walter || 107 Timber Hollow Court #335 || || Senior Network Consultant || Chapel Hill, NC 27514 || || Fortean Technologies, Inc. || Tel: 919-967-4766 || || Information Technology Consultants || Fax: 919-967-4395 || ======================================================================== || BSD Unix -- It's not just a job, it's a way of life! || ========================================================================
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