On Wed, 19 Feb 1997, Masami and Ken Nakata wrote:

> On Tue, 18 Feb 1997 15:15:16 -0600 (CST),
> "The Great Mr. Kurtz [David A. Gatwood]" <davagatw@Mars.utm.edU> wrote:
> > 1. What VA rating would you suggest to achieve that (the system's power
> > supply is rated at 3 amps max, no idea what the real drain is, though),
> 
> You mean VAh?  But sorry, I can't say anything about this.

That's what I was _expecting_ to find, but no, the catalogs _all_ say
simply VA.  I assume that theu don't really provide 280 VAh for $100
because that would run a system that maxes out at 3 amps for 10 hours.
Instead, one catalog rated a similarly-sized unit at somewhere along the
lines of 6 minutes.  Weird.

> > 2. How hard is it to set up LAN signalling on a free unix clone (i.e. is
> > powerd or the equivalent available in source code form, and if not, how
> > hard would something like that be to write)? 

<snip>

> Anyway, the APS' UPS we used had an RS232-level signal output which
> got grounded when the AC power went down.  I connected the signal to
> one of the serial port, and wrote a small daemon which periodically
> polled for the status of the line.  If it went down, the daemon would
> bring the server down by "shutdown -h now".  We never had to really
> use it during the Web-polling operation, but I tested it a couple of
> times (yanked the plug out) and it worked beautifully.

Do any of those UPS systems have the ability to signal, say... 5 or 10
minutes before they would run out of power?  something like that?  I'd
almost be afraid to guess at a time and count down from there, because
batteries do degrade over time, and with my luck, the system wouldn't go
down in time.  All it would take is once....   :-)

Later,

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