Followup to: UPS initiated autoshutdown

[Daniel Ray]

Hi. A few weeks ago I posted an article here asking about a daemon that would
sense a power failure and initiate an automatic shutdown within a controllable
period of time. This would be used in conjunction with an uninterruptable
power supply (battery backup) so the system could be brought down cleanly
while power was still available thru the UPS. This was in the wake of a full
hard disk destruction after a power failure, and we were not to be burned
again.

I received an enormous number of inquiries from people who wanted to know
how to implement this!

Here on The Northern Lights, we have solved the problem (getting a UPS),
and are about to solve the autoshutdown daemon issue also. Several guidelines
went into TNL's decision:

 a. Money *was* an object. TNL charges no fees, and I don't make very much
thru my job, so getting a good deal was a central factor. I expected to
make the purchases thru mail order, a method I am familiar with (and have
saved literally $1000s of dollars!).

 b. Both a UPS and the power failure sensor/autoshutdown daemon would have
to be obtained. Some UPSs implement both functions, others need a seperate
sensor/daemon. The minimum wattage needed to be 450 watts, enough to provide
10 minutes of backup for an Acer 1100 (386 AT clone), an EGA console monitor,
and an Avatex 2400 external modem. The CPU uses about 190 watts, so 450 adds
a comfortable measure of reserve. As for the power sensor/shutdown daemon,
the sensor would HAVE TO communicate with the daemon via an unused serial
port. TNL has plenty of those, but not one available slot on the motherboard,
which is the other way some of the sensors work. The UPS was expected to
possess surge suppressor and voltage regulation capability in addition to
the power failure backup.

The printer and other external peripherals would NOT be on the UPS
protected circuit. UPSs come in all shapes and sizes starting at 200
watts thru 2000 or more. 200 turns out to be pathetically insufficient
protection for a UNIX size PC. We desired an audible power failure alarm
for the UPS, and often the 200 watt units don't include this feature.


So, I went thru about 60 mail order ads, and found a wide divergence of
prices for the same unit. Finally we decided on the following two
purchases:

1. A TrippLite 450 Watt battery backup power supply (model BC-450), costing
$299 thru Advanced Computer Products (714-558-8813). This same unit cost
from $100 more up to nearly $600 thru other mail order companies, so watch
out! Often almost all ads will be around the same price, but there will be
ONE company that offers something $100 less, and is easy to miss. This UPS
provides 10-30 min of protection, has an audible alarm, a circuit breaker
to protect against overloads, voltage regulation, square wave AC during
battery power (some say this is not as good as pure sine waves, others say
that square is better for electronic equipment, don't know which to believe).
Other UPSs were available having more wattage, or a power sensor/daemon
feature, often using a motherboard slot. They were much more expensive.
The TrippLite is good for around 5 years or up to 500 battery/recharge
cycles, and the manufacturer warns to always leave it plugged in or the
battery can become damaged. Unfortunately the TrippLite does NOT have
power sensor/autoshutdown capabilities, nor is this a separate option you
can buy from the company (that we know of).

2. We are about to get Showdown unattended shutdown software/sensor from
Continental Information Systems, 320 W. Irving Park Rd, Itasca, IL 60143
(312-250-8111). This provides a device that plugs in and connects with
a serial port for XENIX, 3B2, or System V/386 UNIX, and the daemon
software which is configurable. TNL can't vouch for this one since we
haven't done it yet. The cost is $195 right now.

We tested the UPS and it works beautifully, seems well-made and reliable.
There are a lot of TrippLites out there, and I think I'll be very satisfied
with it. (This message is not an advertisement, but a case history, telling
what we actually did. You may be able to find a better deal somewhere else).
Up until last week, we thought we'd have to write the daemon portion or
get one written by a couple of people who sent mail, but then discovered
item 2 above in Unix World. The price isn't bad, it solves the hardware
sensor issue, so we'll go with that once I get another bunch of cash to
part with.

It's good to be giving so you should part with the cash whenever you can!
"Power" to the people! :@)

norstar
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