[ale] APC UPS

Transam bob at verysecurelinux.com
Thu May 8 12:16:57 EDT 2003


On Wed, May 07, 2003 at 03:23:42PM -0400, Robert E. Karaffa, II wrote:
> I've always been led to believe that one wants a UPS that can talk to the
> computer so that when power fails and the humans are away, the computer can
> take care of itself.

My comment was to suggest that, while desirable for automatic shutdown
when the UPS battery is running down, it is not critical.  The chance
of file system damage from an abrupt shutdown of a desktop or other
Linux system that is not very active when the humans are away seems
to be in the 1%-5% range.

Thus, it is far better to have a UPS connected for the 95% of power
interruptions that are sufficiently brief that the UPS can "ride them
through" and risk the occasional abrupt loss of power than to not
use any UPS.

To respond the the question earlier on power conditioners, in most
areas the voltage is sufficiently stable that conditioners do not
seem necessary.  UPSes are so cheap these days that there's no reason
for conditioners in any case.

Btw, I was totaly amazed by E-Delta's flywheel motor-generator setup.
Wow!

> -Bob K.

-- Bob T.


> on 5/7/03 2:55 PM, tfreeman at intel.digichem.net at
> tfreeman at intel.digichem.net wrote:

> > On Wed, 7 May 2003, Transam wrote:

> >> On Tue, May 06, 2003 at 09:55:13AM -0400, Hogg, Russell E wrote:

> >>> I'm considering a UPS for home use.  I'm doing some reading now about what
> >>> numbers matter and what is worth paying for when it comes to a UPS.

> >>> I'm curious what sentiment the group at large has.  Surely a lot of you know
> >>> more about UPS(es) than I.

> > <<snip usual excellent response>>

> >> Regarding surge suppressors (that one should have on peripherals), the

> > Question time - There used to be power conditioners which were
> > intermediate between a surge suppressor and a UPS in price. You didn't see
> > them often, but I haven't seen any in ages. They could tame _big_ power
> > surges, big short voltage drops, longer slight voltage drops, and in
> > general clean up the line power to something pretty nice.

> > Question is are these things still around for sale and worth the effort?

> > Thanks in advance.

> >> cheap ones are essentially worthless.  They have merely a diode to
> >> absorbe

> > <<snip again>>
> >> number of spikes, who needs it.  Most outages are for only a few seconds
> >> so there probably is not a need for most even to bother with the "wire
> >> the UPS to the computers to shut down the computers stuff".  It IS nice
> >> to have for commercial use.

> > Given that I've had two multiday outages and a single day outage in the
> > last six months, I probably need to reimplement that "shutdown wire"
> > stuff.

> -- 
> **************************
> Robert E. Karaffa, II
> Technical Director
> Emory University
> Flow Cytometry Core Facility
> 954 Gatewood Dr.
> Atlanta, Ga 30329
> voice: 404/712-4429
> e-mail: rkaraff at emory.edu
> web:  http://www.emory.edu/WHSC/MED/RESEARCH/FLOWCYT/
> **************************
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