[CentOS] Power-outage

Marko Vojinovic vvmarko at gmail.com
Sat Jul 2 23:34:18 UTC 2011


On Saturday 02 July 2011 21:13:59 Robert Heller wrote:
> > I'm using an UPS for my desktop system, but I don't need it for the
> > laptop. If the AC power drops, even for a moment, the laptop battery
> > will kick in and sustain the machine. I just think that the same thing
> > can be implemented for the desktop too. If I understood the OP
> > correctly... ;-)
> 
> A laptop effectively contains its own UPS in the form of a power brick,
> battery and power supply on its motherboard.
> 
> Yes, one *could* build a desktop or server that way, but why bother,
> since AC wall outlets are everywhere one might want to use a desktop or
> server?

Well, one reason I can think of is that one cannot always trust the AC wall 
outlet to provide uninterrupted power? By that I don't mean AC power going 
down for an hour, but for a fraction of a second.

I happen to live near an industrial zone, and every morning between 10 and 11h 
someone turns on something in the nearby factory, which makes my light-bulbs 
blink twice. Of course, that's enough to reboot my desktop machine no problem. 
I had to buy an UPS system just because of that. Granted, an UPS turned out to 
be a good investment, but still I wonder why there are no offers on the market 
with a "boosted" PSU units that can sustain DC power for a couple of seconds 
during the AC "blinks". They don't even need to use a battery, maybe a set of 
condensers could sustain power for a short period (although I might be wrong, 
never did the numbers on that).

A friend of mine lives near the Technical Sciences university (in the middle 
of the city, they don't have a campus), where they have a medium-sized wind 
tunnel for the aero-engineering courses. Every time they turn the thing on, 
the whole city block loses power for cca 5 seconds. Sure, it's bad AC grid 
design, but bad designs are usually a fact of life. :-)

I'm speculating here about an improved PSU device which would be more 
expensive than the ordinary one, but less expensive than a typical UPS system. 
Given that I believe there certainly is a market for such a PSU, I'm just 
surprised nobody is selling it yet. You cannot assume that the AC wall outlet 
will always provide perfect power... ;-)

> There is (in the SciFi world) the idea that someday
> 'desktops' in the current / conventional sense may completely vanish
> from the universe, taken over progressably by laptops, tablets, smart
> phones, wearable computers (motherboard == shirt, monitor == shades,
> power supply == hat with embedded solar cells, virtual mouse/keyboard
> via motion sensors in your shirt sleves/gloves, etc.),

I could in principle imagine all that coming in the future, but the
"monitor == shades" thing is just only Fi with no Sci in it. A human eye 
cannot focus properly on any object which is closer to the eye than 10-15 cm 
(depending on the eye quality), so there is absolutely no way one can use 
shades or contact lenses or something similar as a monitor, regardless of 
technological levels of any human or alien races (James Bond notwithstanding). 
Unless of course one surgically adapts the eye lense itself, in which case the 
person would not be able to see anything else... ;-)

> or even
> implanted computers (eg as a thin circuit board between your skull and
> scalp, and 'wired' directly into your brain).

I would never wire a brain to a machine. Brains make errors, are susceptible 
to emotions, hormons, vanity, etc., and just introduce a large point of 
failure for the otherwise-correct machines. ;-)

> This seems to already be
> happening to some extent, in that laptops are becoming the computer of
> choise and desktops are becomming an 'old school' sort of thing.

Yeah, the laptops are becoming cheap enough, so that once your computing needs 
grow out of your current laptop, you don't even think of "upgrading" it, but 
rather just buy a new model. Desktops will be in use only for custom things 
(professionals who need, say, five audio cards in one machine) and small 
servers. But we're getting sort-of OT here... ;-)

Best, :-)
Marko





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