[Nut-upsdev] Questions on the state of the UPS market
Eric S. Raymond
esr at snark.thyrsus.com
Fri Jan 16 00:35:02 UTC 2009
As previously noted, I need to replace a UPS and want to do my
product research in public so others can benefit. The information
I elicit on this thread will be merged into the UPS-HOWTO.
I went to my local computer-equiuipment big-box store, a place called
MicroCenter in Ardmore, Pennsylvania. I looked at the range of "UPS"
devices they sell and was *completely* confused.
Bear in mind as I ask these questions that whaty I'm looking at, and
focusing on in the HOWTO, is consumer-grade systems in the $70-$200
range. The ones available at MicroCenter seem mainly to be from
APC, CyberPower and Belkin.
1. What's a "Battery Backup"?
One major source of my confusion was that vendors have changed, and
apparently dumbed down, the marketing terminology they use. Everything
I saw was labeled "Battery Backup". The term "UPS" seems to have been
abandoned, though it is still visible in the model numbers in the
pictures on the boxes.
The source of my confusion is this. I learned years ago to
distinguish between three categories of product:
1. Line conditioners (LCs) and surge suppressors. The are just spike
filters, with no battery.
2. SPS = Standby power supply. These normally filter mains power,
switching to a battery when the mains have a dropout.
3. UPS = Uninterruptible Power Supply. These continuuosly feed power
to a battery, which discharges continuously to run the equipment.
When the mains go down, the battery stops charging.
My problem is this: The way these products are now labeled, I
could not work out a way to tell which are which. Some look so
small that they almost have to be mere line conditoners, because
there;s no room in the case for a serious battery pack. Others
could be SPS or UPS devices, but I can't tell which. All are now
just labeled "Battery Backups"!
1a: Does anyone have good heuristics for telling the LCs, SPSes,
and UPSes apart based on the packaging or the specs visible on them?
When I last seriously examined the market (mid-2005), SPS designs
appeared to be on their way out because the switching electronics for
full UPS operation were dropping in cost fast enough to make SPS
designs a pointless economy. In the 2005 and 2007 revisions of the
UPS HOWTO, I must have believed SPSes were one with the dust of
history, because I didn't mention them anywhere.
I'd still believe that, except that it's 2009 and I saw at Ardmore
that APC is still selling not only units with serial-port interfaces
but units that I know for a fact have the old-fashioned single-pin
dumb interface. And if they're still selling *that* kind of obsolete
crap, I have to think maybe there are still SPSes in the world.
1b: Is the SPS in fact dead as a technical category? If not, why not?
Oh, and this, too:
1c: RS232C, on consumer devices, in 2009? Ferfuckssake, *why*?
It's not like USB chips are expensive or anything. I know all about
this from GPS-land, actually; pl2303s are so cheap that even if the
vendors wanted to retread their RS232 designs, the cost of goods to
refit them with USB-to-serial conversion is close to zip. Does anyone
have a clue why this interface type didn't die five years ago?
<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
It will be of little avail to the people, that the laws are made by
men of their own choice, if the laws be so voluminous that they cannot
be read, or so incoherent that they cannot be understood; if they be
repealed or revised before they are promulgated, or undergo such
incessant changes that no man, who knows what the law is to-day, can
guess what it will be to-morrow. Law is defined to be a rule of
action; but how can that be a rule, which is little known, and less
fixed? -- James Madison, Federalist Papers 62
More information about the Nut-upsdev