Actually, in a round-a-bout way, the US DOES use the metric system. Since around the 1890's, US units have been officially defined in terms of metric units.
"they're refrigerant, just like a whole-house air conditioner"
Technically, they're not "just" like an air-conditioner. They're (like the water based systems also listed under the XD tag) only a heat exchange system - there's no compressor (although they also sell some of those under the XD name). Rather than compressing the vapor before condensing it, they pump the liquid refrigerant after it has condensed, which has the advantage of not cooling it below the room dewpoint, so there's no dripping condensate to deal with, and no overly dried out air to re-humidify.
"With AC/DC, you already have equipment available that can push over 90% efficient" Yes, but when UPSs are designed for maximum load, and redundant UPSs are installed, and you typically are operating below 50% of capacity (e.g. late shifts), that 90% full load efficiency can be below 50% real life efficiency.
"With air conditioning, central home units manage 90-94% efficient, and I'd expect industrial models to do even better" Not even close, if you assume that you're talking about 90-94% of theoretical maximum cooling effect. A common EER (btuh's removed divided by watts consumed . . . yea, I know, US units are crazy compared to metric) is around 10 to 13. That's a Coefficient of Performance of around 3. So you're removing 3 times as much heat as you're putting in, but the theoretical limit would be a COP of around 6 or 7 at typical temperatures.
"you're probably spending 99% of your time not on UPS."
Almost by definition, you're always going thru the UPS; what you're not doing 99% of the time is discharging the batteries. And a large, efficient UPS is proably only around 90% efficient at normal loads. At very low loads, they can actually use more energy than at full loads. So a 250 kVA UPS is going to turn about 20 to 25 kW of energy into heat, even when the equipment it's serving is idling.
My experience with UPS includes a time when I received a roll of mylar sepia architectural drawings to use as backgrounds for the HVAC and plumbing plans (back in the days before CAD). They were totally useless because of the extensive creases. There were tire tracks on the packaging they came in.
Yes, it was one of my more interesting classes, a first year humanities class. Another unusual thing in it was the weekly paper, which had to to 150 words or less. If it was 151 words, it was rejected. It really made you pare your arguments down to their essence.
I had one class that was a third type, where the professor passed out only an general agenda or syllabus, tried to engage the class, and asked us not to take notes because that would distract us. He said if we needed notes, it would be better to go to the library and write them up from memory after the class, though he admitted that no one would do that. The couple of times I did try making notes afterwords, it worked better than taking copious notes during class. Still I occassionally took brief notes during that class, the trick is not to try to write everything down. I did have at least one other class where you had to write everything down from the blackboard, because there was no other source for that info, as the prof really didn't use the books.
Most data centers have humdifiers and dehumidifiers. It used to be critical to keep the humidity close to 50%, but now musch of the rack-based equipment can handle anywhere from a low of 10%-20% RH to a high of 90%-non-condensing. And, yes, unless you get conditions causing condensation, usually avoiding the static from too-low humidities is more important.
"The so-called subsidy of private transportation is paid for by fuel taxes" So why do I have to pay tolls on the local interstate? (Hint - tolls not only help pay for road repairs and construction bonds, they also pay for the toll booths and their army of patronage workers)
"Very heavy vehicles cause most road wear; passenger vehicles pay more than the damage they cause." So you're saying, the trucking industry is being subsidized.
The original construction of the interstates, for example, were subsidized by federal dollars as a homeland security measure (called defense in those days) And last time I looked, a lot of the local road repairs are payed for by property taxes, at least in the cities where property values are high per mile of road. Also, much of the city road repairs are required because of the constant digging up of the streets for sewers, gas, water pipes, etc.
Although fuels taxes help pay for roads, they do not account for all of the costs.
"You can just as well give your employees Wordpad." Please do. Wordpad is a decent program, much better than MS Word, unless you need some of the feature bloat, in which case Worperfect is better. Still I prefer Gedit for most things.
". . . schools don't teach people the details of how to use office suites." Unfortunately, this is not true. When I was in school, we still used typewriters, and calculators were just replacing slide rules. But my youngest has had to submit her homework as MS Word.docs and MS Powerpoints in middle school and high school. And my middle child has taken a for-credit "computer" class in the local college which only taught basic MS Office usage. At least my oldest, who is in graduate school going for a PhD in computer science, tells me that most people in his department use Apples. He sometimes runs XP and Vista, usually in parallels, and uses Linux in the lab. At that level the use of Open Office, Eclipse, Cygwin, etc., is common. But down here in the ordinary work world, which the schools tend to train for (in lieu of educating) the monopoly still monopolizes.
Guessed answers increase the variance in test results. Penalties for wrong guesses improve the test by reducing the randomness of results. Pure guesses do not add to the accuracy of test results, at least they don't if there is no penalty for wrong guesses. Well designed tests will allow for better and worse wrong guesses, reducing the number of possible answers in a guess by a knowledgable test-taker, but that doesn't refute the main point being made in TFA. TFA does get some of the arithmetic very wrong, but the main point is still valid: There will be a large probability of inaccurate ranking of test-takers unless the test is very well designed, and allowing guesses without penalty is poor design in a test where the typical passing grade has a low number of correct answers.
No, his implied definition of a hard test is that most test-takers know few correct answers, but the passing score is lowered to allow a sufficient number of test-takers to pass. Then, if you do the math (which he got somewhat wrong) allowing people to guess without penalty creates a significant probability that someone who knows less than you will pass even though you failed.
Would you say that a gallon is twice the size of a pint? TFA does indeed say that that the dino is twice the height of man at the shoulder. But the sumarry says that it's twice the size. Those aren't the same thing.
And if you look at the picture in the article, it's twice as high, but it carries it's body horizontally and, counting the tail, is 3 or 4 times as long as an average person is tall.
"Why would Sunni Arabs care what we did to a non-Sunni, non-Arab country?"
For one thing, though Sadaam and his ruling class were Sunni, most of Iraqis are Shiite.
For another, examples of the US overthrowing governments does not exactly give loyal citizens of other countries warm and fuzzy feelings about the USA. (who's next?)
Slashdot Mirror
Actually, in a round-a-bout way, the US DOES use the metric system.
Since around the 1890's, US units have been officially defined in terms of metric units.
"install xp in a virtual machine! . . ." that expires on Aufust 17.
"they're refrigerant, just like a whole-house air conditioner"
Technically, they're not "just" like an air-conditioner. They're (like the water based systems also listed under the XD tag) only a heat exchange system - there's no compressor (although they also sell some of those under the XD name). Rather than compressing the vapor before condensing it, they pump the liquid refrigerant after it has condensed, which has the advantage of not cooling it below the room dewpoint, so there's no dripping condensate to deal with, and no overly dried out air to re-humidify.
"I have seen Absorption Chillers running off the transformer heat being used to boost data center cooling"
That must be one mighty hot transformer.
"With AC/DC, you already have equipment available that can push over 90% efficient"
Yes, but when UPSs are designed for maximum load, and redundant UPSs are installed, and you typically are operating below 50% of capacity (e.g. late shifts), that 90% full load efficiency can be below 50% real life efficiency.
"With air conditioning, central home units manage 90-94% efficient, and I'd expect industrial models to do even better"
Not even close, if you assume that you're talking about 90-94% of theoretical maximum cooling effect. A common EER (btuh's removed divided by watts consumed . . . yea, I know, US units are crazy compared to metric) is around 10 to 13. That's a Coefficient of Performance of around 3. So you're removing 3 times as much heat as you're putting in, but the theoretical limit would be a COP of around 6 or 7 at typical temperatures.
"you're probably spending 99% of your time not on UPS."
Almost by definition, you're always going thru the UPS; what you're not doing 99% of the time is discharging the batteries.
And a large, efficient UPS is proably only around 90% efficient at normal loads.
At very low loads, they can actually use more energy than at full loads.
So a 250 kVA UPS is going to turn about 20 to 25 kW of energy into heat, even when the equipment it's serving is idling.
? 20,000 UPSs ?!?
Try 2 to 4 big ones.
My experience with UPS includes a time when I received a roll of mylar sepia architectural drawings to use as backgrounds for the HVAC and plumbing plans (back in the days before CAD).
They were totally useless because of the extensive creases.
There were tire tracks on the packaging they came in.
Yes, it was one of my more interesting classes, a first year humanities class.
Another unusual thing in it was the weekly paper, which had to to 150 words or less. If it was 151 words, it was rejected. It really made you pare your arguments down to their essence.
I had one class that was a third type, where the professor passed out only an general agenda or syllabus, tried to engage the class, and asked us not to take notes because that would distract us. He said if we needed notes, it would be better to go to the library and write them up from memory after the class, though he admitted that no one would do that. The couple of times I did try making notes afterwords, it worked better than taking copious notes during class. Still I occassionally took brief notes during that class, the trick is not to try to write everything down.
I did have at least one other class where you had to write everything down from the blackboard, because there was no other source for that info, as the prof really didn't use the books.
"Are you only you because of that matter that makes you up?"
Is a sound only that sound because of the matter that makes it up?
No/Thing
Most data centers have humdifiers and dehumidifiers.
It used to be critical to keep the humidity close to 50%,
but now musch of the rack-based equipment can handle anywhere
from a low of 10%-20% RH to a high of 90%-non-condensing.
And, yes, unless you get conditions causing condensation,
usually avoiding the static from too-low humidities is more important.
Well, since they're blowing air across the cooling coils, technically it is Air Conditioning.
Yes, it has a dehumidifier, according to another post.
"The so-called subsidy of private transportation is paid for by fuel taxes"
So why do I have to pay tolls on the local interstate? (Hint - tolls not only help pay for road repairs and construction bonds, they also pay for the toll booths and their army of patronage workers)
"Very heavy vehicles cause most road wear; passenger vehicles pay more than the damage they cause."
So you're saying, the trucking industry is being subsidized.
The original construction of the interstates, for example, were subsidized by federal dollars as a homeland security measure (called defense in those days)
And last time I looked, a lot of the local road repairs are payed for by property taxes, at least in the cities where property values are high per mile of road.
Also, much of the city road repairs are required because of the constant digging up of the streets for sewers, gas, water pipes, etc.
Although fuels taxes help pay for roads, they do not account for all of the costs.
"You can just as well give your employees Wordpad."
Please do. Wordpad is a decent program, much better than MS Word, unless you need some of the feature bloat, in which case Worperfect is better.
Still I prefer Gedit for most things.
". . . schools don't teach people the details of how to use office suites." .docs and MS Powerpoints in middle school and high school.
Unfortunately, this is not true.
When I was in school, we still used typewriters, and calculators were just replacing slide rules.
But my youngest has had to submit her homework as MS Word
And my middle child has taken a for-credit "computer" class in the local college which only taught basic MS Office usage.
At least my oldest, who is in graduate school going for a PhD in computer science, tells me that most people in his department use Apples. He sometimes runs XP and Vista, usually in parallels, and uses Linux in the lab.
At that level the use of Open Office, Eclipse, Cygwin, etc., is common. But down here in the ordinary work world, which the schools tend to train for (in lieu of educating) the monopoly still monopolizes.
Guessed answers increase the variance in test results.
Penalties for wrong guesses improve the test by reducing the randomness of results.
Pure guesses do not add to the accuracy of test results, at least they don't if there is no penalty for wrong guesses.
Well designed tests will allow for better and worse wrong guesses, reducing the number of possible answers in a guess by a knowledgable test-taker, but that doesn't refute the main point being made in TFA.
TFA does get some of the arithmetic very wrong, but the main point is still valid:
There will be a large probability of inaccurate ranking of test-takers unless the test is very well designed, and allowing guesses without penalty is poor design in a test where the typical passing grade has a low number of correct answers.
Parent post gets the point, and states it better than TFA.
No, his implied definition of a hard test is that most test-takers know few correct answers, but the passing score is lowered to allow a sufficient number of test-takers to pass. Then, if you do the math (which he got somewhat wrong) allowing people to guess without penalty creates a significant probability that someone who knows less than you will pass even though you failed.
I got a VW rabbit (diesel) in 1980 that got 55 mpg highway and 42 mpg city.
How come I can't get a car with better mileage than that by now?
where are your sarcasm tags?
Would you say that a gallon is twice the size of a pint?
TFA does indeed say that that the dino is twice the height of man at the shoulder.
But the sumarry says that it's twice the size.
Those aren't the same thing.
And if you look at the picture in the article, it's twice as high, but it carries it's body horizontally and, counting the tail, is 3 or 4 times as long as an average person is tall.
"Why would Sunni Arabs care what we did to a non-Sunni, non-Arab country?"
For one thing, though Sadaam and his ruling class were Sunni, most of Iraqis are Shiite.
For another, examples of the US overthrowing governments does not exactly give loyal citizens of other countries warm and fuzzy feelings about the USA. (who's next?)