Yaatri

Sorry about "square" I meant a cube. In any case, it's should be obvious from the context that it should be a cube.
I gave an example of how one can perform back of the envelope calculations, without a calculator, to estimate the level of effort required. It illustrates a principle.

Yes a bit muddled. I should not have posted it from my phone. A proper keyboard would have been better.
Your presumption is totally off the mark. You did not have to presume anything to talk about area. I had already made the mistake of calling it a quare. I would have commended you had you presumption had led you to talk about volume.

I used mile to make my point about size of the cell, because most people here understand miles better.
This comment reminds me of your last comment here about "an ad hominem attack".


Math does work. Once you get out of the mindset that what's stated is wrong, apparently misled by my use of "square" in stead of cube.
Both uses, one metre cube/square and one square/cubic metre are acceptable but mean different things. So 1/7th mile cube as well as 1/7th mile are absolutely correct.

It's astounding that someone who worked with GCMS would not consider the possibility that I might have mean cube.
I
And how accurate was it? At what level did you work? I mean what level of detail were you seeking? I have not made, and I am not making any definitive statement about what cell size is adequate.

I did not make any claim about being a GCM expert, just gave an example of how anyone, can do some simple calculations to estimate level of effort. If you worked with GCMS, which I have not, but know from simple commonsense, that those calculations are reiterative. I did not even give any details about what kind of calculation is done for each cell? I used one arithmetic operations per element, which A GCM person would know is ridiculously low, show that we are already to a very very large number of operations.

Again, I have not presented a GCM model. It's a simple illustration of estimating computational effort. A simple division of a portion of the atmosphere into cubic cells does not make a GCM. Any GCM expert would no that. I think you started with the assumption that my GCM model, which it is not, is wrong.

If I knew what NSA was using, I would not be posting it here.

I dodn't know, but I don;t think monitoring conversations, is a computing intensive operation, and computing power alone would not do it. Quality of sensors and their locations is just as important.


I disagree. The statement cited no reasons. It was a belief.


You took my off the cough remarks designed to show how one can estimate requirements for a computational efforts as an instruction on GSM models and an explanation of NSA functions.. I picked two simple examples. I am not a GCM expert, nor do I work for CIA/NSA etc. Are you? If I were, I would not be posting here.
Here is how I did a cell calculations. Again. DON"T challenge my assumptions because they are not directives for a GCM model.
I assumed, that most of the mass of the atmosphere is within the 20 Km layer above the surface of the earth. Hence only that layer interacts with the sun and the universe. I calculated voume of that layer, which is a spherical shell of thickness 20Km. I Chose an arbitrary number of cells, a million/billion/trillion to estimate the size of each cell. All other details were ignored as they are not necessary for my point.
For NSA, I picked a simple task that most people can identify with. Breaking a code, with brute force, trying every possible combination.
Research in a field always requires a lot more effort and expense, than running field applications based on that research.

If you were slighted by my comment that NSA probably does not have the most powerful computers, I apologize. Rest assured that I don't value a person by the size of tools they have. Nor would my opinion deprive NSA of asking for more powerful computers. It was an opinion.

slawecki

http://www.washingtonpost.com/blogs/...RgsV_blog.html

this is probably a very very large computer. the photo in the post showed the 23 fans on the roof. the new photo shows a clean box. if you go to 8540 Electric Avenue, vienna va, and look to the west, the google pic will show the roof, and all the a/c's. these idiots put a building that puts out 90-100db of noise in this secret location???

this is not a real special location, getting in and out at rush hour is pure hell.(i lived in 8544 when electric ave was a dirt road)

ScottC

That doesn't really look any different from any other co-location building. Of course, most of those are nowhere near residential areas. It could just be a normal data center, not a "super computer".

Here is another that hosts a lot of Microsoft, Comcast and other large firms:

https://maps.google.com/maps?q=o'har...e+airport&z=19

uszkanni

Maybe when the FBI says they're putting a detainee on ice they're really putting them on ice!

uszkanni

Discernible, perhaps, but not obvious. I had no idea you were talking about a spherical shell 20km thick and, quite honestly, wasn't planning to go thru a lot of "what if's" to try to determine how you came up with your numbers. Clarity is the responsibility of the poster.

As to the remainder of your response, I could go thru it and refute your statements and assumptions point by point, but that's not useful.

Instead let me just say that you have very grossly overstated the computational complexity of global weather modeling and grossly understated the computational needs of the IC (Intelligence Community, which includes DoD/NSA/CIA/etc), You then used these bad assumptions to support a conclusion (determined a priori?) that is simply wrong. If this were done intentionally, it would fall into the realm of a "strawman argument", but I suspect it was just a matter of "uncareful" estimation.

Nothing wrong with "back of the envelop" or "orders of magnitude" estimation but you need to use valid assumptions and not just pull numbers and tasks out of thin air.