Posts by David Casler

Taylor series

That's x-squared, not x2. He wrote the second and first term of a Taylor Series.

Uh...check the math. 154 MB/sec is more like 6+ PB per 12 hours.

General Parallel File System, not General Purpose File System

BTW, GPFS stands for General Parallel File System, not General Purpose File System. It's IBM's supercomputer file system, with lots of other applications.

What's the noise figure in dB?

Usually the noise figure for receivers is expressed in dB. What's the noise figure for this setup?

Provide the static electricity a path to ground!

I had a wire mesh antenna for awhile and ran into a serious problem that ended up zapping my router. The wire mesh builds up a static charge in winds. This static charge will find a way to ground ("earth" in UK I believe) using whatever path it can, including via the front end of your router! So run a thin wire from the mesh itself down to a good solid ground/earth connection, such as a grounding/earthing rod. It doesn't protect against lightning, but it does protect against the far more common problem of wind-induced static.

Nope--not the "world's first" Space Met

With all due respect, you ought to investigate press releases before just copying them. Space weather prediction has been done for years and years out of the Space Weather Prediction Center in Boulder, Colorado. It's a joint venture between NOAA (the US weather folks) and the US Air Force. You can get to their website easily by searching on the name of the organization.

SIGINT vs COMINT

SIGINT, or signals intelligence, is generally taken to refer to the "externals," such as technical details like who it's sent to, who it's from, what technology the signal is using, etc. It's used to build up patterns of behavior.

COMINT, or communications intelligence, is generally taken to refer to the "internals," meaning the content of the messages. I think you are probably referring to COMINT in the article.

You can see the American NSA's own definition of SIGINT on its website at http://www.nsa.gov/sigint/index.shtml. Note that it conveniently does not include analysis of the contents of a message.

America Doesn't Use Gas? Think Again!

I don't know why the article states that Americans are not heavy users of natural gas. True, the infrastructure is only in the cities, but there it's pervasive. As anyone will tell you, it's better to heat with natural gas than electricity. As for rural Americans, as I am, the local propane company stops by once a month to top up our tank. We use it for heating and cooking.

Re the zero emissions, it's true that CH4 (methane) plus O2 (oxygen) creates only CO2 (carbon dioxide) and H20 (water). But...and this is a big but...real natural gas has impurities, as does the very air around us. How do these fare in the fuel cell?

Need to look at application multiple tenancy

This whole virtualization thing misses the point. All our apps are "single tenant," meaning only one user or enterprise uses it. What's missing are multiple-tenant apps--a single instance of, say, DB2, but used by multiple parties who cannot see each other's data. The technology exists to do this and it would save a bundle. But very little software is written to keep user groups separate from each other with a solid wall between them for security and privacy reasons.

This happened several years ago in the States

What's happening (deleting the defined benefit plan in favor of a souped up savings plan) and the reaction to it (shock, horror, surprise, lawsuits), all happened here in the US several years ago with rather predictable results. The defined benefits plan is now gone except for some old timers who got grandfathered in, which didn't include me. They substituted a fund into which IBM put money, but even that has been discontinued (although the money itself didn't disappear). So now it's down to the company putting a bit into a 401k plan (an American tax-deferred investment plan) and a bit more than that if the employee also saves. Mine got hammered in the recent crash, but shows some signs of life. Unfortunately this is the new way of doing business. Both we Americans and you Brits need to remember that we're competing with you folks in India and China and the great leveling is taking place. I'm just glad to have a job--and a good one at that--even though any thoughts of retirement have now been put on indefinite hold.

Why such poor resolution?

Digital Globe's resolution is far higher than that shown in the photo. Why can't they release a higher-res image?

A New Medical Procedure?

I think the procedure to remove apostrophes should be called an apostronectomy.

Missile Warning Satellite Well Above Chinese Intercept Capability

From unclassified general knowledge, the Defense Support Program (DSP) satellites that watch for missile launches are in geostationary orbit, about 22K miles above the earth. By contrast, the Space Shuttle is seldom more than 200 miles from earth. The American antisat attempts have been against low-earth-orbit objects at around the same elevation as the Space Shuttle. The Chinese attempt, however, went quite a bit above that, which created two problems. First, it endangers a new class of satellites. Second, the explosion created literally thousands of pieces of shrapnel that will stay in orbit essentially forever, thus continuing to endanger satellites at that altitude. A low earth orbit, on the other hand, gradually degrades because of contact with the very thin atmosphere at LEO elevations, so debris from these satellites eventually falls out of orbit.