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Comment Re:Fragmentation (Score 1) 222

Far too frequently in the Android world that you refer to the choice boils down to this: You can either choose to continue running a version of Android that is outdated, or you can buy a new phone and repeat the process in a few months.

I paid $500 for a T-mobile Vibrant, one of Samsung's top-of-the-line Galaxy S models, in July. So we're just barely at the five month mark and it's now two full releases behind mainline Android. The situation is particularly frustrating because the newly released Nexus S, which Samsung also manufactures, is merely a variant of the Galaxy S models. It has exactly the same processor as the Vibrant, and identical hardware specifications aside from the front facing camera and NFC capabilities.

So what do you call it when two nearly identical phones are separated by two major releases of Android? You may not want to call it fragmentation, but in the real world we call it "ridiculous."

Comment Re:Green Text! (Score 1) 721

It's funny that you say "green" because that is actually the corporate color of the company that has been providing me with cell phone service for the past 3 years: Cricket.

Unlimited airtime and unlimited text messaging for $52.50 including tax. That's been my price the entire time. Awesome, awesome company and service.

So there is competition, but it is tough to convince people to become a customer of your scrappy young upstart when "coverage" and "bars" are so important. People seem to worry that the service will be terrible. The reality of it is that I get great reception everywhere that I go and when I travel I get to Roam on Verizon's network for a really reasonable rate (I have thirty minutes of roaming airtime included with my plan and I can still send unlimited text messages!).

MetroPCS is another company who, like Cricket, also provides unlimited plans. If you have the means, and live within an area where they offer service, I cannot recommend them enough. It is so nice to not have to worry about overages or petty fees.

Comment Re:Iron Man's Suit Defies Physics -- Mostly (Score 2, Interesting) 279

Hydrogen peroxide powered rocket packs fly for around 30 seconds, because they have a specific impulse of around 125, meaning that one pound of propellant can make 125 pound-seconds of thrust, meaning that it takes about two pounds of propellant for every second you are in the air. Mass ratios are low for anything strapped to a human, so the exponential nature of the rocket equation can be safely ignored.

A pretty hot (both literally and figuratively) bipropellant rocket could manage about twice the specific impulse, and you could carry somewhat heavier tanks, but two minutes of flight on a rocket pack is probably about the upper limit with conventional propellants.

However, an actual jet pack that used atmospheric oxygen could have an Isp ten times higher, allowing theoretical flights of fifteen minutes or so. Here, it really is a matter of technical development, since jet engines have thrust to weight ratios too low to make it practical. There is movement on this technical front, but it will still take a while.

John Carmack

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