Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
For the out-of-band Slashdot experience (mostly headlines), follow us on Twitter, or Facebook. ×

Comment: Re:The article is useless without benchmarks (Score 2) 76 76

You say "video card" I say 15 years ago it would have been a beyond-top-secret supercomputer at Lawrence Livermore simulating non-linear shock-front neutron transport thingy.

Damit can't you channel your inner gear-head for just one minute?

Comment: Re:The article is useless without benchmarks (Score 1) 76 76

It looks like a strategy.

Rightly or wrongly AMD believes they don't get treated fairly by the trade press. Their reviews often sound like "Well it's OK I guess, but...". And the comments attached to review articles more often than not are "but the drivers..." "but the watts..." "but the hairworks..." "but the spaceheater..." "but the rebadge..." and so forth.

This way at least they get to own the launch day to the extent possible.

Comment: All Hail the HypnoCanada (Score 1, Funny) 339 339

Hello. This is Canada. We want Puerto Rico, and Disney World. And we want border agents on the border formerly known as the Canadian Border to all be girls wearing bikinis. Or we pull off the Big Tarp we got thrown over the permafrost. We call it the Big Tarp. It's a tarpolin^h^h^h^haulin. And it's big. It's very likely not all in my imagination. You want 5000 degrees in Nevada? I know what you're thinking. It's already 5000 degrees in Nevada. Ok fine. But riddle me this: why doesn't the New Jersey mob bury their work in Nunavut? I know right? Permafrost right? You want the NJM burning all that gas driving 5000 km each way just to intern^h the whacked? That's not very ecologically wise is it? Is this not in any way less than unclear? I though so. All replies through Santa's village, North Pole, Canada, H0H 0H0. Hosers.

Edit: This is the wife speaking. Or boys wearing thongs, but only nice ones like Jeff Goldbloom in The Fly, not Jeff Goldbloom in The Switch. Eww.

Comment: Re:Dumb Question (Score 1) 172 172

In your basic gas turbine thermodynamic cycle, the Brayton Cycle, combustion takes place on incoming gas that has been compressed. That's what your compressor stage is for in a jet engine. In a ramjet the kinetic energy of the air is converted to pressure by a converging-diverging compression shock nozzle. (We notice Sabre has a ramjet-type compression inlet). The process is so fast its adiabatic (no heat goes in or out). The more compression you can get before combustion the higher the efficiency.

Adiabatic compression equals heating (ref. Charle's Law). At hypersonic speeds it gets so hot before you even start combustion the materials freak out. You can't make it much hotter by burning your fuel. Low efficiency.

By cooling the air you can get enough compression to yield a decent efficiency. It's not a Brayton Cycle any more though because that features adiabatic compression by definition. Sabre is all about removing heat in the compression stage.

Comment: As we all know (Score 1) 205 205

vorticity is conserved. The flow over a wing is a rotation superimposed on a translation which results in the slower flow underneath and faster on top.The rotation, usually called circulation, embodies a certain value of vorticity which can't disappear. Where it goes is it turns 90 deg at the tip and trails back behind the a/c all the way to the tarmac (vortexes have to terminate at a boundary...the ground).

If the wing is longer, for constant lift, the circulation reduces because a wider swath of air is turned downward so to give the same z-direction momentum flux the amount of "turning" is less.

By flying tip-to-tip, a/c effectively create a longer wing. Physically of course it isn't one wing but happily the highly coherent trailing vortices can be coupled by overlapping them, they rotate in opposite directions so tend to cancel each other out.

(The reason "bees shouldn't be able to fly" is that it appears to take too much energy to create the circulation around their wings every flap. It takes energy to "spin up" the air. How they do it is they slap their wings together at the top, when they separate they shed a vortex back over their wings which gets the circulation going. Not obvious.

Comment: Tangentially... (Score 4, Interesting) 163 163

I have a metaphorical way of making sense of autistic behaviors. Let's say the brain has some kind of sensory input buffer. Defects in that buffer might lead the brain to be overstimulated with sensory input and become preoccupied with them. The other thing the buffer might do...and this is where it gets more metaphorical and maybe less factual...is serve as a feedback path for brain-generated inputs, to sort of test things. Like when someone says "Imagine what it feels like when..." or even when you just think about real experiences you had. I think of dreams as maybe working like that too: brain generated inputs get cycled back through the buffer to serve as virtual experiences for...whatever dreams are for. That way of thinking about it leads to a way of understanding stimming behaviours: they can be thought of as dream-related movement that we don't do during sleep dreams because of sleep paralysis.

I find having a (metaphorical and maybe not correct) mechanistic way of understanding autistic bahaviours makes it a lot easier to deal with them.

Comment: Optical? (Score 2) 386 386

How would optical be wiped by e/m radiation? As for magnetic, as long as there is no physical damage taking place (I'm no Carrington event specialist, but it doesn't seem as if high energy particles do the damage, just warpage of Earth's magnetic field (someone can correct me if I'm wrong)) wouldn't any old Faraday cage do? I wouldn't be surprised if the metal drawers in safety deposit boxes would be sufficient.

Comment: May I Say a Word About Patran (Score 2) 349 349

I have used this program my entire career. For the last 20 years (since MSC bought PDA), it has not changed apart from the odd user-generated macro getting included in. The windowing interface has had the same bugs (e.g. scroll bars that are 1 pixel high) since I was a wee lad. Half the stuff in it that isn't used regularly doesn't work, never has, never will and yet it is the standard for FEM pre/post in aerospace. Staring at this broken-ass POS year after year has filled me with ennui.

May there be a special circle in hell just for MacNeil-Schwendler.

Thank you. That is all.

Comment: Re:Nothing New (Score 1) 349 349

That is because corporate infrastructure software does not generate revenue...

Hi. Corporate infrastructure supports the creation of whatever the corporation sells. Thus, creates wealth.

Where any specific bit of the enterprise fits in the revenue generating chain is an arbitrary organizational decision. Ultimately the entire entity is there to give the sales force something to sell and the ability to accept purchases and support customers.

In other words, the pointy end of the stick is useless without the rest of the stick. It's just prick lying on the forest floor under a pile of bear poo.

You can do this in a number of ways. IBM chose to do all of them. Why do you find that funny? -- D. Taylor, Computer Science 350