Follow Slashdot stories on Twitter


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment Re:A trifle surprising... (Score 1, Interesting) 116

Not really what you were thinking of, but FOGBANK was a bizarre twist on/subversion of the idea:

Basically this material used in US nuclear weapons hadn't been made in 15+ years, and when they tried to make it again, the result failed in testing. Of course, people started assuming they'd "forgotten" how to make it, but it ended up being that they never knew how to make it in the first place -- impurities in one of the ingredients turned out to be important, and the ingredient they were getting 15 years later was "too pure".

Comment Re:Is that bad? (Score 4, Interesting) 291

For more fun and to find out how it works, check out the Spin gravity calculator.

In a nutshell, if you can't built a space station half a mile in diameter, don't even bother thinking about it.

Cool page, but it doesn't really agree with you. Note its quote:

In brief, at 1.0 rpm even highly susceptible subjects were symptom-free, or nearly so. At 3.0 rpm subjects experienced symptoms but were not significantly handicapped. At 5.4 rpm, only subjects with low susceptibility performed well and by the second day were almost free from symptoms. At 10 rpm, however, adaptation presented a challenging but interesting problem. Even pilots without a history of air sickness did not fully adapt in a period of twelve days.

This suggests anywhere from 1-2 RPM could probably be workable, suggesting a practical radius of as little as 0.15 miles, or diameter of 0.3 miles (~241/482 meters). Further, this assumes 1g. It's highly unlikely that 1g is necessary.

Mars is one of the most likely targets for extended-duration missions, and has a surface gravity of 0.376g. So let's say 0.4g. This lowers the diameter to as little as 180 meters (~0.11 miles).

If you bring it up to 400 meters in diameter, or less than 1/4th of a mile, you can have 1 1/3rd RPM at better than Mars-equivalent gravity.

Finally, diameter/radius can be a deceptive way of looking at this, since a basic spinning station need not be circular. A first pass need be little more than a room attached to a counterweight with cables.

Comment Re:Why do politicians even look to NASA for cuts? (Score 1) 134

IIRC, my back-of-the-envelope calculations a year or so ago were that cutting the defense budget in half basically solved US revenue problems, and still left us with a better military than the next ten combined.

It's more complicated than that since you have to compensate for the economic impact of reduced defense spending, but a gradual combination of cuts and redirection to more productive things (e.g. infrastructure, education and job training, alternative energy investments, etc.) would get us into a much better situation.

Of course, this makes too much damn sense to ever happen.

Comment Re:"Modern programmers" who have any clue... (Score 1) 616

You appear to be conflating "user space" with a poorly-defined term "application space", they have no relationship. I can run a kernel in "user" space, and I can run a text editor in "kernel" space. The kernel is not hacked on by application programmers, and the text editor is not hacked on by systems programmers.

VMs are largely a systems issue. People building the applications end-users use are largely not the people building VMs, and the people building VMs actually _do_ have to have a rather close understanding of hardware issues. Libraries like Qt straddle the gap between systems and applications, being strictly neither. Their interaction with VMs they are not themselves running on top of is definitely a systems issue, however, as you are trying to bridge two unrelated systems (the VM, and the host it happens to be running on top of, or possibly even another VM on the same or a different host).

You are also conflating access to the equivalent of "/dev/cdrom" with "direct hardware access". This is also a fallacy. Xine is accessing a special file, not a raw hardware device, and there are several layers of indirection between Xine and the hardware, and you could easily substitute another file and Xine would neither know nor care. Xine isn't what's fiddling with hardware registers and the like, the drivers are. Xine is an application running on top of abstractions others have built.

Comment Re:Headroom... ha! (Score 1) 24

I wonder if this might not be getting dumbed down for public consumption.

Fiber is fiber, and once you have a bunch of good-quality fiber laid down, your theoretical bandwidth is beyond anything we're actually going to use, the trick is waiting for the equipment that hooks up to it to advance.

It's 100gbps today, but as better gear becomes commercially available, gradual upgrades can bring it towards 1tbps, then 10tbps, then...

Comment Re:Completely? (Score 1) 550

There's a legitimate case for psychoactive meds being overprescribed, sometimes to tragic results, but most other drugs are at least trying to treat real problems based on real empirical evidence. Yes, there's marketing of the hot new thing that's supposed to be magically better, and yes the companies are greedy fucks who gouge the public, but that doesn't make the drugs inherently unnecessary.

The problem with psychoactives is there's (usually) no blood test, no rash, no scan, not even a clearly articulable "I have a pain right here", and our understanding of brain chemistry remains so limited that even if you can fully satisfy yourself that "yes this person is clinically depressed", or "yes this person is schizophrenic", the actual results of the medication varies so widely that it often ends up being a long process of trial and error, occasionally punctuated with psychotic breaks and/or suicide attempts, and the entire time there's the niggling detail that sometimes these things eventually just "go away" and the meds might stop being necessary at all.

This is exceedingly different from most non-brain-related medical cases, where standard dosages of standard drugs usually do whatever they're supposed to with few (and minor) side effects and that's the end of it. You can test for infections, blood pressure, organ function, blood sugar, etc. and most patients are perfectly capable of telling you their leg hurts like hell and would you please X-ray it and inject some morphine before they bite your head off.

Psychiatric and neurological problems are a lot like heisenbugs -- you might know they're there, but you're not sure _what_ they they are, _where_ they are, or how to fix them. And when you go looking, you might set off some latent bug that blows up the whole damned system.

Slashdot Top Deals

"Look! There! Evil!.. pure and simple, total evil from the Eighth Dimension!" -- Buckaroo Banzai