Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).


Comment: Re:The real question in my mind... (Score 3, Interesting) 341

I remember how Bill Gates never thought that the Internet would ever take off. Also Edison thought we'd all live in pour-in-place concrete....

Yeah well, I don't think that Bill Gates is a genius. According to this interesting perspective,

What really made him rich was having been in the right place at the right time in 1981 when IBM needed an operating system for its new PC. Gates (with Allen) borrowed heavily, to put it gently, from an existing operating system, Digital Research’s CP/M. (For DR’s version of this history—“Microsoft paid Seattle Software Works for an unauthorized clone of CP/M, and Microsoft licensed this clone to IBM”—see here. A less biased, though still damning, look is here.) In other words, another instance of adopting someone else’s work and taking credit for it—this time with the innovation of litigating aggressively and manipulating markets to defend a monopoly position. Because once it secured that monopoly, Microsoft did everything it could to crush competition.

And Edison was rather similar. Edison used brute force discovery to solve the light-bulb filament problem, and used some, shall we say agressive business tactics to protect his business. In order to make people afraid of his competition (alternating current, Westinghouse), he used AC to electrocute animals such as elephants. He successfully campaigned to have AC used to execute death row prisoners (the electric chair). He was, IMHO not a genius.

Elon Musk is, in my opinion, a bona fide genius. With a bachelors degree in physics, he taught himself rocket science, and was the chief designer of an entire rocket, the Falcon I. This rocket managed to put two objects in orbit before being superceded by the Falcon 9. The amount of information he must have learned is astounding. Fluid dynamics, combustion, orbital dynamics and trajectory control, metallurgy, each in and of itself an entire field of study. He also has a solid background in computer science.

So, I will give what Musk says on the future of transport quite a bit of weight. He has earned it.

Comment: Re:The real question in my mind... (Score 1) 341

cars might be able to park too close to open doors, meaning more cars could park in a given area

Also, cars could park directly head-to-tail. Then when a car three deep is summoned, it could signal the other two cars to move. The lanes through the lot could also be made much narrower. The capacity of parking lots could easily be doubled, and possibly tripled.

In some European cities, it is customary to leave your car parked in neutral and with no parking brake on (obviously on the flat). When someone wishes to park parallel park in a tight spot, they just nudge the cars in front or behind, causing them to roll, widening the spot. This allows cars to be parked "nose to tail".

Comment: Ice "boulders" visible in photo (Score 1) 21

by catchblue22 (#49180499) Attached to: Rosetta Photographs Its Own Shadow On Comet 67P/C-G

What I notice in this photo (hi-res version) around the area of the shadow are the apparent shapes of the ice "boulders" that came together to form the comet in the first place. It reminds me of looking at chondrules in meteorites, that show the siliceous "hailstones" that formed as the planetary disc that would go on the form the planets cooled.

Comment: Re:Just damn (Score 4, Interesting) 411

by catchblue22 (#49150535) Attached to: Leonard Nimoy Dies At 83

Don't forget his underrated first leading man big-screen role as Kid Monk Baroni, 1952...

"Leonard Nimoy is "Kid" Monk Baroni, the leader of a street gang who becomes a professional boxer to escape his life in "Little Italy" New York."

Hard to believe it's the same guy.

And his photography.

RIP. Sad sad sad.


The Science of a Bottomless Pit 122

Posted by samzenpus
from the free-falling dept.
StartsWithABang writes It's the ultimate dream of many children with time on their hands and their first leisurely attempt at digging: to go clear through the Earth to the other side, creating a bottomless pit. Most of us don't get very far in practice, but in theory, it should be possible to construct one, and consider what would happen to a very clever test subject who took all the proper precautions, and jumped right in. Here's what you would have to do to travel clear through the Earth, come out the other side, and make the return trip to right back where you started.

Comment: Re:Sigh... Yet another scam (Score 1) 233

by catchblue22 (#49070743) Attached to: Mars One: Final 100 Candidates Selected

To be fair, if you're off by 50% on a $1M project, you're out a couple year's salary for one engineer... if you're off by 50% on a $10B project, you owe somebody an aircraft carrier. You'd be an idiot to not be conservative on pricing things when they are that expensive, unless the contract covers development costs.

You do know what cost-plus contracting is, don't you? In essence, the company says, the project will cost what we say. And then add 20% profit on top. The government will then put auditing systems to track almost every purchase. However, that doesn't stop the company over-designing the system, or choosing a design that costs far more than it should. Or hiring layers upon layers of middle managers who do next to nothing. It costs what it will cost. And then Lockmart gets 20% profit on their already inflated prices.

This is why aerospace is so expensive in America. Lockmart and Boeing both rely on cost-plus financing. SpaceX does not. They give price per performance. Price to launch. Price to design and build. They only get paid if they do what they say.

Comment: Re:Sigh... Yet another scam (Score 1) 233

by catchblue22 (#49067673) Attached to: Mars One: Final 100 Candidates Selected

I agree that Mars One sounds fishy. The lack of technical details is suspicious.

I think we can go to Mars. I think we can build the technology. And I don't think that Lockmart and Boeing (through NASA) can do it, because their reflexive position is to magnify costs. I suspect that Elon Musk is the most likely force that will push us to Mars, if only because his obsessive motivation towards that goal causes him not to magnify costs, because he realizes that excessive costs will make his goal impossible. I think that the government would do well to divert some of the funds that were headed towards Lockmart/Boeing towards SpaceX instead. They will get better value for their investment.

Comment: Re:lagrange point (Score 4, Informative) 75

At this point, the pull from the earth will cancel out the pull from the sun, and the satellite will effectively stay positioned exactly between the earth and sun as the earth rotates around.

Not quite. From NASA:

The Lagrange Points are positions where the gravitational pull of two large masses precisely equals the centripetal force required for a small object to move with them.

Lagrangian Point 1 (L1) is located on the line between the Earth and the Sun. At L1, the opposing gravitational force from the Earth partially cancels the force from the Sun, reducing the overall centripetal force. In orbital mechanics, the periods of Sun orbiting objects increase with increasing radius, due to the decreasing gravitational force (lower force, lower acceleration, lower speed, increasing circumference). Because the satellite at L1 feels a weaker centripital force than it would normally experience at that solar orbital radius, it can orbit the Sun at a period of 365.25 days, in spite of being closer to the Sun than the Earth. Thus it maintains its relative position between the Sun and the Earth.


MIT Randomizes Tasks To Speed Massive Multicore Processors 63

Posted by samzenpus
from the greased-lightning dept.
itwbennett writes Researchers at the Massachusetts Institute of Technology have created a data structure that they claim can help large multicore processors churn through their workloads more effectively. Their trick? Do away with the traditional first-come, first-served work queue and assign tasks more randomly. The SprayList algorithm allows processors with many cores to spread out their work so they don't stumble over one another, creating bottlenecks that hamper performance.

Comment: Re:How did they run out of fluid? (Score 3, Informative) 248

by catchblue22 (#48832873) Attached to: SpaceX Landing Attempt Video Released

Hydraulic systems are in a loop, with the "spent" fluid recirculating back to the reservoir. How did they "run out"?

Where did the fluid go?

The system is an open hydraulic system. Closed systems require tanks and pumps which carry a mass penalty. They only need the system to function for about 4 minutes. Why bother with a closed system when the functioning period is so short. They will increase the amount of fluid by 50% so this shouldn't happen again. All in all a nearly successful experiment.

Comment: This test was a successful failure (Score 5, Informative) 248

by catchblue22 (#48832677) Attached to: SpaceX Landing Attempt Video Released

This was the first time SpaceX had flown the new grid fin control system on a real first stage under real conditions. They did not know exactly how well the grid fins would behave. As it turned out, the grid fins had to move more than they expected during the descent (or the forces were larger than they expected), so they ran out of hydraulic fluid 30 seconds before landing. This is similar to an airplane losing control of its elevator just before landing. The fact that the rocket reached the barge and that its vertical speed was reasonably slow (certainly not 100m/s) indicates the resiliency of their systems. They are putting 50% more fluid into the system, so this shouldn't happen next time.

I think this video is epically cool. I can watch it again and again. Simply awesome.

Saliva causes cancer, but only if swallowed in small amounts over a long period of time. -- George Carlin