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


Forgot your password?

Comment Re:No place for 'almost', 'not quite' and 'nearly' (Score 1) 423

Well, there isn't enough demand to put a hobby electronics shop in every mall and on every major highway. In fact it's a mystery to me how Radio Shack got as big as it is, other than it predated big box consumer electronics store.

What you need to support a bricks and mortar store network like this is an answer to these two questions:

(1) Why will people go to the store?

(2) What will they end up buying when they get there?

Have you noticed how bookstores tend to have coffee bars in them now? It's because you're thinking about going to Starbucks for coffee, so why not go to the one in Barnes and Nobles and do a little browsing while you're there? Granted, you may go there specifically for books some time, but having a coffee bar gets you in the door enough more times that you end up spending more money there annually than you would otherwise.

If you're going to buy a phone, why go to Radio Shack instead of your carrier's store? If you're going to buy a radio or a set of speakers, why go to Radio Shack instead of a big box electronics retailer? About the only reason I can think of to go to Radio Shack is if I needed an odd sized battery, which is not such a bad draw but it wouldn't draw me in more than once or twice a year.

Sure, if Radio Shack had a great parts counter it might get people like you or me to go there, and we might walk out with a headset or a cell phone. But there aren't enough people like you or me to put a Radio Shack in every mall and along most major highways. If they could just get enough people in the doors, they could sell them all kinds of electronics-y stuff, but there's nothing that will bring lots of people in the door. Every time I go to Radio Shack, it seems like the number of customers is something like 1.2x the number of staff. That's no way to make money.

Comment Re:Helps to know conventional crypto's weaknesses. (Score 1) 84

Although the ties to other countries, the shared work, etc. also describes scholarly research and peer review -- the very things you need to put faith in some kind of cryptographic scheme.

If you have a problem that you don't know who to trust, a proprietary black box is no solution. Then you're trusting both the box and the person selling it to you.

Comment Helps to know conventional crypto's weaknesses. (Score 1) 84

Well tested, familiar conventional crypto algorithms are very, very hard to break. With correctly generated keys of sufficient length, they are practically unbreakable for longer than most secrets need to be kept.

But that doesn't mean *systems* built around those algorithms are unbreakable. It's all that stuff around the strong cryptographic algorithms that introduces weakness.

So claims of "unbreakable" algorithms or system components don't get me excited. If you want to make me sit up and take notice, claim that your invention makes secure cryptographic systems *simpler*.

Comment Re:Education (Score 5, Insightful) 482

Well,I think you're onto something, although it's certainly not the case that anti-vaccination ideology is confined to "uneducated redneck hicks". It is rampant among educated, middle class people too who *do* have the tools to evaluate claims. They just don't have the inclination to use those tools. I know because I have a niece who is an anti-vaccine crusader; she's always posting links to anti-vaccine screeds on Facebook, only to get knocked down by all her science geek aunties and uncles. She is not an ignorant, uneducated moron. She is an intelligent, accomplished and educated suburban mom who just happens to be off her rocker about this one thing.

The problem, I think, is that anti-vaccine hysteria actually arises out a healthy impulse: distrust of authority. We've raised a generation on tales of the Tuskeegee experiment, of bungled CIA actions in Iran, of government leaders' deceptions about the course of the Vietnam war. But the line between healthy distrust and paranoia is often fuzzy. In attempting to raise a generation of healthy skeptics, we've also made paranoia respectable.

This explains the counter-intuitive result in the study. Convincing people to distrust anti-vaccine information doesn't make them trust their doctors or public health authorities. It makes them distrust everyone. And some of the mud probably still sticks. Here's where knowing what the anti-vaccine crowd is saying helps. They've moved well beyond the autism thing; their message has two prongs: "vaccines aren't as effective as claimed" and "vaccines put children at risk for a wide spectrum of harms".

Finally there's another misunderstood aspect about who these people are. They've been raised to admire crusaders like Dr. King who stood up against authority figures, and they've been taught to emulate them. We've raised them to be firm and determined in their convictions, even the face of ridicule and condemnation. But that attitude of Emersonian self-reliance has a dark side: it's very hard to change your mind once you've donned your crusader surcoat and drawn your greatsword.

So the idea that these people are anti-vaccine crusaders *because* they're contemptible is wrong. These people are attempting to do something heroic. In other circumstances they *would* be heroic. The problem with self-righteousness is that it feels *exactly the same* as righteousness.

Comment Re:Almost as if (Score 1) 127

You know, you touch on something that bugged me when I watched the Iron Man movies. Where is the reaction mass for Iron Man's flight coming from? Even a lightweight, unlimited power source wouldn't solve the problem of reaction mass. The Iron Man suit obviously uses some kind of reactionless drive -- not inconceivable, given that it also has "repulsor" technology which has no plausible physical explanation and violates classical physics.

The arc reactor idea actually is interesting to think about. Suppose you had an unlimited energy source with negligible weight. Could you build something like a rocket belt? I think you could, say by driving a turbine or some more exotic method of accelerating air. Technically it wouldn't be a "rocket" belt, but it would fit the bill. Even you'd still be limited in how small you could make the thruster due to the hazards the high velocity of the exhaust would present to the user and the surroundings.

Comment Re:What is "computer-directed flight control"? (Score 2) 353

Well, electrical, mechanical and electro-mechanical analog computation was a hot research in the 30s and 40s. People forget that "op-amp" (invented in 1941) stands for "operational amplifier" -- a device originally intended to do analog integration.

The fire control computers on WW2 naval ships were highly sophisticated electromechanical computers, although obviously too large for an airborne system. On the other hand the contemporary Norden bomb sight was, in effect, a compact, specialized analog computer.

The idea of connecting such a system directly to control something directly would have been very advanced for its time. Cybernetics as a practical discipline was in its infancy. I suspect the "computer-directed flight control" refers to flight surfaces that are automatically adjusted based on several user inputs such as throttle and yoke. This is the kind of thing that would be handled by a computer in a modern high performance aircraft, or by some complicated manual procedure in a racing aircraft of the era. That woudl arguably a kind of special purpose computation although calling it a "computer-controlled flight controller" would be a stretch.

Comment Re:Almost as if (Score 1) 127

Jet packs make sense if you can get them to work.

There's the rub right there. Feasibility is a prerequisite of "making sense", and in the real world you have to deal with physics and the physical limitations of human beings. Antigravity would "make sense" if you could get it to work.

The physics of a jet pack are governed by the rocket equation: V = Ve * ln(Mt/Mp). You need to carry enough mass, ejected at a sufficient speed, to produce 9.8 m/s v every second.

The upshot is that to counterbalance the weight of a soldier and his gear you can either have your rocket eject a lot of mass at low velocity or a small amount of mass at high velocity. That's why the rocket belts thus far have only had a very, very short burn time. To increase the burn time you'd need to carry more fuel than a man could lift.

A typical infantry solider or marine carries over a hundred pounds of gear into battle. Even accounting for things he could dispense with if he had greater mobility, he can't carry much fuel to power his rocket belt. A practical battlefield air transport machine would be a small vehicle which carries more weight than an individual solider can. In other words: a helicopter.

Similar concerns attach to asteroid mining. You *can* physically go out there and return materials from asteroids, just like you *can* strap a rocket belt on a soldier. The question isn't whether physics permits it, but rather whether physics permits economically feasible retrieval of asteroid material, and that's a lot tougher than it sounds. Even the "asteroid belt" is practically empty by terrestrial standards; your chance of randomly encountering anything larger than a dust speck while crossing it is less than hitting the lottery. So prospecting for nuggets of stuff like platinum is physically possible, but not feasible. Unless we hit the jackpot with a near earth object like 433 Eros, we won't see asteroid mining until v in space becomes much, much cheaper.

Comment Re:The primitive division of both sides is appalli (Score 1) 479

Why couldn't Ukraine become a model of a bi-ethnic state? Russians and Ukrainians are so similar.

There's your answer right there.

It's a bit like the uncanny valley. People who are very different from you are interesting and exotic; you know it takes some effort to understand them. People who are just a little bit different from you are too incorrigibly stubborn to bring themselves up to snuff and think and act the right way.

That's why civil wars are so bitter and inhumane. In some ways it's harder to see humanity in someone who is culturally similar but irreconcilably different than in someone who is alien. Rudyard Kipling could wax lyrical about the noble savages in "Gunga Din" and "Fuzzy-Wuzzy", but he never once penned a poem in praise of the Liberal Party.

Comment Re:"pro-Russian forces in Crimea" (Score 1) 479

and now let's talk about the leaked documents involving the "pro-western forces in the Ukraine""

OK, lets. The US government is far from lilly-white, but if it and allied governments were coordinating violent opposition to the Ukrainian government too, that would surely be in the cable leak.

Comment Re:By first throwing out. (Score 2) 195

Which fits with something which characterizes most effective sorting algorithms: they get rid of a lot of entropy early on. This works for tidying the house too. Start by throwing out stuff, then by moving things to the room they belong in, then putting them away.

To answer the question, I tend to quick sort things into manageable unsorted piles, insertion sort the piles and reassemble the piles.

Comment Re:Could somebody explain wayland, please? (Score 2) 77


Thank you for the additional details. You are right -- I meant to make it clear that the Wayland design was thought up by people with some serious experience of the internals and limitations of X, and not a competing team of newcomers, as appears to be assumed all too often. But yes, things aren't as simple as I made them look and there is only a partial overlap between the Wayland devs and the Xorgs devs. Thank you for the correction.

I also agree that Wayland is largely about canning the legacy in order to make current and future needs easier to tackle.

I don't agree with your opinion of the move as a technical choice, though, for three reasons.

1/ Taking X out of the rendering loop does not mean dropping X altogether. It just means that future X servers, when and where they are still needed, will run on top of Wayland. It does deprecate X as the default API, yes. But that's not remotely the same as breaking compatibility.

2/ The comments that Daniel Stone (core Xorg and Wayland dev) made in that oft linked video aren't in agreement with the idea that everything Wayland does can be done on top of X, let alone done well. In his talk, DS mentions e.g. issues with input management when one window wants to grab every input that can't be solved in X.

3/ As a more general philosophical principle, the world moves and everything changes. Everything has a shelf life, up to the universe itself, and there is a point where resisting change for the sake of keeping past things going becomes harmful. And this is the actual reason I've been so active in this thread. Not just because I've got a pretty good hunch that once the dust settles Wayland will largely work better than X. But because I think that we, Slashdotters, Linux users, geeks and nerds, are becoming fearful of change, and that's not a good thing. This, here, is an entire new toy and it opens entire new possibilities! It may break shit and it may be awesome and it will probably be a bit of both. Let's freaking check out the code and play with it! Is this not exactly what we should be about? :)

Have a safe flight, and thank you for the constructive reply!

Slashdot Top Deals

Nobody's gonna believe that computers are intelligent until they start coming in late and lying about it.