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Comment: Exactly (Score 4, Insightful) 278

by l2718 (#46552243) Attached to: Don't Help Your Kids With Their Homework

Homework -- self practice -- is where you actually learn the material. When parents do their kids' homework, the kids lose the opportunity to learn the material for themselves.

This isn't to say that students don't need help. Rather, they need help thinking through the material instead of the "help" of being told the solution.

Comment: This isn't BSD! (Score 4, Informative) 64

by l2718 (#46300459) Attached to: BSD Real-Time Operating System NuttX Makes Its 100th Release: NuttX 6.33

The headline creates the impression that this is a real-time adaptation of BSD (the "Berkeley Software Distribution", that is, BSD Unix). In fact, this OS is an original development; it is merely licensed under the terms that BSD is licensed under.

Would the headline have said "A GNU real-time OS" if it was licensed under the GPL, the license of the GNU operating system?

Comment: Paywalled articles on slashdot (Score 5, Interesting) 441

by l2718 (#46045219) Attached to: Why Whistleblowers Can't Get a Fair Trial
The link is to a news story behind the Wall Street Journal's paywall; I think such stories should be reconsidered. Such situations are acceptable with posts on science, which often link both to a popular-science write-up and to the original journal article: probably those readers with the expertise to read the original literature are subscribers. Links to ordinary news stories should follow the same policy: if there must be a link to a paywalled story, a link to a generally accessible version should be expected as well.

Comment: Usually, no (Score 2) 341

by l2718 (#45835485) Attached to: Linux Distributions Storing Wi-Fi Passwords In Plain Text

What is your threat model?

  • -- If your main concern is someone remotely accessing your machine while it is connected to the internet, then full-disk encryption is irrelevant. Programs running on your computer must be able to read the disk. Specifically regarding those WiFi passwords the article is trying to scare you with, they are stored in a file which is only readable by the root (=administrator) user. If the "evil" program can read the file, it has already achieved full privileges on your machine, and it reading WiFi passwords is the least of your concerns.
  • -- If, on the other hand, you would like protection against people who physically hold your machine (border guards when leaving/entering countries, or your business competitor who has stolen your machine) then you absolutely need full-disk encryption. Having restrictions on which programs can read a file is no protection against someone who can extract the harddrive from your machine and plug it into theirs (or simply boot your machine from a live-CD), gaining automatic access to every bit of information.

In short, in order to decide what security you need, you must first formulate your threat model. For a funny take on this see XKCD.

Comment: Numerical computation is pervasive (Score 4, Informative) 154

by l2718 (#45729711) Attached to: 'Approximate Computing' Saves Energy

This is not about data centers and databases. This is about scientific computation -- video and audio playback, physics simulation, and the like.

The idea of doing a computation approximately first, and then refining the results only in the parts where more accuracy is useful is an old idea; one manifestation are multigrid algorithms.

Comment: Lock down I/O (Score 3, Funny) 107

by l2718 (#45516577) Attached to: Researchers Build Covert Acoustical Mesh Networks In Air
An "air gap" means making sue a computer cannot exchange information with other computers. LAN is one way to do so, but other sensors on the computer can be used for input, and other devices for output. Is it really a surprise that the microphone on a computer can be used as an input device?

Comment: Simple restructing of the fee (Score 5, Insightful) 363

by l2718 (#45442683) Attached to: Arizona Approves Grid-Connection Fees For Solar Rooftops

The cost of delivering power has two components: fixed costs (say, power lines to the home) and variable costs (say, of producing the power) The current system was to bundle the fixed costs into the variable ones, and just chage proportional to consumption. Since those selling back power to the grid still need to pay for the fixed costs, this principle of this change seems right. Better execution would have been to add the fixed cost to everyone and make a corresponding reduction to the marginal (per KWh) tariff, at which point those with and without solar panels would be treated equally.

Comment: Raising the tax doesn't have to raise revenue (Score 1) 658

by l2718 (#45206717) Attached to: Oregon Extends Push To Track, Tax Drivers Per Mile

If you assume that consumption of gas is independent of price (totally ineslastic demand), then raising the tax will increase revenue. But in the real world, when prices go up consumption goes down, and at current prices it is very well possible that raising the tax rate will lower consumption enought to lower revenue -- at which point lowering the rate would be the way to raise more revenue.

The problem with a gas tax is that as energy-efficient vehicles become more common, the state's expenses (road maintenance) are becoming less and less correlated with fuel consumption. But since tracking drivers to collect actual usage tax is far worse, I agree that gas taxes are better.

Comment: Bad for science education (Score 4, Interesting) 282

by l2718 (#44962527) Attached to: Will New Red-Text Warnings Kill Casual Use of Java?

Java applets are an essential tool for science education -- as simulators, calculators etc. Are all these research groups supposed to get some authority to digitally sign their applets?

Fundametally, a major aspect of Java security is that, since it runs on a VM, an applet it is inherently encapsulated. Yes, VM bugs can cause problems, but the value of all the free educational applets online far exceeds any possibly security benefits of unptached VM bugs.

Comment: The other half of the backdoor (Score 1) 128

by l2718 (#44914189) Attached to: RSA Warns Developers Not To Use RSA Products

When it was discovered in 2007 that the NSA insisted on adding this PRNG to the standard, with constants they chose the general reaction was "so what? after all, this is one of many alternatives, and it is the slowest and least efficient". I assumed their idea was to somehow choose the PRNG in applications where they were one of the parties, but that seemed unlikely.

It's now clear what the idea was: secretly having companies use this PRNG. The original assumption was that companies voluntarily choose what products to put out, and that no-one would choose the obviously worst alternative. But if the NSA chould be the ones choosing ...

Comment: Less waste of human labour (Score 5, Insightful) 736

by l2718 (#44709909) Attached to: Technologies Like Google's Self-Driving Car: Destroying Jobs?

This is the old Luddite argument: without technology a lot more effort is required to get things done -- so more people get work. It follows that technology is bad.

In fact, the situation is exactly the opposite: if a machine can drive a car, then having a person drive the car is a waste of the person's time. They can instead do something else with their time, so society get both that and the driving done. In the 19th century, more than 80% of US population directly worked in agriculture. Today, the propotion is 2-3% -- yet we have a lot more food, and many other things to boot.

It's true that in the short term, there is a loss when the specialized skills (say driving) of the people displaced become less valuable, and those people lose their jobs. But this is a transient effect. Some skills were standard 30 years ago, yet rare today.

The more important issue is that technology more easily replaces low-skilled workers. Computers have reduced the demand for secretarial work; robots and other industrial automation reduce the demand for factory workers, and so on. This increases the returns to IQ and education, and reduces the number of well-paying jobs available to less-educated workers. But this seems inevitable, and needs to be solved by changing the attitudes of society toward education rather than by hamstringing technological progress.

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