Slashdot is powered by your submissions, so send in your scoop


Forgot your password?

Comment: Re:your crap gets in my way (Score 1) 616

by dgatwood (#49714879) Attached to: Editor-in-Chief of the Next Web: Adblockers Are Immoral

Not at all. This is simply saying that the companies holding the analytics data for advertisement and using it to sell ads should be separate and distinct from the companies selling products, and that the companies selling the products should be providing info to them without providing any PII, tracked only by a persistent advertising identifier, and that a cookie nuke should reset that advertising identifier, destroying all prior history.

Comment: Re:your crap gets in my way (Score 5, Interesting) 616

by dgatwood (#49711411) Attached to: Editor-in-Chief of the Next Web: Adblockers Are Immoral

This. I don't mind static ads. Heck, I don't even mind analytics and tracking as long as it is anonymous and the raw data is not made available to anyone who could de-anonymize it.

What I mind are the seizure-inducing flashing ads that tell me I'm broadcasting an IP address, the ads that take over my screen if my mouse happens to cross the edge of the ad as I go to click a link on the page or scroll it, the ads that make annoying sounds on my work computer, the ads that play video and audio on my work computer, etc.

I know the advertisers think that they're going to get better results by being more annoying, but the reality is that it is an escalation in an arms race that can only result in that ad network getting blocked en masse.

Comment: Re:How powered off is "powered off"? (Score 1) 184

by dgatwood (#49696069) Attached to: Enterprise SSDs, Powered Off, Potentially Lose Data In a Week

The sector translation able is what I was talking about. That table is in the form of a log journal. If a drive is writing to that journal, thus recording the fact that the block moved from point A to point B, prior to actually finishing writing the data at point B, the drive is defective by design. Period. And if the drive did not write that journal block, then the data did not move to a new flash page, and the write didn't happen. It should not be possible for background updates to cause data loss, because the old copy will always still be there on the disk until such time as the new copy has been fully written and the translation table/log journal has been updated.

Comment: Re:Too old (Score 3, Insightful) 125

by dgatwood (#49687393) Attached to: Ask Slashdot: Security Certification For an Old Grad?

That said, if you have a below 2.5 GPA...good lord, go get a new diploma and with a higher GPA. Only your most recent GPA counts. Getting a good GPA isn't hard, it just requires you to actually give a shit. Employers tend to not care so much for people who don't give a shit.

Do any employers actually care what someone's GPA was in college? I don't think I've ever put that information on my resumé, and I've never had any prospective employer ask. Never. Yes, for a new college grad, it might be relevant, but for everybody else, going back to college would probably be a waste of your time.

IMO, you'd be much better off taking classes in a particular specialization that will be relevant to your future career as the original poster suggested, rather than wasting four years just to prove that you are capable of getting higher grades in a pile of non-major classes whose subjects mostly won't provide any real benefit in your future career.

Comment: Re:$30 (Score 1) 515

The way I interpreted the question was not what kind of vehicle can do it for $30, but rather what kind of vehicle can do it on 3/4ths of a tank. The answer is "Almost all of them". To find out what kind of vehicle can do it for $30, find the highest MPG non-Toyota out there, and you probably have your answer, give or take. :-)

Comment: Re:$30 (Score 1) 515

That's because Toyota uses undersized tanks in all their cars to artificially inflate their fuel economy numbers. Contrast that with, for example, a Ford Windstar, which has a theoretical highway range of 596 miles—only about a hundred miles short of a round trip from San Francisco to Los Angeles and back.

Comment: Re:$30 (Score 1) 515

... if everyone stopped driving so much and took trains more, then road costs would decrease and less of our tax dollars would be needed for that.

Actually, if by "everyone", you mean passenger vehicles (as your sentence implies), then road costs would be largely unaffected. A single large truck does about as much damage as several thousand cars. The percentage of road damage caused by all passenger cars put together is likely in the low single-digits, if it even makes it to a whole percent. Now if we could get all the &^@$*@& tractor trailers off the roads and get all their cargo onto trains, then road costs would drop to almost zero, but that isn't very likely.

Of course, we could start by making the trucking industry pay their fair share of the cost of the roads by cranking up the diesel fuel tax charged at truck stops to about $100 per gallon, and that would probably have the desired effect, but....

Comment: Re:$30 (Score 1) 515

A commuter rail line between SF and Morgan Hill. This is well needed. I know this because I live in the bay area.

Caltrain already runs trains all the way down to Gilroy. So there's already a commuter rail line for that entire stretch. As I understand it, the only major things they're doing along that stretch are electrifying those lines and upgrading the signaling to meet new federal requirements. Both would probably have happened with or without HSR; the HSR project just provided an easier way to get the needed funding. :-)

They're doing other minor stuff, like adding a few stretches of passing tracks to allow the HSR to bypass stopped Caltrain trains.

On the flip side, for the relatively small cost of providing funding for those small projects, the HSR project gets access to tracks through prime real estate, so that approach probably made the HSR project a lot cheaper, not more expensive.

AFAIK, the only significant new Bay Area rail lines they're adding for HSR are a short stretch from Gilroy that goes due east and meets the inland high-speed rail corridor, plus a really short underground stretch from 4th and King station to the under-construction Transbay Terminal (maybe ten blocks or so) for future connection to BART and buses.

Comment: Re:How powered off is "powered off"? (Score 1) 184

by dgatwood (#49660421) Attached to: Enterprise SSDs, Powered Off, Potentially Lose Data In a Week

By definition, all drives lose data when power disappears suddenly. You can't guarantee that a filesystem metadata change won't be halfway complete unless the OS is in control over when the drive powers down.

Consumer drives shouldn't be at any higher risk of data loss than enterprise drives in this regard. Either data is on disk or it isn't. If a file gets halfway written, it will still be halfway written whether the drive stays up for an extra few hundred milliseconds to flush its buffer or not. More to the point, assuming the buffer is flushed to disk at the same speed, the average risk should be almost precisely the same.

Say you're writing data for ten seconds, and it takes an extra 200 milliseconds at the end to flush the buffer to flash. (These numbers are arbitrary.) During the first 200 milliseconds, the first block is effectively not yet on disk, because the drive has not written out the log entry indicating that the block is now on a different flash page than before). If power fails during those 200 milliseconds, the consumer drive will not lose data, whereas the enterprise drive will, because that initial write will get written to disk.

Thus, on average flushing the buffer (outside of the operating system's direct control) should cause data loss by allowing a write to start that wouldn't have started otherwise almost exactly as often as it will prevent data loss by allowing a write to complete. So IMO, the whole "extra capacitors" thing is a cute idea to sell more drives, but in practice, it is basically worthless.

BTW, although write order isn't necessarily preserved, if such behavior is really important, that's where you need to take advantage of a sync system call, which guarantees that all data previously sent towards the disk is complete before the call returns. (Note that in some operating systems, the first sync system call returns immediately, but a second sync system call blocks until the first one completes. For this reason, you should always make that system call in pairs.)

If a sync system call fails to enforce write ordering, then we have a word for drives that report that a sync operation is complete before it actually is. Defective. Such a disk is fundamentally untrustworthy for any purpose. Fortunately, with the exception of a few badly broken USB drives from many years ago, that should never happen in practice.

Comment: Re:How powered off is "powered off"? (Score 1) 184

by dgatwood (#49660289) Attached to: Enterprise SSDs, Powered Off, Potentially Lose Data In a Week

It really is unsurprising. IIRC, enterprise drives and consumer drives are usually the same basic drive mechanism, with the main differences being the lack of a park ramp in enterprise drives and firmware differences, such as parking the heads less frequently, spinning down less frequently, etc. And while those firmware differences could make a difference if they happen to tickle some serious design flaw, for the most part, I'd expect the differences to be lost in the noise.

There are some exceptions, of course. Some of the newer enterprise drives have extra bearings so that the motor shaft is suspended in two places to reduce vibration. This mainly results in a performance win (fewer and faster head position calibrations), but in theory could slightly reduce the rate of head crashes in an enclosure with a large number of drives. (In practice, I'd imagine you'd have a hard time measuring an effect that small, though.) And in theory, it could slightly reduce the risk of writing a track slightly out of place, forcing the disk to retry a couple of times while reading it back. Neither of these constitutes a significantly increased risk of hardware failure, though, I don't think.

Of course, hard drive manufacturers tell us that consumer drives aren't rated for continuous use. That seems pretty unlikely to me. After all, a motor is under the least stress when it is either spinning at a constant speed or stopped. It takes very little power and very little force to keep something spinning. Based on that, I'd expect a drive to last longer when spinning constantly than when spun up and down constantly. That was certainly true historically; I have many drives that spun continuously for more than a decade. The hard drives I've owned that have failed (ignoring purely acoustical failures of ball bearings) have invariably been the ones that were spun up and down routinely. (Well, okay, I did see bad blocks in one swap partition of one drive that had been spinning for seven or eight years, but after disabling that swap partition, I kept using the drive for about another half a decade or so before retiring the server, so I'm not sure I'd call that a failure, per se.)

And it isn't as though we're still using ball bearings, where one could reasonably be concerned about a continuously spinning drive not having full lubrication because the lubricant is spun out towards the outside of the bearing or something (hence "acoustical failures"). So I can't really think of any plausible reason why a drive operating 24x7 would ever have a higher failure rate than a drive spinning for a fraction of that time, hence I have a hard time believing that there is any truth to the manufacturers' claims. I suspect it is mostly a scare tactic to make more money off of those customers who can afford to spend more... or perhaps an excuse to renege on their warranties if they suffer another round of capacitor plague. Either way....

Comment: Re:Indian Point == Ticking Timb Bomb (Score 1) 213

by dgatwood (#49658435) Attached to: Transformer Explosion Closes Nuclear Plant Unit North of NYC

It's not just the time factor, though as I hinted in my post, that is a big problem. There's also the problem that most of the older nuke plant designs (translation: most of the U.S. nuke plans) require external power for cooling. Lose that, and you have to use emergency generators and/or batteries. Lose that for long enough, or experience a multiple generator failure (Fukushima), and you're in trouble.

So scram conditions do actually represent a much higher risk for a nuke plant than for a coal plant. The risk is mitigated to the best of the designers' ability at the time, but that doesn't mean it is zero. And the continued use of older nuclear plants (thanks largely to NIMBYism) puts us at greater risk because of the lack of passive safety that you'd find in newer designs.

Comment: Re:Barber or Masseuse (Score 1) 420

by dgatwood (#49658365) Attached to: Ask Slashdot: Moving To an Offshore-Proof Career?

But what's the point of jumping to a new career to avoid potential threats to your current career if you don't consider the potential threats to the career you are jumping to

There is no point. There's also no point in seriously considering going from a tech career to burger flipping just because the latter job is currently less likely to be outsourced. Consider a career change only if you can't come up with any other alternative. Otherwise, if you lose your job, find another job, not another line of work, and save money for the future so that if you lose your job, you won't lose your shirt. That's the only good advice. Choosing a career based on whether it potentially could be outsourced is silly. Therefore, any possible answer to the question is likely to be equally silly.

"They that can give up essential liberty to obtain a little temporary saftey deserve neither liberty not saftey." -- Benjamin Franklin, 1759