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Comment: Re:Little disturbing (Score 1) 491

by khb (#46565305) Attached to: How Satellite Company Inmarsat Tracked Down MH370

The published text of the PM's speech makes it clear its based on the analysis (what you are calling "statistical probability") not debris or black box.

I don't know why anyone would find that disturbing.

Even if he had debris, for any given family there would still be some "statistical probability" that their loved one survived (infinitely close to zero) involving some sort of miracle, a hidden parachute or a missed connection, etc. Just as we'd discard such false hope, pretending that there is some other place folks ought to be looking or that there is any realistic chance that their family members are safe as hostages in some terrorist base.

It is exceedingly unfortunate that the data analysis was relatively slow (and the data itself was never open sourced); the delay resulted in much lost time and resources by many naval and air groups, and lots of needless gnashing of international teeth.

If there's any lesson here, the satellite data feed(s) should become a bit more formalized, and their release in the event of an accident be as standardized as the black box information. As for the $10/flight for the data, even if the airline doesn't pay for it up front, the data collectors should collect it, and save it until after the flight has landed. If it doesn't land, the airline can pay some much larger fee to get the data ahead of it going public ;>

Comment: $100K? (Score 1) 382

Yesterday the discussion seemed to center on how bloody expensive it would be to track the planes and how special equipment and etc. would be required. Now everyone seems to understand that messages can come from the planes ... indeed, it would have been trivial (although it would have involved a fee) to record the rest of the plane sensor data.

Instead of reinventing the wheel, and making some magical device to transmit just before an accident ... the folks who maintain the current system record the last 5 positions ... but not release them except when they are paid OR there is an accident. The amount of data storage would be small, and the infrastructure apparently already exists.

Obviously, old enough airframes might not *yet* have the equipment, but rolling them in as engines and/or other major renovations occur should be feasible.

Comment: Re:What's the problem? (Score 2) 342

by khb (#46461165) Attached to: New Jersey Auto Dealers Don't Want to Face Tesla

"Are the dealers afraid that the majors are going to copy Tesla's model and cut them out of the business?"

Yes, precisely. Just as Amazon reduced the number of bookstores by a pretty wide margin. Dealerships suck up a lot of the profit, GM could sell direct for a lot less than current prices *and* make more $$.

The "term of art" for this is disintermediation. And the dealers are well advised to fear it. But its unclear to me why in the world government should protect them from it. Customers outnumber dealers by a wide margin at the voting booth.

Comment: Those who... (Score 1) 451

by khb (#46422139) Attached to: Ask Slashdot: How Do I Change Tech Careers At 30?

jokes aside, the most obvious thing is for you to:

a) Do enough consulting/hands on work to get a firm grounding (do that in the summers even if you keep your teaching slot)
b) Move up to community college, vocational school, private tutoring, etc If you are a great teacher, focus on that. But expand your turf so you can teach more

I suppose if you are tired of the actual teaching, then this isn't very sound advice ;>

Comment: IANAL! (Score 1) 212

by khb (#46420325) Attached to: Fedora To Have a "Don't Ask, Don't Tell" For Contributors

'but should these governmental restrictions apply to an open-source software project?' there would appear to be two different questions here. (1) does the current law apply and (2) should the law apply.

w.r.t. (1) Sounds like some cognizant group has determined that the law does (or at least may) apply, so the Fedora team is taking the steps they can.

As for (2), that is a matter for Congress. Lobby them if you think the law should carve out an exception for Open Source projects (all or some specific licenses).

Comment: Web design isn't CS (Score 4, Interesting) 246

by khb (#46390277) Attached to: Ask Slashdot: Modern Web Development Applied Science Associates Degree?

Such a degree, if it were to exist, should focus NOT on the basics of CS, but on good design.

1) Do cover human factor engineering principles and techniques. Include lab work to do usability testing.
2) Do cover the basics of good design (perhaps a joint Art department effort).
3) Do cover the foundations of programming, but using several web focused languages. C/C++/Algol and friends are wonderful, but you have limited hours.
4) Do provide an introduction to computer security. Chances are it is folks in the backend that need to focus on it, but security holes can occur anywhere.

Good luck.

Comment: Troll bait? (Score 1) 365

by khb (#45901275) Attached to: Ask Slashdot: How Many (Electronics) Gates Is That Software Algorithm?

The question seems so ill-posed that one has to wonder if there's a product or service advert lurking... but assuming this is real.

Software doesn't automatically translate directly to hardware. As others have noted, break out the algorithmic core from the setup and finish. Presumably there is some part of the code which is the most critical in steady state. Describe that to their hardware engineers in whatever depth is required. Depending on the algorithm, the ASIC library elements available (or FPGA units, etc.) you may want to make some substantial adjustments to the "code" to make it fit within the design parameters of the available device. This should be an iterative process, not a single estimate based on a pure software perspective.

If there isn't a clearly identifiable set of "hot blocks" the chances of there being a good hw implementation fit is poor. If there is, it may still be necessary to change the algorithm details to fit but it should be "doable". Whether it is worthwhile depends on the volumes and the performance gains.

Comment: Re:Plastic Discs (Score 1) 418

I've had kids destroy a lot of plastic disks (car usage). There's a lot to be said for digital bits. Obviously, technically savvy people can copy plastic disks, but a lot of people can't/won't/don't.

For a lot of content, watching it 10 times is "enough". Of course, kids may want to watch it more than that. But it can drive parents nuts.

Comment: Aeropress vs. Clever Coffee Dripper? (Score 1) 76

by khb (#45706519) Attached to: Interview: Ask Alan Adler About Flying Toys and the Perfect Cup of Coffee

I've long enjoyed my Aeropress for travel. But for the office/cube I've usually used the Clever Coffee Dripper ( as it produces as good (or better IMHO) results with a little less excitement (misalignment of the Aeropress considered harmful ;>). At home I alternate between espresso and various other techniques.

Do you consider the Aeropress the pinnacle of coffee brewing, or just a really good portable approach? Are you working on any further improvements?

Comment: Re:Good (Score 1) 1010

by khb (#45601215) Attached to: EV Owner Arrested Over 5 Cents Worth of Electricity From School's Outlet

*sigh*. years ago I had a Sparrow (3 wheeled freeway legal EV). It charged exclusively on 110-120v. Most of the time I couldn't *find* anyone who had a clue as to who would have authority to permit plugging in. So I'd ask when practical, didn't when not. Kept the cord short. Engaged anyone who asked in an appropriate discussion about the pros and cons of EVs and the electricity usage. Offered to pay if they appeared to be connected in any meaningful way to the outlet.

With the exception of my place of employment (Sun Microsystems, RIP) the total usage was pennies or less. I once paid $5 to make a point. Sun not only permitted it, but provided formal EV stations (long before it was popular).

Since the guy was there to watch his kid play, it seems to me that the appropriate action (if any) by the cop would be a citation. The school board should put the issue on their docket, adopt a policy and post it. either to sell permits, give it away, or prohibit it. But leaving an unlocked, unmarked outlet near where cars park is an "attractive nuisance" if you mean to prosecute anyone who dares use it.

As many others pointed out, unlike a place of business, the school is publicly funded ... so the public has some rights regarding access to fields, water fountains, etc. unless otherwise marked.

Comment: Did anyone read the article itself? (Score 3, Insightful) 260

by khb (#45569775) Attached to: A Review of the "Mental Illness" Definition Might Prevent Crime

I know, on /. we don't need to. But it seems to me that the point that the Fuller appears to be making is that the current environment (presumably in the UK where he practices) is that a very large number of people are diagnosed with "mental illness" which is fine if they are continuing to be largely functional, seeing a therapist of their choosing, etc. The problem is that when someone is arrested the question of "mental illness" has two different dimensions ... is the person legally responsible for their actions (the legal dimension) vs. is the person undergoing treatment (or has ever undergone treatment).

People who are not responsible for their actions are a tiny minority. But IF someone has been identified as not responsible for their actions, why are they left roaming the streets? That isn't fair to them or to society.

Admittedly, there is always the question of "who is to say" and that begs the question to appropriate due process (clearly, it shouldn't just be some random doctor or family member has nominated them for commitment). And clearly there were abuses in the past. I don't think Fuller is the first to notice that the current situation is arguably worse (fraction of homeless people who are seriously ill ... of course, that begs the question of whether their mental condition caused the homelessness or the other way around :).

I'm far from sure that I agree with Fuller, but the vast majority of the comments seem to be missing his core argument.

Comment: No, for many reasons (Score 1) 226

by khb (#45488343) Attached to: Ask Slashdot: How Reproducible Is Arithmetic In the Cloud?

The short answer is no. The long answer is no ... and a very long list of reasons why.

Start with reading Goldbergs classic paper "What Every Computer Scientist Should Know About Computer Arithmetic" Sun's floating point group made some improvements to the paper and paid for rights to redistribute. Oracle continues to do so.

If that isn't depressing enough, and you use trig functions, read you can get the source from netlib for "fdlibm" which is under a BSD flavor license.

If the purely software issues haven't made you realize that you haven't got much of a prayer, please note that different revs of the same intel chips sometimes provide slightly different results (sometimes intentionally, sometimes as a result of tweaking the order of execution in the out of order execution engine). Older x87 arithmetic was 80-bit, newer x64 arithmetic is pure 64-bit, providing no end of fun. Using the SSE instructions provides more variation.

If the pretty much (in principle) "simple" and potentially deterministic software issues aren't enough consider the reality of hw. Chessin has a very good, yet amusing, explanation of the key problems

Lest you think they only apply to a particular generation of boutique processor, most HPC ensembles are now built out of standard server motherboards and chips. The issue of undetected soft errors is big and growing, as can be seen from the activity in the literature. SC13 "ACR: Automatic Checkpoint/Restart for Soft and Hard Error Protection" (which has lots of good citations of earlier work, including field data such as 27 soft errors per week leading to fatal node failures (that is, wrong enough results that while the hw didn't detect any problem, the issue caused the node to crash) on just one ensemble (ASC Q). its going mainstream in that HPCwire caught wind and in 31 Oct 2013 had a nice tabloidesqe writeup entitled "Addressing the Threat of Silent Data Corruption"

Neutron's don't only disrupt memory elements, but can hit logic as well. See the upcoming issue (already available via IEEE xplorer for member/subscribers) JOURNAL OF SOLID-STATE CIRCUITS, VOL. 49, NO. 1, JANUARY 2014 The 10th Generation 16-Core SPARC64 Processor for Mission Critical UNIX Server" which details the lengths some (but not many) go to ensure that there are no undetected errors (wide range of techniques, ranging from where wires are placed on the chip, ECC, parity, residue arithmetic, automatic retry, etc.). No doubt there are some good (similar) papers in the IBM Technical Journal.

No doubt a good literature search would turn up dozens of other papers, and circuit design textbooks cover some of the territory.

In principle, interval arithmetic could provide a solution (you might not get the same interval, but if the intervals nest, you have consistent results and if they are disjoint you have a bug ... and if they nest, the narrower one is "sharper" which is better). In practice, most algorithms haven't been reworked for good interval implementation, languages don't provide very good support, nor does most hardware. All fixable in principle, but unlikely to be the solution you seek for todays off the shelf virtual systems available cheaply.

Comment: No mention of weibull? (Score 1) 277

by khb (#45401821) Attached to: 25,000-Drive Study Gives Insight On How Long Hard Drives Actually Last

The behavior described is just what we should expect.

Of course, in many installations the failures aren't random but correlate to power, cooling or batch issues. Especially important to beat in mind in disk arrays with long RAID rebuild times. The 2nd or even 3rd failure may come a lot quicker than you'd expect.

This is why even with reliable storage arrays one needs backups.

% APL is a natural extension of assembler language programming; ...and is best for educational purposes. -- A. Perlis