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Comment Re:We developers knew this for a long time.. (Score 1) 274

Oh so instead of IN the editor at the same time and it breaks right into the debugger? Or is it a separate step? Oh and do you have the right plugin's? Oh ding 'bad parameters passed in?', oh 'that line caused a memory overwrite', and 'thread race conditions'? Oh and a suggestion on what to fix? Oh and as you are debugging it? Oh I use these tools. Use both for *many* years. Like most linux tools they are 'almost there' but what I call 'scatter brained'.

Properly *configured* valgrind can do very well. But oh the configuration part... Most windows tools you are ready to rock after install. By default does valgrind do what you are talking about? No. Oh you need 4 different command line settings. Then it *starts* to produce useful information. Oh you need this other thing oh you run again and hopefully you have the right plugin.

By default (no arguments, out of the box) valgrind gives a description of the problem and a stack backtrace with the names of the procedures, files and linenumbers. You can tell it to also drop you into the debugger of your choice at the offending line.

The point is, your accusation "You goto valgrind and bisect issues" (exact quote) would make unfamiliar readers think that valgrind does not give the exact source code location where the errors occur and that, sir, is a flat out lie. I'm sorry that there are no weaker words for it.

Comment Re:We developers knew this for a long time.. (Score 2) 274

I know I am going to come off as a 'shill' but MS tools rock (I am not talking about their frameworks). It is the one thing that holds me to windows these days. All those tools you mention are available in windows and usually better polished. Valgrind compaired to say using boundschecker. You goto valgrind and bisect issues, boundschecker puts you right on the offending line that they think either overwrote memory or leaked. .

You're going to come off as an MS shill because you are flat out lying. Valgrind tells you exactly what line is offending.

char *p = malloc(8);
p[10] = 42;

Let valgrind run that code and it will immediately tell you that the source filename and linenumber that p[10]=42; is on along with a callstack backtrace. Ditto with leaked memory, reads of uninitialized memory etc.

Comment Re:C is great (Score 1) 793

Efficiency matters. Python is great, but you don't want to use it for embedded work.

Actually, I am currently working on an ARM based commercial embedded system that is almost entirely written in Python (on Linux).

Once you make the leap of adding external ram and flash, which you need to run Linux reasonably, using python is not really a big deal. The whole system is still only a few square cm big; you could hide it in your fist.

Comment Re:Good question (Score 1) 1134

Oh - vipw's for wimps. /etc/passwd's a text file, designed to be easily maintained by hand. If you can't hand edit it without fucking up, you don't deserve root permissions to the system.

You're not thinking multiuser scenarios.

The main feature of vipw is that it does locking. This prevents two admins from editing /etc/passwd at the same time, which could corrupt it completely. It also keeps it from getting corrupted because some user happens to be changing their password while /etc/passwd is being edited.

Comment Re:You ares testing students the wrong way (Score 1) 241

Most questions on calculus tests I've taken don't have numeric answers. "Solve for X" was to be answered with the equation..

My example with a normal calculator above shows how to verify your answer.

As a trivial example, "solve d(x^2)/dx". Well duh, the answer is 2*x, but you can numerically verify that: Evaluate x^2 at 1 and 1.001. You get 1 and 1.002001. The difference times 1000 then is 2.001. Now evaluate your answer at 1: You get 2. Yup, your answer is probably right.

Similarly, even the lamest programmable calculator can do numerical integration. So again, just numerically integrate your original function from 0 to 1 or whatever and verify that your integral answer formula produces a similar number.

I did this quite regularly in calculus exams. Saved my ass repeatedly. You can also plug your test number into your intermediate steps to see where it changes -- that will be the place you made a mistake.

So yes calculators are useful in calculus exams, even if it's not a monster like the HP50g that does full symbolic calculus.

Comment Re:You ares testing students the wrong way (Score 1) 241

Any sane prof would require that you show your work.

That's fine; the HP50g has a mode where it shows the intermediate steps when solving a calculus problem.

Even if it didn't, don't you think having a device that gives you the correct answer on a silver platter is a pretty handy thing to have in a calculus exam?

Comment Re:You ares testing students the wrong way (Score 1) 241

That's crazy. Fancy calculators like the HP50g can do symbolic calculus..

Even less fancy calculators can be useful: I used my programmable calculator to check my answers. For a derivative, for example, evaluate the original formula at some arbitrary value, and then again at that same value plus .001. The difference of the results times 1000 is roughly the derivative, so now you can plug that same arbitrary value in your derivative as a confirmation that you probably got the right answer.

The same calculator could also do numeric integration, so integrals could be checked as well.

Comment Re:Tick mark == approval (Score 1) 713

When I grew up in Sweden, tests were marked with "R" for correct and a checkmark for wrong. Then we moved to Canada, and one of my first quizzes was math. I took it up to the teacher, who checked off every question and handed the test back to me with a big smile and the exclamation "good!".

I was devastated. I sat at my desk completely baffled as to how I could have gotten every question wrong. I was thinking that maybe math is different in Canada. Eventually I went back to the teacher to complain, and after some confusion we were both sorted out.

So yeah, don't count on checkmark meaning what you think it does to everyone.

Comment Re:Protect magnetic storage? (Score 1) 87

Well it could, but it's overkill. The big deal about this thing is that it doesn't distort any magnetic field it's in, making it effectively "invisible" from the magnetic field

If you just want to protect something from a magnetic field and you don't care who knows it, just contain it in something like mu-metal

Comment Re:Arrogance of geomodelers? (Score 1) 120

Is there some part of "it could be measurement error" that is unclear to you?

I'll just ignore that unnecessary insult.

As I said, I've done tons of undergrad labs and in most all cases of conflict the measuring was the problem. So your sentence "It could be measurement error, but it's more likely that your models are wrong" is completely at polar opposites with my experience doing science right in the lab.

Measuring tiny gravity variations while in orbit of a tiny planet in the vicinity of a huge sun with a vicious solar wind, wildly fluctuating magnetic fields and insane temperature variations is not easy. In fact, TFA itself admits that it was very difficult. It would be unprofessional for the modelling crew to not question unusual results. They did, they checked everything over, eventually concluded that the numbers must be good, therefore the model must be adjusted.

THAT'S what's called being scientists.

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