What is low latency kernel?  When do we need to use it? Any something may be affected when we use low latency kernel?
After installing Ubuntu Studio 12.04, I have found that it uses a low latency kernel.   I searched for an explanation and how to change back it to a real-time or generic one. However, it looks like this part of Linux hasn't been covered to explain the details.   Q: Why choose a low latency kernel over a generic or real-time one?  PS: I have already read the answers from  question and  post.
Is it possible to run commands from spotlight? I run commands in terminal a lot and i'm wondering if it is possible to run the commands from spotlight. For example in spotlight  would like to run the command(because i have a lot of network issues):   ping google.com   And then spotlight to load terminal and execute the command instead of having to load terminal because it takes so long to load. So is this possible? Narrow-phase collision detection algorithms Does the 90 days VWP rule expire if you travel from the US to Canada? I'm on a New Zealand passport.  From most US Embassy webpages:     The Visa Waiver Program (VWP) enables nationals of certain countries,   including Australia, New Zealand, and the U.K., to travel to the   United States for tourism or business for stays of 90 days or less   without obtaining a visa, if certain requirements are met. Under the   VWP, time spent in Canada, Mexico, and adjacent islands counts towards   the maximum of 90 days stay allowed under the program.   I'll be there on a 1-year working holiday visa starting when I arrive in Vancouver. I'm spending 3 days in Hawaii en route to Vancouver. This seems to imply that 90 days after landing in Hawaii, my time will be up and I won't be able to get back into the US, as my living in Canada will not reset the clock. What if after this time I want to say, pop across the border to Seattle? How can I restart the 90 days, without having to resort to say, flying to Japan and back just to reset it? "He walks as if he is drunk." Grammatically correct ? Any difference in meaning from "...as if he were drunk."? Is it grammatically correct to use an indicative verb after "as if", or "as though" for that matter?        I've heard someone say: "He walks as if he is drunk."  Would there have been any difference if he had said "He walks as if he were drunk."?   A second example might be:        It looks as if it is going to rain.   It looks as if it were going to rain. Miraak is stealing all my dragon souls Quadratic Formula in Complex Variables If $[G' : G'']\leq p^2$, then $G'$ is abelian. How do moving charges produce magnetic fields? How does gravity escape a black hole? My understanding is that light can not escape from within a black hole (within the event horizon).  I've also heard that information cannot propagate faster than the speed of light.  It would seem to me that the gravitational attraction caused by a black hole carries information about the amount of mass within the black hole.  So, how does this information escape?  Looking at it from a particle point of view: do the gravitons (should they exist) travel faster than the photons? OBB vs OBB Collision Detection Say you have two Bounding Box Objects each of them storing the current vertices of the box in a vector with all the vertices of the object rotated and translated relative to a common axis.  Here is an image to illustrate my problem:   How can I work out if the two OBB's are overlapping any links to help explain the solution to the problem would be welcome. Nothing too convoluted please... Storing C++ template function definitions in a .CPP file Prove that if $n \in \mathbb{N}$, then $$\sum_{d|n}{(d(n))^3}=(\sum_{d|n}{d(n)})^2$$ where $d(n)$ is the divisor function. I have know only information is $d(n)=\sum_{d|n}{1}$. How to blur a texture node in cycles material? For a Cycles material I need to blur a texture. If the texture where a Texture Image node, I can blur the image before adding it but in my case I need to blur a Voronoi Texture and so I can't do it.  I have searched but I didn't find a blur node. Can this be achieved? How to to resize an ext4 partition from the command line? What's the easiest way to resize an ext4 partition (or any type partition depending on the method) from the command line (potentially with the fewest commands, but also the easiest to understand)?  Using a tool like Gparted is obviously easy in a GUI, but what about in the command line? I guess text-based GUIs can count for the answer too since it's technically still in the command line. It just needs to be easy.  By partition I mean a simple partition on a single disk of a personal computer (e.g. on a laptop). For example, I want to resize /dev/sda4. There's no RAIDs, there's not more than one disk drive, there's not anything complicated here. Just a simple partition on a single disk (/dev/sdaX on /dev/sda). I want to prove, that $GL(n,K)$ is open in $M(n,K)$, where ($K=\{\mathbb{R},\mathbb{C},\mathbb{H}\}$.  For the prove I don't want to use that the determinant is continous. Alternativly I assume a submultiplicative norm.  First step: Define $U_A:=\{B\in M(n,K):\Vert A-B\Vert&lt;\frac{1}{\Vert A^{-1}\Vert}\}$ and show that it is a neighbourhod of $A$ in $M(n,K)$.  Second step: I show that the series $\sum_{k\ge0}(1-A^{-1}B)^kA^{-1}$ converges absolutely and the limit is inverse to $B$.  For the second step I should use the Neumann series, right? But I have some problems with the first step. Any help? How should I detect unnecessary #include files in a large C++ project? If $\gcd(a,b)=1$, then $\gcd(a+b,a^2 -ab+b^2)=1$ or $3$. Here is the dictionary I have  propertyList = {     "id":           "int",     "name":         "char(40)",      "team":         "int",     "realOwner":    "int",      "x":            "int",     "y":            "int",      "description":  "char(255)",      "port":         "bool",     "secret":       "bool",     "dead":         "bool",     "nomadic":      "bool",      "population":   "int",     "slaves":       "int", }   But when I print it out with "\n".join(myDict) I get this  name nomadic dead port realOwner secret slaves team y x population id description   I know that a dictionary is unordered but it comes out the same every time and I've no idea why. Is there any reason to use this-> I am programming in C++ for many years, still I have doubt about one thing. In many places in other people code I see something like:  void Classx::memberfunction() {     this-&gt;doSomething(); }   If I need to import/use that code, I simply remove the this-> part, and I have never seen anything broken or having some side-effects.  void Classx::memberfunction() {     doSomething(); }   So, do you know of any reason to use such construct?  EDIT: Please note that I'm talking about member functions here, not variables. I understand it can be used when you want to make a distinction between a member variable and function parameter.  EDIT: apparent duplicate: How can I safely create a nested directory in Python? What is the most elegant way to check if the directory a file is going to be written to exists, and if not, create the directory using Python? Here is what I tried:  import os  file_path = "/my/directory/filename.txt" directory = os.path.dirname(file_path)  try:     os.stat(directory) except:     os.mkdir(directory)         f = file(filename)   Somehow, I missed os.path.exists (thanks kanja, Blair, and Douglas). This is what I have now:  def ensure_dir(file_path):     directory = os.path.dirname(file_path)     if not os.path.exists(directory):         os.makedirs(directory)   Is there a flag for "open", that makes this happen automatically?