How is malloc() implemented internally?
How do malloc() and free() work?
"NG NS" on ticket after airport security I went through security at the Sacramento Airport with a friend. He got something written on his boarding pass "NG NS". I didn't have that. We both went through the same metal detector, neither beeped nor had random checks. Flying to Edmonton through Seattle connection. Early for flight.  I have tried searching for "what is tsa ng ns" on Google but nothing useful came up. Any ideas? I'm programming a presentation in LaTeX using the beamer class.  However, it defaults to 4:3 aspect ratio slides, while everything I use is 16:9. Is there an easy way to change this using a command or two? How can I lock a folder so that it CANNOT be erased? On my computer running Windows XP Pro SP3 I have a folder on my desktop that is very important. How can I lock it so that I can alter anything in it, but the folder itself cannot be removed without resetting a (lock/unlock?) switch? What is it called when you use many words to describe the word you want to use? What is it called when you use many words to describe the word you want to use?  I know there is a technical word that's used in foreign language acquisition that means using many words to describe a word you don't know.  I'm doing it now, just talking and beating around the bush until someone can tell me the word I'm looking for. I know this question is asked a lot, but the solutions I saw didn't work for me.  I only have one virtual host enabled, and I'm trying to enable access to a folder that's not under the document root  ServerAdmin webmaster@localhost DocumentRoot /var/www/html  Alias /movies /home/username/Videos/Movies  &lt;Directory /home/username/Videos/Movies/&gt;     Options Indexes FollowSymLinks     AllowOverride None     Require all granted &lt;/Directory&gt;   I set /etc/apache2/envvars as follows  export APACHE_RUN_USER=www-data export APACHE_RUN_GROUP=public   I made sure that /home/username/Videos/ and its sub folders are owned by username:public, set the permissions to 777 (after 775 didn't work) and made sure that user www-data belongs to group public.  Now, when I browse to http://localhost/movies I get  [Mon Apr 21 11:28:14.971844 2014] [core:error] [pid 1385:tid 140067725104896] (13)Permission denied: [client 127.0.0.1:46603] AH00035: access to /movies/ denied (filesystem path '/home/username/Videos') because search permissions are missing on a component of the path   But when I set /etc/apache2/envvars to run Apache under username (my own username) everything works fine. The problem is permission related, but I don't see how in my case; especially when I set the permissions to 777. Any ideas?  P.S. Ubuntu version is 14.04, Apache is 2.4.7 and I didn't edit other configuration files. Where are Steam games installed? I want to buy a new notebook in the near future to play games on it. I'm looking forward for the new Steam for Linux client. My question is that where does the Steam install the games, on the home partition, or in the usr folder, or somewhere else? I do not use pre-release (i.e. beta) versions of either Steam or Ubuntu. Simulation software to solve high school level mechanics problems I'm a physics teacher and I would like to find a simulation software that could be used to give exact numerical answers to high school level problems in Newtonian mechanics.  I want the students to first calcultate a numerical answer to a physics problem and then use the simulator to visualize the problem in order to understand it better and verify that the simlator gives the same answer that they got when doing the calculation themselves.  Here are some examples of what kind of problems I want the students to be able to solve with the simulator:   A slope with a specific angle of inclination and a ball starts rolling at a certain point. Determine the speed, angular momentum and total mechanical energy of the ball after a specific time t. A ladder of known mass and length is leaning against the wall at a specific angle. The contact between the ladder and the wall is frictionless. Calcultate the x and y components of the force between the floor and the ladder.   I would like the software to have the following features:  - Simulation in 2D. No 3D simulations are necessary and the software should at least have the option of doing simulations only in 2D.  - Position all objects exactly by writing numbers (just positioning the objects using the mouse is not precise enough).  - Show animations of the time evolution of the system.  - Show forces, velocities and accelerations as arrows.  - Give exact numerical results so that the students can use the software to verify their calculation.  Ideally the software would have a graphical user interface, but if no suitable software with graphical interface exixts, I could also consider a software with text-based inputs. I would consider both free and commercial software.  My question is: Is there any software that would meet these requirements and if there is, where could I get it? I am curious if it is possible to have a VPS that has data on it that is not readable by the hosting provider, but is still usable on the VPS.  Obviously there are some things that you could do to prevent them from reading anything...   You could change all the passwords, including root. But then, they could still use some alternate boot to reset the password, or they could just mount the disk another way. So, you could encrypt the disk or at least some of the contents on the disk. But then it seems that if you decrypted the content, they could still "peer in" to see what you were doing at the console, because after all, the virtualization platform should allow this. And even if you could stop that, it seems they could just read the RAM of the VPS directly.   Of course, the VPS can store data on it and as long as the key is not on the VPS and the data is never decrypted there, then the host cannot get the data.  But it seems to me that if any point the data on the VPS is decrypted...for use on the VPS...then the hosting provider can get the data.  So, my two questions are:   Is this correct? Is it true that there is no way to 100% secure data on a VPS from a host from seeing it, while keeping it accessable by the VPS? If it is possible to make it 100% secure, then how? If it is not possible, then what is the closest you can get to hiding data from the web host? A two column loop with one lead post I got a loop from internet (I forgot the site) for two column post view. It has a nice CSS for it too. But skipping that for the question now.  &lt;?php $counter = 1; ?&gt;                  &lt;?php query_posts( 'cat=3&amp;showposts=6' ); //Find whether the catID is 3 ?&gt;             &lt;?php while ( have_posts() ) : the_post() ?&gt;                   &lt;?php /* Two Column Support get class */ ?&gt;              &lt;?php $class = ( $counter % 2  ? ' one' : '' ) ?&gt;                  &lt;?php /* Two Column output open the div class */ ?&gt;              &lt;div class="column&lt;?php echo $class;// echo $first; ?&gt;"&gt;              &lt;?php news_format(); ?&gt;             &lt;/div&gt; &lt;!-- End Two Column Support close div class --&gt; &lt;?php $counter++; //Update counter ?&gt;   It printed my posts into 2 columns like:  ========= | 1 | 2 | --------- | 3 | 4 | --------- | 5 | 6 | =========  It's fine. But I want to print it like this:  ========= |   1   | --------- | 2 | 3 | --------- | 4 | 5 | --------- | 6 | 7 | =========  What the modification I need to do? I can't pass any custom limit into the WordPress' custom loop &lt;?php while ( have_posts() ) : the_post() ?&gt;. It's for a custom theme. I did it, but the problem is, it's showing like:  ========= |   1   | --------- | 1 | 2 | --------- | 3 | 4 | --------- | 5 | 6 | =========   is my whole bunch of code. glob() - sort array of files by last modified datetime stamp What WordPress API function lists active/inactive plugins? Minecraft Survival Mode How to "pretty" format JSON output in Ruby on Rails I would like my JSON output in Ruby on Rails to be "pretty" or nicely formatted.   Right now, I call to_json and my JSON is all on one line.  At times this can be difficult to see if there is a problem in the JSON output stream.  Is there way to configure to make my JSON "pretty" or nicely formatted in Rails? Installing titling.sty onto an offline Windows machine I'm trying to compile a file for which I need titling.sty:  ! LaTeX Error: File `titling.sty` not found.  The two biggest issues are 1) it's on a Windows machine (I'm really only &quot;comfortable&quot; with the Unix command line) and 2) the machine cannot be connected to the internet (so automatic approaches are impossible). Assuming the error means I'm missing a package and following some related advice (e.g., ), I downloaded the file , transferred it to the offline machine, and unzipped it, then tried to run: latex titling.ins  But this gave me an error (given I can't copy-paste, I'm including what I think may be relevant):  ******************************************************** * No Configuration file found, using default settings. * ******************************************************** ! ************************************************** * Could not find your \batchfile=titling.ins. **************************************************. \processbatchFile ...****************************}                                                  \fi \else \ifDefault \Msg ... 1.1092 \process@first@batchfile  I have no idea how to proceed from this. How can I install titling.sty on this machine? Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag. Determining ethnicity according to ancestry? EntityFieldQuery display pager How do I display pager using EntityFieldQuery for fetch results? I can't find complete example.  I am doing simmilar to:   But I miss part to output simple pagination links (1,2,3... for every next page). What is the difference between conditioning on regressors vs. treating them as fixed? List has No Rows for Assignment to SObject: Error Solving "mv: Argument list too long"?