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  • Proper fstab entry to mount a samba share in 12.04

    - by JPbuntu
    I am a little confused on the proper fstab entry for a samba share in Ubuntu 12.04 I can get the drive to mount manually by using: sudo mount -t cifs //192.168.2.2/raid_drive /mnt/homeserver -o username=jon,password=password So I tried putting this in fstab: //192.168.2.2/raid_drive /mnt/homeserver cifs username=jon,password=password,iocharset=utf8,mode=0777,dir_mode=07??77 0 0 Which gives me this error in syslog: kernel: [ 2217.925354] CIFS: Unknown mount option mode kernel: [ 2217.936345] CIFS VFS: default security mechanism requested. The default security mechanism will be upgraded from ntlm to ntlmv2 in kernel release 3.3 This guide says to use smbfs although I believe smbfs is deprecated? What is a common fstab configuration for a samba share in Ubuntu 12.04? EDIT: Using the accepted answer below I was initially getting this error message (from dmesg): [ 45.520883] CIFS VFS: Error connecting to socket. Aborting operation [ 45.520990] CIFS VFS: cifs_mount failed w/return code = -115 although it turns out this was due to network connectivity issues, and not related to improper fstab entry.

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  • Error when setting Piwik analytics

    - by bertran
    I've uploaded the latest version of Piwik unto my web server, which is hosted by go daddy.com, on a linux hosting plan. I'm setting it up (accessing it from my browser as instructed) and I have the "Piwikinstallation" page open on step 3 (database set-up ) of 9. I don't know what to imput in the field "database server"... the default is the number 127.0.0.1 When I leave that input as is, and click "Next" leaving the gives the error: "Error when trying to connect to database server: SQLSTATE[HY000] [2013] Lost connection to MySQL server at 'reading initial communication packet', system error: 111" and changing that input to "localhost" gives me another error: "Error when trying to connect to database server:SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)"

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  • RPi and Java Embedded GPIO: Sensor Reading using Java Code

    - by hinkmond
    And, now to program the Java code for reading the fancy-schmancy static electricity sensor connected to your Raspberry Pi, here is the source code we'll use: First, we need to initialize ourselves... /* * Java Embedded Raspberry Pi GPIO Input app */ package jerpigpioinput; import java.io.FileWriter; import java.io.RandomAccessFile; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Calendar; /** * * @author hinkmond */ public class JerpiGPIOInput { static final String GPIO_IN = "in"; // Add which GPIO ports to read here static String[] GpioChannels = { "7" }; /** * @param args the command line arguments */ public static void main(String[] args) { try { /*** Init GPIO port(s) for input ***/ // Open file handles to GPIO port unexport and export controls FileWriter unexportFile = new FileWriter("/sys/class/gpio/unexport"); FileWriter exportFile = new FileWriter("/sys/class/gpio/export"); for (String gpioChannel : GpioChannels) { System.out.println(gpioChannel); // Reset the port unexportFile.write(gpioChannel); unexportFile.flush(); // Set the port for use exportFile.write(gpioChannel); exportFile.flush(); // Open file handle to input/output direction control of port FileWriter directionFile = new FileWriter("/sys/class/gpio/gpio" + gpioChannel + "/direction"); // Set port for input directionFile.write(GPIO_IN); directionFile.flush(); } And, next we will open up a RandomAccessFile pointer to the GPIO port. /*** Read data from each GPIO port ***/ RandomAccessFile[] raf = new RandomAccessFile[GpioChannels.length]; int sleepPeriod = 10; final int MAXBUF = 256; byte[] inBytes = new byte[MAXBUF]; String inLine; int zeroCounter = 0; // Get current timestamp with Calendar() Calendar cal; DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS"); String dateStr; // Open RandomAccessFile handle to each GPIO port for (int channum=0; channum Then, loop forever to read in the values to the console. // Loop forever while (true) { // Get current timestamp for latest event cal = Calendar.getInstance(); dateStr = dateFormat.format(cal.getTime()); // Use RandomAccessFile handle to read in GPIO port value for (int channum=0; channum Rinse, lather, and repeat... Compile this Java code on your host PC or Mac with javac from the JDK. Copy over the JAR or class file to your Raspberry Pi, "sudo -i" to become root, then start up this Java app in a shell on your RPi. That's it! You should see a "1" value get logged each time you bring a statically charged item (like a balloon you rub on the cat) near the antenna of the sensor. There you go. You've just seen how Java Embedded technology on the Raspberry Pi is an easy way to access sensors. Hinkmond

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  • JPedal Action for Converting PDF to JavaFX

    - by Geertjan
    The question of the day comes from Mark Stephens, from JPedal (JPedal is the leading 100% Java PDF library, providing a Java PDF viewer, PDF to image conversion, PDF printing or adding PDF search and PDF extraction features), in the form of a screenshot: The question is clear. By looking at the annotations above, you can see that Mark has an ActionListener that has been bound to the right-click popup menu on PDF files. Now he needs to get hold of the file to which the Action has been bound. How, oh  how, can one get hold of that file? Well, it's simple. Leave everything you see above exactly as it is but change the Java code section to this: public final class PDF2JavaFXContext implements ActionListener {     private final DataObject context;     public PDF2JavaFXContext(DataObject context) {         this.context = context;     }     public void actionPerformed(ActionEvent ev) {         FileObject fo = context.getPrimaryFile();         File theFile = FileUtil.toFile(fo);         //do something with your file...     } } The point is that the annotations at the top of the class bind the Action to either Actions.alwaysEnabled, which is a factory method for creating always-enabled Actions, or Actions.context, which is a factory method for creating context-sensitive Actions. How does the Action get bound to the factory method? The annotations are converted, when the module is compiled, into XML registration entries in the "generated-layer.xml", which you can find in your "build" folder, in the Files window, after building the module. In Mark's case, since the Action should be context-sensitive to PDF files, he needs to bind his PDF2JavaFXContext ActionListener (which should probably be named "PDF2JavaFXActionListener", since the class is an ActionListener) to Actions.context. All he needs to do that is pass in the object he wants to work with into the constructor of the ActionListener. Now, when the module is built, the annotation processor is going to take the annotations and convert them to XML registration entries, but the constructor will also be checked to see whether it is empty or not. In this case, the constructor isn't empty, hence the Action should be context-sensitive and so the ActionListener is bound to Actions.context. The Actions.context will do all the enablement work for Mark, so that he will not need to provide any code for enabling/disabling the Action. The Action will be enabled whenever a DataObject is selected. Since his Action is bound to Nodes in the Projects window that represent PDF files, the Action will always be enabled whenever Mark right-clicks on a PDF Node, since the Node exposes its own DataObject. Once Mark has access to the DataObject, he can get the underlying FileObject via getPrimaryFile and he can then convert the FileObject to a java.io.File via FileUtil.getConfigFile. Once he's got the java.io.File, he can do with it whatever he needs. Further reading: http://bits.netbeans.org/dev/javadoc/

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  • What are the basics (best practices, etc) of writing a good Flash application?

    - by donut
    I've been tasked with writing a Flash application for facilitating a Fantasy Football draft pick. Normally, my choice would be to write this application in JavaScript. Unfortunately, it will require the use of sockets and since we don't have enough experience with Web Socket JS to be sure it would work in this situation I need to learn Flash. Currently, I'm most proficient in JavaScript/HTML/CSS/PHP/MySQL and have never really used Flash in a meaningful way. As best as I can I want to start this project off "the right way". So, what are good to know best practices and/or references/resources that will teach my the right way of doing things in Flash?

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  • About Solaris 11 and UltraSPARC II/III/IV/IV+

    - by nospam(at)example.com (Joerg Moellenkamp)
    I know that I will get the usual amount of comments like "Oh, Jörg ? you can't be negative about Oracle" for this article. However as usual I want to explain the logic behind my reasoning. Yes ? I know that there is a lot of UltraSPARC III, IV and IV+ gear out there. But there are some very basic questions: Does your application you are currently running on this gear stops running just because you can't run Solaris 11 on it? What is the need to upgrade a system already in production to Solaris 11? I have the impression, that some people think that the systems get useless in the moment Oracle releases Solaris 11. I know that Sun sold UltraSPARC IV+ systems until 2009. The Sun SF490 introduced 2004 for example, that was a Sun SF480 with UltraSPARC IV and later with UltraSPARC IV+. And yes, Sun made some speedbumps. At that time the systems of the UltraSPARC III to IV+ generations were supported on Solaris 8, on Solaris 9 and on Solaris 10. However from my perspective we sold them to customers, which weren't able to migrate to Solaris 10 because they used applications not supported on Solaris 9 or who just didn't wanted to migrate to Solaris 10. Believe it or not ? I personally know two customers that migrated core systems to Solaris 10 in ? well 2008/9. This was especially true when the M3000 was announced in 2008 when it closed the darned single socket gap. It may be different at you site, however that's what I remember about that time when talking with customers. At first: Just because there is no Solaris 11 for UltraSPARC III, IV and IV+, it doesn't mean that Solaris 10 will go away anytime soon. I just want to point you to "Expect Lifetime Support - Hardware and Operating Systems". It states about Premier Support:Maintenance and software upgrades are included for Oracle operating systems and Oracle VM for a minimum of eight years from the general availability date.GA for Solaris 10 was in 2005. Plus 8 years ? 2013 ? at minimum. Then you can still opt for 3 years of "Extended Support" ? 2016 ? at minimum. 2016 your systems purchased in 2009 are 7 years old. Even on systems purchased at the very end of the lifetime of that system generation. That are the rules as written in the linked document. I said minimum The actual dates are even further in the future: Premier Support for Solaris 10 ends in 2015, Extended support ends 2018. Sustaining support ? indefinite. You will find this in the document "Oracle Lifetime Support Policy: Oracle Hardware and Operating Systems".So I don't understand when some people write, that Oracle is less protective about hardware investments than Sun. And for hardware it's the same as with Sun: Service 5 years after EOL as part of Premier Support. I would like to write about a different perspective as well: I have to be a little cautious here, because this is going in the roadmap area, so I will mention the public sources here: John Fowler told last year that we have to expect at at least 3x the single thread performance of T3 for T4. We have 8 cores in T4, as stated by Rick Hetherington. Let's assume for a moment that a T4 core will have the performance of a UltraSPARC core (just to simplify math and not to disclosing anything about the performance, all existing SPARC cores are considered equal). So given this pieces of information, you could consolidate 8 V215, 4 or 8 V245, 2 full blown V445,2 full blown 490, 2 full blown M3000 on a single T4 SPARC processor. The Fowler roadmap prezo talked about 4-socket systems with T4. So 32 V215, 16 to 8 V245, 8 fullblown V445, 8 full blown V490, 8 full blown M3000 in a system image. I think you get the idea. That said, most of the systems we are talking about have already amortized and perhaps it's just time to invest in new systems to yield other advantages like reduced space consumptions, like reduced power consumption, like some of the neat features sun4v gives you, and yes ? reduced number of processor licenses for Oracle and less money for Oracle HW/SW support. As much as I dislike it myself that my own UltraSPARC III and UltraSPARC II based systems won't run on Solaris 11 (and I have quite a few of them in my personal lab), I really think that the impact on production environments will be much less than most people think now. By the way: The reason for this move is a quite significant new feature. I will tell you that it was this feature, when it's out. I assume, telling just a word more could lead to much more time to blog.

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  • Avoid GPL violation by moving library out of process

    - by Andrey
    Assume there is a library that is licensed under GPL. I want to use it is closed source project. I do following: Create small wrapper application around that GPL library that listens to socket, parse messages and call GPL library. Then returns results back. Release it's sources (to comply with GPL) Create client for this wrapper in my main application and don't release sources. I know that this adds huge overhead compared to static/dynamic linking, but I am interested in theoretical way.

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  • GConf Error: No D-BUS daemon running?! How to reinstall or fix?

    - by v2r
    After installing Konquerer and restarting my laptop i got the following error while trying to open, edit or access files as root from within Terminal (which is existencial for me). root@linuxBox:/home/v2r# gnome-open /home/ (gnome-open:2686): GConf-WARNING **: Client failed to connect to the D-BUS daemon: //bin/dbus-launch terminated abnormally with the following error: No protocol specified Autolaunch error: X11 initialization failed. GConf Error: No D-BUS daemon running root@linuxBox:/home/v2r# No protocol specified Could not parse arguments: Cannot open display: Also it seems, that dbus is not installed properly anymore in /bin/ and /usr/bin/ See screenshot: How would i go about fixing this problem and thank you in advance?!!! Thank you for your answer SirCharlo! It does not resolve the problem at all. Please note, that it only happens while beeing root! root@linuxBox:/home/v2r# gnome-open /home/ (gnome-open:5170): GConf-WARNING **: Client failed to connect to the D-BUS daemon: Failed to connect to socket /tmp/dbus-2RdCUjrZ9k: Connection refused GConf Error: No D-BUS daemon running root@linuxBox:/home/v2r# No protocol specified Could not parse arguments: Cannot open display:

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  • mysql does not start or work

    - by Artem Moskalev
    Recently I installed LAMP with tasksel. Then I remember I issued some commands to get into the mysql console - it worked. Right now I checked - apache and php modules work perfectly. But as for mysql - whatever commands I issue - it does not start the console. It writes: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' How can I fix it and start mysql? Why did this happen? Where is it installed (I used the default location for the installation), because I dont understand what is started when I issue the commands?

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  • Creating symlink for Postgres

    - by Edwin
    As a developer, I often ssh right into my local database, just to test my application before pushing my code. However, I find that every time I want to access Postgres, I have to type in postgres@ubuntu:~$ /usr/local/pgsql/bin/psql test whereas on my work machine, all I have to do is type postgres@ubuntu:~$ psql --dbname=test --username=user I tried creating a symlink, which was successful, but whenever I try connecting to it through this shortcut, I get the following error message: psql: could not connect to server: No such file or directory Is the server running locally and accepting connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"? How do I get this to work? In case it makes any difference, I'm using a self-compiled version of the 9.1.x series.

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  • Is it worth it to switch from home-grown remote command interface to using JMX

    - by Sam Goldberg
    Without knowing too much about JMX, I've always assumed that it would be the best approach for building in remote management to our standalone Java server application. Our server application has some minimal remote control capability, using text commands sent via TCP/IP socket to it. Using the home grown approach, it is fairly to add a new command. (Just create new command text, and the code to handle that in the message receiver). On the other hand, we have hardly implemented any commands, even though there are many things we would like to be able to execute remotely. I am trying to weigh the value of moving to incorporating JMX (learning it, and building the interfaces), versus just sticking with the home-grown approach. Does anyone have any experience or advice regarding changing an existing application to use JMX?

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  • No databases showing in phpMyAdmin

    - by Thein Hla Maw
    My website is hosted in shared hosting service and is working fine with updated news stored in MySQL database. To manage the database of website, I install phpMyAdmin in a sub-folder with the same username and password used in website. When I login to phpMyAdmin, I don't see my database. phpMyAdmin is showing "No databases" in left pane. Is there any thing I need to configure in phpMyAdmin? Edited: This is the settings in config.inc.php. I can login to phpMyAdmin successfully. $cfg['Servers'][$i]['host'] = 'hostname'; $cfg['Servers'][$i]['port'] = ''; $cfg['Servers'][$i]['socket'] = ''; $cfg['Servers'][$i]['connect_type'] = 'tcp'; $cfg['Servers'][$i]['extension'] = 'mysqli'; $cfg['Servers'][$i]['auth_type'] = 'cookie'; $cfg['Servers'][$i]['user'] = 'dbuser'; $cfg['Servers'][$i]['password'] = 'password';

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  • Simple Math Multiplayer game - is Ajax sufficient?

    - by Christian Strang
    I'm planning to create a simple math multiplayer game and I plan to just use Ajax for the server/client communication but I'm not sure if this is sufficient or if I need a socket server. The game will look like this: 2-4 users all get a simple math task (like: "37 + 14") they have to solve it as fast as possible first user who solves it is the winner I will track the time for each user, since the game started, on the client side and everytime a user gives an answer, the answer and the passed time will be send to the server. Additionally I'll add a function which will check every 3 seconds if the other users finished, how much time they needed and who won. Do you think this is possible just using Ajax? What alternatives are there?

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  • How to effectively gather info about how players play my HTML5 game?

    - by Bane
    I'm finishing another HTML5 game, and this time I'd like to do some spying business on the players... Mostly just basic stuff: when they are playing, for how long, what upgrades they are buying the most and so on. Now, my first idea was just to collect this information during the gameplay, and then have a Javascript function fire when they close the tab/browser, and said function would send it to my server via Socket.io. This, of course, wouldn't work, because anyone who takes a look at the code would realize it and could start sending a tonne of false info which would mess up my statistics. Questions: Is there a way to effectively do this? If yes, what kind of info should I be looking for, aside from stuff I already mentioned?

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  • Crashing trying to install Ubuntu 12.04 LTS

    - by Daniel Evans
    Hardware: Dell Inspiron 1545 Steps are as follows: 1. Insert 64 bit Ubuntu 12.04 disc 2. Boot computer Output is as follows: error: unexpectedly disconnected from boot status daemon Generating locales... en_US.UTF-8... done Generation complete. MEMORY-ERROR: glib-compile-schemas[569]: GSlice: assertion failed: aligned_memory == (gpointer) addr Aborted pwconv: failed to change the mode of /etc/passwd- to 0600 MEMORY-ERROR: [996]: GSlice: assertion failed: aligned_memory == (gpointer) addr MEMORY-ERROR: glib-compile-scehmas[1034]: GSlice: assertion failed: aligned_memory == gpointer) addr Aborted /usr/lib/python2.7/dist-packages/LanguageSelector/LocaleInfo.py:256: UserWarning: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory warnings.warn(msg.args[0].encode('UTF-8')) Using CD-ROM mount point /cdrom ... etc etc... End up at a prompt line ubuntu@ubuntu:~$

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  • One True Event Loop

    - by CyberShadow
    Simple programs that collect data from only one system need only one event loop. For example, Windows applications have the message loop, POSIX network programs usually have a select/epoll/etc. loop at their core, pure SDL games use SDL's event loop. But what if you need to collect events from several subsystems? Such as an SDL game which doesn't use SDL_net for networking. I can think of several solutions: Polling (ugh) Put each event loop in its own thread, and: Send messages to the main thread, which collects and processes the events, or Place the event-processing code of each thread in a critical section, so that the threads can wait for events asynchronously but process them synchronously Choose one subsystem for the main event loop, and pass events from other subsystems via that subsystem as custom messages (for example, the Windows message loop and custom messages, or a socket select() loop and passing events via a loopback connection). Option 2.1 is more interesting on platforms where message-passing is a well-developed threading primitive (e.g. in the D programming language), but 2.2 looks like the best option to me.

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  • Ubuntu 13.10 install VMware 9.0

    - by user212290
    After I install the VMware workstation 9.0, while when I want open the VM, there come the dialogue "Before you can run VMware, several modules must be complied and loaded into the running kernel CANCEL INSTALL",while I clicked the INSTALL button, nothing happened. When: sudo apt-get install linux-headers-3.11.0-12-generic sudo /usr/bin/vmware-modconfig --icon=vmware-workstation --appname=VMware come: cc1: some warnings being treated as errors make[2]: *** [/tmp/modconfig-T9k19t/vmci-only/linux/driver.o] Error 1 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [_module_/tmp/modconfig-T9k19t/vmci-only] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-3.11.0-12-generic' make: *** [vmci.ko] Error 2 make: Leaving directory `/tmp/modconfig-T9k19t/vmci-only' Failed to build vmci. Failed to execute the build command. Starting VMware services: Virtual machine monitor done Virtual machine communication interface failed VM communication interface socket family done Blocking file system done Virtual ethernet failed VMware Authentication Daemon done

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  • How to use OpenGL functions from multiples thread?

    - by Robert
    I'm writing a small game using OpenGL. I'm implementing basic networking in this game and I'm facing a problem. I have a thread in my client socket class that check for available data, when there are data I raise an event like this : immutable int len = this.m_socket.receive(data); if(len > 0) { this.m_onDataEvent(data); } Then on my game class, I have a function that handle and parse data like this : switch(msgId) { case ProtocolID.CharacterData: // Load terrain with opengl, character model.... Im not able to call opengl functions because my opengl context is created from a different thread. But I really don't know how I can solve this problem, I tried Google but it's really hard to find a solution. I'm using D programming language if it can help.

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  • how Computer Networks is related to Web/Desktop Java programming

    - by C4CodeE4Exe
    Being a Java programmer , I am wondering how could my work experience would help me learning networking skills. I know C language is used in network socket programming. I know if one knows how to program in one language its not tough to learn another language. Question is I am not able to find much on networks when it comes to Java(may be my knowledge is limited). Do companies like CISCO,TELUS Inc. rely heavily on programmers with such background.

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  • How To Troubleshoot Internet Connection Problems

    - by Chris Hoffman
    Internet connection problems can be frustrating. Rather than mashing F5 and desperately trying to reload your favorite website when you experience a problem, here are some ways you can troubleshoot the problem and identify the cause. Ensure you check the physical connections before getting too involved with troubleshooting. Someone could have accidentally kicked the router or modem’s power cable or pulled an Ethernet cable out of a socket, causing the problem. Image Credit: photosteve101 on Flickr 7 Ways To Free Up Hard Disk Space On Windows HTG Explains: How System Restore Works in Windows HTG Explains: How Antivirus Software Works

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  • Is there any difference between processor and core?

    - by Salvador
    The following two command seems to give me different information about the same hardware srs@ubuntu:~$ cat /proc/cpuinfo | grep -e processor -e cores processor : 0 cpu cores : 4 processor : 1 cpu cores : 4 processor : 2 cpu cores : 4 processor : 3 cpu cores : 4 srs@ubuntu:~$ sudo dmidecode -t processor # dmidecode 2.9 SMBIOS 2.6 present. Handle 0x0004, DMI type 4, 42 bytes Processor Information Socket Designation: LGA1155 Type: Central Processor Family: <OUT OF SPEC> Manufacturer: Intel ID: A7 06 02 00 FF FB EB BF Version: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz Voltage: 1.0 V External Clock: 100 MHz Max Speed: 3800 MHz Current Speed: 3300 MHz Status: Populated, Enabled Upgrade: Other L1 Cache Handle: 0x0005 L2 Cache Handle: 0x0006 L3 Cache Handle: 0x0007 Serial Number: To Be Filled By O.E.M. Asset Tag: To Be Filled By O.E.M. Part Number: To Be Filled By O.E.M. Core Count: 4 Core Enabled: 1 Characteristics: 64-bit capable Until today I thought I had a single processor with 4 independent cores. I also thought that within each core can be used different threads.

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  • Plugging two external screens to laptop via VGA and HDMI

    - by avilella
    I have an Asus U30JC laptop with a VGA and HDMI ports. I can connect my external screen (1920x1200) to either of those ports but I wonder if I would be able to use two screens at the same time, one plugged to the VGA and the other to the HDMI socket. Any ideas? Where should I find out? Doing xrandr, I get: Screen 0: minimum 320 x 200, current 1366 x 768, maximum 8192 x 8192 LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 293mm x 164mm 1366x768 60.0*+ 1360x768 59.8 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) DP1 disconnected (normal left inverted right x axis y axis)

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  • Optimization of a Hybrid Pagination Scheme

    - by Kaustubh Karkare
    I'm working on a Web Application using node.js in which I'm building a partial copy of the database on the client-side to decrease the load on my server. Right now, I have a function like this (expressed as python-style pseudocode, but implemented in JavaScript): get(table_name,primary_key): if primary_key in cache[table_name]: return cache[table_name][primary_key] else: x = get_data_from_server(table_name,primary_key) # socket.io return cache[table_name][primary_key] = x While this scheme works perfectly well for caching individual rows, I'd like to extend it to support the creation of paginated tables ordered according to the primary_key, and loading additional data using the above function for only the current and possibly the adjacent pages. Now, I don't want to keep the list of primary keys on the server to be retrieved every time I need to change the page (which, for reasons beyond the scope here, will be very frequent), and keeping it on the client side, subject to real-time create/delete events from the server, doesn't seem that good an idea, even after compression (using ranges, instead of individual values). What is the best way to calculate which items are to be displayed on a random page, minimizing the space requirements & the need for communication with the server?

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  • Serializing Data Structures in C

    - by src
    I've recently read three separate books on algorithms and data structures, tcp/ip socket programming, and programming with memory. The book about memory briefly discussed the topic of serializing data structures for the purposes of storing it to disk, or sending it across a network. I can't help but wonder why the the other two books didn't discuss serialization at all. After an unsuccessful web/book search I'm left wondering where I can find a good book/paper/tutorial on serializing data structures in C? Where or how did you learn it?

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  • Collision detection in multiplayer games

    - by Bane
    This a followup to my previous question: How to implement physics and AoE spells in an MMO game?. There, we concluded that all physics have to be done on the server, and that I should use cylinders for calculations. Now, how can I check for collision detection on a ground-to-player basis on the server? It's fairly easy if the ground is a flat space, I just check if the player's z coordinate is lower than some value and voila, but, what if the map/ground itself is a model? How do I know where hills are on the server-side? How do I know when object collisions happen? I'm using node.js and socket.io.

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