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• How to Run Low-Cost Minecraft on a Raspberry Pi for Block Building on the Cheap

  - by Jason Fitzpatrick

  We’ve shown you how to run your own blocktastic personal Minecraft server on a Windows/OSX box, but what if you crave something lighter weight, more energy efficient, and always ready for your friends? Read on as we turn a tiny Raspberry Pi machine into a low-cost Minecraft server you can leave on 24/7 for around a penny a day. Why Do I Want to Do This? There’s two aspects to this tutorial, running your own Minecraft server and specifically running that Minecraft server on a Raspberry Pi. Why would you want to run your own Minecraft server? It’s a really great way to extend and build upon the Minecraft play experience. You can leave the server running when you’re not playing so friends and family can join and continue building your world. You can mess around with game variables and introduce mods in a way that isn’t possible when you’re playing the stand-alone game. It also gives you the kind of control over your multiplayer experience that using public servers doesn’t, without incurring the cost of hosting a private server on a remote host. While running a Minecraft server on its own is appealing enough to a dedicated Minecraft fan, running it on the Raspberry Pi is even more appealing. The tiny little Pi uses so little resources that you can leave your Minecraft server running 24/7 for a couple bucks a year. Aside from the initial cost outlay of the Pi, an SD card, and a little bit of time setting it up, you’ll have an always-on Minecraft server at a monthly cost of around one gumball. What Do I Need? For this tutorial you’ll need a mix of hardware and software tools; aside from the actual Raspberry Pi and SD card, everything is free. 1 Raspberry Pi (preferably a 512MB model) 1 4GB+ SD card This tutorial assumes that you have already familiarized yourself with the Raspberry Pi and have installed a copy of the Debian-derivative Raspbian on the device. If you have not got your Pi up and running yet, don’t worry! Check out our guide, The HTG Guide to Getting Started with Raspberry Pi, to get up to speed. Optimizing Raspbian for the Minecraft Server Unlike other builds we’ve shared where you can layer multiple projects over one another (e.g. the Pi is more than powerful enough to serve as a weather/email indicator and a Google Cloud Print server at the same time) running a Minecraft server is a pretty intense operation for the little Pi and we’d strongly recommend dedicating the entire Pi to the process. Minecraft seems like a simple game, with all its blocky-ness and what not, but it’s actually a pretty complex game beneath the simple skin and required a lot of processing power. As such, we’re going to tweak the configuration file and other settings to optimize Rasbian for the job. The first thing you’ll need to do is dig into the Raspi-Config application to make a few minor changes. If you’re installing Raspbian fresh, wait for the last step (which is the Raspi-Config), if you already installed it, head to the terminal and type in “sudo raspi-config” to launch it again. One of the first and most important things we need to attend to is cranking up the overclock setting. We need all the power we can get to make our Minecraft experience enjoyable. In Raspi-Config, select option number 7 “Overclock”. Be prepared for some stern warnings about overclocking, but rest easy knowing that overclocking is directly supported by the Raspberry Pi foundation and has been included in the configuration options since late 2012. Once you’re in the actual selection screen, select “Turbo 1000MhHz”. Again, you’ll be warned that the degree of overclocking you’ve selected carries risks (specifically, potential corruption of the SD card, but no risk of actual hardware damage). Click OK and wait for the device to reset. Next, make sure you’re set to boot to the command prompt, not the desktop. Select number 3 “Enable Boot to Desktop/Scratch”  and make sure “Console Text console” is selected. Back at the Raspi-Config menu, select number 8 “Advanced Options’. There are two critical changes we need to make in here and one option change. First, the critical changes. Select A3 “Memory Split”: Change the amount of memory available to the GPU to 16MB (down from the default 64MB). Our Minecraft server is going to ruin in a GUI-less environment; there’s no reason to allocate any more than the bare minimum to the GPU. After selecting the GPU memory, you’ll be returned to the main menu. Select “Advanced Options” again and then select A4 “SSH”. Within the sub-menu, enable SSH. There is very little reason to keep this Pi connected to a monitor and keyboard, by enabling SSH we can remotely access the machine from anywhere on the network. Finally (and optionally) return again to the “Advanced Options” menu and select A2 “Hostname”. Here you can change your hostname from “raspberrypi” to a more fitting Minecraft name. We opted for the highly creative hostname “minecraft”, but feel free to spice it up a bit with whatever you feel like: creepertown, minecraft4life, or miner-box are all great minecraft server names. That’s it for the Raspbian configuration tab down to the bottom of the main screen and select “Finish” to reboot. After rebooting you can now SSH into your terminal, or continue working from the keyboard hooked up to your Pi (we strongly recommend switching over to SSH as it allows you to easily cut and paste the commands). If you’ve never used SSH before, check out how to use PuTTY with your Pi here. Installing Java on the Pi The Minecraft server runs on Java, so the first thing we need to do on our freshly configured Pi is install it. Log into your Pi via SSH and then, at the command prompt, enter the following command to make a directory for the installation: sudo mkdir /java/ Now we need to download the newest version of Java. At the time of this publication the newest release is the OCT 2013 update and the link/filename we use will reflect that. Please check for a more current version of the Linux ARMv6/7 Java release on the Java download page and update the link/filename accordingly when following our instructions. At the command prompt, enter the following command: sudo wget --no-check-certificate http://www.java.net/download/jdk8/archive/b111/binaries/jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz Once the download has finished successfully, enter the following command: sudo tar zxvf jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz -C /opt/ Fun fact: the /opt/ directory name scheme is a remnant of early Unix design wherein the /opt/ directory was for “optional” software installed after the main operating system; it was the /Program Files/ of the Unix world. After the file has finished extracting, enter: sudo /opt/jdk1.8.0/bin/java -version This command will return the version number of your new Java installation like so: java version "1.8.0-ea" Java(TM) SE Runtime Environment (build 1.8.0-ea-b111) Java HotSpot(TM) Client VM (build 25.0-b53, mixed mode) If you don’t see the above printout (or a variation thereof if you’re using a newer version of Java), try to extract the archive again. If you do see the readout, enter the following command to tidy up after yourself: sudo rm jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz At this point Java is installed and we’re ready to move onto installing our Minecraft server! Installing and Configuring the Minecraft Server Now that we have a foundation for our Minecraft server, it’s time to install the part that matter. We’ll be using SpigotMC a lightweight and stable Minecraft server build that works wonderfully on the Pi. First, grab a copy of the the code with the following command: sudo wget http://ci.md-5.net/job/Spigot/lastSuccessfulBuild/artifact/Spigot-Server/target/spigot.jar This link should remain stable over time, as it points directly to the most current stable release of Spigot, but if you have any issues you can always reference the SpigotMC download page here. After the download finishes successfully, enter the following command: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Note: if you’re running the command on a 256MB Pi change the 256 and 496 in the above command to 128 and 256, respectively. Your server will launch and a flurry of on-screen activity will follow. Be prepared to wait around 3-6 minutes or so for the process of setting up the server and generating the map to finish. Future startups will take much less time, around 20-30 seconds. Note: If at any point during the configuration or play process things get really weird (e.g. your new Minecraft server freaks out and starts spawning you in the Nether and killing you instantly), use the “stop” command at the command prompt to gracefully shutdown the server and let you restart and troubleshoot it. After the process has finished, head over to the computer you normally play Minecraft on, fire it up, and click on Multiplayer. You should see your server: If your world doesn’t popup immediately during the network scan, hit the Add button and manually enter the address of your Pi. Once you connect to the server, you’ll see the status change in the server status window: According to the server, we’re in game. According to the actual Minecraft app, we’re also in game but it’s the middle of the night in survival mode: Boo! Spawning in the dead of night, weaponless and without shelter is no way to start things. No worries though, we need to do some more configuration; no time to sit around and get shot at by skeletons. Besides, if you try and play it without some configuration tweaks first, you’ll likely find it quite unstable. We’re just here to confirm the server is up, running, and accepting incoming connections. Once we’ve confirmed the server is running and connectable (albeit not very playable yet), it’s time to shut down the server. Via the server console, enter the command “stop” to shut everything down. When you’re returned to the command prompt, enter the following command: sudo nano server.properties When the configuration file opens up, make the following changes (or just cut and paste our config file minus the first two lines with the name and date stamp): #Minecraft server properties #Thu Oct 17 22:53:51 UTC 2013 generator-settings= #Default is true, toggle to false allow-nether=false level-name=world enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false force-gamemode=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=false spawn-animals=true texture-pack= snooper-enabled=true hardcore=false online-mode=true pvp=true difficulty=1 player-idle-timeout=0 gamemode=0 #Default 20; you only need to lower this if you're running #a public server and worried about loads. max-players=20 spawn-monsters=true #Default is 10, 3-5 ideal for Pi view-distance=5 generate-structures=true spawn-protection=16 motd=A Minecraft Server In the server status window, seen through your SSH connection to the pi, enter the following command to give yourself operator status on your Minecraft server (so that you can use more powerful commands in game, without always returning to the server status window). op [your minecraft nickname] At this point things are looking better but we still have a little tweaking to do before the server is really enjoyable. To that end, let’s install some plugins. The first plugin, and the one you should install above all others, is NoSpawnChunks. To install the plugin, first visit the NoSpawnChunks webpage and grab the download link for the most current version. As of this writing the current release is v0.3. Back at the command prompt (the command prompt of your Pi, not the server console–if your server is still active shut it down) enter the following commands: cd /home/pi/plugins sudo wget http://dev.bukkit.org/media/files/586/974/NoSpawnChunks.jar Next, visit the ClearLag plugin page, and grab the latest link (as of this tutorial, it’s v2.6.0). Enter the following at the command prompt: sudo wget http://dev.bukkit.org/media/files/743/213/Clearlag.jar Because the files aren’t compressed in a .ZIP or similar container, that’s all there is to it: the plugins are parked in the plugin directory. (Remember this for future plugin downloads, the file needs to be whateverplugin.jar, so if it’s compressed you need to uncompress it in the plugin directory.) Resart the server: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Be prepared for a slightly longer startup time (closer to the 3-6 minutes and much longer than the 30 seconds you just experienced) as the plugins affect the world map and need a minute to massage everything. After the spawn process finishes, type the following at the server console: plugins This lists all the plugins currently active on the server. You should see something like this: If the plugins aren’t loaded, you may need to stop and restart the server. After confirming your plugins are loaded, go ahead and join the game. You should notice significantly snappier play. In addition, you’ll get occasional messages from the plugins indicating they are active, as seen below: At this point Java is installed, the server is installed, and we’ve tweaked our settings for for the Pi.  It’s time to start building with friends!     

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• Pain Comes Instantly

  - by user701213

  When I look back at recent blog entries – many of which are not all that current (more on where my available writing time is going later) – I am struck by how many of them focus on public policy or legislative issues instead of, say, the latest nefarious cyberattack or exploit (or everyone’s favorite new pastime: coining terms for the Coming Cyberpocalypse: “digital Pearl Harbor” is so 1941). Speaking of which, I personally hope evil hackers from Malefactoria will someday hack into my bathroom scale – which in a future time will be connected to the Internet because, gosh, wouldn’t it be great to have absolutely everything in your life Internet-enabled? – and recalibrate it so I’m 10 pounds thinner. The horror. In part, my focus on public policy is due to an admitted limitation of my skill set. I enjoy reading technical articles about exploits and cybersecurity trends, but writing a blog entry on those topics would take more research than I have time for and, quite honestly, doesn’t play to my strengths. The first rule of writing is “write what you know.” The bigger contributing factor to my recent paucity of blog entries is that more and more of my waking hours are spent engaging in “thrust and parry” activity involving emerging regulations of some sort or other. I’ve opined in earlier blogs about what constitutes good and reasonable public policy so nobody can accuse me of being reflexively anti-regulation. That said, you have so many cycles in the day, and most of us would rather spend it slaying actual dragons than participating in focus groups on whether dragons are really a problem, whether lassoing them (with organic, sustainable and recyclable lassos) is preferable to slaying them – after all, dragons are people, too - and whether we need lasso compliance auditors to make sure lassos are being used correctly and humanely. (A point that seems to evade many rule makers: slaying dragons actually accomplishes something, whereas talking about “approved dragon slaying procedures and requirements” wastes the time of those who are competent to dispatch actual dragons and who were doing so very well without the input of “dragon-slaying theorists.”) Unfortunately for so many of us who would just get on with doing our day jobs, cybersecurity is rapidly devolving into the “focus groups on dragon dispatching” realm, which actual dragons slayers have little choice but to participate in. The general trend in cybersecurity is that powers-that-be – which encompasses groups other than just legislators – are often increasingly concerned and therefore feel they need to Do Something About Cybersecurity. Many seem to believe that if only we had the right amount of regulation and oversight, there would be no data breaches: a breach simply must mean Someone Is At Fault and Needs Supervision. (Leaving aside the fact that we have lots of home invasions despite a) guard dogs b) liberal carry permits c) alarm systems d) etc.) Also note that many well-managed and security-aware organizations, like the US Department of Defense, still get hacked. More specifically, many powers-that-be feel they must direct industry in a multiplicity of ways, up to and including how we actually build and deploy information technology systems. The more prescriptive the requirement, the more regulators or overseers a) can be seen to be doing something b) feel as if they are doing something regardless of whether they are actually doing something useful or cost effective. Note: an unfortunate concomitant of Doing Something is that often the cure is worse than the ailment. That is, doing what overseers want creates unfortunate byproducts that they either didn’t foresee or worse, don’t care about. After all, the logic goes, we Did Something. Prescriptive practice in the IT industry is problematic for a number of reasons. For a start, prescriptive guidance is really only appropriate if: • It is cost effective• It is “current” (meaning, the guidance doesn’t require the use of the technical equivalent of buggy whips long after horse-drawn transportation has become passé)*• It is practical (that is, pragmatic, proven and effective in the real world, not theoretical and unproven)• It solves the right problem With the above in mind, heading up the list of “you must be joking” regulations are recent disturbing developments in the Payment Card Industry (PCI) world. I’d like to give PCI kahunas the benefit of the doubt about their intentions, except that efforts by Oracle among others to make them aware of “unfortunate side effects of your requirements” – which is as tactful I can be for reasons that I believe will become obvious below - have gone, to-date, unanswered and more importantly, unchanged. A little background on PCI before I get too wound up. In 2008, the Payment Card Industry (PCI) Security Standards Council (SSC) introduced the Payment Application Data Security Standard (PA-DSS). That standard requires vendors of payment applications to ensure that their products implement specific requirements and undergo security assessment procedures. In order to have an application listed as a Validated Payment Application (VPA) and available for use by merchants, software vendors are required to execute the PCI Payment Application Vendor Release Agreement (VRA). (Are you still with me through all the acronyms?) Beginning in August 2010, the VRA imposed new obligations on vendors that are extraordinary and extraordinarily bad, short-sighted and unworkable. Specifically, PCI requires vendors to disclose (dare we say “tell all?”) to PCI any known security vulnerabilities and associated security breaches involving VPAs. ASAP. Think about the impact of that. PCI is asking a vendor to disclose to them: • Specific details of security vulnerabilities • Including exploit information or technical details of the vulnerability • Whether or not there is any mitigation available (as in a patch) PCI, in turn, has the right to blab about any and all of the above – specifically, to distribute all the gory details of what is disclosed - to the PCI SSC, qualified security assessors (QSAs), and any affiliate or agent or adviser of those entities, who are in turn permitted to share it with their respective affiliates, agents, employees, contractors, merchants, processors, service providers and other business partners. This assorted crew can’t be more than, oh, hundreds of thousands of entities. Does anybody believe that several hundred thousand people can keep a secret? Or that several hundred thousand people are all equally trustworthy? Or that not one of the people getting all that information would blab vulnerability details to a bad guy, even by accident? Or be a bad guy who uses the information to break into systems? (Wait, was that the Easter Bunny that just hopped by? Bringing world peace, no doubt.) Sarcasm aside, common sense tells us that telling lots of people a secret is guaranteed to “unsecret” the secret. Notably, being provided details of a vulnerability (without a patch) is of little or no use to companies running the affected application. Few users have the technological sophistication to create a workaround, and even if they do, most workarounds break some other functionality in the application or surrounding environment. Also, given the differences among corporate implementations of any application, it is highly unlikely that a single workaround is going to work for all corporate users. So until a patch is developed by the vendor, users remain at risk of exploit: even more so if the details of vulnerability have been widely shared. Sharing that information widely before a patch is available therefore does not help users, and instead helps only those wanting to exploit known security bugs. There’s a shocker for you. Furthermore, we already know that insider information about security vulnerabilities inevitably leaks, which is why most vendors closely hold such information and limit dissemination until a patch is available (and frequently limit dissemination of technical details even with the release of a patch). That’s the industry norm, not that PCI seems to realize or acknowledge that. Why would anybody release a bunch of highly technical exploit information to a cast of thousands, whose only “vetting” is that they are members of a PCI consortium? Oracle has had personal experience with this problem, which is one reason why information on security vulnerabilities at Oracle is “need to know” (we use our own row level access control to limit access to security bugs in our bug database, and thus less than 1% of development has access to this information), and we don’t provide some customers with more information than others or with vulnerability information and/or patches earlier than others. Failure to remember “insider information always leaks” creates problems in the general case, and has created problems for us specifically. A number of years ago, one of the UK intelligence agencies had information about a non-public security vulnerability in an Oracle product that they circulated among other UK and Commonwealth defense and intelligence entities. Nobody, it should be pointed out, bothered to report the problem to Oracle, even though only Oracle could produce a patch. The vulnerability was finally reported to Oracle by (drum roll) a US-based commercial company, to whom the information had leaked. (Note: every time I tell this story, the MI-whatever agency that created the problem gets a bit shirty with us. I know they meant well and have improved their vulnerability handling/sharing processes but, dudes, next time you find an Oracle vulnerability, try reporting it to us first before blabbing to lots of people who can’t actually fix the problem. Thank you!) Getting back to PCI: clearly, these new disclosure obligations increase the risk of exploitation of a vulnerability in a VPA and thus, of misappropriation of payment card data and customer information that a VPA processes, stores or transmits. It stands to reason that VRA’s current requirement for the widespread distribution of security vulnerability exploit details -- at any time, but particularly before a vendor can issue a patch or a workaround -- is very poor public policy. It effectively publicizes information of great value to potential attackers while not providing compensating benefits - actually, any benefits - to payment card merchants or consumers. In fact, it magnifies the risk to payment card merchants and consumers. The risk is most prominent in the time before a patch has been released, since customers often have little option but to continue using an application or system despite the risks. However, the risk is not limited to the time before a patch is issued: customers often need days, or weeks, to apply patches to systems, based upon the complexity of the issue and dependence on surrounding programs. Rather than decreasing the available window of exploit, this requirement increases the available window of exploit, both as to time available to exploit a vulnerability and the ease with which it can be exploited. Also, why would hackers focus on finding new vulnerabilities to exploit if they can get “EZHack” handed to them in such a manner: a) a vulnerability b) in a payment application c) with exploit code: the “Hacking Trifecta!“ It’s fair to say that this is probably the exact opposite of what PCI – or any of us – would want. Established industry practice concerning vulnerability handling avoids the risks created by the VRA’s vulnerability disclosure requirements. Specifically, the norm is not to release information about a security bug until the associated patch (or a pretty darn good workaround) has been issued. Once a patch is available, the notice to the user community is a high-level communication discussing the product at issue, the level of risk associated with the vulnerability, and how to apply the patch. The notices do not include either the specific customers affected by the vulnerability or forensic reports with maps of the exploit (both of which are required by the current VRA). In this way, customers have the tools they need to prioritize patching and to help prevent an attack, and the information released does not increase the risk of exploit. Furthermore, many vendors already use industry standards for vulnerability description: Common Vulnerability Enumeration (CVE) and Common Vulnerability Scoring System (CVSS). CVE helps ensure that customers know which particular issues a patch addresses and CVSS helps customers determine how severe a vulnerability is on a relative scale. Industry already provides the tools customers need to know what the patch contains and how bad the problem is that the patch remediates. So, what’s a poor vendor to do? Oracle is reaching out to other vendors subject to PCI and attempting to enlist then in a broad effort to engage PCI in rethinking (that is, eradicating) these requirements. I would therefore urge all who care about this issue, but especially those in the vendor community whose applications are subject to PCI and who may not have know they were being asked to tell-all to PCI and put their customers at risk, to do one of the following: • Contact PCI with your concerns• Contact Oracle (we are looking for vendors to sign our statement of concern)• And make sure you tell your customers that you have to rat them out to PCI if there is a breach involving the payment application I like to be charitable and say “PCI meant well” but in as important a public policy issue as what you disclose about vulnerabilities, to whom and when, meaning well isn’t enough. We need to do well. PCI, as regards this particular issue, has not done well, and has compounded the error by thus far being nonresponsive to those of us who have labored mightily to try to explain why they might want to rethink telling the entire planet about security problems with no solutions. By Way of Explanation… Non-related to PCI whatsoever, and the explanation for why I have not been blogging a lot recently, I have been working on Other Writing Venues with my sister Diane (who has also worked in the tech sector, inflicting upgrades on unsuspecting and largely ungrateful end users). I am pleased to note that we have recently (self-)published the first in the Miss Information Technology Murder Mystery series, Outsourcing Murder. The genre might best be described as “chick lit meets geek scene.” Our sisterly nom de plume is Maddi Davidson and (shameless plug follows): you can order the paper version of the book on Amazon, or the Kindle or Nook versions on www.amazon.com or www.bn.com, respectively. From our book jacket: Emma Jones, a 20-something IT consultant, is working on an outsourcing project at Tahiti Tacos, a restaurant chain offering Polynexican cuisine: refried poi, anyone? Emma despises her boss Padmanabh, a brilliant but arrogant partner in GD Consulting. When Emma discovers His-Royal-Padness’s body (verdict: death by cricket bat), she becomes a suspect.With her overprotective family and her best friend Stacey providing endless support and advice, Emma stumbles her way through an investigation of Padmanabh’s murder, bolstered by fusion food feeding frenzies, endless cups of frou-frou coffee and serious surfing sessions. While Stacey knows a PI who owes her a favor, landlady Magda urges Emma to tart up her underwear drawer before the next cute cop with a search warrant arrives. Emma’s mother offers to fix her up with a PhD student at Berkeley and showers her with self-defense gizmos while her old lover Keoni beckons from Hawai’i. And everyone, even Shaun the barista, knows a good lawyer. Book 2, Denial of Service, is coming out this summer. * Given the rate of change in technology, today’s “thou shalts” are easily next year’s “buggy whip guidance.”

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• AIX Checklist for stable obiee deployment

  - by user554629

  Common AIX configuration issues     ( last updated 27 Aug 2012 ) OBIEE is a complicated system with many moving parts and connection points.The purpose of this article is to provide a checklist to discuss OBIEE deployment with your systems administrators. The information in this article is time sensitive, and updated as I discover new  issues or details. What makes OBIEE different? When Tech Support suggests AIX component upgrades to a stable, locked-down production AIX environment, it is common to get "push back".  "Why is this necessary?  We aren't we seeing issues with other software?"It's a fair question that I have often struggled to answer; here are the talking points: OBIEE is memory intensive.  It is the entire purpose of the software to trade memory for repetitive, more expensive database requests across a network. OBIEE is implemented in C++ and is very dependent on the C++ runtime to behave correctly. OBIEE is aggressively thread efficient;  if atomic operations on a particular architecture do not work correctly, the software crashes. OBIEE dynamically loads third-party database client libraries directly into the nqsserver process.  If the library is not thread-safe, or corrupts process memory the OBIEE crash happens in an unrelated part of the code.  These are extremely difficult bugs to find. OBIEE software uses 99% common source across multiple platforms:  Windows, Linux, AIX, Solaris and HPUX.  If a crash happens on only one platform, we begin to suspect other factors.  load intensity, system differences, configuration choices, hardware failures.  It is rare to have a single product require so many diverse technical skills.   My role in support is to understand system configurations, performance issues, and crashes.   An analyst trained in Business Analytics can't be expected to know AIX internals in the depth required to make configuration choices.  Here are some guidelines. AIX C++ Runtime must be at  version 11.1.0.4$ lslpp -L | grep xlC.aixobiee software will crash if xlC.aix.rte is downlevel;  this is not a "try it" suggestion.Nov 2011 11.1.0.4 version  is appropriate for all AIX versions ( 5, 6, 7 )Download from here:https://www-304.ibm.com/support/docview.wss?uid=swg24031426 No reboot is necessary to install, it can even be installed while applications are using the current version.Restart the apps, and they will pick up the latest version. AIX 5.3 Technology Level 12 is required when running on Power5,6,7 processorsAIX 6.1 was introduced with the newer Power chips, and we have seen no issues with 6.1 or 7.1 versions.Customers with an unstable deployment, dozens of unexplained crashes, became stable after the upgrade.If your AIX system is 5.3, the minimum TL level should be at or higher than this:$ oslevel -s  5300-12-03-1107IBM typically supports only the two latest versions of AIX ( 6.1 and 7.1, for example).  AIX 5.3 is still supported and popular running in an LPAR. obiee userid limits$ ulimit -Ha  ( hard limits )$ ulimit -a   ( default limits )core file size (blocks)     unlimiteddata seg size (kbytes)      unlimitedfile size (blocks)          unlimitedmax memory size (kbytes)    unlimitedopen files                  10240 cpu time (seconds)          unlimitedvirtual memory (kbytes)     unlimitedIt is best to establish the values in /etc/security/limitsroot user is needed to observe and modify this file.If you modify a limit, you will need to relog in to change it again.  For example,$ ulimit -c 0$ ulimit -c 2097151cannot modify limit: Operation not permitted$ ulimit -c unlimited$ ulimit -c0There are only two meaningful values for ulimit -c ; zero or unlimited.Anything else is likely to produce a truncated core file that cannot be analyzed. Deploy 32-bit or 64-bit ?Early versions of OBIEE offered 32-bit or 64-bit choice to AIX customers.The 32-bit choice was needed if a database vendor did not supply a 64-bit client library.That's no longer an issue and beginning with OBIEE 11, 32-bit code is no longer shipped.A common error that leads to "out of memory" conditions to to accept the 32-bit memory configuration choices on 64-bit deployments.  The significant configuration choices are: Maximum process data (heap) size is in an AIX environment variableLDR_CNTRL=IGNOREUNLOAD@LOADPUBLIC@PREREAD_SHLIB@MAXDATA=0x... Two thread stack sizes are made in obiee NQSConfig.INI[ SERVER ]SERVER_THREAD_STACK_SIZE = 0;DB_GATEWAY_THREAD_STACK_SIZE = 0; Sort memory in NQSConfig.INI[ GENERAL ]SORT_MEMORY_SIZE = 4 MB ;SORT_BUFFER_INCREMENT_SIZE = 256 KB ; Choosing a value for MAXDATA:0x080000000  2GB Default maximum 32-bit heap size ( 8 with 7 zeros )0x100000000  4GB 64-bit breaking even with 32-bit ( 1 with 8 zeros )0x200000000  8GB 64-bit double 32-bit max0x400000000 16GB 64-bit safetyUsing 2GB heap size for a 64-bit process will almost certainly lead to an out-of-memory situation.Registers are twice as big ... consume twice as much memory in the heap.Upgrading to a 4GB heap for a 64-bit process is just "breaking even" with 32-bit.A 32-bit process is constrained by the 32-bit virtual addressing limits.  Heap memory is used for dynamic requirements of obiee software, thread stacks for each of the configured threads, and sometimes for shared libraries. 64-bit processes are not constrained in this way;  extra heap space can be configured for safety against a query that might create a sudden requirement for excessive storage.  If the storage is not available, this query might crash the whole server and disrupt existing users.There is no performance penalty on AIX for configuring more memory than required;  extra memory can be configured for safety.  If there are no other considerations, start with 8GB.Choosing a value for Thread Stack size:zero is the value documented to select an appropriate default for thread stack size.  My preference is to change this to an absolute value, even if you intend to use the documented default;  it provides better documentation and removes the "surprise" factor.There are two thread types that can be configured. GATEWAY is used by a thread pool to call a database client library to establish a DB connection.The default size is 256KB;  many customers raise this to 512KB ( no performance penalty for over-configuring ). This value must be set to 1 MB if Teradata connections are used. SERVER threads are used to run queries.  OBIEE uses recursive algorithms during the analysis of query structures which can consume significant thread stack storage.  It's difficult to provide guidance on a value that depends on data and complexity.  The general notion is to provide more space than you think you need,  "double down" and increase the value if you run out, otherwise inspect the query to understand why it is too complex for the thread stack.  There are protections built into the software to abort a single user query that is too complex, but the algorithms don't cover all situations.256 KB  The default 32-bit stack size.  Many customers increased this to 512KB on 32-bit.  A 64-bit server is very likely to crash with this value;  the stack contains mostly register values, which are twice as big.512 KB  The documented 64-bit default.  Some early releases of obiee didn't set this correctly, resulting in 256KB stacks.1 MB  The recommended 64-bit setting.  If your system only ever uses 512KB of stack space, there is no performance penalty for using 1MB stack size.2 MB  Many large customers use this value for safety.  No performance penalty.nqscheduler does not use the NQSConfig.INI file to set thread stack size.If this process crashes because the thread stack is too small, use this to set 2MB:export OBI_BACKGROUND_STACK_SIZE=2048 Shared libraries are not (shared) When application libraries are loaded at run-time, AIX makes a decision on whether to load the libraries in a "public" memory segment.  If the filesystem library permissions do not have the "Read-Other" permission bit, AIX loads the library into private process memory with two significant side-effects:* The libraries reduce the heap storage available.      Might be significant in 32-bit processes;  irrelevant in 64-bit processes.* Library code is loaded into multiple real pages for execution;  one copy for each process.Multiple execution images is a significant issue for both 32- and 64-bit processes.The "real memory pages" saved by using public memory segments is a minor concern.  Today's machines typically have plenty of real memory.The real problem with private copies of libraries is that they consume processor cache blocks, which are limited.   The same library instructions executing in different real pages will cause memory delays as the i-cache ( instruction cache 128KB blocks) are refreshed from real memory.   Performance loss because instructions are delayed is something that is difficult to measure without access to low-level cache fault data.   The machine just appears to be running slowly for no observable reason.This is an easy problem to detect, and an easy problem to correct.Detection:  "genld -l" AIX command produces a list of the libraries used by each process and the AIX memory address where they are loaded.32-bit public segment is 13 ( "dxxxxxxx" ).   private segments are 2-a.64-bit public segment is 9 ( "9xxxxxxxxxxxxxxx") ; private segment is 8.genld -l | grep -v ' d| 9' | sort +2provides a list of privately loaded libraries. Repair: chmod o+r <libname>AIX shared libraries will have a suffix of ".so" or ".a".Another technique is to change all libraries in a selected directory to repair those that might not be currently loaded.   The usual directories that need repair are obiee code, httpd code and plugins, database client libraries and java.chmod o+r /shr/dir/*.a /shr/dir/*.so Configure your system for diagnosticsProduction systems shouldn't crash, and yet bad things happen to good software.If obiee software crashes and produces a core, you should configure your system for reliable transfer of the failing conditions to Oracle Tech Support.  Here's what we need to be able to diagnose a core file from your system.* fullcore enabled. chdev -lsys0 -a fullcore=true* core naming enabled. chcore -n on -d* ulimit must not truncate core. see item 3.* pstack.sh is used to capture core documentation.* obidoc is used to capture current AIX configuration.* snapcore  AIX utility captures core and libraries. Use the proper syntax. $ snapcore -r corename executable-fullpath   /tmp/snapcore will contain the .pax.Z output file.  It is compressed.* If cores are directed to a common directory, ensure obiee userid can write to the directory.  ( chcore -p /cores -d ; chmod 777 /cores )The filesystem must have sufficient space to hold a crashing obiee application.Use:  df -k  Check the "Free" column ( not "% Used" )  8388608 is 8GB. Disable Oracle Client Library signal handlingThe Oracle DB Client Library is frequently distributed with the sqlplus development kit.By default, the library enables a signal handler, which will document a call stack if the application crashes.   The signal handler is not needed, and definitely disruptive to obiee diagnostics.   It needs to be disabled.   sqlnet.ora is typically located at:   $ORACLE_HOME/network/admin/sqlnet.oraAdd this line at the top of the file:   DIAG_SIGHANDLER_ENABLED=FALSE Disable async query in the RPD connection pool.This might be an obiee 10.1.3.4 issue only ( still checking  )."async query" must be disabled in the connection pools.It was designed to enable query cancellation to a database, and turned out to have too many edge conditions in normal communication that produced random corruption of data and crashes.  Please ensure it is turned off in the RPD. Check AIX error report (errpt).Errors external to obiee applications can trigger crashes.  $ /bin/errpt -aHardware errors ( firmware, adapters, disks ) should be reported to IBM support.All application core files are recorded by AIX;  the most recent ones are listed first. Reserved for something important to say.

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• CodePlex Daily Summary for Tuesday, May 13, 2014

  CodePlex Daily Summary for Tuesday, May 13, 2014Popular ReleasesWinAudit: WinAudit Freeware v3.0: WinAudit.exe v3.0 MD5: 88750CCF49FF7418199B2645755830FA Known Issues: 1. Report creation can be very slow when right-to-left (Hebrew) characters are present. 2. Emsisoft Anti-Malware may stop and/or quarantine WinAudit. This happens when WinAudit attempts to obtain a list if running programmes. You will need to set an exception rule in Emsisoft to allow WinAudit to run.MVCwCMS - ASP.NET MVC CMS: MVCwCMS 2.2.2: Updated CKFinder config. For the installation instructions visit the documentation page: https://mvcwcms.codeplex.com/documentationTerraMap (Terraria World Map Viewer): TerraMap 1.0.4: Added support for the new Terraria v1.2.4 update. New items, walls, and tiles Fixed Issue 35206: Hightlight/Find doesn't work for Demon Altars Fixed finding Demon Hearts/Shadow Orbs Added ability to find Enchanted Swords (in the stone) and Water Bolt books Fixed installer not uninstalling older versions The setup file will make sure .NET 4 is installed, install TerraMap, create desktop and start menu shortcuts, add a .wld file association, and launch TerraMap. If you prefer the zip ...WPF Localization Extension: v2.2.1: Issue #9277 Issue #9292 Issue #9311 Issue #9312 Issue #9313 Issue #9314CtrlAltStudio Viewer: CtrlAltStudio Viewer 1.2.1.41167 Release: This release of the CtrlAltStudio Viewer includes the following significant features: Oculus Rift support. Stereoscopic 3D display support. Variable walking / flying speed. Xbox 360 Controller support. Kinect for Windows support. Based on Firestorm viewer 4.6.5 codebase. For more details, see the release notes linked to below. Release notes: http://ctrlaltstudio.com/viewer/release-notes/1-2-1-41167-release Support info: http://ctrlaltstudio.com/viewer/support Privacy policy: http:/...ExtJS based ASP.NET Controls: FineUI v4.0.6: FineUI（???） ?? ExtJS ??? ASP.NET ??? FineUI??? ?? No JavaScript，No CSS，No UpdatePanel，No ViewState，No WebServices ??????? ?????? IE 8.0+、Chrome、Firefox、Opera、Safari ???? Apache License v2.0 ?：ExtJS ?? GPL v3 ?????(http://www.sencha.com/license) ???? ??：http://fineui.com/ ??：http://fineui.com/bbs/ ??：http://fineui.com/demo/ ??：http://fineui.com/doc/ ??：http://fineui.codeplex.com/ FineUI ???? ExtJS ????????，???? ExtJS ?，?????： 1. ????? FineUI ? ExtJS ? http://fineui.com/bbs/forum.ph...Office App Model Samples: Office App Model Samples v2.0: Office App Model Samples v2.0GMare: GMare Beta 1.1: Features Added: Overhauled interface Re-wrote most controls and forms Automatic room creation on application open Room properties bar to change various room properties Now able to use a background from a supported Game Maker project file Block instances implemented More instance editing features like multi-Select, cherry pick select, replace, and set position More instance options on the instance list Flexible XML based .gmpx human readable project file format Game...Readable Passphrase Generator: KeePass Plugin 0.13.0: Version 0.13.0 Added "mutators" which add uppercase and numbers to passphrases (to help complying with upper, lower, number complexity rules). Additional API methods which help consuming the generator from 3rd party c# projects. 13,160 words in the default dictionary (~600 more than previous release).CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.25.0: Release v1.0.25.0 MemberInfo/MethodInfo popup is now positioned properly to fit the screen In MethodInfo popup method signatures are word-wrapped Implemented Debug text value visualizer Pining sub-values from Watch PanelxFunc: xFunc 2.15.3: Added #53R.NET: R.NET 1.5.12: R.NET 1.5.12 is a beta release towards R.NET 1.6. You are encouraged to use 1.5.12 now and give feedback. See the documentation for setup and usage instructions. Main changes for R.NET 1.5.12: The C stack limit was not disabled on Windows. For reasons possibly peculiar to R, this means that non-concurrent access to R from multiple threads was not stable. This is now fixed, with the fix validated with a unit test. Thanks to Odugen, skyguy94, and previously others (evolvedmicrobe, tomasp) fo...CTI Text Encryption: CTI Text Encryption 5.2: Change log: 5.2 - Remove Cut button. - Fixed Reset All button does not reset encrypted text column. - Switch button location between Copy and Paste. - Enable users to use local fonts to display characters of their language correctly. (A font settings file will be saved at the same folder of this program.) 5.1 - Improve encryption process. - Minor UI update. - Version 5.1 is not compatible with older version. 5.0 - Improve encryption algorithm. - Simply inner non-encryption related mec...SEToolbox: SEToolbox 01.029.006 Release 1: Fix to allow keyboard search on load dialog. (type the first few letters of your save) Fixed check for new release. Changed the way ship details are loaded to alleviate load time for worlds with very large ships (100,000+ blocks). Fixed Image importer, was incorrectly listing 'Asteroid' as import option. Minor changes to menus (text and appearance) for clarity and OS consistency. Added in reading of world palette for color dialog editor. WIP on subsystem editor. Can now multiselec...Media Companion: Media Companion MC3.597b: Thank you for being patient, againThere are a number of fixes in place with this release. and some new features added. Most are self explanatory, so check out the options in Preferences. Couple of new Features:* Movie - Allow save Title and Sort Title in Title Case format. * Movie - Allow save fanart.jpg if movie in folder. * TV - display episode source. Get episode source from episode filename. Fixed:* Movie - Added Fill Tags from plot keywords to Batch Rescraper. * Movie - Fixed TMDB s...SimCityPak: SimCityPak 0.3.0.0: Contains several bugfixes, newly identified properties and some UI improvements. Main new features UI overhaul for the main index list: Icons for each different index, including icons for different property files Tooltips for all relevant fields Removed clutter Identified hundreds of additional properties (thanks to MaxisGuillaume) - this should make modding gameplay easierMagick.NET: Magick.NET 6.8.9.002: Magick.NET linked with ImageMagick 6.8.9.0.VidCoder: 1.5.22 Beta: Added ability to burn SRT subtitles. Updated to HandBrake SVN 6169. Added checks to prevent VidCoder from running with a database version newer than it expects. Tooltips in the Advanced Video panel now trigger on the field labels as well as the fields themselves. Fixed updating preset/profile/tune/level settings on changing video encoder. This should resolve some problems with QSV encoding. Fixed tunes and profiles getting set to blank when switching between x264 and x265. Fixed co...Tiny Deduplicator: Tiny Deduplicator 1.0.0.1: Project Description Tiny Deduplicator is a file deduplicator which can scan for duplicate files, and allows the user to control which duplicates they are going to keep, and which are going to be recycled. Tiny Deduplicator will never delete files directly-- rather, it sends them to the recycle bin for you to confirm the deletion of. In its current form, Tiny Deduplicator is a mere 23KB (including the GUI); however, it has the following features: Easily browse and select which directory to ...NuGet: NuGet 2.8.2: We will be releasing a 2.8.2 version of our own NuGet packages and the NuGet.exe command-line tool. The 2.8.2 release will not include updated VS or WebMatrix extensions. NuGet.Server.Extensions.dll needs to be used alongside NuGet-Signed.exe to provide the NuGet.exe mirror functionality.New Projects2112110004: bùi th? bé di?m2112110007: l?p trình hu?ng d?i tu?ng (OOP) Ph?m H?u Dung2112110019: Nguy?n Duy Hòa_2112110019 CCQ1211A2112110032: Truong Ha Mi2112110041: nguyen manh thuong quan2112110079: VU TH? MAI ANH - L?P TRÌNH HU?NG Ð?I TU?NG(OOP) - L?P CCQ1211B - MSSV 2112110079Adapter Pattern: Super duper simple project that explains how the Adapter Design Pattern works.Aspose for Sitefinity: Aspose Sitefinity Content Export Add-on allow users to export online content into Microsoft Word or Adobe Acrobat PDF document using Aspose.Words.baitapHDT: le ba thuan thanhCaltech Software: Caltech SoftwareDCM Ventas: DCMEntityBinder: Entity Binder is a C# library to help you to read data from xml or json file and bind them directly to data object.FATCAClient: A simple application for populating and viewing XML files which comply with the published FATCA schema.Grade Calculator For BTEC First Diploma in IT level 2: Grade Calculator For BTEC First Diploma in IT level 2HMS_TEST: ????? ???? ??????.lock Keywords Demo: ?? lock ????????，????? this、string、typeof(MyType) ?????mbtPdfAsm: command line pdf file assembler/merger.Orchard CMS Syndication: Implementation of a module that provides OData protocol and then enables third parties to query (custom) creatable content types embedded in an Orchard CMS SitePerfAnalyzer: TemporaryPluralSight Downloader: This project allow to Download PluralSight (PluralSight downloader) video tutorials even with free account and many more features. Use at your own risk.ProView: Image viewer and data entry application for renaming image files.Real Estate website Clark: Real Estate website ClarkSE Community Modding API: This project aims to simplify the modding process of Space Engineers® game from Keen Software HouseSirGorn robi PeHaPa: Projekt na prace zespolowa.TPC1 Grupo14: TPC1Grupo14TypeScriptSheet (Spreadsheet webapp create using TypeScript): TypeScriptSheet. This project is Spread sheet Web Application. It is medium featured spread sheet built using TypeScript and JQuery.VB Converter: Convert your VB6 code to .NET (C# and VB .NET) with this tool.Web Site For Instagram: This is a web app for Instagram using asp.net MVC.WorkProject: This is WorkProject.Z Entity Framework Extensions: ab??????-??????【??】??????????: ??????,?????????,?????????????。?????????????,?????????,???????。 ??????-??????【??】??????????: ??????????????????????????,???????????????,????????????????！ ??????-??????【??】??????????: ??????????????????,???????、????、????、??????、???????,??????,???????????。 ????-????【??】????????: ??????????????,???????、???????????,????????,????,?????????,??????,??????! ????-????【??】????????: ???????????????"????,????"???,????????????????????????,??????????????。 ??????-??????【??】??????????: ????????????,????,??????????? ???? ???? ?????????,???,??,?????! ??????-??????【??】??????????: ???????????? ???? ???? ???? ???? ???? ??????? ?????，????????????????. ????-????【??】????????: ??????????????、????、????、??????、????、????????,????????、?????????,?????。 ?????-?????【??】?????????: ??????????????????????????,???????????????????????,???????。 ?????-?????【??】?????????: ??????????????:?????? ???? ??????,???????,??????,???????。 ??????-??????【??】??????????: ?????????????????,???????????????。?????????????,???????,?????????。 ??????-??????【??】??????????: ????????????????????,?????????????,???????????.????????????,????????????! ????-????【??】????????: ????????????:????,????,????,???????,????????,??????:????????,?????! ?????-?????【??】?????????: ?????????????????,??:??????,????,????,????,?????,??????????????. ?????-?????【??】?????????: ??????,??,????????。 ... ??????????????????、??????????????????... ??????-??????【??】??????????: ?????????????????,??????????????、???????、???????、???????、?????！ ??????-??????【??】??????????: ?????????????????,?????????????。????????????,???????,???????,?????,?????。 ??????-??????【??】??????????: ??????????????????????????,???????????,????????,?????????????????????。 ????-????【??】????????: ??????????????????????,????,????,??????????。???????????????,??,??,??????????,??????... ??????-??????【??】??????????: ??????????????、?????????,?????????,????,????????,????????????????! ????-????【??】????????: ??????????????????????,?????????,??????????,????????,?????! ??????-??????【??】??????????: ???????????????、????、????、??????、????、???????,?????,?????????! ??????-??????【??】??????????: ????????????????????????、??????,????、?????、????， ?????????，?????????????！ ????-????【??】????????: ????????????????、????、??????、????????,????????????,???????????！ ?????-?????【??】?????????: ????????????????????、????、????、??????、???????,??????、??????。 ?????-?????【??】?????????: ???????,??????,?????????????????????,???????????????????????。 ??????-??????【??】??????????: ????????????????????,?????????????????????,?????,????,???????. ??????-??????【??】??????????: ??????????????、??????、????、?????、?????!????,????????????????!????。 ????-????【??】????????: ??????????????????,?????,???????,???????????,??????! ?????-?????【??】?????????: ???????????、??、???????????,??????,????????,??????????????????...????。 ?????-?????【??】?????????: ??????????????、???????,?????????,???????????????,?????????????。

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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• 12c - flashforward, flashback or see it as of now...

  - by noreply(at)blogger.com (Thomas Kyte)

  Oracle 9i exposed flashback query to developers for the first time.  The ability to flashback query dates back to version 4 however (it just wasn't exposed).  Every time you run a query in Oracle it is in fact a flashback query - it is what multi-versioning is all about.However, there was never a flashforward query (well, ok, the workspace manager has this capability - but with lots of extra baggage).  We've never been able to ask a table "what will you look like tomorrow" - but now we do.The capability is called Temporal Validity.  If you have a table with data that is effective dated - has a "start date" and "end date" column in it - we can now query it using flashback query like syntax.  The twist is - the date we "flashback" to can be in the future.  It works by rewriting the query to transparently the necessary where clause and filter out the right rows for the right period of time - and since you can have records whose start date is in the future - you can query a table and see what it would look like at some future time.Here is a quick example, we'll start with a table:ops$tkyte%ORA12CR1> create table addresses  2  ( empno       number,  3    addr_data   varchar2(30),  4    start_date  date,  5    end_date    date,  6    period for valid(start_date,end_date)  7  )  8  /Table created.the new bit is on line 6 (it can be altered into an existing table - so any table  you have with a start/end date column will be a candidate).  The keyword is PERIOD, valid is an identifier I chose - it could have been foobar, valid just sounds nice in the query later.  You identify the columns in your table - or we can create them for you if they don't exist.  Then you just create some data:ops$tkyte%ORA12CR1> insert into addresses (empno, addr_data, start_date, end_date )  2  values ( 1234, '123 Main Street', trunc(sysdate-5), trunc(sysdate-2) );1 row created.ops$tkyte%ORA12CR1>ops$tkyte%ORA12CR1> insert into addresses (empno, addr_data, start_date, end_date )  2  values ( 1234, '456 Fleet Street', trunc(sysdate-1), trunc(sysdate+1) );1 row created.ops$tkyte%ORA12CR1>ops$tkyte%ORA12CR1> insert into addresses (empno, addr_data, start_date, end_date )  2  values ( 1234, '789 1st Ave', trunc(sysdate+2), null );1 row created.and you can either see all of the data:ops$tkyte%ORA12CR1> select * from addresses;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 123 Main Street                27-JUN-13 30-JUN-13      1234 456 Fleet Street               01-JUL-13 03-JUL-13      1234 789 1st Ave                    04-JUL-13or query "as of" some point in time - as  you can see in the predicate section - it is just doing a query rewrite to automate the "where" filters:ops$tkyte%ORA12CR1> select * from addresses as of period for valid sysdate-3;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 123 Main Street                27-JUN-13 30-JUN-13ops$tkyte%ORA12CR1> @planops$tkyte%ORA12CR1> select * from table(dbms_xplan.display_cursor);PLAN_TABLE_OUTPUT-------------------------------------------------------------------------------SQL_ID  cthtvvm0dxvva, child number 0-------------------------------------select * from addresses as of period for valid sysdate-3Plan hash value: 3184888728-------------------------------------------------------------------------------| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |-------------------------------------------------------------------------------|   0 | SELECT STATEMENT  |           |       |       |     3 (100)|          ||*  1 |  TABLE ACCESS FULL| ADDRESSES |     1 |    48 |     3   (0)| 00:00:01 |-------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------   1 - filter((("T"."START_DATE" IS NULL OR              "T"."START_DATE"<=SYSDATE@!-3) AND ("T"."END_DATE" IS NULL OR              "T"."END_DATE">SYSDATE@!-3)))Note-----   - dynamic statistics used: dynamic sampling (level=2)24 rows selected.ops$tkyte%ORA12CR1> select * from addresses as of period for valid sysdate;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 456 Fleet Street               01-JUL-13 03-JUL-13ops$tkyte%ORA12CR1> @planops$tkyte%ORA12CR1> select * from table(dbms_xplan.display_cursor);PLAN_TABLE_OUTPUT-------------------------------------------------------------------------------SQL_ID  26ubyhw9hgk7z, child number 0-------------------------------------select * from addresses as of period for valid sysdatePlan hash value: 3184888728-------------------------------------------------------------------------------| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |-------------------------------------------------------------------------------|   0 | SELECT STATEMENT  |           |       |       |     3 (100)|          ||*  1 |  TABLE ACCESS FULL| ADDRESSES |     1 |    48 |     3   (0)| 00:00:01 |-------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------   1 - filter((("T"."START_DATE" IS NULL OR              "T"."START_DATE"<=SYSDATE@!) AND ("T"."END_DATE" IS NULL OR              "T"."END_DATE">SYSDATE@!)))Note-----   - dynamic statistics used: dynamic sampling (level=2)24 rows selected.ops$tkyte%ORA12CR1> select * from addresses as of period for valid sysdate+3;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 789 1st Ave                    04-JUL-13ops$tkyte%ORA12CR1> @planops$tkyte%ORA12CR1> select * from table(dbms_xplan.display_cursor);PLAN_TABLE_OUTPUT-------------------------------------------------------------------------------SQL_ID  36bq7shnhc888, child number 0-------------------------------------select * from addresses as of period for valid sysdate+3Plan hash value: 3184888728-------------------------------------------------------------------------------| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |-------------------------------------------------------------------------------|   0 | SELECT STATEMENT  |           |       |       |     3 (100)|          ||*  1 |  TABLE ACCESS FULL| ADDRESSES |     1 |    48 |     3   (0)| 00:00:01 |-------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------   1 - filter((("T"."START_DATE" IS NULL OR              "T"."START_DATE"<=SYSDATE@!+3) AND ("T"."END_DATE" IS NULL OR              "T"."END_DATE">SYSDATE@!+3)))Note-----   - dynamic statistics used: dynamic sampling (level=2)24 rows selected.All in all a nice, easy way to query effective dated information as of a point in time without a complex where clause.  You need to maintain the data - it isn't that a delete will turn into an update the end dates a record or anything - but if you have tables with start/end dates, this will make it much easier to query them.

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• Troubleshooting .NET "Fatal Execution Engine Error"

  - by JYelton

  Summary: I periodically get a .NET Fatal Execution Engine Error on an application which I cannot seem to debug. The dialog that comes up only offers to close the program or send information about the error to Microsoft. I've tried looking at the more detailed information but I don't know how to make use of it. Error: The error is visible in Event Viewer under Applications and is as follows: .NET Runtime version 2.0.50727.3607 - Fatal Execution Engine Error (7A09795E) (80131506) The computer running it is Windows XP Professional SP 3. (Intel Core2Quad Q6600 2.4GHz w/ 2.0 GB of RAM) Other .NET-based projects that lack multi-threaded downloading (see below) seem to run just fine. Application: The application is written in C#/.NET 3.5 using VS2008, and installed via a setup project. The app is multi-threaded and downloads data from multiple web servers using System.Net.HttpWebRequest and its methods. I've determined that the .NET error has something to do with either threading or HttpWebRequest but I haven't been able to get any closer as this particular error seems impossible to debug. I've tried handling errors on many levels, including the following in Program.cs: // handle UI thread exceptions Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException); // handle non-UI thread exceptions AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); // force all windows forms errors to go through our handler Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException); More Notes and What I've Tried... Installed Visual Studio 2008 on the target machine and tried running in debug mode, but the error still occurs, with no hint as to where in source code it occurred. When running the program from its installed version (Release) the error occurs more frequently, usually within minutes of launching the application. When running the program in debug mode inside of VS2008, it can run for hours or days before generating the error. Reinstalled .NET 3.5 and made sure all updates are applied. Broke random cubicle objects in frustration. Rewritten parts of code that deal with threading and downloading in attempts to catch and log exceptions, though logging seemed to aggravate the problem (and never provided any data). Question: What steps can I take to troubleshoot or debug this kind of error? Memory dumps and the like seem to be the next step, but I'm not experienced at interpreting them. Perhaps there's something more I can do in the code to try and catch errors... It would be nice if the "Fatal Execution Engine Error" was more informative, but internet searches have only told me that it's a common error for a lot of .NET-related items.

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• Does VBA have an equivalent of "Text To" from Visual FoxPro

  - by David Stein

  Visual FoxPro supports syntax such as the following: Text To VariableName TEXTMERGE noshow select * from..... EndText This assigns the value of all text between "Text To" and "EndText" to the variable. It eliminates the need for multi line statements separateed by "+ ;" Does VBA have something similar?

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• Sharepoint: Convert a SPFieldMultilineText to SPFieldText

  - by driAn

  Hi Is it possible to programmatically change a "multi-line text field" to "single-line text field" ? SPFieldMultiLineText field = list.Fields["sample"] as SPFieldMultiLineText; // how to change the type to 'single line' now ? Or do I need to create an additional field (with a similiar name) and migrate the content? Thanks for any help.

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• Facebook connect displaying invite friends dialog and closing on completion

  - by Dougnukem

  I'm trying to create a Facebook Connect application that displays a friend invite dialog within the page using Facebook's Javascript API (through a FBMLPopupDialog). The trouble is to display a friend invite dialog you use a multi-friend form which requires an action="url" attribute that represents the URL to redirect your page to when the user completes or skips the form. The problem is that I want to just close the FBMLPopupDialog (the same behavior as if the user just hit the 'X' button on the popup dialog). The best I can do is redirect the user back to the page they were on basically a reload but they lose all AJAX/Flash application state. I'm wondering if any Facebook Connect developers have run into this issue and have a good way to simply display a friend invite "lightbox" dialog within their website where they don't want to "refresh" or "redirect" when the user finishes. The facebook connect JS API provides a FB.Connect.inviteConnectUsers, which provides a nice dialog but only connects existing users of your application who also have a Facebook account and haven't connected. http://bugs.developers.facebook.com/show%5Fbug.cgi?id=4916 function fb_inviteFriends() { //Invite users log("Inviting users..."); FB.Connect.requireSession( function() { //Connect succes var uid = FB.Facebook.apiClient.get_session().uid; log('FB CONNECT SUCCESS: ' + uid); //Invite users log("Inviting users..."); //Update server with connected account updateAccountFacebookUID(); var fbml = fb_getInviteFBML() ; var dialog = new FB.UI. FBMLPopupDialog("Weblings Invite", fbml) ; //dialog.setFBMLContent(fbml); dialog.setContentWidth(650); dialog.setContentHeight(450); dialog.show(); }, //Connect cancelled function() { //User cancelled the connect log("FB Connect cancelled:"); } ); } function fb_getInviteFBML() { var uid = FB.Facebook.apiClient.get_session().uid; var fbml = ""; fbml = '<fb:fbml>\n' + '<fb:request-form\n'+ //Redirect back to this page ' action="'+ document.location +'"\n'+ ' method="POST"\n'+ ' invite="true"\n'+ ' type="Weblings Invite"\n' + ' content="I need your help to discover all the Weblings and save the Internet! WebWars: Weblings is a cool new game where we can collect fantastic creatures while surfing our favorite websites. Come find the missing Weblings with me!'+ //Callback the server with the appropriate Webwars Account URL ' <fb:req-choice url=\''+ WebwarsFB.WebwarsAccountServer +'/SplashPage.aspx?action=ref&reftype=Facebook' label=\'Check out WebWars: Weblings\' />"\n'+ '>\n'+ ' <fb:multi-friend-selector\n'+ ' rows="2"\n'+ ' cols="4"\n'+ ' bypass="Cancel"\n'+ ' showborder="false"\n'+ ' actiontext="Use this form to invite your friends to connect with WebWars: Weblings."/>\n'+ ' </fb:request-form>'+ ' </fb:fbml>'; return fbml; }

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• WPF DataGrid multiselect binding

  - by JZ

  I have a datagrid that is multi-select enabled. I need to change the selection in the viewmodel. However, the SelectedItems property is read only and can't be directly bound to a property in the viewmodel. So how do I signal to the view that the selection has changed?

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• Uploading multiple images through Tumblr API

  - by Joseph Carrington

  I have about 300 images I want to upload to my new Tumblr account, becuase my old wordpress site got hacked and I no longer wish to use wordpress. I uploaded one image a day for 300 days, and I'd like to be able to take these images and upload them to my tumblr site using the api. The images are currently local, stored in /images/. They all have the date they were uploaded as the first ten characters of the filename, (01-01-2009-filename.png) and I went to send this date parameter along as well. I want to be able to see the progress of the script by outputting the responses from the API to my error_log. Here is what I have so far, based on the tumblr api page. // Authorization info $tumblr_email = '[email protected]'; $tumblr_password = 'password'; // Tumblr script parameters $source_directory = "images/"; // For each file, assign the file to a pointer here's the first stumbling block. How do I get all of the images in the directory and loop through them? Once I have a for or while loop set up I assume this is the next step $post_data = fopen(dir(__FILE__) . $source_directory . $current_image, 'r'); $post_date = substr($current_image, 0, 10); // Data for new record $post_type = 'photo'; // Prepare POST request $request_data = http_build_query( array( 'email' => $tumblr_email, 'password' => $tumblr_password, 'type' => $post_type, 'data' => $post_data, 'date' => $post_date, 'generator' => 'Multi-file uploader' ) ); // Send the POST request (with cURL) $c = curl_init('http://www.tumblr.com/api/write'); curl_setopt($c, CURLOPT_POST, true); curl_setopt($c, CURLOPT_POSTFIELDS, $request_data); curl_setopt($c, CURLOPT_RETURNTRANSFER, true); $result = curl_exec($c); $status = curl_getinfo($c, CURLINFO_HTTP_CODE); curl_close($c); // Output response to error_log error_log($result); So, I'm stuck on how to use PHP to read a file directory, loop through each of the files, and do things to the name / with the file itself. I also need to know how to set the data parameter, as in choosing multi-part / formdata. I also don't know anything about cURL.

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• PHP - What are the best/popular libraries for developing CLI apps/scripts?

  - by John Himmelman

  Many of the component libraries and toolkits I'm familiar with lack CLI-specific libraries (zend, kohana, etc..). Are there any libraries/tools that are designed specifically for developing CLI application (such as an abstraction of php's multi-threading library, pcntl/posix)?

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• Is WCF netMsmqBinding multithreaded?

  - by Balaji

  We are using .net WCF with netMsmqBinding. Is the netMsmqBinding multi threaded? Is there a way to change the bindings to use single thread?

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• jquery chain search filter in joomla /php

  - by vipinsahu

  hi i want to create a multi-field chain search module in joomla using jquery like in this site left corner. If is there any tutorial please put the link here Thanks

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• Zend Framework Project - Calendar: Need web calendar with events (like google calendar) for every u

  - by Yosef

  Hi, I doing multi users website (it should works for more than 100,000 users) with Zend Framework. I need to create event calendar like google calendar (If it was possible to use google calendar i will do it- please tell me). I have to do that from zero or exist some good Calendar that will work well with Zend? Thanks

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• Custom fonts, ellipsis on MultiLine TextViews, Glyphs and glitches.

  - by Samuh

  I am required to use custom fonts in my application. Problem: For ListViews that contain rows with Multi-Line TextViews having ellipsize property set to true, I can see some illegible characters after the ellipsis. Apparently Android pads the String(in TextView) with some characters unknown to my custom font. Single line TextView seem to work just fine. What is the best way to hide these characters or remove the padding? Thanks.

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• How to synchronize a python dict with multiprocessing

  - by Peter Smit

  I am using Python 2.6 and the multiprocessing module for multi-threading. Now I would like to have a synchronized dict (where the only atomic operation I really need is the += operator on a value). Should I wrap the dict with a multiprocessing.sharedctypes.synchronized() call? Or is another way the way to go?

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• Always use multiple cores (/MP) flag with Visual Studio?

  - by dwj

  I'm using Visual Studio 2008 on my main build system. I've been playing with Visual Studio 2010 on another one. It appears that the tool still only wants to use one core when compiling unless you specify the /MP switch in the compiler switches (see http://stackoverflow.com/questions/1422601/how-do-i-turn-on-multi-cpu-core-c-compiles-in-the-visual-studio-ide-2008). I have to do this for every project. Is there a way to make VS always do this?

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• Parallel programming patterns for C#?

  - by VoidDweller

  With Intel's launch of a Hexa-Core processor for the desktop, it looks like we can no longer wait for Microsoft to make many-core programming "easy". I just order a copy of Joe Duffy's book Concurrent Programming on Windows. This looks like a great place to start, though, I am hoping some of you who have been targeting multi/many core systems would point me to some good resources that have or would have helped on your projects?

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• wordpress mu theme per-user options

  - by pixeline

  Is it possible to add an options screen to a Wordpress MU theme (options being saved for each user, so blogwide, not sitewide) ? I'm used to program wordpress themes, but i'm a bit puzzled as to how make customization happen in a multi-user environment.

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• Windows Phone 7 SDK and Visual Studio 2010 RTM

  - by Alex DeLarge

  Hmmm, wonder if I have the first VS 2010 RTM question? Anyway.. Installing the Windows Phone 7 SDK I get the following error Incompatible Products VC 10.0 Runtime .NET Framework 4 Multi-Targeting Pack Microsoft.NET Framework 4 Client Profile Microsoft .NET Framework 4 Extended This was reported as an issue with Beta 2 and the fix was to install the RC. Anyone know why it's incompatible with the RTM? Will we have to wait for an update to the SDK? Regards, Alex..

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• django: CheckboxMultiSelect problem with db queries

  - by xiackok

  firstly sorry for my bad english there is a simple model Person. That contains just languages: LANGUAGE_LIS = ( (1, 'English'), (2, 'Turkish'), (3, 'Spanish') ) class Person(models.Model): languages = models.CharField(max_length=100, choices=LANGUAGE_LIST) #languages is multi value (CheckBoxSelectMultiple) and here person_save_form: class person_save_form(forms.ModelForm): languages = forms.CharField(widget=forms.CheckBoxSelectMultiple(choices=LANGUAGE_LIST)) class Meta: model = Person it is ok. but how can i search persons for languages like "get persons who knows turkish and english" in the database (MySQL) record "languages" column seen like "[u'1', u'2']". but i want search persons like this: persons = Person.objects.filter(languages__in=request.POST.getlist('languages'))

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• jQuery MultiFile - how to clear / reset ?

  - by eidylon

  Hi all, I'm using the jQuery multi-file upload plugin found here: http://www.fyneworks.com/jquery/multiple-file-upload/ I don't see in any of the examples though a way to "reset" the file-picker, clearing out any currently selected items. Any one know how to do this? Thanks!

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• How to wordWrap the text in a column using ObjectListView

  - by Tiago

  For example I have a big sentence: "I like to eat pie and have fun around the house all day long!" And I want it to appear like this: "I like to eat pie and have fun around the house all day long!" In this post: http://stackoverflow.com/questions/1673963/multi-line-list-items-on-winforms-listview-control Grammarian said that you only need to have WordWrap on but I cannot find that option. Thanks for the help in advanced

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