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  • Best and safest Java Profiler for production use?

    - by Pete
    I'm looking for a Java Profiler for use in a very high demand production environment, either commercial or free, that meets all of the following requirements: Lightweight integration with code (no recompile with special options, no code hooks, etc). Dropping some profiler specific .jars alongside the application code is ok. Should be able to connect/disconnect to the JVM without restarting the application. When profiling is not active, no impact to performance When profiling is active, negligible impact to performance. Very slight degradation is acceptable. Must do all the 'expected' stuff a profiler does - time spent in each method to find hotspots, object allocation/memory profiling, etc. Essentially I need something that can sit dormant in production when everything is fine without anyone knowing or caring that it is there, but then be able to connect to it hassle (and performance degradation) free to pinpoint the hard to find problems like hotspots and synchronization issues.

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  • How to debug solve 500 Internal error aws micro ec2 with suexec, Apache and php CGi

    - by Oudin
    I'm running WordPress multi-site on an amazon micro ec2 with suexec, Apache and php CGi On Ubuntu 12.04 However I've been experiencing a lot of Internal server 500 errors and I'm in the process of debugging it to find a solution. I've posted my error logs below example.com error.log: [Fri Oct 26 10:10:08 2012] [warn] [client 23.23.xxx.xx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server [Fri Oct 26 10:10:08 2012] [error] [client 23.23.xxx.xx] Premature end of script headers: wp-cron.php [Fri Oct 26 10:50:04 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/ [Fri Oct 26 10:50:04 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: admin.php, referer: https://www.example.com/wp-admin/ [Fri Oct 26 10:58:14 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:58:15 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: admin-ajax.php, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:58:56 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:58:57 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: plugins.php, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:59:18 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:59:18 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: admin-ajax.php, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 11:01:49 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/ [Fri Oct 26 11:01:49 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: ap_pass_brigade failed in handle_request_ipc function, referer: https://www.example.com/wp-admin/ Apache Log: php (pre-forking): Cannot allocate memory php (pre-forking): Cannot allocate memory Recipient names must be specified Recipient names must be specified php (pre-forking): Cannot allocate memory php (pre-forking): Cannot allocate memory php (pre-forking): Cannot allocate memory [Fri Oct 26 10:49:33 2012] [warn] mod_fcgid: cleanup zombie process 2852 [Fri Oct 26 10:49:33 2012] [warn] mod_fcgid: cleanup zombie process 2851 [Fri Oct 26 10:49:33 2012] [warn] mod_fcgid: cleanup zombie process 2853 [Fri Oct 26 10:58:22 2012] [warn] mod_fcgid: process 2892 graceful kill fail, sending SIGKILL php (pre-forking): Cannot allocate memory [Fri Oct 26 10:59:21 2012] [warn] mod_fcgid: process 2894 graceful kill fail, sending SIGKILL [Fri Oct 26 10:59:25 2012] [warn] mod_fcgid: process 2866 graceful kill fail, sending SIGKILL suexec.log: [2012-10-25 16:05:36]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:09:38]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:09:51]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:14:03]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:14:06]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:14:35]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 20:20:27]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 20:20:29]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 20:20:31]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 21:42:12]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 22:56:50]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 02:34:43]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 04:25:07]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 06:35:19]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 06:40:05]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 07:22:45]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 10:10:05]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 10:49:24]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 10:49:24]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi based on the logs can any determine what might be the cause of this? Thinking that it might be the micro instance I'm thinking of upgrading to a small. Any help would be greatly appreciated.

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  • Desktop Fun: Big Game Cats Wallpaper Collection Series 2

    - by Asian Angel
    Two years ago we shared a wonderful collection of big game cats wallpapers with you and today we are back with more cattitude goodness for you. Fill your desktop with these sleek and graceful friends from the animal kingdom with the second in our series of Big Game Cats Wallpaper collections. How To Create a Customized Windows 7 Installation Disc With Integrated Updates How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using?

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  • Oracle and ROLTA: Collaboration for Analytical Master Data Management

    - by Mala Narasimharajan
    Oracle and ROLTA have joined forces to put together an educational webinar series on best practices for maximizing data integrity using analytical master data management.  Hear replays of webcasts by Gartner as well as customer success at Navistar and learn how Master Data Management in the enterprise is the right choice for heterogeneity, data degradation and improved analysis of your business. For more information on this collaboration click here. For additional information on Oracle's solution suite for MDM, click here. 

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  • No Significant Fragmentation? Look Closer…

    If you are relying on using 'best-practice' percentage-based thresholds when you are creating an index maintenance plan for a SQL Server that checks the fragmentation in your pages, you may miss occasional 'edge' conditions on larger tables that will cause severe degradation in performance. It is worth being aware of patterns of data access in particular tables when judging the best threshold figure to use.

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  • No Significant Fragmentation? Look Closer…

    If you are relying on using 'best-practice' percentage-based thresholds when you are creating an index maintenance plan for a SQL Server that checks the fragmentation in your pages, you may miss occasional 'edge' conditions on larger tables that will cause severe degradation in performance. It is worth being aware of patterns of data access in particular tables when judging the best threshold figure to use.

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  • Multiuser's impact on Access Database

    - by SilentRage47
    Can someone explain to me how are effected the performances of an Access 2003 DB when it's used by a lot (30) of users on the same LAN? I'm working on a vb6 project with this access 2003 DB wich performs ok on my local PC, but it's terrible when used across 20-30 users. It's there something I can do to improve performance? How can I understand what's the cause of this degradation in performance?

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  • Skip all warning prompts on ACPI shutdown?

    - by N Rahl
    When I issue an ACPI shutdown command to a Windows XP guest machine from the host VM server, I want Windows to shutdown. The problem is, Windows always wants to ask some question or another, rather than just shutting down. I need shutdown to be reliable, no matter what is running or going on, so I can automate shutdowns from the host machine. But I want it to be as graceful as possible, rather than just pulling the plug. Some problems: If a user is logged in, ACPI shutdown causes a box to appear that says, "are you sure you want to shutdown while other users are logged in"? And this prevents shutdown until someone connects to the machine and clicks "yes". In this case, it should try its best to gracefully log out all users, using force if necessary, and then shutdown without promoting. Busy or non-responding programs or programs asking to save data can prevent Windows from shutting down until a user answers a prompt. This should attempt to save data, wait maybe 30 seconds for non-responding programs, but should get aggressive with stubborn programs. "nope, time's up! 3,2,1, Goodbye!" Is there a registry setting that I can change from: ACPI_Shutdown: "Shut down if Windows feels like it" to ACPI_Shutdown: "Just do it. Kill programs, bump users, try to be graceful about it, but when I come back, I expect you to be off." This should respond to the ACPI shutdown command, and not be a script on windows, unless that script is triggered by the ACPI power button. I'm hoping this can be changed with registry options.

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  • APC Smart UPS network shutdown issue

    - by Rob Clarke
    Here is a bit about our setup: We have 2x Smart-UPS RT 6000 XL units with network management cards We are running Powerchute from a network server Powerchute is connected to the management cards of both UPSs UPSs are set to do a graceful shutdown via Powerchute when the battery duration is under 20 minutes We also have a command file that runs with Powerchute Although our setup is redundant we do not have an equal load on each server due to APC switches for single power devices The problem is that as we do not have an equal load on each server the batteries drain at different rates. This means that the UPSs both get to the specified low battery duration at completely different times. The problem here is that UPS 1 may have run down to 5 minutes and is in desperate need of initiating a Powerchute shutdown - UPS 2 still has 25 minutes of runtime so no shutdown is initiated. Consequently UPS 1 goes down and takes all the servers with and then shuts down UPS 2 as well! What we need to happen are 1 of either 2 things: Powerchute initiates the shutdown as soon as either UPS reaches the 20 minutes low battery duration setting - and doesnt wait for both The UPS with the heavier load expends its entire battery but does not shutdown both UPSs and lets the load be switched across to the UPS that still has runtime remaining. That way when the UPS that still has runtime reaches its low battery duration it can proceed with the graceful shutdown via Powerchute. Hope that makes sense, any help is greatly appreciated!

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  • Formatting an external HDD stuck at 70%

    - by mahmood
    My external HDD which is a 250GB WD (powered by USB) seems to have problem! Whenever i try to copy some files, it stuck while copying. I decided to format it. So I used windows tool and performed the format (not quickly) however at nearly 70% it stuck. Then I decided to perform a low level format with lowlevel. Again it stuck at 70%. I endup that the HDD has bad sector. So is there any tool that mark the bad sectors and bypass them? It is not very reasonable to through 250GB because of some bad sectors! P.S: I saw a similar topic but there were no conclusion there either. The smart data is Attribute, raw value, value, threshold, status Read Error Rate, 50, 200, 51, OK Spin-Up Time, 3275, 154, 21, OK Start/Stop Count, 2729, 98, 0, OK Reallocated Sectors Count,0, 200, 140, OK Seek Error Rate, 0, 100, 51, OK Power-On Hours (POH), 1057, 99, 0, OK Spin Retry Count, 0, 100, 51, OK Recalibration Retries ,0, 100, 51 , OK Power Cycle Count, 1385, 99, 0, OK Power-off Retract Count, 425, 200, 0, OK Load /Unload Cycle Count,12974, 196, 0, OK Temperature, 43, 43, 0, OK Reallocation Event Count,0, 200, 0, OK Current Pending Sector Count,23,200, 0, Degradation Uncorrectable Sector Count, 0, 100, 0, OK UltraDMA CRC Error Count,6, 200, 0, OK Write Error Rate/Multi-Zone Error Rate,0,100,51, OK It seems that the most important thing is this line Current Pending Sector Count,23,200, 0, Degradation Any idea on that?

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  • APC Smart UPS network shutdown issue

    - by Rob Clarke
    Here is a bit about our setup: We have 2x Smart-UPS RT 6000 XL units with network management cards We are running Powerchute from a network server Powerchute is connected to the management cards of both UPSs UPSs are set to do a graceful shutdown via Powerchute when the battery duration is under 20 minutes We also have a command file that runs with Powerchute Although our setup is redundant we do not have an equal load on each server due to APC switches for single power devices The problem is that as we do not have an equal load on each server the batteries drain at different rates. This means that the UPSs both get to the specified low battery duration at completely different times. The problem here is that UPS 1 may have run down to 5 minutes and is in desperate need of initiating a Powerchute shutdown - UPS 2 still has 25 minutes of runtime so no shutdown is initiated. Consequently UPS 1 goes down and takes all the servers with and then shuts down UPS 2 as well! What we need to happen are 1 of either 2 things: Powerchute initiates the shutdown as soon as either UPS reaches the 20 minutes low battery duration setting - and doesnt wait for both The UPS with the heavier load expends its entire battery but does not shutdown both UPSs and lets the load be switched across to the UPS that still has runtime remaining. That way when the UPS that still has runtime reaches its low battery duration it can proceed with the graceful shutdown via Powerchute. Hope that makes sense, any help is greatly appreciated!

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  • Hard drive degredation from large memory usage and paging files?

    - by Stephen R
    I've had a question(s) regarding computer degradation going through my head for a while and haven't found many good resources for researching it. 1) First off, when is the virtual RAM/paging file on a hard drive used by Windows? Is it used when the RAM is full? Or does it use the Virtual RAM/paging file as intermediate caching between the RAM and actual hard drive space all the time? 2) If I were to run many applications on my computer at the same time and have a bad habit of doing this for the entire lifetime of the computer, does it use more of the virtual RAM/paging file than if I were to have fewer programs running? Just to note, the RAM never fills up on my computer but it is used heavily. 3) By extension of question 2, if the virtual RAM/paging file is used more heavily, would that result in rapid hard drive degradation? I have seen a pattern among all of the computers that I have owned or used in the past 5 years. I am the kind of person to leave my web browser up with 40 tabs among other programs which will eat up 40% of my memory typically. Over time my computer will slow down, browsers start crashing, programs start seizing up or crashing themselves, eventually the computer becomes essentially unusable. I have been trying to rack my mind to come up with a solution other than to purchase a new PC to have it die on me in the next couple years as well. This is the only thought that has come to mind that might have a simple hardware fix...Windows ReadyBoost...Maybe? I'd like to be able to discuss this so I can learn something about all of the above. Thanks.

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  • Unleash the Power of Cryptography on SPARC T4

    - by B.Koch
    by Rob Ludeman Oracle’s SPARC T4 systems are architected to deliver enhanced value for customer via the inclusion of many integrated features.  One of the best examples of this approach is demonstrated in the on-chip cryptographic support that delivers wire speed encryption capabilities without any impact to application performance.  The Evolution of SPARC Encryption SPARC T-Series systems have a long history of providing this capability, dating back to the release of the first T2000 systems that featured support for on-chip RSA encryption directly in the UltraSPARC T1 processor.  Successive generations have built on this approach by support for additional encryption ciphers that are tightly coupled with the Oracle Solaris 10 and Solaris 11 encryption framework.  While earlier versions of this technology were implemented using co-processors, the SPARC T4 was redesigned with new crypto instructions to eliminate some of the performance overhead associated with the former approach, resulting in much higher performance for encrypted workloads. The Superiority of the SPARC T4 Approach to Crypto As companies continue to engage in more and more e-commerce, the need to provide greater degrees of security for these transactions is more critical than ever before.  Traditional methods of securing data in transit by applications have a number of drawbacks that are addressed by the SPARC T4 cryptographic approach. 1. Performance degradation – cryptography is highly compute intensive and therefore, there is a significant cost when using other architectures without embedded crypto functionality.  This performance penalty impacts the entire system, slowing down performance of web servers (SSL), for example, and potentially bogging down the speed of other business applications.  The SPARC T4 processor enables customers to deliver high levels of security to internal and external customers while not incurring an impact to overall SLAs in their IT environment. 2. Added cost – one of the methods to avoid performance degradation is the addition of add-in cryptographic accelerator cards or external offload engines in other systems.  While these solutions provide a brute force mechanism to avoid the problem of slower system performance, it usually comes at an added cost.  Customers looking to encrypt datacenter traffic without the overhead and expenditure of extra hardware can rely on SPARC T4 systems to deliver the performance necessary without the need to purchase other hardware or add-on cards. 3. Higher complexity – the addition of cryptographic cards or leveraging load balancers to perform encryption tasks results in added complexity from a management standpoint.  With SPARC T4, encryption keys and the framework built into Solaris 10 and 11 means that administrators generally don’t need to spend extra cycles determining how to perform cryptographic functions.  In fact, many of the instructions are built-in and require no user intervention to be utilized.  For example, For OpenSSL on Solaris 11, SPARC T4 crypto is available directly with a new built-in OpenSSL 1.0 engine, called the "t4 engine."  For a deeper technical dive into the new instructions included in SPARC T4, consult Dan Anderson’s blog. Conclusion In summary, SPARC T4 systems offer customers much more value for applications than just increased performance. The integration of key virtualization technologies, embedded encryption, and a true Enterprise Operating System, Oracle Solaris, provides direct business benefits that supersedes the commodity approach to data center computing.   SPARC T4 removes the roadblocks to secure computing by offering integrated crypto accelerators that can save IT organizations in operating cost while delivering higher levels of performance and meeting objectives around compliance. For more on the SPARC T4 family of products, go to here.

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  • H.264 / FLV best practices for HTML

    - by Steve Murch
    I run a website with about 700 videos (And no, it's not porn -- get your mind out of the gutter :-) ). The videos are currently in FLV format. We use the JWPlayer to render those videos. IIS6 hosted. Everything works just fine. As I understand it, H.264 (not FLV and likely not OGG) is the emerging preferred HTML5 video standard. Today, the iPad really only respects H.264 or YouTube. Presumably, soon many more important browsers will follow Apple's lead and respect only the HTML5 tag. OK, so I think I can figure out how to convert my existing videos into the proper H.264 format. There are various tools available, including ffmpeg.exe. I haven't tried it yet, but I don't think that's going to be a problem after fiddling with the codec settings. My question is more about the container itself -- that is, planning graceful transition for all users. What's the best-practice recommendation for rendering these videos? If I just use the HTML5 tag, then presumably any browser that doesn't yet support HTML5 won't see the videos. And if I render them in Flash format via the JWPlayer or some other player, then they won't be playable on the iPad. Do I have to do ugly UserAgent detection here to figure out what to render? I know the JWPlayer supports H.264 media, but isn't the player itself a Flash component and therefore not playable on the iPad? Sorry if I'm not being clear, but I'm scratching my head on a graceful transition plan that will work for current browsers, the iPad and the upcoming HTML5 wave. I'm not a video expert, so any advice would be most welcome, thanks.

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  • Using linq2xml to query a single item deep within

    - by BrettRobi
    I'm wondering if there is a robust and graceful way using linq2xml to query an item deep within an xml hierarchy. For example: <?xml version="1.0" encoding="utf-8" ?> <data> <core id="01234"> <field1>some data</field1> <field2>more data</field2> <metadata> <response> <status code="0">Success</status> <content> <job>f1b5c3f8-e6b1-4ae4-905a-a7c5de3f13c6</job> <id>id of the content</id> </content> </response> </metadata> </core> </data> With this xml how do I query the value of without using something like this: var doc = XElement.Load("file.xml"); string id = (string)doc.Element("core") .Element("metadata") .Element("response") .Element("content") .Element("id"); I don't like the above approach because it is error prone (throws exception if any tag is missing in the hierarchy) and honestly ugly. Is there a more robust and graceful approach, perhaps using the sql-like syntax of linq?

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  • Detecting HTML5/CSS3 Features using Modernizr

    - by dwahlin
    HTML5, CSS3, and related technologies such as canvas and web sockets bring a lot of useful new features to the table that can take Web applications to the next level. These new technologies allow applications to be built using only HTML, CSS, and JavaScript allowing them to be viewed on a variety of form factors including tablets and phones. Although HTML5 features offer a lot of promise, it’s not realistic to develop applications using the latest technologies without worrying about supporting older browsers in the process. If history has taught us anything it’s that old browsers stick around for years and years which means developers have to deal with backward compatibility issues. This is especially true when deploying applications to the Internet that target the general public. This begs the question, “How do you move forward with HTML5 and CSS3 technologies while gracefully handling unsupported features in older browsers?” Although you can write code by hand to detect different HTML5 and CSS3 features, it’s not always straightforward. For example, to check for canvas support you need to write code similar to the following:   <script> window.onload = function () { if (canvasSupported()) { alert('canvas supported'); } }; function canvasSupported() { var canvas = document.createElement('canvas'); return (canvas.getContext && canvas.getContext('2d')); } </script> If you want to check for local storage support the following check can be made. It’s more involved than it should be due to a bug in older versions of Firefox. <script> window.onload = function () { if (localStorageSupported()) { alert('local storage supported'); } }; function localStorageSupported() { try { return ('localStorage' in window && window['localStorage'] != null); } catch(e) {} return false; } </script> Looking through the previous examples you can see that there’s more than meets the eye when it comes to checking browsers for HTML5 and CSS3 features. It takes a lot of work to test every possible scenario and every version of a given browser. Fortunately, you don’t have to resort to writing custom code to test what HTML5/CSS3 features a given browser supports. By using a script library called Modernizr you can add checks for different HTML5/CSS3 features into your pages with a minimal amount of code on your part. Let’s take a look at some of the key features Modernizr offers.   Getting Started with Modernizr The first time I heard the name “Modernizr” I thought it “modernized” older browsers by added missing functionality. In reality, Modernizr doesn’t actually handle adding missing features or “modernizing” older browsers. The Modernizr website states, “The name Modernizr actually stems from the goal of modernizing our development practices (and ourselves)”. Because it relies on feature detection rather than browser sniffing (a common technique used in the past – that never worked that great), Modernizr definitely provides a more modern way to test features that a browser supports and can even handle loading additional scripts called shims or polyfills that fill in holes that older browsers may have. It’s a great tool to have in your arsenal if you’re a web developer. Modernizr is available at http://modernizr.com. Two different types of scripts are available including a development script and custom production script. To generate a production script, the site provides a custom script generation tool rather than providing a single script that has everything under the sun for HTML5/CSS3 feature detection. Using the script generation tool you can pick the specific test functionality that you need and ignore everything that you don’t need. That way the script is kept as small as possible. An example of the custom script download screen is shown next. Notice that specific CSS3, HTML5, and related feature tests can be selected. Once you’ve downloaded your custom script you can add it into your web page using the standard <script> element and you’re ready to start using Modernizr. <script src="Scripts/Modernizr.js" type="text/javascript"></script>   Modernizr and the HTML Element Once you’ve add a script reference to Modernizr in a page it’ll go to work for you immediately. In fact, by adding the script several different CSS classes will be added to the page’s <html> element at runtime. These classes define what features the browser supports and what features it doesn’t support. Features that aren’t supported get a class name of “no-FeatureName”, for example “no-flexbox”. Features that are supported get a CSS class name based on the feature such as “canvas” or “websockets”. An example of classes added when running a page in Chrome is shown next:   <html class=" js flexbox canvas canvastext webgl no-touch geolocation postmessage websqldatabase indexeddb hashchange history draganddrop websockets rgba hsla multiplebgs backgroundsize borderimage borderradius boxshadow textshadow opacity cssanimations csscolumns cssgradients cssreflections csstransforms csstransforms3d csstransitions fontface generatedcontent video audio localstorage sessionstorage webworkers applicationcache svg inlinesvg smil svgclippaths"> Here’s an example of what the <html> element looks like at runtime with Internet Explorer 9:   <html class=" js no-flexbox canvas canvastext no-webgl no-touch geolocation postmessage no-websqldatabase no-indexeddb hashchange no-history draganddrop no-websockets rgba hsla multiplebgs backgroundsize no-borderimage borderradius boxshadow no-textshadow opacity no-cssanimations no-csscolumns no-cssgradients no-cssreflections csstransforms no-csstransforms3d no-csstransitions fontface generatedcontent video audio localstorage sessionstorage no-webworkers no-applicationcache svg inlinesvg smil svgclippaths">   When using Modernizr it’s a common practice to define an <html> element in your page with a no-js class added as shown next:   <html class="no-js">   You’ll see starter projects such as HTML5 Boilerplate (http://html5boilerplate.com) or Initializr (http://initializr.com) follow this approach (see my previous post for more information on HTML5 Boilerplate). By adding the no-js class it’s easy to tell if a browser has JavaScript enabled or not. If JavaScript is disabled then no-js will stay on the <html> element. If JavaScript is enabled, no-js will be removed by Modernizr and a js class will be added along with other classes that define supported/unsupported features. Working with HTML5 and CSS3 Features You can use the CSS classes added to the <html> element directly in your CSS files to determine what style properties to use based upon the features supported by a given browser. For example, the following CSS can be used to render a box shadow for browsers that support that feature and a simple border for browsers that don’t support the feature: .boxshadow #MyContainer { border: none; -webkit-box-shadow: #666 1px 1px 1px; -moz-box-shadow: #666 1px 1px 1px; } .no-boxshadow #MyContainer { border: 2px solid black; }   If a browser supports box-shadows the boxshadow CSS class will be added to the <html> element by Modernizr. It can then be associated with a given element. This example associates the boxshadow class with a div with an id of MyContainer. If the browser doesn’t support box shadows then the no-boxshadow class will be added to the <html> element and it can be used to render a standard border around the div. This provides a great way to leverage new CSS3 features in supported browsers while providing a graceful fallback for older browsers. In addition to using the CSS classes that Modernizr provides on the <html> element, you also use a global Modernizr object that’s created. This object exposes different properties that can be used to detect the availability of specific HTML5 or CSS3 features. For example, the following code can be used to detect canvas and local storage support. You can see that the code is much simpler than the code shown at the beginning of this post. It also has the added benefit of being tested by a large community of web developers around the world running a variety of browsers.   $(document).ready(function () { if (Modernizr.canvas) { //Add canvas code } if (Modernizr.localstorage) { //Add local storage code } }); The global Modernizr object can also be used to test for the presence of CSS3 features. The following code shows how to test support for border-radius and CSS transforms:   $(document).ready(function () { if (Modernizr.borderradius) { $('#MyDiv').addClass('borderRadiusStyle'); } if (Modernizr.csstransforms) { $('#MyDiv').addClass('transformsStyle'); } });   Several other CSS3 feature tests can be performed such as support for opacity, rgba, text-shadow, CSS animations, CSS transitions, multiple backgrounds, and more. A complete list of supported HTML5 and CSS3 tests that Modernizr supports can be found at http://www.modernizr.com/docs.   Loading Scripts using Modernizr In cases where a browser doesn’t support a specific feature you can either provide a graceful fallback or load a shim/polyfill script to fill in missing functionality where appropriate (more information about shims/polyfills can be found at https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills). Modernizr has a built-in script loader that can be used to test for a feature and then load a script if the feature isn’t available. The script loader is built-into Modernizr and is also available as a standalone yepnope script (http://yepnopejs.com). It’s extremely easy to get started using the script loader and it can really simplify the process of loading scripts based on the availability of a particular browser feature. To load scripts dynamically you can use Modernizr’s load() function which accepts properties defining the feature to test (test property), the script to load if the test succeeds (yep property), the script to load if the test fails (nope property), and a script to load regardless of if the test succeeds or fails (both property). An example of using load() with these properties is show next: Modernizr.load({ test: Modernizr.canvas, yep: 'html5CanvasAvailable.js’, nope: 'excanvas.js’, both: 'myCustomScript.js' }); In this example Modernizr is used to not only load scripts but also to test for the presence of the canvas feature. If the target browser supports the HTML5 canvas then the html5CanvasAvailable.js script will be loaded along with the myCustomScript.js script (use of the yep property in this example is a bit contrived – it was added simply to demonstrate how the property can be used in the load() function). Otherwise, a polyfill script named excanvas.js will be loaded to add missing canvas functionality for Internet Explorer versions prior to 9. Once excanvas.js is loaded the myCustomScript.js script will be loaded. Because Modernizr handles loading scripts, you can also use it in creative ways. For example, you can use it to load local scripts when a 3rd party Content Delivery Network (CDN) such as one provided by Google or Microsoft is unavailable for whatever reason. The Modernizr documentation provides the following example that demonstrates the process for providing a local fallback for jQuery when a CDN is down:   Modernizr.load([ { load: '//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.js', complete: function () { if (!window.jQuery) { Modernizr.load('js/libs/jquery-1.6.4.min.js'); } } }, { // This will wait for the fallback to load and // execute if it needs to. load: 'needs-jQuery.js' } ]); This code attempts to load jQuery from the Google CDN first. Once the script is downloaded (or if it fails) the function associated with complete will be called. The function checks to make sure that the jQuery object is available and if it’s not Modernizr is used to load a local jQuery script. After all of that occurs a script named needs-jQuery.js will be loaded. Conclusion If you’re building applications that use some of the latest and greatest features available in HTML5 and CSS3 then Modernizr is an essential tool. By using it you can reduce the amount of custom code required to test for browser features and provide graceful fallbacks or even load shim/polyfill scripts for older browsers to help fill in missing functionality. 

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  • Detecting HTML5/CSS3 Features using Modernizr

    - by dwahlin
    HTML5, CSS3, and related technologies such as canvas and web sockets bring a lot of useful new features to the table that can take Web applications to the next level. These new technologies allow applications to be built using only HTML, CSS, and JavaScript allowing them to be viewed on a variety of form factors including tablets and phones. Although HTML5 features offer a lot of promise, it’s not realistic to develop applications using the latest technologies without worrying about supporting older browsers in the process. If history has taught us anything it’s that old browsers stick around for years and years which means developers have to deal with backward compatibility issues. This is especially true when deploying applications to the Internet that target the general public. This begs the question, “How do you move forward with HTML5 and CSS3 technologies while gracefully handling unsupported features in older browsers?” Although you can write code by hand to detect different HTML5 and CSS3 features, it’s not always straightforward. For example, to check for canvas support you need to write code similar to the following:   <script> window.onload = function () { if (canvasSupported()) { alert('canvas supported'); } }; function canvasSupported() { var canvas = document.createElement('canvas'); return (canvas.getContext && canvas.getContext('2d')); } </script> If you want to check for local storage support the following check can be made. It’s more involved than it should be due to a bug in older versions of Firefox. <script> window.onload = function () { if (localStorageSupported()) { alert('local storage supported'); } }; function localStorageSupported() { try { return ('localStorage' in window && window['localStorage'] != null); } catch(e) {} return false; } </script> Looking through the previous examples you can see that there’s more than meets the eye when it comes to checking browsers for HTML5 and CSS3 features. It takes a lot of work to test every possible scenario and every version of a given browser. Fortunately, you don’t have to resort to writing custom code to test what HTML5/CSS3 features a given browser supports. By using a script library called Modernizr you can add checks for different HTML5/CSS3 features into your pages with a minimal amount of code on your part. Let’s take a look at some of the key features Modernizr offers.   Getting Started with Modernizr The first time I heard the name “Modernizr” I thought it “modernized” older browsers by added missing functionality. In reality, Modernizr doesn’t actually handle adding missing features or “modernizing” older browsers. The Modernizr website states, “The name Modernizr actually stems from the goal of modernizing our development practices (and ourselves)”. Because it relies on feature detection rather than browser sniffing (a common technique used in the past – that never worked that great), Modernizr definitely provides a more modern way to test features that a browser supports and can even handle loading additional scripts called shims or polyfills that fill in holes that older browsers may have. It’s a great tool to have in your arsenal if you’re a web developer. Modernizr is available at http://modernizr.com. Two different types of scripts are available including a development script and custom production script. To generate a production script, the site provides a custom script generation tool rather than providing a single script that has everything under the sun for HTML5/CSS3 feature detection. Using the script generation tool you can pick the specific test functionality that you need and ignore everything that you don’t need. That way the script is kept as small as possible. An example of the custom script download screen is shown next. Notice that specific CSS3, HTML5, and related feature tests can be selected. Once you’ve downloaded your custom script you can add it into your web page using the standard <script> element and you’re ready to start using Modernizr. <script src="Scripts/Modernizr.js" type="text/javascript"></script>   Modernizr and the HTML Element Once you’ve add a script reference to Modernizr in a page it’ll go to work for you immediately. In fact, by adding the script several different CSS classes will be added to the page’s <html> element at runtime. These classes define what features the browser supports and what features it doesn’t support. Features that aren’t supported get a class name of “no-FeatureName”, for example “no-flexbox”. Features that are supported get a CSS class name based on the feature such as “canvas” or “websockets”. An example of classes added when running a page in Chrome is shown next:   <html class=" js flexbox canvas canvastext webgl no-touch geolocation postmessage websqldatabase indexeddb hashchange history draganddrop websockets rgba hsla multiplebgs backgroundsize borderimage borderradius boxshadow textshadow opacity cssanimations csscolumns cssgradients cssreflections csstransforms csstransforms3d csstransitions fontface generatedcontent video audio localstorage sessionstorage webworkers applicationcache svg inlinesvg smil svgclippaths"> Here’s an example of what the <html> element looks like at runtime with Internet Explorer 9:   <html class=" js no-flexbox canvas canvastext no-webgl no-touch geolocation postmessage no-websqldatabase no-indexeddb hashchange no-history draganddrop no-websockets rgba hsla multiplebgs backgroundsize no-borderimage borderradius boxshadow no-textshadow opacity no-cssanimations no-csscolumns no-cssgradients no-cssreflections csstransforms no-csstransforms3d no-csstransitions fontface generatedcontent video audio localstorage sessionstorage no-webworkers no-applicationcache svg inlinesvg smil svgclippaths">   When using Modernizr it’s a common practice to define an <html> element in your page with a no-js class added as shown next:   <html class="no-js">   You’ll see starter projects such as HTML5 Boilerplate (http://html5boilerplate.com) or Initializr (http://initializr.com) follow this approach (see my previous post for more information on HTML5 Boilerplate). By adding the no-js class it’s easy to tell if a browser has JavaScript enabled or not. If JavaScript is disabled then no-js will stay on the <html> element. If JavaScript is enabled, no-js will be removed by Modernizr and a js class will be added along with other classes that define supported/unsupported features. Working with HTML5 and CSS3 Features You can use the CSS classes added to the <html> element directly in your CSS files to determine what style properties to use based upon the features supported by a given browser. For example, the following CSS can be used to render a box shadow for browsers that support that feature and a simple border for browsers that don’t support the feature: .boxshadow #MyContainer { border: none; -webkit-box-shadow: #666 1px 1px 1px; -moz-box-shadow: #666 1px 1px 1px; } .no-boxshadow #MyContainer { border: 2px solid black; }   If a browser supports box-shadows the boxshadow CSS class will be added to the <html> element by Modernizr. It can then be associated with a given element. This example associates the boxshadow class with a div with an id of MyContainer. If the browser doesn’t support box shadows then the no-boxshadow class will be added to the <html> element and it can be used to render a standard border around the div. This provides a great way to leverage new CSS3 features in supported browsers while providing a graceful fallback for older browsers. In addition to using the CSS classes that Modernizr provides on the <html> element, you also use a global Modernizr object that’s created. This object exposes different properties that can be used to detect the availability of specific HTML5 or CSS3 features. For example, the following code can be used to detect canvas and local storage support. You can see that the code is much simpler than the code shown at the beginning of this post. It also has the added benefit of being tested by a large community of web developers around the world running a variety of browsers.   $(document).ready(function () { if (Modernizr.canvas) { //Add canvas code } if (Modernizr.localstorage) { //Add local storage code } }); The global Modernizr object can also be used to test for the presence of CSS3 features. The following code shows how to test support for border-radius and CSS transforms:   $(document).ready(function () { if (Modernizr.borderradius) { $('#MyDiv').addClass('borderRadiusStyle'); } if (Modernizr.csstransforms) { $('#MyDiv').addClass('transformsStyle'); } });   Several other CSS3 feature tests can be performed such as support for opacity, rgba, text-shadow, CSS animations, CSS transitions, multiple backgrounds, and more. A complete list of supported HTML5 and CSS3 tests that Modernizr supports can be found at http://www.modernizr.com/docs.   Loading Scripts using Modernizr In cases where a browser doesn’t support a specific feature you can either provide a graceful fallback or load a shim/polyfill script to fill in missing functionality where appropriate (more information about shims/polyfills can be found at https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills). Modernizr has a built-in script loader that can be used to test for a feature and then load a script if the feature isn’t available. The script loader is built-into Modernizr and is also available as a standalone yepnope script (http://yepnopejs.com). It’s extremely easy to get started using the script loader and it can really simplify the process of loading scripts based on the availability of a particular browser feature. To load scripts dynamically you can use Modernizr’s load() function which accepts properties defining the feature to test (test property), the script to load if the test succeeds (yep property), the script to load if the test fails (nope property), and a script to load regardless of if the test succeeds or fails (both property). An example of using load() with these properties is show next: Modernizr.load({ test: Modernizr.canvas, yep: 'html5CanvasAvailable.js’, nope: 'excanvas.js’, both: 'myCustomScript.js' }); In this example Modernizr is used to not only load scripts but also to test for the presence of the canvas feature. If the target browser supports the HTML5 canvas then the html5CanvasAvailable.js script will be loaded along with the myCustomScript.js script (use of the yep property in this example is a bit contrived – it was added simply to demonstrate how the property can be used in the load() function). Otherwise, a polyfill script named excanvas.js will be loaded to add missing canvas functionality for Internet Explorer versions prior to 9. Once excanvas.js is loaded the myCustomScript.js script will be loaded. Because Modernizr handles loading scripts, you can also use it in creative ways. For example, you can use it to load local scripts when a 3rd party Content Delivery Network (CDN) such as one provided by Google or Microsoft is unavailable for whatever reason. The Modernizr documentation provides the following example that demonstrates the process for providing a local fallback for jQuery when a CDN is down:   Modernizr.load([ { load: '//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.js', complete: function () { if (!window.jQuery) { Modernizr.load('js/libs/jquery-1.6.4.min.js'); } } }, { // This will wait for the fallback to load and // execute if it needs to. load: 'needs-jQuery.js' } ]); This code attempts to load jQuery from the Google CDN first. Once the script is downloaded (or if it fails) the function associated with complete will be called. The function checks to make sure that the jQuery object is available and if it’s not Modernizr is used to load a local jQuery script. After all of that occurs a script named needs-jQuery.js will be loaded. Conclusion If you’re building applications that use some of the latest and greatest features available in HTML5 and CSS3 then Modernizr is an essential tool. By using it you can reduce the amount of custom code required to test for browser features and provide graceful fallbacks or even load shim/polyfill scripts for older browsers to help fill in missing functionality. 

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  • Reload signal for UWSGI when using Supervisord?

    - by Kerem Ulutas
    I have been using UWSGI behind Nginx and I've set supervisord to restart the Nginx and UWSGI instances in case of a server reboot. I am debugging my application and sometimes need to reload the application. According to this page I should be sending SIGHUP in order to do a graceful reload. I could find a stopsignal config setting on this page, but I couldn't find any entry related to something like "reloadsignal" or "restartsignal". Any ideas?

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  • RabbitMQ and persistence (blocking writes?)

    - by daharon
    I want to create a RabbitMQ server on a virtual machine (VMware) to be used in production. It will contain persistent queues. I'm wondering if it is a bad idea to store the server on a NAS that's accessed over NFS. Basically my questions are: Will RabbitMQ's writes be blocking? Will the entire queue's operation halt on a write? How much performance degradation should I expect when persisting over NFS?

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  • I just restarted Apache and now the server is down

    - by James
    I am pretty terrified right now. I'm scared I'm going to get a call in a couple minutes from a hundred people saying the website doesn't work. I was at the terminal changing some configuration files when I went to restart the server to update the .conf files with this command: /etc/init.d/apache2 graceful After I ran that, none of the websites work and I have no idea what to do. There are about 100 errors I am getting according to the log files. They all begin with "PHP Notice" and most relate to "use of undefined constant" Also, I just spoke with a coworker, describing what I did, and he noticed that there are two installations of apache on the server and that I restarted the one that we don't use. This is what the error log says (assuming it's the correct error log): [Wed Jan 05 11:52:06 2011] [notice] Graceful restart requested, doing restart Warning: DocumentRoot [/u/apps/staging/antetr/current/public/] does not exist [Wed Jan 05 11:52:08 2011] [warn] NameVirtualHost *:80 has no VirtualHosts (98)Address already in use: make_sock: could not bind to address [::]:80 (98)Address already in use: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs FINAL UPDATE: Ok, I fixed it. The problem was (as you experts facepalming probably know) that it couldn't access an error log in the directory I was working in. I created an empty error log file and tried the restart command again and now all the sites are back up... Though my original problem is still there.. Thanks to all those who offered advice, it really helped and let me breathe for a moment.

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  • I just restarted Apache and now the server is down

    - by James
    I am pretty terrified right now. I'm scared I'm going to get a call in a couple minutes from a hundred people saying the website doesn't work. I was at the terminal changing some configuration files when I went to restart the server to update the .conf files with this command: /etc/init.d/apache2 graceful After I ran that, none of the websites work and I have no idea what to do. There are about 100 errors I am getting according to the log files. They all begin with "PHP Notice" and most relate to "use of undefined constant" Also, I just spoke with a coworker, describing what I did, and he noticed that there are two installations of apache on the server and that I restarted the one that we don't use. This is what the error log says (assuming it's the correct error log): [Wed Jan 05 11:52:06 2011] [notice] Graceful restart requested, doing restart Warning: DocumentRoot [/u/apps/staging/antetr/current/public/] does not exist [Wed Jan 05 11:52:08 2011] [warn] NameVirtualHost *:80 has no VirtualHosts (98)Address already in use: make_sock: could not bind to address [::]:80 (98)Address already in use: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs (2)No such file or directory: apache2: could not open error log file /u/apps/production/madfilmdash/current/log/apache-error.log. Unable to open logs FINAL UPDATE: Ok, I fixed it. The problem was (as you experts facepalming probably know) that it couldn't access an error log in the directory I was working in. I created an empty error log file and tried the restart command again and now all the sites are back up... Though my original problem is still there.. Thanks to all those who offered advice, it really helped and let me breathe for a moment.

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  • Editting HD Quicktime .mov files in Windows

    - by NoCarrier
    I recently purchased one of those new wave of point & shoot digicams (canon SD780) that shoot high definition 720p video. Unfortunately it only writes to Quicktime files. How can I go about editing these in Windows without spending any money? I found a few MOV to AVI or WMV converters but am experiencing some quality degradation in the output.

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  • DVD won't play in Ubuntu Jaunty after codes and css support has been added.

    - by C. Ross
    Using Totem Video Player v2.26.1 on Ubuntu Jaunty 9.04, dvd's won't play after I've installed libdvdread4, added the Medibuntu packages, and run sudo /usr/share/doc/libdvdread4/install-css.sh If I click on the dvd I get an error *"Could not read from resource". If I navigate to one of the videos directly and run it, the movie will play, but with obvious degradation or encryption (like cable tv you aren't paying for).

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  • Why does Microsoft Windows' performance appear to degrade over time?

    - by Ben Aston
    Windows XP/2k3 and earlier (can't attest to Vista, but suspect it's the same) all appear to become more sluggish over time as applications are installed and uninstalled. This is not a scientifically tested observation, but more of a learned-through-experience piece of wisdom. (I've always suspected the registry as being behind the issue.) Does anyone have any concrete evidence of this degradation occurring, or it just an invalid perception of mine?

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