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  • Silverlight for Everyone!!

    - by subodhnpushpak
    Someone asked me to compare Silverlight / HTML development. I realized that the question can be answered in many ways: Below is the high level comparison between a HTML /JavaScript client and Silverlight client and why silverlight was chosen over HTML / JavaScript client (based on type of users and major functionalities provided): 1. For end users Browser compatibility Silverlight is a plug-in and requires installation first. However, it does provides consistent look and feel across all browsers. For HTML / DHTML, there is a need to tweak JavaScript for each of the browser supported. In fact, tags like <span> and <div> works differently on different browser / version. So, HTML works on most of the systems but also requires lot of efforts coding-wise to adhere to all standards/ browsers / versions. Out of browser support No support in HTML. Third party tools like  Google gears offers some functionalities but there are lots of issues around platform and accessibility. Out of box support for out-of-browser support. provides features like drag and drop onto application surface. Cut and copy paste in HTML HTML is displayed in browser; which, in turn provides facilities for cut copy and paste. Silverlight (specially 4) provides rich features for cut-copy-paste along with full control over what can be cut copy pasted by end users and .advanced features like visual tree printing. Rich user experience HTML can provide some rich experience by use of some JavaScript libraries like JQuery. However, extensive use of JavaScript combined with various versions of browsers and the supported JavaScript makes the solution cumbersome. Silverlight is meant for RIA experience. User data storage on client end In HTML only small amount of data can be stored that too in cookies. In Silverlight large data may be stored, that too in secure way. This increases the response time. Post back In HTML / JavaScript the post back can be stopped by use of AJAX. Extensive use of AJAX can be a bottleneck as browser stack is used for the calls. Both look and feel and data travel over network.                           In Silverlight everything run the client side. Calls are made to server ONLY for data; which also reduces network traffic in long run. 2. For Developers Coding effort HTML / JavaScript can take considerable amount to code if features (requirements) are rich. For AJAX like interfaces; knowledge of third party kits like DOJO / Yahoo UI / JQuery is required which has steep learning curve. ASP .Net coding world revolves mostly along <table> tags for alignments whereas most popular tools provide <div> tags; which requires lots of tweaking. AJAX calls can be a bottlenecks for performance, if the calls are many. In Silverlight; coding is in C#, which is managed code. XAML is also very intuitive and Blend can be used to provide look and feel. Event handling is much clean than in JavaScript. Provides for many clean patterns like MVVM and composable application. Each call to server is asynchronous in silverlight. AJAX is in built into silverlight. Threading can be done at the client side itself to provide for better responsiveness; etc. Debugging Debugging in HTML / JavaScript is difficult. As JavaScript is interpreted; there is NO compile time error handling. Debugging in Silverlight is very helpful. As it is compiled; it provides rich features for both compile time and run time error handling. Multi -targeting browsers HTML / JavaScript have different rendering behaviours in different browsers / and their versions. JavaScript have to be written to sublime the differences in browser behaviours. Silverlight works exactly the same in all browsers and works on almost all popular browser. Multi-targeting desktop No support in HTML / JavaScript Silverlight is very close to WPF. Bot the platform may be easily targeted while maintaining the same source code. Rich toolkit HTML /JavaScript have limited toolkit as controls Silverlight provides a rich set of controls including graphs, audio, video, layout, etc. 3. For Architects Design Patterns Silverlight provides for patterns like MVVM (MVC) and rich (fat)  client architecture. This segregates the "separation of concern" very clearly. Client (silverlight) does what it is expected to do and server does what it is expected of. In HTML / JavaScript world most of the processing is done on the server side. Extensibility Silverlight provides great deal of extensibility as custom controls may be made. Extensibility is NOT restricted by browser but by the plug-in silverlight runs in. HTML / JavaScript works in a certain way and extensibility is generally done on the server side rather than client end. Client side is restricted by the limitations of the browser. Performance Silverlight provides localized storage which may be used for cached data storage. this reduces the response time. As processing can be done on client side itself; there is no need for server round trips. this decreases the round about time. Look and feel of the application is downloaded ONLY initially, afterwards ONLY data is fetched form the server. Security Silverlight is compiled code downloaded as .XAP; As compared to HTML / JavaScript, it provides more secure sandboxed approach. Cross - scripting is inherently prohibited in silverlight by default. If proper guidelines are followed silverlight provides much robust security mechanism as against HTML / JavaScript world. For example; knowing server Address in obfuscated JavaScript is easier than a compressed compiled obfuscated silverlight .XAP file. Some of these like (offline and Canvas support) will be available in HTML5. However, the timelines are not encouraging at all. According to Ian Hickson, editor of the HTML5 specification, the specification to reach the W3C Candidate Recommendation stage during 2012, and W3C Recommendation in the year 2022 or later. see http://en.wikipedia.org/wiki/HTML5 for details. The above is MY opinion. I will love to hear yours; do let me know via comments. Technorati Tags: Silverlight

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  • C#: LINQ vs foreach - Round 1.

    - by James Michael Hare
    So I was reading Peter Kellner's blog entry on Resharper 5.0 and its LINQ refactoring and thought that was very cool.  But that raised a point I had always been curious about in my head -- which is a better choice: manual foreach loops or LINQ?    The answer is not really clear-cut.  There are two sides to any code cost arguments: performance and maintainability.  The first of these is obvious and quantifiable.  Given any two pieces of code that perform the same function, you can run them side-by-side and see which piece of code performs better.   Unfortunately, this is not always a good measure.  Well written assembly language outperforms well written C++ code, but you lose a lot in maintainability which creates a big techncial debt load that is hard to offset as the application ages.  In contrast, higher level constructs make the code more brief and easier to understand, hence reducing technical cost.   Now, obviously in this case we're not talking two separate languages, we're comparing doing something manually in the language versus using a higher-order set of IEnumerable extensions that are in the System.Linq library.   Well, before we discuss any further, let's look at some sample code and the numbers.  First, let's take a look at the for loop and the LINQ expression.  This is just a simple find comparison:       // find implemented via LINQ     public static bool FindViaLinq(IEnumerable<int> list, int target)     {         return list.Any(item => item == target);     }         // find implemented via standard iteration     public static bool FindViaIteration(IEnumerable<int> list, int target)     {         foreach (var i in list)         {             if (i == target)             {                 return true;             }         }           return false;     }   Okay, looking at this from a maintainability point of view, the Linq expression is definitely more concise (8 lines down to 1) and is very readable in intention.  You don't have to actually analyze the behavior of the loop to determine what it's doing.   So let's take a look at performance metrics from 100,000 iterations of these methods on a List<int> of varying sizes filled with random data.  For this test, we fill a target array with 100,000 random integers and then run the exact same pseudo-random targets through both searches.                       List<T> On 100,000 Iterations     Method      Size     Total (ms)  Per Iteration (ms)  % Slower     Any         10       26          0.00046             30.00%     Iteration   10       20          0.00023             -     Any         100      116         0.00201             18.37%     Iteration   100      98          0.00118             -     Any         1000     1058        0.01853             16.78%     Iteration   1000     906         0.01155             -     Any         10,000   10,383      0.18189             17.41%     Iteration   10,000   8843        0.11362             -     Any         100,000  104,004     1.8297              18.27%     Iteration   100,000  87,941      1.13163             -   The LINQ expression is running about 17% slower for average size collections and worse for smaller collections.  Presumably, this is due to the overhead of the state machine used to track the iterators for the yield returns in the LINQ expressions, which seems about right in a tight loop such as this.   So what about other LINQ expressions?  After all, Any() is one of the more trivial ones.  I decided to try the TakeWhile() algorithm using a Count() to get the position stopped like the sample Pete was using in his blog that Resharper refactored for him into LINQ:       // Linq form     public static int GetTargetPosition1(IEnumerable<int> list, int target)     {         return list.TakeWhile(item => item != target).Count();     }       // traditionally iterative form     public static int GetTargetPosition2(IEnumerable<int> list, int target)     {         int count = 0;           foreach (var i in list)         {             if(i == target)             {                 break;             }               ++count;         }           return count;     }   Once again, the LINQ expression is much shorter, easier to read, and should be easier to maintain over time, reducing the cost of technical debt.  So I ran these through the same test data:                       List<T> On 100,000 Iterations     Method      Size     Total (ms)  Per Iteration (ms)  % Slower     TakeWhile   10       41          0.00041             128%     Iteration   10       18          0.00018             -     TakeWhile   100      171         0.00171             88%     Iteration   100      91          0.00091             -     TakeWhile   1000     1604        0.01604             94%     Iteration   1000     825         0.00825             -     TakeWhile   10,000   15765       0.15765             92%     Iteration   10,000   8204        0.08204             -     TakeWhile   100,000  156950      1.5695              92%     Iteration   100,000  81635       0.81635             -     Wow!  I expected some overhead due to the state machines iterators produce, but 90% slower?  That seems a little heavy to me.  So then I thought, well, what if TakeWhile() is not the right tool for the job?  The problem is TakeWhile returns each item for processing using yield return, whereas our for-loop really doesn't care about the item beyond using it as a stop condition to evaluate. So what if that back and forth with the iterator state machine is the problem?  Well, we can quickly create an (albeit ugly) lambda that uses the Any() along with a count in a closure (if a LINQ guru knows a better way PLEASE let me know!), after all , this is more consistent with what we're trying to do, we're trying to find the first occurence of an item and halt once we find it, we just happen to be counting on the way.  This mostly matches Any().       // a new method that uses linq but evaluates the count in a closure.     public static int TakeWhileViaLinq2(IEnumerable<int> list, int target)     {         int count = 0;         list.Any(item =>             {                 if(item == target)                 {                     return true;                 }                   ++count;                 return false;             });         return count;     }     Now how does this one compare?                         List<T> On 100,000 Iterations     Method         Size     Total (ms)  Per Iteration (ms)  % Slower     TakeWhile      10       41          0.00041             128%     Any w/Closure  10       23          0.00023             28%     Iteration      10       18          0.00018             -     TakeWhile      100      171         0.00171             88%     Any w/Closure  100      116         0.00116             27%     Iteration      100      91          0.00091             -     TakeWhile      1000     1604        0.01604             94%     Any w/Closure  1000     1101        0.01101             33%     Iteration      1000     825         0.00825             -     TakeWhile      10,000   15765       0.15765             92%     Any w/Closure  10,000   10802       0.10802             32%     Iteration      10,000   8204        0.08204             -     TakeWhile      100,000  156950      1.5695              92%     Any w/Closure  100,000  108378      1.08378             33%     Iteration      100,000  81635       0.81635             -     Much better!  It seems that the overhead of TakeAny() returning each item and updating the state in the state machine is drastically reduced by using Any() since Any() iterates forward until it finds the value we're looking for -- for the task we're attempting to do.   So the lesson there is, make sure when you use a LINQ expression you're choosing the best expression for the job, because if you're doing more work than you really need, you'll have a slower algorithm.  But this is true of any choice of algorithm or collection in general.     Even with the Any() with the count in the closure it is still about 30% slower, but let's consider that angle carefully.  For a list of 100,000 items, it was the difference between 1.01 ms and 0.82 ms roughly in a List<T>.  That's really not that bad at all in the grand scheme of things.  Even running at 90% slower with TakeWhile(), for the vast majority of my projects, an extra millisecond to save potential errors in the long term and improve maintainability is a small price to pay.  And if your typical list is 1000 items or less we're talking only microseconds worth of difference.   It's like they say: 90% of your performance bottlenecks are in 2% of your code, so over-optimizing almost never pays off.  So personally, I'll take the LINQ expression wherever I can because they will be easier to read and maintain (thus reducing technical debt) and I can rely on Microsoft's development to have coded and unit tested those algorithm fully for me instead of relying on a developer to code the loop logic correctly.   If something's 90% slower, yes, it's worth keeping in mind, but it's really not until you start get magnitudes-of-order slower (10x, 100x, 1000x) that alarm bells should really go off.  And if I ever do need that last millisecond of performance?  Well then I'll optimize JUST THAT problem spot.  To me it's worth it for the readability, speed-to-market, and maintainability.

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  • Windows Azure Myths

    - by BuckWoody
    Windows Azure is part of the Microsoft "stack" - the suite of software and services we offer. Because we have so many products in almost every part of technology, it's hard to know everything about all parts of what we do - even for those of us who work here. So it's no surprise that some folks are not as familiar with Windows and SQL Azure as they are, say Windows Server or XBox. As I chat with folks about a solution for a business or organization need, I put Windows Azure into the mix. I always start off with "What do you already know about Windows Azure?" so that I don't bore folks with information they already have. I some cases they've checked out the product ahead of time and have specific questions, in others they aren't as familiar, and in still others there is a fair amount of mis-information. Sometimes that's because of a marketing failure, sometimes it's hearsay, and somtetimes it's active misinformation. I thought I might lay out a few of these misconceptions. As always - do your fact-checking! Never take anyone's word alone (including mine) as gospel. Make sure you educate yourself on your options. Your company or your clients depend on you to have the right information on IT, so make sure you live up to that. Myth 1: Nobody uses Windows Azure It's true that we don't give out numbers on the amount of clients on Windows and SQL Azure. But lots of folks are here - companies you may have heard of like Boeing, NASA, Fujitsu, The City of London, Nuedesic, and many others. I deal with firms small and large that use Windows Azure for mission-critical applications, sometimes totally on Windows and/or SQL Azure, sometimes in conjunction with an on-premises system, sometimes for only a specific component in Windows Azure like storage. The interesting thing is that many sites you visit have a Windows Azure component, or are running on Windows Azure. They just don't announce it. Just like the other cloud providers, the companies have asked to be completely branded themselves - they don't want you to be aware or care that they are on Windows Azure. Sometimes that's for security, other times it's for different reasons. It's just like the web sites you visit. For the most part, they don't advertise which OS or Web Server they use. It really just shouldn't matter. The point is that they just use what works to solve a given problem. Check out a few public case studies here: https://www.windowsazure.com/en-us/home/case-studies/ Myth 2: It's only for Microsoft stuff - can't use Open Source This is the one I face the most, and am the most dismayed by. We work just fine with many open source products, including Java, NodeJS, PHP, Ruby, Python, Hadoop, and many other languages and applications. You can quickly deploy a Wordpress, Umbraco and other "kits". We have software development kits (SDK's) for iPhones, iPads, Android, Windows phones and more. We have an SDK to work with FaceBook and other social networks. In short, we play well with others. More on the languages and runtimes we support here: https://www.windowsazure.com/en-us/develop/overview/ More on the SDK's here: http://www.wadewegner.com/2011/05/windows-azure-toolkit-for-ios/, http://www.wadewegner.com/2011/08/windows-azure-toolkits-for-devices-now-with-android/, http://azuretoolkit.codeplex.com/ Myth 3: Microsoft expects me to switch everything to "the cloud" No, we don't. That would be disasterous, unless the only things you run in your company uses works perfectly in Azure. Use Windows Azure  - or any cloud for that matter - where it works. Whenever I talk to companies, I focus on two things: Something that is broken and needs to be re-architected Something you want to do that is new If something is broken, and you need new tools to scale, extend, add capacity dynamically and so on, then you can consider using Windows or SQL Azure. It can help solve problems that you have, or it may include a component you don't want to write or architect yourself. Sometimes you want to do something new, like extend your company's offerings to mobile phones, to the web, or to a social network. More info on where it works here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx Myth 4: I have to write code to use Windows and SQL Azure If Windows Azure is a PaaS - a Platform as a Service - then don't you have to write code to use it? Nope. Windows and SQL Azure are made up of various components. Some of those components allow you to write and deploy code (like Compute) and others don't. We have lots of customers using Windows Azure storage as a backup, to securely share files instead of using DropBox, to distribute videos or code or firmware, and more. Others use our High Performance Computing (HPC) offering to rent a supercomputer when they need one. You can even throw workloads at that using Excel! In addition there are lots of other components in Windows Azure you can use, from the Windows Azure Media Services to others. More here: https://www.windowsazure.com/en-us/home/scenarios/saas/ Myth 5: Windows Azure is just another form of "vendor lock-in" Windows Azure uses .NET, OSS languages and standard interfaces for the code. Sure, you're not going to take the code line-for-line and run it on a mainframe, but it's standard code that you write, and can port to something else. And the data is yours - you can bring it back whever you want. It's either in text or binary form, that you have complete control over. There are no licenses - you can "pay as you go", and when you're done, you can leave the service and take all your code, data and IP with you.   So go out there, read up, try it. Use it where it works. And don't believe everything you hear - sometimes the Internet doesn't get it all correct. :)

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  • CodePlex Daily Summary for Wednesday, May 19, 2010

    CodePlex Daily Summary for Wednesday, May 19, 2010New Projects3FD - Framework For Fast Development: This is a C++ framework that provides a solid error handling structure, garbage collection, multi-threading and portability between compilers. The ...ali test project: test projectAttribute Builder: The Attribute Builder builds an attribute from a lambda expression because it can.BDK0008: it is a food lovers websitecgdigest: cg digest template for non-profit orgCokmez: Bilmuh cokmez duyuru sistemiDot Game: It is a dot game that our Bangladeshi people used to play at their childhood time and their last time when they are poor for working.ESRI Javascript .NET Integration: Visual Studio project that shows how to integrate the Esri Javascript API with .NET Exchange 2010 RBAC Editor (RBAC GUI): Exchange 2010 RBAC Editor (RBAC GUI) Developed in C# and using Powershell behind the scenes RBAC tool to simplfy RBAC administrationFile Validator (Validador de Archivos): Componente que permite realizar la validación de archivos (txt, imagenes, PDF, etc) actualmente solo tiene implementado la parte de los txt, permit...Grip 09 Lab4: GripjPageFlipper: This is a wonderful implementation of page flipper entirely based on HTML 5 <canvas> tag. It means that it can work in any browser that supports HT...Main project: Index bird families and associated species. Malware Analysis and Can Handler: MACH is a tool to organize and catalog your malware analysis canned responses, and to track the topic response lifecycle for forum experts.Perf Web: Performance team web sitePiPiBugNet: PiPiBugNet是一套全新的开源Bug管理系统。 PiPiBugNet代码基于ASP.NET 2.0平台开发,编程语言为C#。 PiPiBugNet界面基于Ext JS设计,提供了极佳的用户体验。RemoteDesktop: integrated remote console, desktop and chat utilityRuneScape emulation done right.: RuneScape emulator.Sandkasten: SandkastenSilverlight Metro Theme: Metro Theme for Silverlight.Silverlight Stereoscopy: Stereoscopy with Silverlight.Twitivia: Twitivia is an online trivia service that runs through twitter and is being used as an example set of projects. C#, MVC, Windows Services, Linq ...XPool: A simple school project.New ReleasesDot Game: 'Dot Game' first release: Dot Game first release This is the 'Dot Game' first release.DotNetNuke® Store: 02.01.35: What's New in this release? Bugs corrected: - Fixed a resource for the header in the Category list of the Store Admin module. - Added several test...ESRI Javascript .NET Integration: Map search results in a DataView: Visual Studio 2010 example showing how to pass Map results back to ASP.NET for use in a DataView.Exchange 2010 RBAC Editor (RBAC GUI): RBAC Editor: This binary is still beta (0.0.9.1) but in most case it's very stableExtending C# editor - Outlining, classification: first revision: a couple of bug has been eliminated, performance improvementFloe IRC Client: Floe IRC Client 2010-05 R6: Corrected bug where text would be unexpectedly copied to the clipboard.Floe IRC Client: Floe IRC Client 2010-05 R7: - Fixed bug where text would show up in a query window with someone if they said something on a channel that you are both present on.Free Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts v3.0.9 GA released: Hi, Today we have released the final version of Visifire v3.0.9 which contains the following enhancements: * Two new properties ActualAxisMin...Free Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts v3.5.2 GA Released: Hi, Today we have released the final version of Visifire v3.5.2 which contains the following enhancements: Two new properties ActualAxisMinimum a...HB Batch Encoder Mk 2: HB Batch Encoder Mk2 v1.02: Added .mov support.jPageFlipper: jPageFlipper 0.9: This is an initial community preview of jPageFlipper. It's not ready for production usage but has almost all functionality implemented.linq.js - LINQ for JavaScript: ver 2.1.0.0: Add Class Dictionary Lookup Grouping OrderedEnumerable Add Method ToDictionary MemoizeAll Share Let Add Overload ...Microsoft Research Biology Extension for Excel: MSR Biology Extension for Excel - M9: M9 Release includes the following updates to the previous release: > Import / Export support from Excel for multiple file formats > Bug fixes and ...Nifty CSharp Tools: Event Watcher: Event Watcher!Paint.NET Bulk Image Processor: Paint.NET Bulk Image Processor v1.0: This is the initial release of the Paint.NET Bulk Image processor plugin. All feedback is welcome.PiPiBugNet: PiPiBugNet架构设计: PiPiBugNet架构设计,未包含功能实现RuneScape emulation done right.: rc0: Release cantidate 0.Rx Contrib: V1.6: Adding CCR queue as adapter for the ReactiveQueue credits goes to Yuval Mazor http://blogs.microsoft.co.il/blogs/yuvmaz/Silverlight Metro Theme: Silverlight Metro Theme Alpha 1: Silverlight Metro Theme Alpha 1Silverlight Stereoscopy: Silverlight Stereoscopy Alpha 1: Silverlight Stereoscopy Alpha 20100518Stratosphere: Stratosphere 1.0.6.0: Introduced support for batch put Introduced Support for conditional updates and consistent read Added support for select conditions Brought t...VCC: Latest build, v2.1.30518.0: Automatic drop of latest buildVideo Downloader: Example Program - 1.1: Example Program showing the features of the DLL and what can be achieved using it. For DLL Version 1.1.Video Downloader: Version 1.1: Version 1.1 See Home Page for usage and more information regarding new features. Please remember changes at You-Tube can prevent this software from...WatchersNET.TagCloud: WatchersNET.TagCloud 01.06.00: Whats New New Tag Mode: Show Tags from Ventrian.com NewsArticles Module New Tag Mode: Show Tags from Ventrian.com SimpleGallery Module Hyperlin...Windows Double Explorer: WDE v0.4: -optimization -switch to new vst2010 -viewer close now by pressing escape -reorder tabs -send selected fullname or shortnames via email (eye button...Most Popular ProjectsRawrWBFS ManagerAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)patterns & practices – Enterprise LibraryMicrosoft SQL Server Community & SamplesPHPExcelASP.NETMost Active Projectspatterns & practices – Enterprise LibraryRawrPHPExcelGMap.NET - Great Maps for Windows Forms & PresentationCustomer Portal Accelerator for Microsoft Dynamics CRMBlogEngine.NETWindows Azure Command-line Tools for PHP DevelopersCassiniDev - Cassini 3.5/4.0 Developers EditionSQL Server PowerShell ExtensionsFluent Ribbon Control Suite

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  • Learning content for MCSDs: Web Applications and Windows Store Apps using HTML5

    Recently, I started again to learn for various Microsoft certifications. First candidate on my way to MSCD: Web Applications is the Exam 70-480: Programming in HTML5 with JavaScript and CSS3. Motivation to go for a Microsoft exam I guess, this is quite personal but let me briefly describe my intentions to go that exam. First, I'm doing web development since the 1990's. Working with HTML, CSS and Javascript is happening almost daily in my workspace. And honestly, I do not only do 'pure' web development but already integrated several HTML/CSS/Javascript frontend UIs into an existing desktop application (written in Visual FoxPro) inclusive two-way communication and data exchange. Hm, might be an interesting topic for another blog article here... Second, this exam has a very interesting aspect which is listed at the bottom of the exam's details: Credit Toward Certification When you pass Exam 70-480: Programming in HTML5 with JavaScript and CSS3, you complete the requirements for the following certification(s): Programming in HTML5 with JavaScript and CSS3 Specialist Exam 70-480: Programming in HTML5 with JavaScript and CSS3: counts as credit toward the following certification(s): MCSD: Web Applications MCSD: Windows Store Apps using HTML5 So, passing one single exam will earn you specialist certification straight-forward, and opens the path to higher levels of certifications. Preparations and learning path Well, due to a newsletter from Microsoft Learning (MSL) I caught interest in picking up the circumstances and learning materials for this particular exam. As of writing this article there is a promotional / voucher code available which enables you to register for this exam for free! Simply register yourself with or log into your existing account at Prometric, choose the exam for a testing facility near to you and enter the voucher code HTMLJMP (available through 31.03.2013 or while supplies last). Hurry up, there are restrictions... As stated above, I'm already very familiar with web development and the programming flavours involved into this. But of course, it is always good to freshen up your knowledge and reflect on yourself. Microsoft is putting a lot of effort to attract any kind of developers into the 'App Development'. Whether it is for the Windows 8 Store or the Windows Phone 8 Store, doesn't really matter. They simply need more apps. This demand for skilled developers also comes with a nice side-effect: Lots and lots of material to study. During the first couple of hours, I could easily gather high quality preparation material - again for free! Following is just a small list of starting points. If you have more resources, please drop me a message in the comment section, and I'll be glad to update this article accordingly. Developing HTML5 Apps Jump Start This is an accelerated jump start video course on development of HTML5 Apps for Windows 8. There are six modules that are split into two video sessions per module. Very informative and intense course material. This is packed stuff taken from an official preparation course for exam 70-480. Developing Windows Store Apps with HTML5 Jump Start Again, an accelerated preparation video course on Windows 8 Apps. There are six modules with two video sessions each which will catapult you to your exam. This is also related to preps for exam 70-481. Programming Windows 8 Apps with HTML, CSS, and JavaScript Kraig Brockschmidt delves into the ups and downs of Windows 8 App development over 800+ pages. Great eBook to read, study, and to practice the samples - best of all, it's for free. codeSHOW() This is a Windows 8 HTML/JS project with the express goal of demonstrating simple development concepts for the Windows 8 platform. Code, code and more code... absolutely great stuff to study and practice. Microsoft Virtual Academy I already wrote about the MVA in a previous article. Well, if you haven't registered yourself yet, now is the time. The list is not complete for sure, but this might keep you busy for at least one or even two weeks to go through the material. Please don't hesitate to add more resources in the comment section. Right now, I'm already through all videos once, and digging my way through chapter 4 of Kraig's book. Additional material - Pluralsight Apart from those free online resources, I also following some courses from the excellent library of Pluralsight. They already have their own section for Windows 8 development, but of course, you get companion material about HTML5, CSS and Javascript in other sections, too. Introduction to Building Windows 8 Applications Building Windows 8 Applications with JavaScript and HTML Selling Windows 8 Apps HTML5 Fundamentals Using HTML5 and CSS3 HTML5 Advanced Topics CSS3 etc... Interesting to see that Michael Palermo provides his course material on multiple platforms. Fantastic! You might also pay a visit to his personal blog. Hm, it just came to my mind that Aaron Skonnard of Pluralsight publishes so-called '24 hours Learning Paths' based on courses available in the course library. Would be interested to see a combination for Windows 8 App development using HTML5, CSS3 and Javascript in the future. Recommended workspace environment Well, you might have guessed it but this requires Windows 8, Visual Studio 2012 Express or another flavour, and a valid Developers License. Due to an MSDN subscription I working on VS 2012 Premium with some additional tools by Telerik. Honestly, the fastest way to get you up and running for Windows 8 App development is the source code archive of codeSHOW(). It does not only give you all source code in general but contains a couple of SDKs like Bing Maps, Microsoft Advertising, Live ID, and Telerik Windows 8 controls... for free! Hint: Get the Windows Phone 8 SDK as well. Don't worry, while you are studying the material for Windows 8 you will be able to leverage from this knowledge to development for the phone platform, too. It takes roughly one to two hours to get your workspace and learning environment, at least this was my time frame due to slow internet connection and an aged spare machine. ;-) Oh, before I forget to mention it, as soon as you're done, go quickly to the Windows Store and search for ClassBrowserPlus. You might not need it ad hoc for your development using HTML5, CSS and Javascript but I think that it is a great developer's utility that enables you to view the properties, methods and events (along with help text) for all Windows 8 classes. It's always good to look behind the scenes and to explore how it is made. Idea: Start/join a learning group The way you learn new things or intensify your knowledge in a certain technology is completely up to your personal preference. Back in my days at the university, we used to meet once or twice a week in a small quiet room to exchange our progress, questions and problems we ran into. In general, I recommend to any software craftsman to lift your butt and get out to exchange with other developers. Personally, I like this approach, as it gives you new points of view and an insight into others' own experience with certain techniques and how they managed to solve tricky issues. Just keep it relaxed and not too formal after all, and you might a have a good time away from your dull office desk. Give your machine a break, too.

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  • Charms and the App Bar

    - by Dennis Vroegop
    Ok. I admit. I made a mistake in the last post about our planespotter app. I have dedicated a full part of the hub to Social. I also had a section called Friends but that made sense since I said that “Friends” is a special group of people that connect to each other through our app and only our app. Social however is sharing our spots with Twitter, Facebook and so on. Now, we could write that functionality in our app in a different section but there is one small problem with that: users don’t expect that. Ok, I admit. The mistake was quite deliberate to give me an excuse to write this part. But still: the mistake is one I see a lot. People are trying to do stuff in their application that they shouldn’t be doing. This always strike me as slightly odd: why do some work when others have already done it for you and you can just use it? After all: good developers are lazy (lazy people will always try to find the easiest way to do something and in development land this usually means the cleanest and best to support way…) So. What is that part that Microsoft has done for us and we don’t have to do ourselves? The answer lies on the right hand of your Win8 screen: This is a screenshot of my tablet (as you can see I am writing this right now….) When I swipe my finger from out of the screen on the right inside the screen (or move the mouse to the upper right corner) this menu will appear. Next to settings and the start menu button we’ll find the Search and the Share charms. These are two ways that your app can share the information it contains with the rest of the world, or at least: the rest of your system. So don’t write a Search feature in your app. Don’t write a Share feature in your app. It’s here already. Users, once they are used to Windows 8, will use that feature and expect it to work. If it doesn’t, they won’t like your app and you can kiss you dreams of everlasting fame goodbye. So use these two. What are they? Well, simply they are parts of a contract. In your app you say somewhere in code that you are supporting Search and Share. So when the user selects Share the system will interrogate the current app in the foreground if it supports this feature. Your app will say “But why, yes, I do!” Then the system will ask the app “Ok then, wisecrack, then share!” and you will have to provide the system with some information about the format. Other applications have subscribed to be at the receiving end of the Share contract. They have told the system that they support Sharing (receiving) and which formats they understand. If one or more of them support the formats you specify, the user will see them. The user clicks / taps on the app of their choice and data is moved from your app to the new one. So if you say you support Facebook and Twitter users can post data from your app to these networks by selecting Share. The same applies to Search. Don’t make a “search” button in your app but use the contract to tell the system that you support search and use that instead. Users will be grateful (remember that bar with men/women/creatures that are waiting for you?) The more and more people get to know Windows 8, the more they will use this. And if you are one of the people who wrote an app that helped them learn the system, well, that’s even better. So. We don’t have a Share or a Search button. We do have other buttons. Most important: we probably need a “New Spot” button. And a “Filter” might be useful. Or someway to open the camera so you can add a picture to the spot. Where will be put those? The answer is the “Appbar” . This is a application / context aware menu that slides up from the bottom of the screen when you move your finger / mouse from below the screen into it. From above downwards works just as well. Here you see an example of the appbar from the People app. (click on it for a larger version). This appears whenever you slide your finger up from below of down from above. This is where you put your commands. Remember, this is context aware so this menu will change when you are in different parts of your app or when you have selected different items. There are a few conventions when you create this appbar. First, the items on the right are “General” items, meaning they have little to do with what is on the screen right now. I think this would be a great place to add our “New Spot” icon. On the far left are items associated with the current selected item or screen. So if you have a spot selected, the button for Add Photo should be visible here and on the left hand side. Not everything is as clear as this, but this is what you should strive for. Group items together. And please note: this is the only place in Metro design where we are allowed to use lines as separators. So when you want to separate a group of icons from another group, add a line. Also note the simplicity of the buttons. No colors, no lights or shadows, no 3D. After a couple of years of fancy almost realistic looking icons people have finally decided that hey, this is a virtual world: it’s ok to look virtual as well. So make things as readable and clear as possible and don’t try to duplicate nature. It’s all about the information, remember? (If you don’t remember I’d like to point you to a older blog post of mine about the what and why of Metro). So.. think about the buttons a bit and think about Share and Search. What will you put there? Remember: this is the way the users interact with your apps and while you shouldn’t judge a book by its covers when it comes to people, this isn’t entirely so when it comes to apps. People DO judge an app by its looks and the way it feels. Take advantage of that. History has learned that a crappy app with a GREAT user interface gets better reviews than a GREAT app with a lousy UI… I know: developers will find this extremely unfair but that’s the world we live in (No, I am not saying you should deliver rubbish apps). Next time: we’ll start by building the darn thing!

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  • SQL SERVER – Thinking about Deprecated, Discontinued Features and Breaking Changes while Upgrading to SQL Server 2012 – Guest Post by Nakul Vachhrajani

    - by pinaldave
    Nakul Vachhrajani is a Technical Specialist and systems development professional with iGATE having a total IT experience of more than 7 years. Nakul is an active blogger with BeyondRelational.com (150+ blogs), and can also be found on forums at SQLServerCentral and BeyondRelational.com. Nakul has also been a guest columnist for SQLAuthority.com and SQLServerCentral.com. Nakul presented a webcast on the “Underappreciated Features of Microsoft SQL Server” at the Microsoft Virtual Tech Days Exclusive Webcast series (May 02-06, 2011) on May 06, 2011. He is also the author of a research paper on Database upgrade methodologies, which was published in a CSI journal, published nationwide. In addition to his passion about SQL Server, Nakul also contributes to the academia out of personal interest. He visits various colleges and universities as an external faculty to judge project activities being carried out by the students. Disclaimer: The opinions expressed herein are his own personal opinions and do not represent his employer’s view in anyway. Blog | LinkedIn | Twitter | Google+ Let us hear the thoughts of Nakul in first person - Those who have been following my blogs would be aware that I am recently running a series on the database engine features that have been deprecated in Microsoft SQL Server 2012. Based on the response that I have received, I was quite surprised to know that most of the audience found these to be breaking changes, when in fact, they were not! It was then that I decided to write a little piece on how to plan your database upgrade such that it works with the next version of Microsoft SQL Server. Please note that the recommendations made in this article are high-level markers and are intended to help you think over the specific steps that you would need to take to upgrade your database. Refer the documentation – Understand the terms Change is the only constant in this world. Therefore, whenever customer requirements, newer architectures and designs require software vendors to make a change to the keywords, functions, etc; they ensure that they provide their end users sufficient time to migrate over to the new standards before dropping off the old ones. Microsoft does that too with it’s Microsoft SQL Server product. Whenever a new SQL Server release is announced, it comes with a list of the following features: Breaking changes These are changes that would break your currently running applications, scripts or functionalities that are based on earlier version of Microsoft SQL Server These are mostly features whose behavior has been changed keeping in mind the newer architectures and designs Lesson: These are the changes that you need to be most worried about! Discontinued features These features are no longer available in the associated version of Microsoft SQL Server These features used to be “deprecated” in the prior release Lesson: Without these changes, your database would not be compliant/may not work with the version of Microsoft SQL Server under consideration Deprecated features These features are those that are still available in the current version of Microsoft SQL Server, but are scheduled for removal in a future version. These may be removed in either the next version or any other future version of Microsoft SQL Server The features listed for deprecation will compose the list of discontinued features in the next version of SQL Server Lesson: Plan to make necessary changes required to remove/replace usage of the deprecated features with the latest recommended replacements Once a feature appears on the list, it moves from bottom to the top, i.e. it is first marked as “Deprecated” and then “Discontinued”. We know of “Breaking change” comes later on in the product life cycle. What this means is that if you want to know what features would not work with SQL Server 2012 (and you are currently using SQL Server 2008 R2), you need to refer the list of breaking changes and discontinued features in SQL Server 2012. Use the tools! There are a lot of tools and technologies around us, but it is rarely that I find teams using these tools religiously and to the best of their potential. Below are the top two tools, from Microsoft, that I use every time I plan a database upgrade. The SQL Server Upgrade Advisor Ever since SQL Server 2005 was announced, Microsoft provides a small, very light-weight tool called the “SQL Server upgrade advisor”. The upgrade advisor analyzes installed components from earlier versions of SQL Server, and then generates a report that identifies issues to fix either before or after you upgrade. The analysis examines objects that can be accessed, such as scripts, stored procedures, triggers, and trace files. Upgrade Advisor cannot analyze desktop applications or encrypted stored procedures. Refer the links towards the end of the post to know how to get the Upgrade Advisor. The SQL Server Profiler Another great tool that you can use is the one most SQL Server developers & administrators use often – the SQL Server profiler. SQL Server Profiler provides functionality to monitor the “Deprecation” event, which contains: Deprecation announcement – equivalent to features to be deprecated in a future release of SQL Server Deprecation final support – equivalent to features to be deprecated in the next release of SQL Server You can learn more using the links towards the end of the post. A basic checklist There are a lot of finer points that need to be taken care of when upgrading your database. But, it would be worth-while to identify a few basic steps in order to make your database compliant with the next version of SQL Server: Monitor the current application workload (on a test bed) via the Profiler in order to identify usage of features marked as Deprecated If none appear, you are all set! (This almost never happens) Note down all the offending queries and feature usages Run analysis sessions using the SQL Server upgrade advisor on your database Based on the inputs from the analysis report and Profiler trace sessions, Incorporate solutions for the breaking changes first Next, incorporate solutions for the discontinued features Revisit and document the upgrade strategy for your deployment scenarios Revisit the fall-back, i.e. rollback strategies in case the upgrades fail Because some programming changes are dependent upon the SQL server version, this may need to be done in consultation with the development teams Before any other enhancements are incorporated by the development team, send out the database changes into QA QA strategy should involve a comparison between an environment running the old version of SQL Server against the new one Because minimal application changes have gone in (essential changes for SQL Server version compliance only), this would be possible As an ongoing activity, keep incorporating changes recommended as per the deprecated features list As a DBA, update your coding standards to ensure that the developers are using ANSI compliant code – this code will require a change only if the ANSI standard changes Remember this: Change management is a continuous process. Keep revisiting the product release notes and incorporate recommended changes to stay prepared for the next release of SQL Server. May the power of SQL Server be with you! Links Referenced in this post Breaking changes in SQL Server 2012: Link Discontinued features in SQL Server 2012: Link Get the upgrade advisor from the Microsoft Download Center at: Link Upgrade Advisor page on MSDN: Link Profiler: Review T-SQL code to identify objects no longer supported by Microsoft: Link Upgrading to SQL Server 2012 by Vinod Kumar: Link Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Upgrade

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  • CEN/CENELEC Lacks Perspective

    - by trond-arne.undheim
    Over the last few months, two of the European Standardization Organizations (ESOs), CEN and CENELEC have circulated an unfortunate position statement distorting the facts around fora and consortia. For the benefit of outsiders to this debate, let's just say that this debate regards whether and how the EU should recognize standards and specifications from certain fora and consortia based on a process evaluating the openness and transparency of such deliverables. The topic is complex, and somewhat confusing even to insiders, but nevertheless crucial to the European economy. As far as I can judge, their positions are not based on facts. This is unfortunate. For the benefit of clarity, here are some of the observations they make: a)"Most consortia are in essence driven by technology companies making hardware and software solutions, by definition very few of the largest ones are European-based". b) "Most consortia lack a European presence, relevant Committees, even those that are often cited as having stronger links with Europe, seem to lack an overall, inclusive set of participants". c) "Recognising specific consortia specifications will not resolve any concrete problems of interoperability for public authorities; interoperability depends on stringing together a range of specifications (from formal global bodies or consortia alike)". d) "Consortia already have the option to have their specifications adopted by the international formal standards bodies and many more exercise this than the two that seem to be campaigning for European recognition. Such specifications can then also be adopted as European standards." e) "Consortium specifications completely lack any process to take due and balanced account of requirements at national level - this is not important for technologies but can be a critical issue when discussing cross-border issues within the EU such as eGovernment, eHealth and so on". f) "The proposed recognition will not lead to standstill on national or European activities, nor to the adoption of the specifications as national standards in the CEN and CENELEC members (usually in their official national languages), nor to withdrawal of conflicting national standards. A big asset of the European standardization system is its coherence and lack of fragmentation." g) "We always miss concrete and specific examples of where consortia referencing are supposed to be helpful." First of all, note that ETSI, the third ESO, did not join the position. The reason is, of course, that ETSI beyond being an ESO, also has a global perspective and, moreover, does consider reality. Secondly, having produced arguments a) to g), CEN/CENELEC has the audacity to call a meeting on Friday 25 February entitled "ICT standardization - improving collaboration in Europe". This sounds very nice, but they have not set the stage for constructive debate. Rather, they demonstrate a striking lack of vision and lack of perspective. I will back this up by three facts, and leave it there. 1. Since the 1980s, global industry fora and consortia, such as IETF, W3C and OASIS have emerged as world-leading ICT standards development organizations with excellent procedures for openness and transparency in all phases of standards development, ex post and ex ante. - Practically no ICT system can be built without using fora and consortia standards (FCS). - Without using FCS, neither the Internet, upon which the EU economy depends, nor EU institutions would operate. - FCS are of high relevance for achieving and promoting interoperability and driving innovation. 2. FCS are complementary to the formally recognized standards organizations including the ESOs. - No work will be taken away from the ESOs should the EU recognize certain FCS. - Each FCS would be evaluated on its merit and on the openness of the process that produced it. ESOs would, with other stakeholders, have a say. - ESOs could potentially educate and assist European stakeholders to engage more actively and constructively with FCS. - ETSI, also an ESO, seems to clearly recognize these facts. 3. Europe and its Member States have a strong voice in several of the most relevant global industry fora and consortia. - W3C: W3C was founded in 1994 by an Englishman, Sir Tim Berners-Lee, in collaboration with CERN, the European research lab. In April 1995, INRIA (Institut National de Recherche en Informatique et Automatique) in France became the first European W3C host and in 2003, ERCIM (European Research Consortium in Informatics and Mathematics), also based in France, took over the role of European W3C host from INRIA. Today, W3C has 326 Members, 40% of which are European. Government participation is also strong, and it could be increased - a development that is very much desired by W3C. Current members of the W3C Advisory Board includes Ora Lassila (Nokia) and Charles McCathie Nevile (Opera). Nokia is Finnish company, Opera is a Norwegian company. SAP's Claus von Riegen is an alumni of the same Advisory Board. - OASIS: its membership - 30% of which is European - represents the marketplace, reflecting a balance of providers, user companies, government agencies, and non-profit organizations. In particular, about 15% of OASIS members are governments or universities. Frederick Hirsch from Nokia, Claus von Riegen from SAP AG and Charles-H. Schulz from Ars Aperta are on the Board of Directors. Nokia is a Finnish company, SAP is a German company and Ars Aperta is a French company. The Chairman of the Board is Peter Brown, who is an Independent Consultant, an Austrian citizen AND an official of the European Parliament currently on long-term leave. - IETF: The oversight of its activities is by the Internet Architecture Board (IAB), since 2007 chaired by Olaf Kolkman, a Dutch national who lives in Uithoorn, NL. Kolkman is director of NLnet Labs, a foundation chartered to develop open source software and open source standards for the Internet. Other IAB members include Marcelo Bagnulo whose affiliation is the University Carlos III of Madrid, Spain as well as Hannes Tschofenig from Nokia Siemens Networks. Nokia is a Finnish company. Siemens is a German company. Nokia Siemens is a European joint venture. - Member States: At least 17 European Member States have developed Interoperability Frameworks that include FCS, according to the EU-funded National Interoperability Framework Observatory (see list and NIFO web site on IDABC). This also means they actively procure solutions using FCS, reference FCS in their policies and even in laws. Member State reps are free to engage in FCS, and many do. It would be nice if the EU adjusted to this reality. - A huge number of European nationals work in the global IT industry, on European soil or elsewhere, whether in EU registered companies or not. CEN/CENELEC lacks perspective and has engaged in an effort to twist facts that is quite striking from a publicly funded organization. I wish them all possible success with Friday's meeting but I fear all of the most important stakeholders will not be at the table. Not because they do not wish to collaborate, but because they just have been insulted. If they do show up, it would be a gracious move, almost beyond comprehension. While I do not expect CEN/CENELEC to line up perfectly in favor of fora and consortia, I think it would be to their benefit to stick to more palatable observations. Actually, I would suggest an apology, straightening out the facts. This works among friends and it works in an organizational context. Then, we can all move on. Standardization is important. Too important to ignore. Too important to distort. The European economy depends on it. We need CEN/CENELEC. It is an important organization. But CEN/CENELEC needs fora and consortia, too.

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  • Using Node.js as an accelerator for WCF REST services

    - by Elton Stoneman
    Node.js is a server-side JavaScript platform "for easily building fast, scalable network applications". It's built on Google's V8 JavaScript engine and uses an (almost) entirely async event-driven processing model, running in a single thread. If you're new to Node and your reaction is "why would I want to run JavaScript on the server side?", this is the headline answer: in 150 lines of JavaScript you can build a Node.js app which works as an accelerator for WCF REST services*. It can double your messages-per-second throughput, halve your CPU workload and use one-fifth of the memory footprint, compared to the WCF services direct.   Well, it can if: 1) your WCF services are first-class HTTP citizens, honouring client cache ETag headers in request and response; 2) your services do a reasonable amount of work to build a response; 3) your data is read more often than it's written. In one of my projects I have a set of REST services in WCF which deal with data that only gets updated weekly, but which can be read hundreds of times an hour. The services issue ETags and will return a 304 if the client sends a request with the current ETag, which means in the most common scenario the client uses its local cached copy. But when the weekly update happens, then all the client caches are invalidated and they all need the same new data. Then the service will get hundreds of requests with old ETags, and they go through the full service stack to build the same response for each, taking up threads and processing time. Part of that processing means going off to a database on a separate cloud, which introduces more latency and downtime potential.   We can use ASP.NET output caching with WCF to solve the repeated processing problem, but the server will still be thread-bound on incoming requests, and to get the current ETags reliably needs a database call per request. The accelerator solves that by running as a proxy - all client calls come into the proxy, and the proxy routes calls to the underlying REST service. We could use Node as a straight passthrough proxy and expect some benefit, as the server would be less thread-bound, but we would still have one WCF and one database call per proxy call. But add some smart caching logic to the proxy, and share ETags between Node and WCF (so the proxy doesn't even need to call the servcie to get the current ETag), and the underlying service will only be invoked when data has changed, and then only once - all subsequent client requests will be served from the proxy cache.   I've built this as a sample up on GitHub: NodeWcfAccelerator on sixeyed.codegallery. Here's how the architecture looks:     The code is very simple. The Node proxy runs on port 8010 and all client requests target the proxy. If the client request has an ETag header then the proxy looks up the ETag in the tag cache to see if it is current - the sample uses memcached to share ETags between .NET and Node. If the ETag from the client matches the current server tag, the proxy sends a 304 response with an empty body to the client, telling it to use its own cached version of the data. If the ETag from the client is stale, the proxy looks for a local cached version of the response, checking for a file named after the current ETag. If that file exists, its contents are returned to the client as the body in a 200 response, which includes the current ETag in the header. If the proxy does not have a local cached file for the service response, it calls the service, and writes the WCF response to the local cache file, and to the body of a 200 response for the client. So the WCF service is only troubled if both client and proxy have stale (or no) caches.   The only (vaguely) clever bit in the sample is using the ETag cache, so the proxy can serve cached requests without any communication with the underlying service, which it does completely generically, so the proxy has no notion of what it is serving or what the services it proxies are doing. The relative path from the URL is used as the lookup key, so there's no shared key-generation logic between .NET and Node, and when WCF stores a tag it also stores the "read" URL against the ETag so it can be used for a reverse lookup, e.g:   Key Value /WcfSampleService/PersonService.svc/rest/fetch/3 "28cd4796-76b8-451b-adfd-75cb50a50fa6" "28cd4796-76b8-451b-adfd-75cb50a50fa6" /WcfSampleService/PersonService.svc/rest/fetch/3    In Node we read the cache using the incoming URL path as the key and we know that "28cd4796-76b8-451b-adfd-75cb50a50fa6" is the current ETag; we look for a local cached response in /caches/28cd4796-76b8-451b-adfd-75cb50a50fa6.body (and the corresponding .header file which contains the original service response headers, so the proxy response is exactly the same as the underlying service). When the data is updated, we need to invalidate the ETag cache – which is why we need the reverse lookup in the cache. In the WCF update service, we don't need to know the URL of the related read service - we fetch the entity from the database, do a reverse lookup on the tag cache using the old ETag to get the read URL, update the new ETag against the URL, store the new reverse lookup and delete the old one.   Running Apache Bench against the two endpoints gives the headline performance comparison. Making 1000 requests with concurrency of 100, and not sending any ETag headers in the requests, with the Node proxy I get 102 requests handled per second, average response time of 975 milliseconds with 90% of responses served within 850 milliseconds; going direct to WCF with the same parameters, I get 53 requests handled per second, mean response time of 1853 milliseconds, with 90% of response served within 3260 milliseconds. Informally monitoring server usage during the tests, Node maxed at 20% CPU and 20Mb memory; IIS maxed at 60% CPU and 100Mb memory.   Note that the sample WCF service does a database read and sleeps for 250 milliseconds to simulate a moderate processing load, so this is *not* a baseline Node-vs-WCF comparison, but for similar scenarios where the  service call is expensive but applicable to numerous clients for a long timespan, the performance boost from the accelerator is considerable.     * - actually, the accelerator will work nicely for any HTTP request, where the URL (path + querystring) uniquely identifies a resource. In the sample, there is an assumption that the ETag is a GUID wrapped in double-quotes (e.g. "28cd4796-76b8-451b-adfd-75cb50a50fa6") – which is the default for WCF services. I use that assumption to name the cache files uniquely, but it is a trivial change to adapt to other ETag formats.

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  • At most how many customized P3 attributes could be added into Agile?

    - by Jie Chen
    I have one customer/Oracle Partner Consultant asking me such question: how many customized attributes can be allowed to add to Agile's subclass Page Three? I never did research against this because Agile User Guide never says this and theoretically Agile supports unlimited amount of customized attributes, unless the browser itself cannot handle them in allocated memory. However my customers says when to add almost 1000 attributes, the browser (Web Client) will not show any Page Three attributes, including all the out-of-box attributes. Let's see why. Analysis It is horrible to add 1000 attributes manually. Let's do it by a batch SQL like below to add them to Item's subclass Page Three tab. Do not execute below SQL because it will not take effect due to your different node id. CREATE OR REPLACE PROCEDURE createP3Text(v_name IN VARCHAR2) IS v_nid NUMBER; v_pid NUMBER; BEGIN select SEQNODETABLE.nextval into v_nid from dual; Insert Into nodeTable ( id,parentID,description,objType,inherit,helpID,version,name ) values ( v_nid,2473003, v_name ,1,0,0,0, v_name); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,925, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,1,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,2,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,2,0,1,3,'50'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,5, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,2,0,1,6,'50'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,2,0,0,7,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,8,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,9,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,1,10,v_name); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,11,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,11743,1,14,'2'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,30, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,38, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,59,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,60,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,724,0,61, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,0,232,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,233,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,12239,1,415,'13307'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,0,605,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,610,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,716,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,795,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,2000008821,1,864,'2'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,923,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,0,719,'0'); Insert Into tableInfo ( tabID,tableID,classID,att,ordering ) values ( 2473005,1501,2473002,v_nid,9999); commit; END createP3Text; / BEGIN FOR i in 1..1000 LOOP createP3Text('MyText' || i); END LOOP; END; / DROP PROCEDURE createP3Text; COMMIT; Now restart Agile Server and check the Server's log, we noticed below: ***** Node Created : 85625 ***** Property Created : 184579 +++++++++++++++++++++++++++++++++++++ + Agile PLM Server Starting Up... + +++++++++++++++++++++++++++++++++++++ However the previously log before batch SQL is ***** Node Created : 84625 ***** Property Created : 157579 +++++++++++++++++++++++++++++++++++++ + Agile PLM Server Starting Up... + +++++++++++++++++++++++++++++++++++++ Obviously we successfully imported 1000 (85625-84625) attributes. Now go to JavaClient and confirm if we have them or not. Theoretically we are able to open such item object and see all these 1000 attributes and their values, but we get below error. We have no error tips in server log. But never mind we have the Java Console for JavaClient. If to open the same item in JavaClient we get a clear error and detailed trace in Java Console. ORA-01795: maximum number of expressions in a list is 1000 java.sql.SQLException: ORA-01795: maximum number of expressions in a list is 1000 at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:125) ... ... at weblogic.jdbc.wrapper.PreparedStatement.executeQuery(PreparedStatement.java:128) at com.agile.pc.cmserver.base.AgileFlexUtil.setFlexValuesForOneRowTable(AgileFlexUtil.java:1104) at com.agile.pc.cmserver.base.BaseFlexTableDAO.loadExtraFlexAttValues(BaseFlexTableDAO.java:111) at com.agile.pc.cmserver.base.BasePageThreeDAO.loadTable(BasePageThreeDAO.java:108) If you are interested in the background of the problem, you may de-compile the class com.agile.pc.cmserver.base.AgileFlexUtil.setFlexValuesForOneRowTable and find the root cause that Agile happens to hit Oracle Database's limitation that more than 1000 values in the "IN" clause. Check here http://ora-01795.ora-code.com If you need Oracle Agile's final solution, please contact Oracle Agile Support. Performance Below two screenshot are jvm heap usage from before-SQL and after-SQL. We can see there is no big memory gap between two cases. So definitely there is no performance impact to Agile Application Server unless you have more than 1000 attributes for EACH of your dozens of  subclasses. And for client, 1000 attributes should not impact the browser's performance because in HTML we only use dt and dd for each attribute's pair: label and value. It is quite lightweight.

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  • HTML5 Input type=date Formatting Issues

    - by Rick Strahl
    One of the nice features in HTML5 is the abililty to specify a specific input type for HTML text input boxes. There a host of very useful input types available including email, number, date, datetime, month, number, range, search, tel, time, url and week. For a more complete list you can check out the MDN reference. Date input types also support automatic validation which can be useful in some scenarios but maybe can get in the way at other times. One of the more common input types, and one that can most benefit of a custom UI for selection is of course date input. Almost every application could use a decent date representation and HTML5's date input type seems to push into the right direction. It'd be nice if you could just say:<form action="DateTest.html"> <label for="FromDate">Enter a Date:</label> <input type="date" id="FromDate" name="FromDate" value="11/08/2012" class="date" /> <hr /> <input type="submit" id="btnSubmit" name="btnSubmit" value="Save Date" class="smallbutton" /> </form> but if you'd expect to just work, you're likely to be pretty disappointed. Problem #1: Browser Support For starters there's browser support. Out of the major browsers only the latest versions of WebKit and Opera based browsers seem to support date input. Neither FireFox, nor any version of Internet Explorer (including the new touch enabled IE10 in Windows RT) support input type=date. Browser support is an issue, but it would be OK if it wasn't for problem #2. Problem #2: Date Formatting If you look at my date input from before:<input type="date" id="FromDate" name="FromDate" value="11/08/2012" class="date" /> You can see that my date is formatted in local date format (ie. en-us). Now when I run this sadly the form that comes up in Chrome (and also iOS mobile browsers) comes up like this: Chrome isn't recognizing my local date string. Instead it's expecting my date format to be provided in ISO 8601 format which is: 2012-11-08 So if I change the date input field to:<input type="date" id="FromDate" name="FromDate" value="2012-10-08" class="date" /> I correctly get the date field filled in: Also when I pick a date with the DatePicker the date value is also returned is also set to the ISO date format. Yet notice how the date is still formatted to the local date time format (ie. en-US format). So if I pick a new date: and then save, the value field is set back to: 2012-11-15 using the ISO format. The same is true for Opera and iOS browsers and I suspect any other WebKit style browser and their date pickers. So to summarize input type=date: Expects ISO 8601 format dates to display intial values Sets selected date values to ISO 8601 Now what? This would sort of make sense, if all browsers supported input type=date. It'd be easy because you could just format dates appropriately when you set the date value into the control by applying the appropriate culture formatting (ie. .ToString("yyyy-MM-dd") ). .NET is actually smart enough to pick up the date on the other end for modelbinding when ISO 8601 is used. For other environments this might be a bit more tricky. input type=date is clearly the way to go forward. Date controls implemented in HTML are going the way of the dodo, given the intricacies of mobile platforms and scaling for both desktop and mobile. I've been using jQuery UI Datepicker for ages but once going to mobile, that's no longer an option as the control doesn't scale down well for mobile apps (at least not without major re-styling). It also makes a lot of sense for the browser to provide this functionality - creating a consistent date input experience across apps only makes sense, which is why I find it baffling that neither FireFox nor IE 10 deign it necessary to support date input natively. The problem is that a large number of even the latest and greatest browsers don't support this. So now you're stuck with not knowing what date format you have to serve since neither the local format, nor the ISO format works in all cases. For my current app I just broke down and used the ISO format and so I'll live with the non-local date format. <input type="date" id="ToDate" name="ToDate" value="2012-11-08" class="date"/> Here's what this looks like on Chrome: Here's what it looks like on my iPhone: Both Chrome and the phone do this the way it should be. For the phone especially this demonstrates why we'd want this - the built-in date picker there certainly beats manually trying to edit the date using finger gymnastics, and it's one of the easiest ways to pick a date I can think of (ie. easier to use than your typical date picker). Finally here's what the date looks like in FireFox: Certainly this is not the ideal date format, but it's clear enough I suppose. If users enter a date in local US format and that works as well (but won't work for other locales). It'll have to do. Over time one can only hope that other browsers will finally decide to implement this functionality natively to provide a unique experience. Until then, incomplete solutions it is. Related Posts Html 5 Input Types - How useful is this really going to be?© Rick Strahl, West Wind Technologies, 2005-2012Posted in HTML5  HTML   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • SQL SERVER – Weekly Series – Memory Lane – #032

    - by Pinal Dave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Complete Series of Database Coding Standards and Guidelines SQL SERVER Database Coding Standards and Guidelines – Introduction SQL SERVER – Database Coding Standards and Guidelines – Part 1 SQL SERVER – Database Coding Standards and Guidelines – Part 2 SQL SERVER Database Coding Standards and Guidelines Complete List Download Explanation and Example – SELF JOIN When all of the data you require is contained within a single table, but data needed to extract is related to each other in the table itself. Examples of this type of data relate to Employee information, where the table may have both an Employee’s ID number for each record and also a field that displays the ID number of an Employee’s supervisor or manager. To retrieve the data tables are required to relate/join to itself. Insert Multiple Records Using One Insert Statement – Use of UNION ALL This is very interesting question I have received from new developer. How can I insert multiple values in table using only one insert? Now this is interesting question. When there are multiple records are to be inserted in the table following is the common way using T-SQL. Function to Display Current Week Date and Day – Weekly Calendar Straight blog post with script to find current week date and day based on the parameters passed in the function.  2008 In my beginning years, I have almost same confusion as many of the developer had in their earlier years. Here are two of the interesting question which I have attempted to answer in my early year. Even if you are experienced developer may be you will still like to read following two questions: Order Of Column In Index Order of Conditions in WHERE Clauses Example of DISTINCT in Aggregate Functions Have you ever used DISTINCT with the Aggregation Function? Here is a simple example about how users can do it. Create a Comma Delimited List Using SELECT Clause From Table Column Straight to script example where I explained how to do something easy and quickly. Compound Assignment Operators SQL SERVER 2008 has introduced new concept of Compound Assignment Operators. Compound Assignment Operators are available in many other programming languages for quite some time. Compound Assignment Operators is operator where variables are operated upon and assigned on the same line. PIVOT and UNPIVOT Table Examples Here is a very interesting question – the answer to the question can be YES or NO both. “If we PIVOT any table and UNPIVOT that table do we get our original table?” Read the blog post to get the explanation of the question above. 2009 What is Interim Table – Simple Definition of Interim Table The interim table is a table that is generated by joining two tables and not the final result table. In other words, when two tables are joined they create an interim table as resultset but the resultset is not final yet. It may be possible that more tables are about to join on the interim table, and more operations are still to be applied on that table (e.g. Order By, Having etc). Besides, it may be possible that there is no interim table; sometimes final table is what is generated when the query is run. 2010 Stored Procedure and Transactions If Stored Procedure is transactional then, it should roll back complete transactions when it encounters any errors. Well, that does not happen in this case, which proves that Stored Procedure does not only provide just the transactional feature to a batch of T-SQL. Generate Database Script for SQL Azure When talking about SQL Azure the most common complaint I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate a script which is compatible with SQL Azure. Convert IN to EXISTS – Performance Talk It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. You can read about this subject in the associated blog post. Subquery or Join – Various Options – SQL Server Engine Knows the Best Every single time whenever there is a performance tuning exercise, I hear the conversation from developer where some prefer subquery and some prefer join. In this two part blog post, I explain the same in the detail with examples. Part 1 | Part 2 Merge Operations – Insert, Update, Delete in Single Execution MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. 2011 Puzzle – Statistics are not updated but are Created Once Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated – WHY? Question to You – When to use Function and When to use Stored Procedure Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. 2012 In year 2012 I had two interesting series ran on the blog. If there is no fun in learning, the learning becomes a burden. For the same reason, I had decided to build a three part quiz around SEQUENCE. The quiz was to identify the next value of the sequence. I encourage all of you to take part in this fun quiz. Guess the Next Value – Puzzle 1 Guess the Next Value – Puzzle 2 Guess the Next Value – Puzzle 3 Guess the Next Value – Puzzle 4 Simple Example to Configure Resource Governor – Introduction to Resource Governor Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. We can limit the amount of CPU and memory consumption by limiting /governing /throttling on the SQL Server. If there are different workloads running on SQL Server and each of the workload needs different resources or when workloads are competing for resources with each other and affecting the performance of the whole server resource governor is a very important task. Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug SQL SERVER – Load Generator – Free Tool From CodePlex The best part of this SQL Server Load Generator is that users can run multiple simultaneous queries again SQL Server using different login account and different application name. The interface of the tool is extremely easy to use and very intuitive as well. A Puzzle – Swap Value of Column Without Case Statement Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Emit Knowledge - social network for knowledge sharing

    - by hajan
    Emit Knowledge, as the words refer - it's a social network for emitting / sharing knowledge from users by users. Those who can benefit the most out of this network is perhaps all of YOU who have something to share with others and contribute to the knowledge world. I've been closely communicating with the core team of this very, very interesting, brand new social network (with specific purpose!) about the concept, idea and the vision they have for their product and I can say with a lot of confidence that this network has real potential to become something from which we will all benefit. I won't speak much about that and would prefer to give you link and try it yourself - http://www.emitknowledge.com Mainly, through the past few months I've been testing this network and it is getting improved all the time. The user experience is great, you can easily find out what you need and it follows some known patterns that are common for all social networks. They have some real good ideas and plans that are already under development for the next updates of their product. You can do micro blogging or you can do regular normal blogging… it’s up to you, and the way it works, it is seamless. Here is a short Question and Answers (QA) interview I made with the lead of the team, Marijan Nikolovski: 1. Can you please explain us briefly, what is Emit Knowledge? Emit Knowledge is a brand new knowledge based social network, delivering quality content from users to users. We believe that people’s knowledge, experience and professional thoughts compose quality content, worth sharing among millions around the world. Therefore, we created the platform that matches people’s need to share and gain knowledge in the most suitable and comfortable way. Easy to work with, Emit Knowledge lets you to smoothly craft and emit knowledge around the globe. 2. How 'old' is Emit Knowledge? In hamster’s years we are almost five years old start-up :). Just kidding. We’ve released our public beta about three months ago. Our official release date is 27 of June 2012. 3. How did you come up with this idea? Everything started from a simple idea to solve a complex problem. We’ve seen that the social web has become polluted with data and is on the right track to lose its base principles – socialization and common cause. That was our start point. We’ve gathered the team, drew some sketches and started to mind map the idea. After several idea refactoring’s Emit Knowledge was born. 4. Is there any competition out there in the market? Currently we don't have any competitors that share the same cause. What makes our platform different is the ideology that our product promotes and the functionalities that our platform offers for easy socialization based on interests and knowledge sharing. 5. What are the main technologies used to build Emit Knowledge? Emit Knowledge was built on a heterogeneous pallet of technologies. Currently, we have four of separation: UI – Built on ASP.NET MVC3 and Knockout.js; Messaging infrastructure – Build on top of RabbitMQ; Background services – Our in-house solution for job distribution, orchestration and processing; Data storage – Build on top of MongoDB; What are the main reasons you've chosen ASP.NET MVC? Since all of our team members are .NET engineers, the decision was very natural. ASP.NET MVC is the only Microsoft web stack that sticks to the HTTP behavioral standards. It is easy to work with, have a tiny learning curve and everyone who is familiar with the HTTP will understand its architecture and convention without any difficulties. 6. What are the main reasons for choosing ASP.NET MVC? Since all of our team members are .NET engineers, the decision was very natural. ASP.NET MVC is the only Microsoft web stack that sticks to the HTTP behavioral standards. It is easy to work with, have a tiny learning curve and everyone who is familiar with the HTTP will understand its architecture and convention without any difficulties. 7. Did you use some of the latest Microsoft technologies? If yes, which ones? Yes, we like to rock the cutting edge tech house. Currently we are using Microsoft’s latest technologies like ASP.NET MVC, Web API (work in progress) and the best for the last; we are utilizing Windows Azure IaaS to the bone. 8. Can you please tell us shortly, what would be the benefit of regular bloggers in other blogging platforms to join Emit Knowledge? Well, unless you are some of the smoking ace gurus whose blogs are followed by a large number of users, our platform offers knowledge based segregated community equipped with tools that will enable both current and future users to expand their relations and to self-promote in the community based on their activity and knowledge sharing. 10. I see you are working very intensively and there is already integration with some third-party services to make the process of sharing and emitting knowledge easier, which services did you integrate until now and what do you plan do to next? We have “reemit” functionality for internal sharing and we also support external services like: Twitter; LinkedIn; Facebook; For the regular bloggers we have an extra cream, Windows Live Writer support for easy blog posts emitting. 11. What should we expect next? Currently, we are working on a new fancy community feature. This means that we are going to support user groups to be formed. So for all existing communities and user groups out there, wait us a little bit, we are coming for rescue :). One of the top next features they are developing is the Community Feature. It means, if you have your own User Group, Community Group or any other Group on which you and your users are mostly blogging or sharing (emitting) knowledge in various ways, Emit Knowledge as a platform will help you have everything you need to promote your group, make new followers and host all the necessary stuff that you have had need of. I would invite you to try the network and start sharing knowledge in a way that will help you gather new followers and spread your knowledge faster, easier and in a more efficient way! Let’s Emit Knowledge!

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  • Sliding collision response

    - by dbostream
    I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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  • Changing CSS with jQuery syntax in Silverlight using jLight

    - by Timmy Kokke
    Lately I’ve ran into situations where I had to change elements or had to request a value in the DOM from Silverlight. jLight, which was introduced in an earlier article, can help with that. jQuery offers great ways to change CSS during runtime. Silverlight can access the DOM, but it isn’t as easy as jQuery. All examples shown in this article can be looked at in this online demo. The code can be downloaded here.   Part 1: The easy stuff Selecting and changing properties is pretty straight forward. Setting the text color in all <B> </B> elements can be done using the following code:   jQuery.Select("b").Css("color", "red");   The Css() method is an extension method on jQueryObject which is return by the jQuery.Select() method. The Css() method takes to parameters. The first is the Css style property. All properties used in Css can be entered in this string. The second parameter is the value you want to give the property. In this case the property is “color” and it is changed to “red”. To specify which element you want to select you can add a :selector parameter to the Select() method as shown in the next example.   jQuery.Select("b:first").Css("font-family", "sans-serif");   The “:first” pseudo-class selector selects only the first element. This example changes the “font-family” property of the first <B></B> element to “sans-serif”. To make use of intellisense in Visual Studio I’ve added a extension methods to help with the pseudo-classes. In the example below the “font-weight” of every “Even” <LI></LI> is set to “bold”.   jQuery.Select("li".Even()).Css("font-weight", "bold");   Because the Css() extension method returns a jQueryObject it is possible to chain calls to Css(). The following example show setting the “color”, “background-color” and the “font-size” of all headers in one go.   jQuery.Select(":header").Css("color", "#12FF70") .Css("background-color", "yellow") .Css("font-size", "25px");   Part 2: More complex stuff In only a few cases you need to change only one style property. More often you want to change an entire set op style properties all in one go.  You could chain a lot of Css() methods together. A better way is to add a class to a stylesheet and define all properties in there. With the AddClass() method you can set a style class to a set of elements. This example shows how to add the “demostyle” class to all <B></B> in the document.   jQuery.Select("b").AddClass("demostyle");   Removing the class works in the same way:   jQuery.Select("b").RemoveClass("demostyle");   jLight is build for interacting with to the DOM from Silverlight using jQuery. A jQueryObjectCss object can be used to define different sets of style properties in Silverlight. The over 60 most common Css style properties are defined in the jQueryObjectCss class. A string indexer can be used to access all style properties ( CssObject1[“background-color”] equals CssObject1.BackgroundColor). In the code below, two jQueryObjectCss objects are defined and instantiated.   private jQueryObjectCss CssObject1; private jQueryObjectCss CssObject2;   public Demo2() { CssObject1 = new jQueryObjectCss { BackgroundColor = "Lime", Color="Black", FontSize = "12pt", FontFamily = "sans-serif", FontWeight = "bold", MarginLeft = 150, LineHeight = "28px", Border = "Solid 1px #880000" }; CssObject2 = new jQueryObjectCss { FontStyle = "Italic", FontSize = "48", Color = "#225522" }; InitializeComponent(); }   Now instead of chaining to set all different properties you can just pass one of the jQueryObjectCss objects to the Css() method. In this case all <LI></LI> elements are set to match this object.   jQuery.Select("li").Css(CssObject1); When using the jQueryObjectCss objects chaining is still possible. In the following example all headers are given a blue backgroundcolor and the last is set to match CssObject2.   jQuery.Select(":header").Css(new jQueryObjectCss{BackgroundColor = "Blue"}) .Eq(-1).Css(CssObject2);   Part 3: The fun stuff Having Silverlight call JavaScript and than having JavaScript to call Silverlight requires a lot of plumbing code. Everything has to be registered and strings are passed back and forth to execute the JavaScript. jLight makes this kind of stuff so easy, it becomes fun to use. In a lot of situations jQuery can call a function to decide what to do, setting a style class based on complex expressions for example. jLight can do the same, but the callback methods are defined in Silverlight. This example calls the function() method for each <LI></LI> element. The callback method has to take a jQueryObject, an integer and a string as parameters. In this case jLight differs a bit from the actual jQuery implementation. jQuery uses only the index and the className parameters. A jQueryObject is added to make it simpler to access the attributes and properties of the element. If the text of the listitem starts with a ‘D’ or an ‘M’ the class is set. Otherwise null is returned and nothing happens.   private void button1_Click(object sender, RoutedEventArgs e) { jQuery.Select("li").AddClass(function); }   private string function(jQueryObject obj, int index, string className) { if (obj.Text[0] == 'D' || obj.Text[0] == 'M') return "demostyle"; return null; }   The last thing I would like to demonstrate uses even more Silverlight and less jLight, but demonstrates the power of the combination. Animating a style property using a Storyboard with easing functions. First a dependency property is defined. In this case it is a double named Intensity. By handling the changed event the color is set using jQuery.   public double Intensity { get { return (double)GetValue(IntensityProperty); } set { SetValue(IntensityProperty, value); } }   public static readonly DependencyProperty IntensityProperty = DependencyProperty.Register("Intensity", typeof(double), typeof(Demo3), new PropertyMetadata(0.0, IntensityChanged));   private static void IntensityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var i = (byte)(double)e.NewValue; jQuery.Select("span").Css("color", string.Format("#{0:X2}{0:X2}{0:X2}", i)); }   An animation has to be created. This code defines a Storyboard with one keyframe that uses a bounce ease as an easing function. The animation is set to target the Intensity dependency property defined earlier.   private Storyboard CreateAnimation(double value) { Storyboard storyboard = new Storyboard(); var da = new DoubleAnimationUsingKeyFrames(); var d = new EasingDoubleKeyFrame { EasingFunction = new BounceEase(), KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.0)), Value = value }; da.KeyFrames.Add(d); Storyboard.SetTarget(da, this); Storyboard.SetTargetProperty(da, new PropertyPath(Demo3.IntensityProperty)); storyboard.Children.Add(da); return storyboard; }   Initially the Intensity is set to 128 which results in a gray color. When one of the buttons is pressed, a new animation is created an played. One to animate to black, and one to animate to white.   public Demo3() { InitializeComponent(); Intensity = 128; }   private void button2_Click(object sender, RoutedEventArgs e) { CreateAnimation(255).Begin(); }   private void button3_Click(object sender, RoutedEventArgs e) { CreateAnimation(0).Begin(); }   Conclusion As you can see jLight can make the life of a Silverlight developer a lot easier when accessing the DOM. Almost all jQuery functions that are defined in jLight use the same constructions as described above. I’ve tried to stay as close as possible to the real jQuery. Having JavaScript perform callbacks to Silverlight using jLight will be described in more detail in a future tutorial about AJAX or eventing.

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  • ANTS Memory Profiler 7.0

    - by James Michael Hare
    I had always been a fan of ANTS products (Reflector is absolutely invaluable, and their performance profiler is great as well – very easy to use!), so I was curious to see what the ANTS Memory Profiler could show me. Background While a performance profiler will track how much time is typically spent in each unit of code, a memory profiler gives you much more detail on how and where your memory is being consumed and released in a program. As an example, I’d been working on a data access layer at work to call a market data web service.  This web service would take a list of symbols to quote and would return back the quote data.  To help consolidate the thousands of web requests per second we get and reduce load on the web services, we implemented a 5-second cache of quote data.  Not quite long enough to where customers will typically notice a quote go “stale”, but just long enough to be able to collapse multiple quote requests for the same symbol in a short period of time. A 5-second cache may not sound like much, but it actually pays off by saving us roughly 42% of our web service calls, while still providing relatively up-to-date information.  The question is whether or not the extra memory involved in maintaining the cache was worth it, so I decided to fire up the ANTS Memory Profiler and take a look at memory usage. First Impressions The main thing I’ve always loved about the ANTS tools is their ease of use.  Pretty much everything is right there in front of you in a way that makes it easy for you to find what you need with little digging required.  I’ve worked with other, older profilers before (that shall remain nameless other than to hint it was created by a very large chip maker) where it was a mind boggling experience to figure out how to do simple tasks. Not so with AMP.  The opening dialog is very straightforward.  You can choose from here whether to debug an executable, a web application (either in IIS or from VS’s web development server), windows services, etc. So I chose a .NET Executable and navigated to the build location of my test harness.  Then began profiling. At this point while the application is running, you can see a chart of the memory as it ebbs and wanes with allocations and collections.  At any given point in time, you can take snapshots (to compare states) zoom in, or choose to stop at any time.  Snapshots Taking a snapshot also gives you a breakdown of the managed memory heaps for each generation so you get an idea how many objects are staying around for extended periods of time (as an object lives and survives collections, it gets promoted into higher generations where collection becomes less frequent). Generating a snapshot brings up an analysis view with very handy graphs that show your generation sizes.  Almost all my memory is in Generation 1 in the managed memory component of the first graph, which is good news to me, because Gen 2 collections are much rarer.  I once3 made the mistake once of caching data for 30 minutes and found it didn’t get collected very quick after I released my reference because it had been promoted to Gen 2 – doh! Analysis It looks like (from the second pie chart) that the majority of the allocations were in the string class.  This also is expected for me because the majority of the memory allocated is in the web service responses, so it doesn’t seem the entities I’m adapting to (to prevent being too tightly coupled to the web service proxy classes, which can change easily out from under me) aren’t taking a significant portion of memory. I also appreciate that they have clear summary text in key places such as “No issues with large object heap fragmentation were detected”.  For novice users, this type of summary information can be critical to getting them to use a tool and develop a good working knowledge of it. There is also a handy link at the bottom for “What to look for on the summary” which loads a web page of help on key points to look for. Clicking over to the session overview, it’s easy to compare the samples at each snapshot to see how your memory is growing, shrinking, or staying relatively the same.  Looking at my snapshots, I’m pretty happy with the fact that memory allocation and heap size seems to be fairly stable and in control: Once again, you can check on the large object heap, generation one heap, and generation two heap across each snapshot to spot trends. Back on the analysis tab, we can go to the [Class List] button to get an idea what classes are making up the majority of our memory usage.  As was little surprise to me, System.String was the clear majority of my allocations, though I found it surprising that the System.Reflection.RuntimeMehtodInfo came in second.  I was curious about this, so I selected it and went into the [Instance Categorizer].  This view let me see where these instances to RuntimeMehtodInfo were coming from. So I scrolled back through the graph, and discovered that these were being held by the System.ServiceModel.ChannelFactoryRefCache and I was satisfied this was just an artifact of my WCF proxy. I also like that down at the bottom of the Instance Categorizer it gives you a series of filters and offers to guide you on which filter to use based on the problem you are trying to find.  For example, if I suspected a memory leak, I might try to filter for survivors in growing classes.  This means that for instances of a class that are growing in memory (more are being created than cleaned up), which ones are survivors (not collected) from garbage collection.  This might allow me to drill down and find places where I’m holding onto references by mistake and not freeing them! Finally, if you want to really see all your instances and who is holding onto them (preventing collection), you can go to the “Instance Retention Graph” which creates a graph showing what references are being held in memory and who is holding onto them. Visual Studio Integration Of course, VS has its own profiler built in – and for a free bundled profiler it is quite capable – but AMP gives a much cleaner and easier-to-use experience, and when you install it you also get the option of letting it integrate directly into VS. So once you go back into VS after installation, you’ll notice an ANTS menu which lets you launch the ANTS profiler directly from Visual Studio.   Clicking on one of these options fires up the project in the profiler immediately, allowing you to get right in.  It doesn’t integrate with the Visual Studio windows themselves (like the VS profiler does), but still the plethora of information it provides and the clear and concise manner in which it presents it makes it well worth it. Summary If you like the ANTS series of tools, you shouldn’t be disappointed with the ANTS Memory Profiler.  It was so easy to use that I was able to jump in with very little product knowledge and get the information I was looking it for. I’ve used other profilers before that came with 3-inch thick tomes that you had to read in order to get anywhere with the tool, and this one is not like that at all.  It’s built for your everyday developer to get in and find their problems quickly, and I like that! Tweet Technorati Tags: Influencers,ANTS,Memory,Profiler

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  • Routes on a sphere surface - Find geodesic?

    - by CaNNaDaRk
    I'm working with some friends on a browser based game where people can move on a 2D map. It's been almost 7 years and still people play this game so we are thinking of a way to give them something new. Since then the game map was a limited plane and people could move from (0, 0) to (MAX_X, MAX_Y) in quantized X and Y increments (just imagine it as a big chessboard). We believe it's time to give it another dimension so, just a couple of weeks ago, we began to wonder how the game could look with other mappings: Unlimited plane with continous movement: this could be a step forward but still i'm not convinced. Toroidal World (continous or quantized movement): sincerely I worked with torus before but this time I want something more... Spherical world with continous movement: this would be great! What we want Users browsers are given a list of coordinates like (latitude, longitude) for each object on the spherical surface map; browsers must then show this in user's screen rendering them inside a web element (canvas maybe? this is not a problem). When people click on the plane we convert the (mouseX, mouseY) to (lat, lng) and send it to the server which has to compute a route between current user's position to the clicked point. What we have We began writing a Java library with many useful maths to work with Rotation Matrices, Quaternions, Euler Angles, Translations, etc. We put it all together and created a program that generates sphere points, renders them and show them to the user inside a JPanel. We managed to catch clicks and translate them to spherical coords and to provide some other useful features like view rotation, scale, translation etc. What we have now is like a little (very little indeed) engine that simulates client and server interaction. Client side shows points on the screen and catches other interactions, server side renders the view and does other calculus like interpolating the route between current position and clicked point. Where is the problem? Obviously we want to have the shortest path to interpolate between the two route points. We use quaternions to interpolate between two points on the surface of the sphere and this seemed to work fine until i noticed that we weren't getting the shortest path on the sphere surface: We though the problem was that the route is calculated as the sum of two rotations about X and Y axis. So we changed the way we calculate the destination quaternion: We get the third angle (the first is latitude, the second is longitude, the third is the rotation about the vector which points toward our current position) which we called orientation. Now that we have the "orientation" angle we rotate Z axis and then use the result vector as the rotation axis for the destination quaternion (you can see the rotation axis in grey): What we got is the correct route (you can see it lays on a great circle), but we get to this ONLY if the starting route point is at latitude, longitude (0, 0) which means the starting vector is (sphereRadius, 0, 0). With the previous version (image 1) we don't get a good result even when startin point is 0, 0, so i think we're moving towards a solution, but the procedure we follow to get this route is a little "strange" maybe? In the following image you get a view of the problem we get when starting point is not (0, 0), as you can see starting point is not the (sphereRadius, 0, 0) vector, and as you can see the destination point (which is correctly drawn!) is not on the route. The magenta point (the one which lays on the route) is the route's ending point rotated about the center of the sphere of (-startLatitude, 0, -startLongitude). This means that if i calculate a rotation matrix and apply it to every point on the route maybe i'll get the real route, but I start to think that there's a better way to do this. Maybe I should try to get the plane through the center of the sphere and the route points, intersect it with the sphere and get the geodesic? But how? Sorry for being way too verbose and maybe for incorrect English but this thing is blowing my mind! EDIT: This code version is related to the first image: public void setRouteStart(double lat, double lng) { EulerAngles tmp = new EulerAngles ( Math.toRadians(lat), 0, -Math.toRadians(lng)); //set route start Quaternion qtStart.setInertialToObject(tmp); //do other stuff like drawing start point... } public void impostaDestinazione(double lat, double lng) { EulerAngles tmp = new AngoliEulero( Math.toRadians(lat), 0, -Math.toRadians(lng)); qtEnd.setInertialToObject(tmp); //do other stuff like drawing dest point... } public V3D interpolate(double totalTime, double t) { double _t = t/totalTime; Quaternion q = Quaternion.Slerp(qtStart, qtEnd, _t); RotationMatrix.inertialQuatToIObject(q); V3D p = matInt.inertialToObject(V3D.Xaxis.scale(sphereRadius)); //other stuff, like drawing point ... return p; } //mostly taken from a book! public static Quaternion Slerp(Quaternion q0, Quaternion q1, double t) { double cosO = q0.dot(q1); double q1w = q1.w; double q1x = q1.x; double q1y = q1.y; double q1z = q1.z; if (cosO < 0.0f) { q1w = -q1w; q1x = -q1x; q1y = -q1y; q1z = -q1z; cosO = -cosO; } double sinO = Math.sqrt(1.0f - cosO*cosO); double O = Math.atan2(sinO, cosO); double oneOverSinO = 1.0f / senoOmega; k0 = Math.sin((1.0f - t) * O) * oneOverSinO; k1 = Math.sin(t * O) * oneOverSinO; // Interpolate return new Quaternion( k0*q0.w + k1*q1w, k0*q0.x + k1*q1x, k0*q0.y + k1*q1y, k0*q0.z + k1*q1z ); } A little dump of what i get (again check image 1): Route info: Sphere radius and center: 200,000, (0.0, 0.0, 0.0) Route start: lat 0,000 °, lng 0,000 ° @v: (200,000, 0,000, 0,000), |v| = 200,000 Route end: lat 30,000 °, lng 30,000 ° @v: (150,000, 86,603, 100,000), |v| = 200,000 Qt dump: (w, x, y, z), rot. angle°, (x, y, z) rot. axis Qt start: (1,000, 0,000, -0,000, 0,000); 0,000 °; (1,000, 0,000, 0,000) Qt end: (0,933, 0,067, -0,250, 0,250); 42,181 °; (0,186, -0,695, 0,695) Route start: lat 30,000 °, lng 10,000 ° @v: (170,574, 30,077, 100,000), |v| = 200,000 Route end: lat 80,000 °, lng -50,000 ° @v: (22,324, -26,604, 196,962), |v| = 200,000 Qt dump: (w, x, y, z), rot. angle°, (x, y, z) rot. axis Qt start: (0,962, 0,023, -0,258, 0,084); 31,586 °; (0,083, -0,947, 0,309) Qt end: (0,694, -0,272, -0,583, -0,324); 92,062 °; (-0,377, -0,809, -0,450)

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  • Big Visible Charts

    - by Robert May
    An important part of Agile is the concept of transparency and visibility. In proper functioning teams, stakeholders can look at any team at any time in the iteration or release and see how that team is doing by simply looking at what we call Big Visible Charts. If you’ve done Scrum, you’ve seen these charts. However, interpreting these charts can often be an art form. There are several different charts that can be useful. In this newsletter, I’ll focus on the Iteration Burndown and Cumulative Flow charts. I’ve included a copy of the spreadsheet that I used to create the charts, and if you don’t have a tool that creates them for you, you can use this spreadsheet to do so. Our preferred tool for managing Scrum projects is Rally. Rally creates all of these charts for you, saving you quite a bit of time. The Iteration Burndown and Cumulative Flow Charts This is the main chart that teams use. Although less useful to stakeholders, this chart is critical to the team and provides quite a bit of information to the team about how their iteration is going. Most charts are a combination of the charts below, so you may need to combine aspects of each section to understand what is happening in your iterations. Ideal Ah, isn’t that a pretty picture? Unfortunately, it’s also very unrealistic. I’ve seen iterations that come close to ideal, but never that match perfectly. If your iteration matches perfectly, chances are, someone is playing with the numbers. Reality is just too difficult to have a burndown chart that matches this exactly. Late Planning Iteration started, but the team didn’t. You can tell this by the fact that the real number of estimated hours didn’t appear until day two. In the cumulative flow, you can also see that nothing was defined in Day one and two. You want to avoid situations like this. You’ll note that the team had to burn faster than is ideal to meet the iteration because of the late planning. This often results in long weeks and days. Testing Starved Determining whether or not testing is starved is difficult without the cumulative flow. The pattern in the burndown could be nothing more that developers not completing stories early enough or could be caused by stories being too big. With the cumulative flow, however, you see that only small bites are in progress and stories were completed early, but testing didn’t start testing until the end of the iteration, and didn’t complete testing all stories in the iteration. When this happens, question whether or not your testing resources are sufficient for your team and whether or not acceptance is adequately defined. No Testing With this one, both graphs show the same thing; the team needs testers and testing! Without testing, what was completed cannot be verified to make sure that it is acceptable to the business. If you find yourself in this situation, review your testing practices and acceptance testing process and make changes today. Late Development With this situation, both graphs tell a story. In the top graph, you can see that the hours failed to burn down as quickly as the team expected. This could be caused by the team not correctly estimating their hours or the team could have had illness or some other issue that affected them. Often, when teams are tackling something that is more unknown, they’ll run into technical barriers that cause the burn down to happen slower than expected. In the cumulative flow graph, you can see that not much was completed in the first few days. This could be because of illness or technical barriers or simply poor estimation. Testing was able to keep up with everything that was completed, however. No Tool Updating When you see graphs that look like this, you can be assured that it’s because the team is not updating the tool that generates the graphs. Review your policy for when they are to update. On the teams that I run, I require that each team member updates the tool at least once daily. You should also check to see how well the team is breaking down stories into tasks. If they’re creating few large tasks, graphs can look similar to this. As a general rule, I never allow tasks, other than Unit Testing and Uncertainty, to be greater than eight hours in duration. Scope Increase I always encourage team members to enter in however much time they think they have left on a task, even if that means increasing the total amount of time left to do. You get a much better and more realistic picture this way. Increasing time remaining could explain the burndown graph, but by looking at the cumulative flow graph, we can see that stories were added to the iteration and scope was increased. Since planning should consume all of the hours in the iteration, this is almost always a bad thing. If the scope change happened late in the iteration and the hours remaining were well below the ideal burn, then increasing scope is probably o.k., but estimation needs to get better. However, with the charts above, that’s clearly not what happened and the team was required to do extra work to make the iteration. If you find this happening, your product owner and ScrumMasters need training. The team also needs to learn to say no. Scope Decrease Scope decreases are just as bad as scope increases. Usually, graphs above show that the team did a poor job of estimating their stories and part way through had to reduce scope to change the iteration. This will happen once in a while, but if you find it’s a pattern on your team, you need to re-evaluate planning. Some teams are hopelessly optimistic. In those cases, I’ll introduce a task I call “Uncertainty.” With Uncertainty, the team estimates how many hours they might need if things don’t go well with the tasks they’ve defined. They try to estimate things that could go poorly and increase the time appropriately. Having an Uncertainty task allows them to have a low and high estimate. Uncertainty should not just be an arbitrary buffer. It must correlate to real uncertainty in the tasks that have been defined. Stories are too Big Often, we see graphs like the ones above. Note that the burndown looks fairly good, other than the chunky acceptance of stories. However, when you look at cumulative flow, you can see that at one point, everything is in progress. This is a bad thing. When you see graphs like this, you’re in one of two states. You may just have a very small team and can only handle one or two stories in your iteration. If you have more than one or two people, then the most likely problem is that your stories are far too big. To combat this, break large high hour stories into smaller pieces that can be completed independently and accepted independently. If you don’t, you’ll likely be requiring your testers to do heroic things to complete testing on the last day of the iteration and you’re much more likely to have the entire iteration fail, because of the limited amount of things that can be completed. Summary There are other charts that can be useful when doing scrum. If you don’t have any big visible charts, you really need to evaluate your process and change. These charts can provide the team a wealth of information and help you write better software. If you have any questions about charts that you’re seeing on your team, contact me with a screen capture of the charts and I’ll tell you what I’m seeing in those charts. I always want this information to be useful, so please let me know if you have other questions. Technorati Tags: Agile

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  • Setting useLegacyV2RuntimeActivationPolicy At Runtime

    - by Reed
    Version 4.0 of the .NET Framework included a new CLR which is almost entirely backwards compatible with the 2.0 version of the CLR.  However, by default, mixed-mode assemblies targeting .NET 3.5sp1 and earlier will fail to load in a .NET 4 application.  Fixing this requires setting useLegacyV2RuntimeActivationPolicy in your app.Config for the application.  While there are many good reasons for this decision, there are times when this is extremely frustrating, especially when writing a library.  As such, there are (rare) times when it would be beneficial to set this in code, at runtime, as well as verify that it’s running correctly prior to receiving a FileLoadException. Typically, loading a pre-.NET 4 mixed mode assembly is handled simply by changing your app.Config file, and including the relevant attribute in the startup element: <?xml version="1.0" encoding="utf-8" ?> <configuration> <startup useLegacyV2RuntimeActivationPolicy="true"> <supportedRuntime version="v4.0"/> </startup> </configuration> .csharpcode { background-color: #ffffff; font-family: consolas, "Courier New", courier, monospace; color: black; font-size: small } .csharpcode pre { background-color: #ffffff; font-family: consolas, "Courier New", courier, monospace; color: black; font-size: small } .csharpcode pre { margin: 0em } .csharpcode .rem { color: #008000 } .csharpcode .kwrd { color: #0000ff } .csharpcode .str { color: #006080 } .csharpcode .op { color: #0000c0 } .csharpcode .preproc { color: #cc6633 } .csharpcode .asp { background-color: #ffff00 } .csharpcode .html { color: #800000 } .csharpcode .attr { color: #ff0000 } .csharpcode .alt { background-color: #f4f4f4; margin: 0em; width: 100% } .csharpcode .lnum { color: #606060 } This causes your application to run correctly, and load the older, mixed-mode assembly without issues. For full details on what’s happening here and why, I recommend reading Mark Miller’s detailed explanation of this attribute and the reasoning behind it. Before I show any code, let me say: I strongly recommend using the official approach of using app.config to set this policy. That being said, there are (rare) times when, for one reason or another, changing the application configuration file is less than ideal. While this is the supported approach to handling this issue, the CLR Hosting API includes a means of setting this programmatically via the ICLRRuntimeInfo interface.  Normally, this is used if you’re hosting the CLR in a native application in order to set this, at runtime, prior to loading the assemblies.  However, the F# Samples include a nice trick showing how to load this API and bind this policy, at runtime.  This was required in order to host the Managed DirectX API, which is built against an older version of the CLR. This is fairly easy to port to C#.  Instead of a direct port, I also added a little addition – by trapping the COM exception received if unable to bind (which will occur if the 2.0 CLR is already bound), I also allow a runtime check of whether this property was setup properly: public static class RuntimePolicyHelper { public static bool LegacyV2RuntimeEnabledSuccessfully { get; private set; } static RuntimePolicyHelper() { ICLRRuntimeInfo clrRuntimeInfo = (ICLRRuntimeInfo)RuntimeEnvironment.GetRuntimeInterfaceAsObject( Guid.Empty, typeof(ICLRRuntimeInfo).GUID); try { clrRuntimeInfo.BindAsLegacyV2Runtime(); LegacyV2RuntimeEnabledSuccessfully = true; } catch (COMException) { // This occurs with an HRESULT meaning // "A different runtime was already bound to the legacy CLR version 2 activation policy." LegacyV2RuntimeEnabledSuccessfully = false; } } [ComImport] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] [Guid("BD39D1D2-BA2F-486A-89B0-B4B0CB466891")] private interface ICLRRuntimeInfo { void xGetVersionString(); void xGetRuntimeDirectory(); void xIsLoaded(); void xIsLoadable(); void xLoadErrorString(); void xLoadLibrary(); void xGetProcAddress(); void xGetInterface(); void xSetDefaultStartupFlags(); void xGetDefaultStartupFlags(); [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)] void BindAsLegacyV2Runtime(); } } Using this, it’s possible to not only set this at runtime, but also verify, prior to loading your mixed mode assembly, whether this will succeed. In my case, this was quite useful – I am working on a library purely for internal use which uses a numerical package that is supplied with both a completely managed as well as a native solver.  The native solver uses a CLR 2 mixed-mode assembly, but is dramatically faster than the pure managed approach.  By checking RuntimePolicyHelper.LegacyV2RuntimeEnabledSuccessfully at runtime, I can decide whether to enable the native solver, and only do so if I successfully bound this policy. There are some tricks required here – To enable this sort of fallback behavior, you must make these checks in a type that doesn’t cause the mixed mode assembly to be loaded.  In my case, this forced me to encapsulate the library I was using entirely in a separate class, perform the check, then pass through the required calls to that class.  Otherwise, the library will load before the hosting process gets enabled, which in turn will fail. This code will also, of course, try to enable the runtime policy before the first time you use this class – which typically means just before the first time you check the boolean value.  As a result, checking this early on in the application is more likely to allow it to work. Finally, if you’re using a library, this has to be called prior to the 2.0 CLR loading.  This will cause it to fail if you try to use it to enable this policy in a plugin for most third party applications that don’t have their app.config setup properly, as they will likely have already loaded the 2.0 runtime. As an example, take a simple audio player.  The code below shows how this can be used to properly, at runtime, only use the “native” API if this will succeed, and fallback (or raise a nicer exception) if this will fail: public class AudioPlayer { private IAudioEngine audioEngine; public AudioPlayer() { if (RuntimePolicyHelper.LegacyV2RuntimeEnabledSuccessfully) { // This will load a CLR 2 mixed mode assembly this.audioEngine = new AudioEngineNative(); } else { this.audioEngine = new AudioEngineManaged(); } } public void Play(string filename) { this.audioEngine.Play(filename); } } Now – the warning: This approach works, but I would be very hesitant to use it in public facing production code, especially for anything other than initializing your own application.  While this should work in a library, using it has a very nasty side effect: you change the runtime policy of the executing application in a way that is very hidden and non-obvious.

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  • Disk Drive not working

    - by user287681
    The CD/DVD drive on my sisters' (I'm helping her shift from Win. XP (now officially deprecated by Microsoft) to Ubuntu) system. Now, it may end up being a failed attempt, all together (Almost the whole last year (when she's been on XP) the disk drive hasn't (not even powering on) been working.), I just want to make sure I've explored every remote possibility. Because I figure, "Huh, now that I've got Ubuntu running, instead of XP, that (just) might make a difference.". I have tried using the sudo lshw command in the terminal, to (seemingly) no avil, but, who knows, you might be able to make something out of it. Here's the output: kyra@kyra-Satellite-P105:~$ sudo lshw [sudo] password for kyra: kyra-satellite-p105 description: Notebook product: Satellite P105 () vendor: TOSHIBA version: PSPA0U-0TN01M serial: 96084354W width: 64 bits capabilities: smbios-2.4 dmi-2.4 vsyscall32 configuration: administrator_password=disabled boot=oem-specific chassis=notebook frontpanel_password=unknown keyboard_password=unknown power-on_password=disabled uuid=00900559-F88E-D811-82E0-00163680E992 *-core description: Motherboard product: Satellite P105 vendor: TOSHIBA physical id: 0 version: Not Applicable serial: 1234567890 *-firmware description: BIOS vendor: TOSHIBA physical id: 0 version: V4.70 date: 01/19/20092 size: 92KiB capabilities: isa pci pcmcia pnp upgrade shadowing escd cdboot acpi usb biosbootspecification *-cpu description: CPU product: Intel(R) Core(TM)2 CPU T5500 @ 1.66GHz vendor: Intel Corp. physical id: 4 bus info: cpu@0 version: Intel(R) Core(TM)2 CPU T5 slot: U2E1 size: 1667MHz capacity: 1667MHz width: 64 bits clock: 166MHz capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx x86-64 constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dtherm cpufreq *-cache:0 description: L1 cache physical id: 5 slot: L1 Cache size: 16KiB capacity: 16KiB capabilities: asynchronous internal write-back *-cache:1 description: L2 cache physical id: 6 slot: L2 Cache size: 2MiB capabilities: burst external write-back *-memory description: System Memory physical id: c slot: System board or motherboard size: 2GiB capacity: 3GiB *-bank:0 description: SODIMM DDR2 Synchronous physical id: 0 slot: M1 size: 1GiB width: 64 bits *-bank:1 description: SODIMM DDR2 Synchronous physical id: 1 slot: M2 size: 1GiB width: 64 bits *-pci description: Host bridge product: Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 03 width: 32 bits clock: 33MHz configuration: driver=agpgart-intel resources: irq:0 *-display:0 description: VGA compatible controller product: Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 03 width: 32 bits clock: 33MHz capabilities: msi pm vga_controller bus_master cap_list rom configuration: driver=i915 latency=0 resources: irq:16 memory:d0200000-d027ffff ioport:1800(size=8) memory:c0000000-cfffffff memory:d0300000-d033ffff *-display:1 UNCLAIMED description: Display controller product: Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller vendor: Intel Corporation physical id: 2.1 bus info: pci@0000:00:02.1 version: 03 width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list configuration: latency=0 resources: memory:d0280000-d02fffff *-multimedia description: Audio device product: NM10/ICH7 Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 02 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:44 memory:d0340000-d0343fff *-pci:0 description: PCI bridge product: NM10/ICH7 Family PCI Express Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:3000(size=4096) memory:84000000-841fffff ioport:84200000(size=2097152) *-pci:1 description: PCI bridge product: NM10/ICH7 Family PCI Express Port 2 vendor: Intel Corporation physical id: 1c.1 bus info: pci@0000:00:1c.1 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:41 ioport:4000(size=4096) memory:84400000-846fffff ioport:84700000(size=2097152) *-network description: Wireless interface product: PRO/Wireless 3945ABG [Golan] Network Connection vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 02 serial: 00:13:02:d6:d2:35 width: 32 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwl3945 driverversion=3.13.0-29-generic firmware=15.32.2.9 ip=10.110.20.157 latency=0 link=yes multicast=yes wireless=IEEE 802.11abg resources: irq:43 memory:84400000-84400fff *-pci:2 description: PCI bridge product: NM10/ICH7 Family PCI Express Port 3 vendor: Intel Corporation physical id: 1c.2 bus info: pci@0000:00:1c.2 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:42 ioport:5000(size=4096) memory:84900000-84afffff ioport:84b00000(size=2097152) *-usb:0 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #1 vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:23 ioport:1820(size=32) *-usb:1 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #2 vendor: Intel Corporation physical id: 1d.1 bus info: pci@0000:00:1d.1 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:19 ioport:1840(size=32) *-usb:2 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #3 vendor: Intel Corporation physical id: 1d.2 bus info: pci@0000:00:1d.2 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:18 ioport:1860(size=32) *-usb:3 description: USB controller product: NM10/ICH7 Family USB UHCI Controller #4 vendor: Intel Corporation physical id: 1d.3 bus info: pci@0000:00:1d.3 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:16 ioport:1880(size=32) *-usb:4 description: USB controller product: NM10/ICH7 Family USB2 EHCI Controller vendor: Intel Corporation physical id: 1d.7 bus info: pci@0000:00:1d.7 version: 02 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci-pci latency=0 resources: irq:23 memory:d0544000-d05443ff *-pci:3 description: PCI bridge product: 82801 Mobile PCI Bridge vendor: Intel Corporation physical id: 1e bus info: pci@0000:00:1e.0 version: e2 width: 32 bits clock: 33MHz capabilities: pci subtractive_decode bus_master cap_list resources: ioport:2000(size=4096) memory:d0000000-d00fffff ioport:80000000(size=67108864) *-pcmcia description: CardBus bridge product: PCIxx12 Cardbus Controller vendor: Texas Instruments physical id: 4 bus info: pci@0000:0a:04.0 version: 00 width: 32 bits clock: 33MHz capabilities: pcmcia bus_master cap_list configuration: driver=yenta_cardbus latency=176 maxlatency=5 mingnt=192 resources: irq:17 memory:d0004000-d0004fff ioport:2400(size=256) ioport:2800(size=256) memory:80000000-83ffffff memory:88000000-8bffffff *-firewire description: FireWire (IEEE 1394) product: PCIxx12 OHCI Compliant IEEE 1394 Host Controller vendor: Texas Instruments physical id: 4.1 bus info: pci@0000:0a:04.1 version: 00 width: 32 bits clock: 33MHz capabilities: pm ohci bus_master cap_list configuration: driver=firewire_ohci latency=64 maxlatency=4 mingnt=3 resources: irq:17 memory:d0007000-d00077ff memory:d0000000-d0003fff *-storage description: Mass storage controller product: 5-in-1 Multimedia Card Reader (SD/MMC/MS/MS PRO/xD) vendor: Texas Instruments physical id: 4.2 bus info: pci@0000:0a:04.2 version: 00 width: 32 bits clock: 33MHz capabilities: storage pm bus_master cap_list configuration: driver=tifm_7xx1 latency=64 maxlatency=4 mingnt=7 resources: irq:17 memory:d0005000-d0005fff *-generic description: SD Host controller product: PCIxx12 SDA Standard Compliant SD Host Controller vendor: Texas Instruments physical id: 4.3 bus info: pci@0000:0a:04.3 version: 00 width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list configuration: driver=sdhci-pci latency=64 maxlatency=4 mingnt=7 resources: irq:17 memory:d0007800-d00078ff *-network description: Ethernet interface product: PRO/100 VE Network Connection vendor: Intel Corporation physical id: 8 bus info: pci@0000:0a:08.0 logical name: eth0 version: 02 serial: 00:16:36:80:e9:92 size: 10Mbit/s capacity: 100Mbit/s width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e100 driverversion=3.5.24-k2-NAPI duplex=half latency=64 link=no maxlatency=56 mingnt=8 multicast=yes port=MII speed=10Mbit/s resources: irq:20 memory:d0006000-d0006fff ioport:2000(size=64) *-isa description: ISA bridge product: 82801GBM (ICH7-M) LPC Interface Bridge vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 02 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: driver=lpc_ich latency=0 resources: irq:0 *-ide description: IDE interface product: 82801GBM/GHM (ICH7-M Family) SATA Controller [IDE mode] vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 version: 02 width: 32 bits clock: 66MHz capabilities: ide pm bus_master cap_list configuration: driver=ata_piix latency=0 resources: irq:19 ioport:1f0(size=8) ioport:3f6 ioport:170(size=8) ioport:376 ioport:18b0(size=16) *-serial UNCLAIMED description: SMBus product: NM10/ICH7 Family SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 02 width: 32 bits clock: 33MHz configuration: latency=0 resources: ioport:18c0(size=32) *-scsi physical id: 1 logical name: scsi0 capabilities: emulated *-disk description: ATA Disk product: ST9250421AS vendor: Seagate physical id: 0.0.0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: SD13 serial: 5TH0B2HB size: 232GiB (250GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 sectorsize=512 signature=000d7fd5 *-volume:0 description: EXT4 volume vendor: Linux physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 logical name: / version: 1.0 serial: 13bb4bdd-8cc9-40e2-a490-dbe436c2a02d size: 230GiB capacity: 230GiB capabilities: primary bootable journaled extended_attributes large_files huge_files dir_nlink recover extents ext4 ext2 initialized configuration: created=2014-06-01 17:37:01 filesystem=ext4 lastmountpoint=/ modified=2014-06-01 21:15:21 mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,data=ordered mounted=2014-06-01 21:15:21 state=mounted *-volume:1 description: Extended partition physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 size: 2037MiB capacity: 2037MiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 2037MiB capabilities: nofs *-remoteaccess UNCLAIMED vendor: Intel physical id: 1 capabilities: inbound kyra@kyra-Satellite-P105:~$

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  • Windows Phone Developer Spotlight: Nikolai Joukov

    - by Lori Lalonde
    Originally posted on: http://geekswithblogs.net/lorilalonde/archive/2014/06/04/windows-phone-developer-spotlight-nikolai-joukov.aspxAs part of an ongoing series, I plan to include a spotlight post on people within the community that are stars in their field and area of expertise. For my first spotlight post, I interviewed Nikolai Joukov, who is a regular attendee at my local area .NET User Group (CTTDNUG), and has also participated in many of the Mobile and Cloud workshops we have hosted over the past few years. Nikolai stood out immediately, because of his passion for developing mobile apps, his interest in continuous learning, and his drive to publish quality apps that people will find useful and entertaining. Background: Nikolai immigrated to Canada in 1995, and has been working in IT since 1997. He moved on to become an independent contractor in 2005, and has worked at various large scale organizations over the course of his career, including BMO, Enbridge, Economical Insurance, Equitable Life, Manulife and Sun Life. Nikolai is an accomplished Windows Phone and Windows Store publisher, with 11 published Windows Phone apps, and 8 published Windows Store apps. He has almost 6000 downloads and favourable reviews. Q & A with Nikolai How many years have you been developing Windows Phone apps? 2 years When did you develop your very first Windows Phone app, and what was it about? Actually, the very first app I wrote was for the Microsoft “Smart Phone” back in 2004. This phone was given to me by Microsoft during the Developers Days Conference in Toronto. It was some kind of experimental model named Smart Phone, but you had to use VB 3 to develop the applications. Needless to say, this was not very successful at that time. My app was a Stock Trades Calculator. Very primitive, but it was working for me. The phone was heavy and the battery barely lasted 4 hours. Microsoft stopped supporting it few months later and the phone stopped working shortly after, but I still have it as a souvenir. For Windows Phone, my first app was “Trip Packing Assistant”. This is a simple trip packing check list that allows you to list items by category, set required quantity of items, and mark off the item in the list when it is packed. I designed it for me and my wife Galina, since we love to travel and this program helps manage our list for us. How did you get started in Windows Phone development? I have to say thanks to our .NET User Group for introducing me to Windows Phone development. I was intrigued and decided to give it a try. In October 2012 during a 2 day training event that ObjectSharp hosted in London, I met Bruce Johnson. On his advice, I registered for Developer Movement, and it is was a good push to actually complete the apps that I started. You have a great series of travel guide apps both for Windows Phone and Windows Store. Tell us about how you came up with the idea to develop those apps and what process you went through to put it all together. Like I said earlier, my wife and I love to travel. Before I created Trip Packing Assistant, every time we were planning to travel somewhere new, Galina would spend 3-4 weeks doing research. She would create a Word document with all of the information. We didn’t want to have to carry our laptop with us all the time, so we printed out the Word document she created, and would take it with us. After we returned from the trip, we would bring back tons of pictures and materials. Then our friends started to ask us about our materials before they planned their trips to the same places we had visited. So I decided to give it a try and started making apps for Windows Phone and for Windows 8. I hope these applications will help people who are planning to travel. So, all of the pictures used in the travel apps you created were actually taken by you during these amazing trips? Yes Do you have another Windows Store/Windows Phone project in development right now? If so, can you give us a hint at what it will be about? I want to stay with travel apps for now. But this time I will try to write an app for us (Galina and I). Usually we go on the trip, then I write the apps after we have all this beautiful pictures in our hands. We are planning a trip to Rome. This app will not have the pictures, but I want to add a map with points of interest and all information that can be useful for us. Then we will go on our trip and test it on location. As well I am planning to work on my existing apps to make them better. What learning resources would you recommend for other developers that want to get started in Window Store and Windows Phone development? I would start with dev.windowsphone.com to get all tools and samples, also links to training materials. I like MVA (Microsoft Virtual Academy). Their videos are really useful and it is free. Pluralsight is good too but it is not free and I do not have a subscription anymore. Our .NET User Group meetings give good insights too. I went to all meetings and full day training events. When you start to develop your app, you need to do research for specific questions that arise during development. The Developer Portal and Nokia Developer are good resources too. Wrap Up Thanks Nikolai for participating in my first Spotlight blog post! Shown below is Nikolai’s publisher page in the Windows Phone Store and his publisher page in the Windows Store. Simply click on it to be taken to there to check out his portfolio of apps. Be sure to download his apps and try them out! They are all free! Nikolai’s Windows Phone apps   Nikolai’s Windows Store Apps

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  • DBCC CHECKDB on VVLDB and latches (Or: My Pain is Your Gain)

    - by Argenis
      Does your CHECKDB hurt, Argenis? There is a classic blog series by Paul Randal [blog|twitter] called “CHECKDB From Every Angle” which is pretty much mandatory reading for anybody who’s even remotely considering going for the MCM certification, or its replacement (the Microsoft Certified Solutions Master: Data Platform – makes my fingers hurt just from typing it). Of particular interest is the post “Consistency Options for a VLDB” – on it, Paul provides solid, timeless advice (I use the word “timeless” because it was written in 2007, and it all applies today!) on how to perform checks on very large databases. Well, here I was trying to figure out how to make CHECKDB run faster on a restored copy of one of our databases, which happens to exceed 7TB in size. The whole thing was taking several days on multiple systems, regardless of the storage used – SAS, SATA or even SSD…and I actually didn’t pay much attention to how long it was taking, or even bothered to look at the reasons why - as long as it was finishing okay and found no consistency errors. Yes – I know. That was a huge mistake, as corruption found in a database several days after taking place could only allow for further spread of the corruption – and potentially large data loss. In the last two weeks I increased my attention towards this problem, as we noticed that CHECKDB was taking EVEN LONGER on brand new all-flash storage in the SAN! I couldn’t really explain it, and were almost ready to blame the storage vendor. The vendor told us that they could initially see the server driving decent I/O – around 450Mb/sec, and then it would settle at a very slow rate of 10Mb/sec or so. “Hum”, I thought – “CHECKDB is just not pushing the I/O subsystem hard enough”. Perfmon confirmed the vendor’s observations. Dreaded @BlobEater What was CHECKDB doing all the time while doing so little I/O? Eating Blobs. It turns out that CHECKDB was taking an extremely long time on one of our frankentables, which happens to be have 35 billion rows (yup, with a b) and sucks up several terabytes of space in the database. We do have a project ongoing to purge/split/partition this table, so it’s just a matter of time before we deal with it. But the reality today is that CHECKDB is coming to a screeching halt in performance when dealing with this particular table. Checking sys.dm_os_waiting_tasks and sys.dm_os_latch_stats showed that LATCH_EX (DBCC_OBJECT_METADATA) was by far the top wait type. I remembered hearing recently about that wait from another post that Paul Randal made, but that was related to computed-column indexes, and in fact, Paul himself reminded me of his article via twitter. But alas, our pathologic table had no non-clustered indexes on computed columns. I knew that latches are used by the database engine to do internal synchronization – but how could I help speed this up? After all, this is stuff that doesn’t have a lot of knobs to tweak. (There’s a fantastic level 500 talk by Bob Ward from Microsoft CSS [blog|twitter] called “Inside SQL Server Latches” given at PASS 2010 – and you can check it out here. DISCLAIMER: I assume no responsibility for any brain melting that might ensue from watching Bob’s talk!) Failed Hypotheses Earlier on this week I flew down to Palo Alto, CA, to visit our Headquarters – and after having a great time with my Monkey peers, I was relaxing on the plane back to Seattle watching a great talk by SQL Server MVP and fellow MCM Maciej Pilecki [twitter] called “Masterclass: A Day in the Life of a Database Transaction” where he discusses many different topics related to transaction management inside SQL Server. Very good stuff, and when I got home it was a little late – that slow DBCC CHECKDB that I had been dealing with was way in the back of my head. As I was looking at the problem at hand earlier on this week, I thought “How about I set the database to read-only?” I remembered one of the things Maciej had (jokingly) said in his talk: “if you don’t want locking and blocking, set the database to read-only” (or something to that effect, pardon my loose memory). I immediately killed the CHECKDB which had been running painfully for days, and set the database to read-only mode. Then I ran DBCC CHECKDB against it. It started going really fast (even a bit faster than before), and then throttled down again to around 10Mb/sec. All sorts of expletives went through my head at the time. Sure enough, the same latching scenario was present. Oh well. I even spent some time trying to figure out if NUMA was hurting performance. Folks on Twitter made suggestions in this regard (thanks, Lonny! [twitter]) …Eureka? This past Friday I was still scratching my head about the whole thing; I was ready to start profiling with XPERF to see if I could figure out which part of the engine was to blame and then get Microsoft to look at the evidence. After getting a bunch of good news I’ll blog about separately, I sat down for a figurative smack down with CHECKDB before the weekend. And then the light bulb went on. A sparse column. I thought that I couldn’t possibly be experiencing the same scenario that Paul blogged about back in March showing extreme latching with non-clustered indexes on computed columns. Did I even have a non-clustered index on my sparse column? As it turns out, I did. I had one filtered non-clustered index – with the sparse column as the index key (and only column). To prove that this was the problem, I went and setup a test. Yup, that'll do it The repro is very simple for this issue: I tested it on the latest public builds of SQL Server 2008 R2 SP2 (CU6) and SQL Server 2012 SP1 (CU4). First, create a test database and a test table, which only needs to contain a sparse column: CREATE DATABASE SparseColTest; GO USE SparseColTest; GO CREATE TABLE testTable (testCol smalldatetime SPARSE NULL); GO INSERT INTO testTable (testCol) VALUES (NULL); GO 1000000 That’s 1 million rows, and even though you’re inserting NULLs, that’s going to take a while. In my laptop, it took 3 minutes and 31 seconds. Next, we run DBCC CHECKDB against the database: DBCC CHECKDB('SparseColTest') WITH NO_INFOMSGS, ALL_ERRORMSGS; This runs extremely fast, as least on my test rig – 198 milliseconds. Now let’s create a filtered non-clustered index on the sparse column: CREATE NONCLUSTERED INDEX [badBadIndex] ON testTable (testCol) WHERE testCol IS NOT NULL; With the index in place now, let’s run DBCC CHECKDB one more time: DBCC CHECKDB('SparseColTest') WITH NO_INFOMSGS, ALL_ERRORMSGS; In my test system this statement completed in 11433 milliseconds. 11.43 full seconds. Quite the jump from 198 milliseconds. I went ahead and dropped the filtered non-clustered indexes on the restored copy of our production database, and ran CHECKDB against that. We went down from 7+ days to 19 hours and 20 minutes. Cue the “Argenis is not impressed” meme, please, Mr. LaRock. My pain is your gain, folks. Go check to see if you have any of such indexes – they’re likely causing your consistency checks to run very, very slow. Happy CHECKDBing, -Argenis ps: I plan to file a Connect item for this issue – I consider it a pretty serious bug in the engine. After all, filtered indexes were invented BECAUSE of the sparse column feature – and it makes a lot of sense to use them together. Watch this space and my twitter timeline for a link.

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  • Refactoring a Single Rails Model with large methods & long join queries trying to do everything

    - by Kelseydh
    I have a working Ruby on Rails Model that I suspect is inefficient, hard to maintain, and full of unnecessary SQL join queries. I want to optimize and refactor this Model (Quiz.rb) to comply with Rails best practices, but I'm not sure how I should do it. The Rails app is a game that has Missions with many Stages. Users complete Stages by answering Questions that have correct or incorrect Answers. When a User tries to complete a stage by answering questions, the User gets a Quiz entry with many Attempts. Each Attempt records an Answer submitted for that Question within the Stage. A user completes a stage or mission by getting every Attempt correct, and their progress is tracked by adding a new entry to the UserMission & UserStage join tables. All of these features work, but unfortunately the Quiz.rb Model has been twisted to handle almost all of it exclusively. The callbacks began at 'Quiz.rb', and because I wasn't sure how to leave the Quiz Model during a multi-model update, I resorted to using Rails Console to have the @quiz instance variable via self.some_method do all the heavy lifting to retrieve every data value for the game's business logic; resulting in large extended join queries that "dance" all around the Database schema. The Quiz.rb Model that Smells: class Quiz < ActiveRecord::Base belongs_to :user has_many :attempts, dependent: :destroy before_save :check_answer before_save :update_user_mission_and_stage accepts_nested_attributes_for :attempts, :reject_if => lambda { |a| a[:answer_id].blank? }, :allow_destroy => true #Checks every answer within each quiz, adding +1 for each correct answer #within a stage quiz, and -1 for each incorrect answer def check_answer stage_score = 0 self.attempts.each do |attempt| if attempt.answer.correct? == true stage_score += 1 elsif attempt.answer.correct == false stage_score - 1 end end stage_score end def winner return true end def update_user_mission_and_stage ####### #Step 1: Checks if UserMission exists, finds or creates one. #if no UserMission for the current mission exists, creates a new UserMission if self.user_has_mission? == false @user_mission = UserMission.new(user_id: self.user.id, mission_id: self.current_stage.mission_id, available: true) @user_mission.save else @user_mission = self.find_user_mission end ####### #Step 2: Checks if current UserStage exists, stops if true to prevent duplicate entry if self.user_has_stage? @user_mission.save return true else ####### ##Step 3: if step 2 returns false: ##Initiates UserStage creation instructions #checks for winner (winner actions need to be defined) if they complete last stage of last mission for a given orientation if self.passed? && self.is_last_stage? && self.is_last_mission? create_user_stage_and_update_user_mission self.winner #NOTE: The rest are the same, but specify conditions that are available to add badges or other actions upon those conditions occurring: ##if user completes first stage of a mission elsif self.passed? && self.is_first_stage? && self.is_first_mission? create_user_stage_and_update_user_mission #creates user badge for finishing first stage of first mission self.user.add_badge(5) self.user.activity_logs.create(description: "granted first-stage badge", type_event: "badge", value: "first-stage") #If user completes last stage of a given mission, creates a new UserMission elsif self.passed? && self.is_last_stage? && self.is_first_mission? create_user_stage_and_update_user_mission #creates user badge for finishing first mission self.user.add_badge(6) self.user.activity_logs.create(description: "granted first-mission badge", type_event: "badge", value: "first-mission") elsif self.passed? create_user_stage_and_update_user_mission else self.passed? == false return true end end end #Creates a new UserStage record in the database for a successful Quiz question passing def create_user_stage_and_update_user_mission @nu_stage = @user_mission.user_stages.new(user_id: self.user.id, stage_id: self.current_stage.id) @nu_stage.save @user_mission.save self.user.add_points(50) end #Boolean that defines passing a stage as answering every question in that stage correct def passed? self.check_answer >= self.number_of_questions end #Returns the number of questions asked for that stage's quiz def number_of_questions self.attempts.first.answer.question.stage.questions.count end #Returns the current_stage for the Quiz, routing through 1st attempt in that Quiz def current_stage self.attempts.first.answer.question.stage end #Gives back the position of the stage relative to its mission. def stage_position self.attempts.first.answer.question.stage.position end #will find the user_mission for the current user and stage if it exists def find_user_mission self.user.user_missions.find_by_mission_id(self.current_stage.mission_id) end #Returns true if quiz was for the last stage within that mission #helpful for triggering actions related to a user completing a mission def is_last_stage? self.stage_position == self.current_stage.mission.stages.last.position end #Returns true if quiz was for the first stage within that mission #helpful for triggering actions related to a user completing a mission def is_first_stage? self.stage_position == self.current_stage.mission.stages_ordered.first.position end #Returns true if current user has a UserMission for the current stage def user_has_mission? self.user.missions.ids.include?(self.current_stage.mission.id) end #Returns true if current user has a UserStage for the current stage def user_has_stage? self.user.stages.include?(self.current_stage) end #Returns true if current user is on the last mission based on position within a given orientation def is_first_mission? self.user.missions.first.orientation.missions.by_position.first.position == self.current_stage.mission.position end #Returns true if current user is on the first stage & mission of a given orientation def is_last_mission? self.user.missions.first.orientation.missions.by_position.last.position == self.current_stage.mission.position end end My Question Currently my Rails server takes roughly 500ms to 1 sec to process single @quiz.save action. I am confident that the slowness here is due to sloppy code, not bad Database ERD design. What does a better solution look like? And specifically: Should I use join queries to retrieve values like I did here, or is it better to instantiate new objects within the model instead? Or am I missing a better solution? How should update_user_mission_and_stage be refactored to follow best practices? Relevant Code for Reference: quizzes_controller.rb w/ Controller Route Initiating Callback: class QuizzesController < ApplicationController before_action :find_stage_and_mission before_action :find_orientation before_action :find_question def show end def create @user = current_user @quiz = current_user.quizzes.new(quiz_params) if @quiz.save if @quiz.passed? if @mission.next_mission.nil? && @stage.next_stage.nil? redirect_to root_path, notice: "Congratulations, you have finished the last mission!" elsif @stage.next_stage.nil? redirect_to [@mission.next_mission, @mission.first_stage], notice: "Correct! Time for Mission #{@mission.next_mission.position}", info: "Starting next mission" else redirect_to [@mission, @stage.next_stage], notice: "Answer Correct! You passed the stage!" end else redirect_to [@mission, @stage], alert: "You didn't get every question right, please try again." end else redirect_to [@mission, @stage], alert: "Sorry. We were unable to save your answer. Please contact the admministrator." end @questions = @stage.questions.all end private def find_stage_and_mission @stage = Stage.find(params[:stage_id]) @mission = @stage.mission end def find_question @question = @stage.questions.find_by_id params[:id] end def quiz_params params.require(:quiz).permit(:user_id, :attempt_id, {attempts_attributes: [:id, :quiz_id, :answer_id]}) end def find_orientation @orientation = @mission.orientation @missions = @orientation.missions.by_position end end Overview of Relevant ERD Database Relationships: Mission - Stage - Question - Answer - Attempt <- Quiz <- User Mission - UserMission <- User Stage - UserStage <- User Other Models: Mission.rb class Mission < ActiveRecord::Base belongs_to :orientation has_many :stages has_many :user_missions, dependent: :destroy has_many :users, through: :user_missions #SCOPES scope :by_position, -> {order(position: :asc)} def stages_ordered stages.order(:position) end def next_mission self.orientation.missions.find_by_position(self.position.next) end def first_stage next_mission.stages_ordered.first end end Stage.rb: class Stage < ActiveRecord::Base belongs_to :mission has_many :questions, dependent: :destroy has_many :user_stages, dependent: :destroy has_many :users, through: :user_stages accepts_nested_attributes_for :questions, reject_if: :all_blank, allow_destroy: true def next_stage self.mission.stages.find_by_position(self.position.next) end end Question.rb class Question < ActiveRecord::Base belongs_to :stage has_many :answers, dependent: :destroy accepts_nested_attributes_for :answers, :reject_if => lambda { |a| a[:body].blank? }, :allow_destroy => true end Answer.rb: class Answer < ActiveRecord::Base belongs_to :question has_many :attempts, dependent: :destroy end Attempt.rb: class Attempt < ActiveRecord::Base belongs_to :answer belongs_to :quiz end User.rb: class User < ActiveRecord::Base belongs_to :school has_many :activity_logs has_many :user_missions, dependent: :destroy has_many :missions, through: :user_missions has_many :user_stages, dependent: :destroy has_many :stages, through: :user_stages has_many :orientations, through: :school has_many :quizzes, dependent: :destroy has_many :attempts, through: :quizzes def latest_stage_position self.user_missions.last.user_stages.last.stage.position end end UserMission.rb class UserMission < ActiveRecord::Base belongs_to :user belongs_to :mission has_many :user_stages, dependent: :destroy end UserStage.rb class UserStage < ActiveRecord::Base belongs_to :user belongs_to :stage belongs_to :user_mission end

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  • Sending HTML to Gmail always lands in Spam

    - by cartaysm
    I am having an issue with sending HTML emails to Gmail. I can send them to Yahoo, Hotmail, RR, AOL, etc. with no problem at all, but when I send them to Gmail I get kicked to spam. I have checked my IP with a lot of different list to make sure it is not listed anywhere, which it is not. spamhaus = is not listed in the DBL abuse.net = is not listed in the SBL abuse.net = is not listed in the PBL abuse.net = is not listed in the XBL spamcop = not listed in bl.spamcop.net host 24.172.204.xxx xxx.204.172.24.in-addr.arpa domain name pointer xxxevents.com. host xxxevents.com xxxevents.com has address 24.172.204.xxx xxxevents.com mail is handled by 10 mail.xxxevents.com. I am just trying to send a very VERY basic HTML message (listed below). I use an Ubuntu server, swiftmailer, multipart/alternative (HTML & plain), SPF = pass, and I am going to setup DKIM today to see if that fixes it (but I doubt it will)... For now I will only post the message I sent that gets kicked to spam and can provide any details needed. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head><title>Triathlon</title></head> <body> <table cellpadding="0" cellspacing="0"> <tr> <td> <p>Thank you for attending our 4th annual Triathlon/Duathlon/5k at Hueston Woods State Park on August 12th. This event is held annually to raise research funding for Crohn's Disease, Ulcerative Colitis, and Muscular Dystrophy diseases.</p> </td> </tr> <tr> <td> <p>As you know the results and pictures have been posted on our home page at since Sunday 8/13/2012. Now we also have updated our Facebook page with those photos and you can start tagging yourself or downloading the pictures now! <br /> our page and tag yourself at </p> <p> test test </p> <p>Race day events is professionally managed by Speedy-Feet</p> </td> </tr> </table> </body> </html> Just plain text works great, I thought maybe wording was messing me up but not the case... I am almost done install opendkim so I will be able to rule that out very soon. Edit: Okay installed opendkim and I am getting passing results so I sent the html I posted above it went through just fine. So now when I start to add a few more lines I am getting kicked back to spam again. Here is updated html code: ` <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head><title>Triathlon</title></head> <body> <table cellpadding="0" cellspacing="0"> <tr> <td> <center><a href='http://xxxevents.com' target="_blank"> <font face="Verdana, Arial, Helvetica, sans-serif" color="#666666" size="2"> <img src="http://xxxevents.com/marketemailimages/xxxlogo.png" alt="xxx It Events | Raising funds for Crohns, Colitis, and Muscular Dystrophy" border="0" /> </font></a></center> </td> <tr> <td> <p>Thank you for attending our 4th annual Triathlon/Duathlon/5k at Hueston Woods State Park on August 12th. This event is held annually to raise research funding for Crohn's Disease, Ulcerative Colitis, and Muscular Dystrophy diseases.</p> </td> </tr> <tr> <td> <p>As you know the results and pictures have been posted on our home page at since Sunday 8/13/2012. Now we also have updated our Facebook page with those photos and you can start tagging yourself or downloading the pictures now! <br /> our page and tag yourself at </p> <p> test test </p> <p>Race day events is professionally managed by Speedy-Feet</p> </td> </tr> </table> <table width="100%" border="0" cellspacing="0" cellpadding="0"> <tr> <td valign="top"> <div align="center" style="font-family:Verdana, Arial, Helvetica, sans-serif; font-size:10px;"><br />PO Box xxx Maineville, OH 45039<br /> <a href="mailto:[email protected]">[email protected]</a> | <a href='http://xxxevents.com' target="_blank">xxxevents.com</a><br /> <br /> </div> </td> </tr> </table> </body> </html>`

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  • Source-control 'wet-work'?

    - by Phil Factor
    When a design or creative work is flawed beyond remedy, it is often best to destroy it and start again. The other day, I lost the code to a long and intricate SQL batch I was working on. I’d thought it was impossible, but it happened. With all the technology around that is designed to prevent this occurring, this sort of accident has become a rare event.  If it weren’t for a deranged laptop, and my distraction, the code wouldn’t have been lost this time.  As always, I sighed, had a soothing cup of tea, and typed it all in again.  The new code I hastily tapped in  was much better: I’d held in my head the essence of how the code should work rather than the details: I now knew for certain  the start point, the end, and how it should be achieved. Instantly the detritus of half-baked thoughts fell away and I was able to write logical code that performed better.  Because I could work so quickly, I was able to hold the details of all the columns and variables in my head, and the dynamics of the flow of data. It was, in fact, easier and quicker to start from scratch rather than tidy up and refactor the existing code with its inevitable fumbling and half-baked ideas. What a shame that technology is now so good that developers rarely experience the cleansing shock of losing one’s code and having to rewrite it from scratch.  If you’ve never accidentally lost  your code, then it is worth doing it deliberately once for the experience. Creative people have, until Technology mistakenly prevented it, torn up their drafts or sketches, threw them in the bin, and started again from scratch.  Leonardo’s obsessive reworking of the Mona Lisa was renowned because it was so unusual:  Most artists have been utterly ruthless in destroying work that didn’t quite make it. Authors are particularly keen on writing afresh, and the results are generally positive. Lawrence of Arabia actually lost the entire 250,000 word manuscript of ‘The Seven Pillars of Wisdom’ by accidentally leaving it on a train at Reading station, before rewriting a much better version.  Now, any writer or artist is seduced by technology into altering or refining their work rather than casting it dramatically in the bin or setting a light to it on a bonfire, and rewriting it from the blank page.  It is easy to pick away at a flawed work, but the real creative process is far more brutal. Once, many years ago whilst running a software house that supplied commercial software to local businesses, I’d been supervising an accounting system for a farming cooperative. No packaged system met their needs, and it was all hand-cut code.  For us, it represented a breakthrough as it was for a government organisation, and success would guarantee more contracts. As you’ve probably guessed, the code got mangled in a disk crash just a week before the deadline for delivery, and the many backups all proved to be entirely corrupted by a faulty tape drive.  There were some fragments left on individual machines, but they were all of different versions.  The developers were in despair.  Strangely, I managed to re-write the bulk of a three-month project in a manic and caffeine-soaked weekend.  Sure, that elegant universally-applicable input-form routine was‘nt quite so elegant, but it didn’t really need to be as we knew what forms it needed to support.  Yes, the code lacked architectural elegance and reusability. By dawn on Monday, the application passed its integration tests. The developers rose to the occasion after I’d collapsed, and tidied up what I’d done, though they were reproachful that some of the style and elegance had gone out of the application. By the delivery date, we were able to install it. It was a smaller, faster application than the beta they’d seen and the user-interface had a new, rather Spartan, appearance that we swore was done to conform to the latest in user-interface guidelines. (we switched to Helvetica font to look more ‘Bauhaus’ ). The client was so delighted that he forgave the new bugs that had crept in. I still have the disk that crashed, up in the attic. In IT, we have had mixed experiences from complete re-writes. Lotus 123 never really recovered from a complete rewrite from assembler into C, Borland made the mistake with Arago and Quattro Pro  and Netscape’s complete rewrite of their Navigator 4 browser was a white-knuckle ride. In all cases, the decision to rewrite was a result of extreme circumstances where no other course of action seemed possible.   The rewrite didn’t come out of the blue. I prefer to remember the rewrite of Minix by young Linus Torvalds, or the rewrite of Bitkeeper by a slightly older Linus.  The rewrite of CP/M didn’t do too badly either, did it? Come to think of it, the guy who decided to rewrite the windowing system of the Xerox Star never regretted the decision. I’ll agree that one should often resist calls for a rewrite. One of the worst habits of the more inexperienced programmer is to denigrate whatever code he or she inherits, and then call loudly for a complete rewrite. They are buoyed up by the mistaken belief that they can do better. This, however, is a different psychological phenomenon, more related to the idea of some motorcyclists that they are operating on infinite lives, or the occasional squaddies that if they charge the machine-guns determinedly enough all will be well. Grim experience brings out the humility in any experienced programmer.  I’m referring to quite different circumstances here. Where a team knows the requirements perfectly, are of one mind on methodology and coding standards, and they already have a solution, then what is wrong with considering  a complete rewrite? Rewrites are so painful in the early stages, until that point where one realises the payoff, that even I quail at the thought. One needs a natural disaster to push one over the edge. The trouble is that source-control systems, and disaster recovery systems, are just too good nowadays.   If I were to lose this draft of this very blog post, I know I’d rewrite it much better. However, if you read this, you’ll know I didn’t have the nerve to delete it and start again.  There was a time that one prayed that unreliable hardware would deliver you from an unmaintainable mess of a codebase, but now technology has made us almost entirely immune to such a merciful act of God. An old friend of mine with long experience in the software industry has long had the idea of the ‘source-control wet-work’,  where one hires a malicious hacker in some wild eastern country to hack into one’s own  source control system to destroy all trace of the source to an application. Alas, backup systems are just too good to make this any more than a pipedream. Somehow, it would be difficult to promote the idea. As an alternative, could one construct a source control system that, on doing all the code-quality metrics, would systematically destroy all trace of source code that failed the quality test? Alas, I can’t see many managers buying into the idea. In reading the full story of the near-loss of Toy Story 2, it set me thinking. It turned out that the lucky restoration of the code wasn’t the happy ending one first imagined it to be, because they eventually came to the conclusion that the plot was fundamentally flawed and it all had to be rewritten anyway.  Was this an early  case of the ‘source-control wet-job’?’ It is very hard nowadays to do a rapid U-turn in a development project because we are far too prone to cling to our existing source-code.

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