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• 8 Reasons Why Even Microsoft Agrees the Windows Desktop is a Nightmare

  - by Chris Hoffman

  Let’s be honest: The Windows desktop is a mess. Sure, it’s extremely powerful and has a huge software library, but it’s not a good experience for average people. It’s not even a good experience for geeks, although we tolerate it. Even Microsoft agrees about this. Microsoft’s Surface tablets with Windows RT don’t support any third-party desktop apps. They consider this a feature — users can’t install malware and other desktop junk, so the system will always be speedy and secure. Malware is Still Common Malware may not affect geeks, but it certainly continues to affect average people. Securing Windows, keeping it secure, and avoiding unsafe programs is a complex process. There are over 50 different file extensions that can contain harmful code to keep track of. It’s easy to have theoretical discussions about how malware could infect Mac computers, Android devices, and other systems. But Mac malware is extremely rare, and has  generally been caused by problem with the terrible Java plug-in. Macs are configured to only run executables from identified developers by default, whereas Windows will run everything. Android malware is talked about a lot, but Android malware is rare in the real world and is generally confined to users who disable security protections and install pirated apps. Google has also taken action, rolling out built-in antivirus-like app checking to all Android devices, even old ones running Android 2.3, via Play Services. Whatever the reason, Windows malware is still common while malware for other systems isn’t. We all know it — anyone who does tech support for average users has dealt with infected Windows computers. Even users who can avoid malware are stuck dealing with complex and nagging antivirus programs, especially since it’s now so difficult to trust Microsoft’s antivirus products. Manufacturer-Installed Bloatware is Terrible Sit down with a new Mac, Chromebook, iPad, Android tablet, Linux laptop, or even a Surface running Windows RT and you can enjoy using your new device. The system is a clean slate for you to start exploring and installing your new software. Sit down with a new Windows PC and the system is a mess. Rather than be delighted, you’re stuck reinstalling Windows and then installing the necessary drivers or you’re forced to start uninstalling useless bloatware programs one-by-one, trying to figure out which ones are actually useful. After uninstalling the useless programs, you may end up with a system tray full of icons for ten different hardware utilities anyway. The first experience of using a new Windows PC is frustration, not delight. Yes, bloatware is still a problem on Windows 8 PCs. Manufacturers can customize the Refresh image, preventing bloatware rom easily being removed. Finding a Desktop Program is Dangerous Want to install a Windows desktop program? Well, you’ll have to head to your web browser and start searching. It’s up to you, the user, to know which programs are safe and which are dangerous. Even if you find a website for a reputable program, the advertisements on that page will often try to trick you into downloading fake installers full of adware. While it’s great to have the ability to leave the app store and get software that the platform’s owner hasn’t approved — as on Android — this is no excuse for not providing a good, secure software installation experience for typical users installing typical programs. Even Reputable Desktop Programs Try to Install Junk Even if you do find an entirely reputable program, you’ll have to keep your eyes open while installing it. It will likely try to install adware, add browse toolbars, change your default search engine, or change your web browser’s home page. Even Microsoft’s own programs do this — when you install Skype for Windows desktop, it will attempt to modify your browser settings t ouse Bing, even if you’re specially chosen another search engine and home page. With Microsoft setting such an example, it’s no surprise so many other software developers have followed suit. Geeks know how to avoid this stuff, but there’s a reason program installers continue to do this. It works and tricks many users, who end up with junk installed and settings changed. The Update Process is Confusing On iOS, Android, and Windows RT, software updates come from a single place — the app store. On Linux, software updates come from the package manager. On Mac OS X, typical users’ software updates likely come from the Mac App Store. On the Windows desktop, software updates come from… well, every program has to create its own update mechanism. Users have to keep track of all these updaters and make sure their software is up-to-date. Most programs now have their act together and automatically update by default, but users who have old versions of Flash and Adobe Reader installed are vulnerable until they realize their software isn’t automatically updating. Even if every program updates properly, the sheer mess of updaters is clunky, slow, and confusing in comparison to a centralized update process. Browser Plugins Open Security Holes It’s no surprise that other modern platforms like iOS, Android, Chrome OS, Windows RT, and Windows Phone don’t allow traditional browser plugins, or only allow Flash and build it into the system. Browser plugins provide a wealth of different ways for malicious web pages to exploit the browser and open the system to attack. Browser plugins are one of the most popular attack vectors because of how many users have out-of-date plugins and how many plugins, especially Java, seem to be designed without taking security seriously. Oracle’s Java plugin even tries to install the terrible Ask toolbar when installing security updates. That’s right — the security update process is also used to cram additional adware into users’ machines so unscrupulous companies like Oracle can make a quick buck. It’s no wonder that most Windows PCs have an out-of-date, vulnerable version of Java installed. Battery Life is Terrible Windows PCs have bad battery life compared to Macs, IOS devices, and Android tablets, all of which Windows now competes with. Even Microsoft’s own Surface Pro 2 has bad battery life. Apple’s 11-inch MacBook Air, which has very similar hardware to the Surface Pro 2, offers double its battery life when web browsing. Microsoft has been fond of blaming third-party hardware manufacturers for their poorly optimized drivers in the past, but there’s no longer any room to hide. The problem is clearly Windows. Why is this? No one really knows for sure. Perhaps Microsoft has kept on piling Windows component on top of Windows component and many older Windows components were never properly optimized. Windows Users Become Stuck on Old Windows Versions Apple’s new OS X 10.9 Mavericks upgrade is completely free to all Mac users and supports Macs going back to 2007. Apple has also announced their intention that all new releases of Mac OS X will be free. In 2007, Microsoft had just shipped Windows Vista. Macs from the Windows Vista era are being upgraded to the latest version of the Mac operating system for free, while Windows PCs from the same era are probably still using Windows Vista. There’s no easy upgrade path for these people. They’re stuck using Windows Vista and maybe even the outdated Internet Explorer 9 if they haven’t installed a third-party web browser. Microsoft’s upgrade path is for these people to pay $120 for a full copy of Windows 8.1 and go through a complicated process that’s actaully a clean install. Even users of Windows 8 devices will probably have to pay money to upgrade to Windows 9, while updates for other operating systems are completely free. If you’re a PC geek, a PC gamer, or someone who just requires specialized software that only runs on Windows, you probably use the Windows desktop and don’t want to switch. That’s fine, but it doesn’t mean the Windows desktop is actually a good experience. Much of the burden falls on average users, who have to struggle with malware, bloatware, adware bundled in installers, complex software installation processes, and out-of-date software. In return, all they get is the ability to use a web browser and some basic Office apps that they could use on almost any other platform without all the hassle. Microsoft would agree with this, touting Windows RT and their new “Windows 8-style” app platform as the solution. Why else would Microsoft, a “devices and services” company, position the Surface — a device without traditional Windows desktop programs — as their mass-market device recommended for average people? This isn’t necessarily an endorsement of Windows RT. If you’re tech support for your family members and it comes time for them to upgrade, you may want to get them off the Windows desktop and tell them to get a Mac or something else that’s simple. Better yet, if they get a Mac, you can tell them to visit the Apple Store for help instead of calling you. That’s another thing Windows PCs don’t offer — good manufacturer support. Image Credit: Blanca Stella Mejia on Flickr, Collin Andserson on Flickr, Luca Conti on Flickr     

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• The Red Gate and .NET Reflector Debacle

  - by Rick Strahl

  About a month ago Red Gate – the company who owns the NET Reflector tool most .NET devs use at one point or another – decided to change their business model for Reflector and take the product from free to a fully paid for license model. As a bit of history: .NET Reflector was originally created by Lutz Roeder as a free community tool to inspect .NET assemblies. Using Reflector you can examine the types in an assembly, drill into type signatures and quickly disassemble code to see how a particular method works.  In case you’ve been living under a rock and you’ve never looked at Reflector, here’s what it looks like drilled into an assembly from disk with some disassembled source code showing: Note that you get tons of information about each element in the tree, and almost all related types and members are clickable both in the list and source view so it’s extremely easy to navigate and follow the code flow even in this static assembly only view. For many year’s Lutz kept the the tool up to date and added more features gradually improving an already amazing tool and making it better. Then about two and a half years ago Red Gate bought the tool from Lutz. A lot of ruckus and noise ensued in the community back then about what would happen with the tool and… for the most part very little did. Other than the incessant update notices with prominent Red Gate promo on them life with Reflector went on. The product didn’t die and and it didn’t go commercial or to a charge model. When .NET 4.0 came out it still continued to work mostly because the .NET feature set doesn’t drastically change how types behave.  Then a month back Red Gate started making noise about a new Version Version 7 which would be commercial. No more free version - and a shit storm broke out in the community. Now normally I’m not one to be critical of companies trying to make money from a product, much less for a product that’s as incredibly useful as Reflector. There isn’t day in .NET development that goes by for me where I don’t fire up Reflector. Whether it’s for examining the innards of the .NET Framework, checking out third party code, or verifying some of my own code and resources. Even more so recently I’ve been doing a lot of Interop work with a non-.NET application that needs to access .NET components and Reflector has been immensely valuable to me (and my clients) if figuring out exact type signatures required to calling .NET components in assemblies. In short Reflector is an invaluable tool to me. Ok, so what’s the problem? Why all the fuss? Certainly the $39 Red Gate is trying to charge isn’t going to kill any developer. If there’s any tool in .NET that’s worth $39 it’s Reflector, right? Right, but that’s not the problem here. The problem is how Red Gate went about moving the product to commercial which borders on the downright bizarre. It’s almost as if somebody in management wrote a slogan: “How can we piss off the .NET community in the most painful way we can?” And that it seems Red Gate has a utterly succeeded. People are rabid, and for once I think that this outrage isn’t exactly misplaced. Take a look at the message thread that Red Gate dedicated from a link off the download page. Not only is Version 7 going to be a paid commercial tool, but the older versions of Reflector won’t be available any longer. Not only that but older versions that are already in use also will continually try to update themselves to the new paid version – which when installed will then expire unless registered properly. There have also been reports of Version 6 installs shutting themselves down and failing to work if the update is refused (I haven’t seen that myself so not sure if that’s true). In other words Red Gate is trying to make damn sure they’re getting your money if you attempt to use Reflector. There’s a lot of temptation there. Think about the millions of .NET developers out there and all of them possibly upgrading – that’s a nice chunk of change that Red Gate’s sitting on. Even with all the community backlash these guys are probably making some bank right now just because people need to get life to move on. Red Gate also put up a Feedback link on the download page – which not surprisingly is chock full with hate mail condemning the move. Oddly there’s not a single response to any of those messages by the Red Gate folks except when it concerns license questions for the full version. It puzzles me what that link serves for other yet than another complete example of failure to understand how to handle customer relations. There’s no doubt that that all of this has caused some serious outrage in the community. The sad part though is that this could have been handled so much less arrogantly and without pissing off the entire community and causing so much ill-will. People are pissed off and I have no doubt that this negative publicity will show up in the sales numbers for their other products. I certainly hope so. Stupidity ought to be painful! Why do Companies do boneheaded stuff like this? Red Gate’s original decision to buy Reflector was hotly debated but at that the time most of what would happen was mostly speculation. But I thought it was a smart move for any company that is in need of spreading its marketing message and corporate image as a vendor in the .NET space. Where else do you get to flash your corporate logo to hordes of .NET developers on a regular basis?  Exploiting that marketing with some goodwill of providing a free tool breeds positive feedback that hopefully has a good effect on the company’s visibility and the products it sells. Instead Red Gate seems to have taken exactly the opposite tack of corporate bullying to try to make a quick buck – and in the process ruined any community goodwill that might have come from providing a service community for free while still getting valuable marketing. What’s so puzzling about this boneheaded escapade is that the company doesn’t need to resort to underhanded tactics like what they are trying with Reflector 7. The tools the company makes are very good. I personally use SQL Compare, Sql Data Compare and ANTS Profiler on a regular basis and all of these tools are essential in my toolbox. They certainly work much better than the tools that are in the box with Visual Studio. Chances are that if Reflector 7 added useful features I would have been more than happy to shell out my $39 to upgrade when the time is right. It’s Expensive to give away stuff for Free At the same time, this episode shows some of the big problems that come with ‘free’ tools. A lot of organizations are realizing that giving stuff away for free is actually quite expensive and the pay back is often very intangible if any at all. Those that rely on donations or other voluntary compensation find that they amount contributed is absolutely miniscule as to not matter at all. Yet at the same time I bet most of those clamouring the loudest on that Red Gate Reflector feedback page that Reflector won’t be free anymore probably have NEVER made a donation to any open source project or free tool ever. The expectation of Free these days is just too great – which is a shame I think. There’s a lot to be said for paid software and having somebody to hold to responsible to because you gave them some money. There’s an incentive –> payback –> responsibility model that seems to be missing from free software (not all of it, but a lot of it). While there certainly are plenty of bad apples in paid software as well, money tends to be a good motivator for people to continue working and improving products. Reasons for giving away stuff are many but often it’s a naïve desire to share things when things are simple. At first it might be no problem to volunteer time and effort but as products mature the fun goes out of it, and as the reality of product maintenance kicks in developers want to get something back for the time and effort they’re putting in doing non-glamorous work. It’s then when products die or languish and this is painful for all to watch. For Red Gate however, I think there was always a pretty good payback from the Reflector acquisition in terms of marketing: Visibility and possible positioning of their products although they seemed to have mostly ignored that option. On the other hand they started this off pretty badly even 2 and a half years back when they aquired Reflector from Lutz with the same arrogant attitude that is evident in the latest episode. You really gotta wonder what folks are thinking in management – the sad part is from advance emails that were circulating, they were fully aware of the shit storm they were inciting with this and I suspect they are banking on the sheer numbers of .NET developers to still make them a tidy chunk of change from upgrades… Alternatives are coming For me personally the single license isn’t a problem, but I actually have a tool that I sell (an interop Web Service proxy generation tool) to customers and one of the things I recommend to use with has been Reflector to view assembly information and to find which Interop classes to instantiate from the non-.NET environment. It’s been nice to use Reflector for this with its small footprint and zero-configuration installation. But now with V7 becoming a paid tool that option is not going to be available anymore. Luckily it looks like the .NET community is jumping to it and trying to fill the void. Amidst the Red Gate outrage a new library called ILSpy has sprung up and providing at least some of the core functionality of Reflector with an open source library. It looks promising going forward and I suspect there will be a lot more support and interest to support this project now that Reflector has gone over to the ‘dark side’…© Rick Strahl, West Wind Technologies, 2005-2011

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• Tools of the Trade

  - by Ajarn Mark Caldwell

  I got pretty excited a couple of days ago when my new laptop arrived. “The new phone books are here!  The new phone books are here!  I’m a somebody!” - Steve Martin in The Jerk It is a Dell Precision M4500 with an Intel i7 Core 2.8 GHZ running 64-bit Windows 7 with a 15.6” widescreen, 8 GB RAM, 256 GB SSD.  For some of you high fliers, this may be nothing to write home about, but compared to the 32–bit Windows XP laptop with 2 GB of RAM and a regular hard disk that I’m coming from, it’s a really nice step forward.  I won’t even bore you with the details of the desktop PC I was first given when I started here 5 1/2 years ago.  Let’s just say that things have improved.  One really nice thing is that while we are definitely running a lean and mean department in terms of staffing, my boss believes in supporting that lean staff with good tools in order to stay lean instead of having to spend even more money on additional employees.  Of course, that only goes so far, and at some point you have to add more people in order to get more work done, which is why we are bringing on-board a new employee and a new contract developer next week.  But that’s a different story for a different time. But the main topic for this post is to highlight the variety of tools that I use in my job and that you might find useful, too.  This is easy to do right now because the process of building up my new laptop from scratch has forced me to assemble a list of software that had to be installed and configured.  Keep in mind as you look through this list that I play many roles in our company.  My official title is Software Engineering Manager, but in addition to managing the team, I am also an active ASP.NET and SQL developer, the Database Administrator, and 50% of the SAN Administrator team.  So, without further ado, here are the tools and some comments about why I use them: Tool Purpose Virtual Clone Drive Easily mount an ISO image as a DVD Drive.  This is particularly handy when you are downloading disk images from Microsoft for your tools. SQL Server 2008 R2 Developer Edition We are migrating all of our active systems to SQL 2008 R2.  Developer Edition has all the features of Enterprise Edition, but intended for development use. SQL Server 2005 Developer Edition (BIDS ONLY) The migration to SSRS 2008 R2 is just getting started, and in the meantime, maintenance work still has to be done on the reports on our SQL 2005 server.  For some reason, you can’t use BIDS from 2008 to write reports for a 2005 server.  There is some different format and when you open 2005 reports in 2008 BIDS, it forces you to upgrade, and they can no longer be uploaded to a 2005 server.  Hopefully Microsoft will fix this soon in some manner similar to Visual Studio now allows you to pick which version of the .NET Framework you are coding against. Visual Studio 2010 Premium All of our application development is in ASP.NET, and we might as well use the tool designed for it. I’ve used a version of Visual Studio going all the way back to VB 6.0 and Visual Interdev. Vault Professional Client Several years ago we replaced Visual Source Safe with SourceGear Vault (then Fortress, and now Vault Pro), and I love it.  It is very reliable with low overhead - perfect for a small to medium size development team.  And being a small ISV, their support is exceptional. Red-Gate Developer Bundle with the SQL Source Control update for Vault I first used, and fell in love with, SQL Prompt shortly before Red-Gate bought it, and then Red-Gate’s first release made me love it even more.  SQL Refactor (which has since been rolled into the latest version of SQL Prompt) has saved me many hours and migraine’s trying to understand somebody else’s code when their indenting was nonexistant, or worse, irrational.  SQL Compare has been awesome for troubleshooting potential schema issues between different instances of system databases.  SQL Data Compare helped us identify the cause behind a bug which appeared in PROD but could not be reproduced in a nearly (but not quite exactly) identical copy in UAT.  And the newest tool we are embracing: SQL Source Control.  I blogged about it here (and here, and here) last December.  This is really going to help us keep each developer’s copy of the database in sync with one another. Fiddler Helps you watch the whole traffic stream on web visits.  Haven’t used it a lot, but it did help me track down some odd 404 errors we were finding in our own application logs.  Has some other JavaScript troubleshooting capabilities, but some of its usefulness has been supplanted by the Developer Tools option in IE8. Funduc Search & Replace Find any string anywhere in a mound of source code really, really fast.  Does RegEx searches, if you understand that foreign language.  Has really helped with some refactoring work to pinpoint, for example, everywhere a particular stored procedure is referenced, whether in .NET code or other SQL procedures (which we have in script files).  Provides in-context preview of the search results.  Fantastic tool, and a bargain price. SciTE SciTE is a Scintilla based Text Editor and it is a fantastic, light-weight tool for quickly reviewing (or writing) program code, SQL scripts, and extract files.  It has language-specific syntax highlighting.  I used it to write several batch and CMD programs a year ago, and to examine data extract files for exchanging information with other systems.  Extremely handy are the options to View End of Line and View Whitespace.  Ever receive a file that is supposed to use CRLF as an end-of-line marker, but really only has CRs?  SciTE will quickly make that visible. Infragistics Controls We do a lot of ASP.NET development, and frequently use the WebGrid, WebTab, and date picker controls.  We will likely be implementing the Hierarchical Data Grid soon.  Infragistics has control suites for WebForms, WinForms, Silverlight, and coming soon MVC/JQuery. WinZip - WITH Command-Line add-in The classic compression program with a great command-line interface that allows me to build those CMD (and soon PowerShell) programs for automated compression jobs.  Our versioned Build packages are zip files. XML Notepad Haven’t used this a lot myself, but one of my team really likes it for examining large XML files. LINQPad Again, haven’t used this one a lot, but it was recommended to me for learning and practicing my LINQ skills which will come in handy as we implement Entity Framework. SQL Sentry Plan Explorer SQL Server Show Plan on steroids.  Great for helping you focus on the parts of a large query that are of most importance.  Also great for just compressing the graphical plan into more readable layout. Araxis Merge A great DIFF and Merge tool.  SourceGear provides a great tool called DiffMerge that we use all the time, but occasionally, I like the cross-edit capabilities of Araxis Merge.  For a while, we also produced DIFF reports in HTML that showed all the changes that occurred between two releases.  This was most important when we were putting out very small, but very important hot fixes on a very politically hot system.  The reports produced by Araxis Merge gave the Director of IS assurance that we were not accidentally introducing ripples throughout the system with our releases. Idera SQL Admin Toolset A great collection of tools including a password checker to help analyze your SQL Server for weak user passwords, a Backup Status tool to quickly scan a large list of servers and databases to identify any that are overdue for backups.  Particularly helpful for highlighting new databases that have been deployed without getting included in your backup processing.  I also like Space Analyzer to keep an eye on disk space consumed by database files. Idera SQL Job Manager This free tool provides a nice calendar view of SQL Server Job Schedules, but to a degree, you also get what you pay for.  We will be purchasing SQL Sentry Event Manager later this year as an even better job schedule reviewer/manager.  But in the meantime, this at least gives me a good view on potential resource conflicts across multiple instances of SQL Server. DBFViewer 2000 I inherited a couple of FoxPro databases that I have to keep an eye on occasionally and have not yet been able to migrate them to SQL Server. Balsamiq Mockups We are still in evaluation-mode on this tool, but I really like it as a quick UI mockup tool that does not require Visual Studio, so someone other than a programmer can do UI design.  The interface looks hand-drawn which definitely has some psychological benefits when communicating to users, too. FeedDemon I have to stay on top of my WAY TOO MANY blog subscriptions somehow.  I may read blogs on a couple of different computers, and FeedDemon’s integration with Google Reader allows me to keep them all in sync.  I don’t particularly like the Google Reader interface, or the fact that it always wanted to mark articles as read just because I scrolled past them.  FeedDemon solves this problem for me, and provides a multi-tabbed interface which is good because fairly frequently one blog will link to something else I want to read, and I can end up with a half-dozen open tabs all from one article. Synergy+ In my office, I run four monitors across two computers all with one mouse and keyboard.  Synergy is the magic software that makes this work. TweetDeck I’m not the most active Tweeter in the world, but when I want to check-in with the Twitterverse, this really helps.  I have found the #sqlhelp and #PoshHelp hash tags particularly useful, and I also have columns setup to make it easy to monitor #sqlpass, #PASSProfDev, and short term events like #sqlsat68.   Whew!  That’s a lot.  No wonder it took me a couple of days to get everything setup the way I wanted it.  Oh, that and actually getting some work accomplished at the same time.  Anyway, I know that is a huge dump of info, and most people never make it here to the end, so for those who did, let me say, CONGRATULATIONS, you made it! I hope you’ll find a new tool or two to make your work life a little easier.

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• CodePlex Daily Summary for Sunday, June 10, 2012

  CodePlex Daily Summary for Sunday, June 10, 2012Popular ReleasesRCon Development Server: BF3DevServer-Console v0.3: Solved issues9 10 11 13 14 15 16 17SVNUG.CodePlex: Cloud Development with Windows Azure: This release contains the slides for the Cloud Development with Windows Azure presentation.Image Cropper for Umbraco 5: Image Cropper for Umbraco 5.1: for Umbraco version 5.1SHA-1 Hash Checker: SHA-1 Hash Checker (for Windows): Fixed major bugs. Removed false negatives.Grid.Mvc: Grid.Mvc 1.3: Added Html helper extension methods (see: Documentation) Fixed minor bugs Changed Namespace to 'GridMvc'AutoUpdaterdotNET: AutoUpdater.NET 1.0: Everything seems perfect if you find any problem you can report to http://www.rbsoft.org/contact.htmlMedia Companion: Media Companion 3.503b: It has been a while, so it's about time we release another build! Major effort has been for fixing trailer downloads, plus a little bit of work for episode guide tag in TV show NFOs.Microsoft SQL Server Product Samples: Database: AdventureWorks Sample Reports 2008 R2: AdventureWorks Sample Reports 2008 R2.zip contains several reports include Sales Reason Comparisons SQL2008R2.rdl which uses Adventure Works DW 2008R2 as a data source reference. For more information, go to Sales Reason Comparisons report.Json.NET: Json.NET 4.5 Release 7: Fix - Fixed Metro build to pass Windows Application Certification Kit on Windows 8 Release Preview Fix - Fixed Metro build error caused by an anonymous type Fix - Fixed ItemConverter not being used when serializing dictionaries Fix - Fixed an incorrect object being passed to the Error event when serializing dictionaries Fix - Fixed decimal properties not being correctly ignored with DefaultValueHandlingLINQ Extensions Library: 1.0.3.0: New to release 1.0.3.0:Combinatronics: Combinations (unique) Combinations (with repetition) Permutations (unique) Permutations (with repetition) Convert jagged arrays to fixed multidimensional arrays Convert fixed multidimensional arrays to jagged arrays ElementAtMax ElementAtMin ElementAtAverage New set of array extension (1.0.2.8):Rotate Flip Resize (maintaing data) Split Fuse Replace Append and Prepend extensions (1.0.2.7) IndexOf extensions (1.0.2.7) Ne...????????API for .Net SDK: SDK for .Net ??? Release 1: ??? - ??.Net 2.0/3.5/4.0????。??????VS2010??????????。VS2008????????，??????????。 ??? - ??.Net 4.0???SDK??????Dynamic????????。 ??? - OAuth??????AccessToken?VerifierAccessToken??。??Token?????????Client?。 ?? - OAuth???2?????。 ?????AccessToken?????????。???AppKey，AppSecret?CallbackUrl ???AccessToken????????API???Client?????。???AppKey，AppSecret?AccessToken ?? - ??OAuth??????????????????????????CallbackUrl??，??GetAuthorizeURL, GetAccessTokenByAuthorizationCode, ClientLogin?????????CallbackUr...Audio Pitch & Shift: Audio Pitch And Shift 4.5.0: Added Instruments tab for modules Open folder content feature Some bug fixesPython Tools for Visual Studio: 1.5 Beta 1: We’re pleased to announce the release of Python Tools for Visual Studio 1.5 Beta. Python Tools for Visual Studio (PTVS) is an open-source plug-in for Visual Studio which supports programming with the Python language. PTVS supports a broad range of features including: • Supports CPython, IronPython, Jython and PyPy • Python editor with advanced member, signature intellisense and refactoring • Code navigation: “Find all refs”, goto definition, and object browser • Local and remote debugging •...Circuit Diagram: Circuit Diagram 2.0 Beta 1: New in this release: Automatically flip components when placing Delete components using keyboard delete key Resize document Document properties window Print document Recent files list Confirm when exiting with unsaved changes Thumbnail previews in Windows Explorer for CDDX files Show shortcut keys in toolbox Highlight selected item in toolbox Zoom using mouse scroll wheel while holding down ctrl key Plugin support for: Custom export formats Custom import formats Open...Umbraco CMS: Umbraco CMS 5.2 Beta: The future of Umbracov5 represents the future architecture of Umbraco, so please be aware that while it's technically superior to v4 it's not yet on a par feature or performance-wise. What's new? For full details see our http://progress.umbraco.org task tracking page showing all items complete for 5.2. In a nutshellPackage Builder Starter Kits Dynamic Extension Methods Querying / IsHelpers Friendly alt template URLs Localization Various bug fixes / performance enhancements Gett...JayData - The cross-platform HTML5 data-management library for JavaScript: JayData 1.0.5: JayData is a unified data access library for JavaScript developers to query and update data from different sources like WebSQL, IndexedDB, OData, Facebook or YQL. See it in action in this 6 minutes video New features in JayData 1.0.5http://jaydata.org/blog/jaydata-1.0.5-is-here-with-authentication-support-and-more http://jaydata.org/blog/release-notes Sencha Touch 2 module (read-only)This module can be used to bind data retrieved by JayData to Sencha Touch 2 generated user interface. (exam...Application Architecture Guidelines: Application Architecture Guidelines 3.0.7: 3.0.7Jolt Environment: Jolt v2 Stable: Many new features. Follow development here for more information: http://www.rune-server.org/runescape-development/rs-503-client-server/projects/298763-jolt-environment-v2.html Setup instructions in downloadSharePoint Euro 2012 - UEFA European Football Predictor: havivi.euro2012.wsp (1.5): New fetures:Multilingual Support Max users property in Standings Web Part Games time zone change (UTC +1) bug fix - Version 1.4 locking problem http://euro2012.codeplex.com/discussions/358262 bug fix - Field Title not found (v.1.3) German SP http://euro2012.codeplex.com/discussions/358189#post844228 Bug fix - Access is denied.for users with contribute rights Bug fix - Installing on non-English version of SharePoint Bug fix - Title Rules Installing SharePoint Euro 2012 PredictorSharePoint E...myManga: myManga v1.0.0.4: ChangeLogUpdating from Previous Version: Extract contents of Release - myManga v1.0.0.4.zip to previous version's folder. Replaces: myManga.exe BakaBox.dll CoreMangaClasses.dll Manga.dll Plugins/MangaReader.manga.dll Plugins/MangaFox.manga.dll Plugins/MangaHere.manga.dll Plugins/MangaPanda.manga.dllNew ProjectsDatabase Based Config Management: This project helps you to consolidate all your app configs into DB and access it from single location. eLogistics: My logistics systemFacebook Web Parts for SharePoint 2010: Going beyond authentication with Facebook and SharePoint 2010.FsJson: A JSON Parser in F#Google Web Service API for Windows Phone: Google Web Service API ported to .NET for Windows Phone.Hedge when you can, not when you have to.: Classic Black-Scholes/Merton option hedging assumes options are continuously hedged. This project is for exploring what happens in the real world of option hedging.Infragistics via PRISM: Using Infragistics RibbonBar and DockManager with PRISMLightBus???????: LightBus???????????????；????,????,????,????,????,????；????,????；??????,??????,????,????；????????。 ????????： 1. Silverlight Out-of-Browser?? 2. Windows 8 Metro??metaPost: metaPost provides a MetaWeblog interface for managing content in DotNetNuke modules using MetaWeblog enabled editors such as Windows Live Writer. The metaPost module defines a framework that can be used to easily add MetaWeblog publishing support to existing DotNetNuke modules.MPerfs Tool: MPerfs is a tool of MSSQL Performance Tool Web site, developped in php/javascript with graphicals and tables, using a MSSQL database contained DMVs data aggregations and historicals. Supported Versions : Microsoft SQLServer 2005 and 2008 R1 (2008 R2 soon). Important : The tool doesn't monitor SSAS, SSIS or SSRSNanoMVVM: a lightweight wpf MVVM framework: This is a lightweight C# 4.0 ViewModel-first MVVM framework designed to aid in the creation of desktop wpf applications.Open Personal Response System: OpenPRS is designed to be an audience-feedback tool for presenters to keep audiences engaged in a presentation as well as facilitating information gathering from the audience and presentation to the presenter and other interested parties. Panda TimeManager: Panda TimeManager is a software for management of timesheets.Progetto Sicurezza: A *VERY* basic implementation of a Certification Authority and a Client to use it, made with vb.net, BouncyCastle and iTextSharp.Proyectos de Pruebas de UTB Minor Sql 2012: Proyectos de Pruebas de UTB Minor Sql 2012Really fast Javascript Base64 encoder/decoder with utf-8 suppot: If you wonder why another one, then focus on the title. I’ve seen a lot of implementations (custom ones and in libraries/frameworks) that are fast, but not as this one. What you get is significant performance in encoding and light speed in decoding.Rezerwior - JSF: Projekt aplikacji webowej w technologi Java Server Faces 2.0Rules of Acquisition: Ferengi rules of acquistion for Windows Phone.SCOMA - FIM Connector for System Center Orchestrator: SCOMA is the acronym for the Web Service-based FIM connector (aka Management Agent) for System Center Orchestrator, short SCO. SCOMA is written in C# and based on the new ECMA2 (Extensible Connectivity 2.0 Management Agents) interface that is part of FIM 2010 R2 and FIM 2010 Update 2.SHA-1 Hash Checker: Offline command line tool that generates a SHA-1 hash for a text string or pass-phrase. Additionally, you may check your hash against published lists of compromised hashes, to check whether your password has been compromised or not.Testprojekt: Dies ist nur ein TestTmib Video Downloader: A small youtube video downloader. Created in C#TVGrid: watch several web streams simultaneously??: ????、???????ARPG

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• How to Audit and Monitor BI Publisher Reports Access?

  - by kanichiro.nishida

  Do you know who is accessing to which report at what time at your reporting environment ? As you delivered the BI Publisher reports to the production environment and your users start using them as part of their daily business operations you might wonder such questions. With compliance becoming an integral part of any business requirement, auditing your reporting environment is also becoming one of the most critical and hot agenda in today’s enterprise reporting deployments. Also, I believe that auditing the reporting environment is not just for the compliance, but also the way to understand how your users are using the reports and be able to improve the user reporting experience. BI Publisher have introduced Enterprise Level Auditing feature with its 11G release, with an integration of Oracle Fusion Middleware Audit Framework, which comes out of the box with the installation. Yes, this is another great example of the benefit of its tight integration with Fusion Middleware introduced with BI Publisher 11g release. What Information Can I Know about our Reporting Environment? With this new Auditing feature you can now gain the following insights. When a particular user login or logout What report is accessed by who and when and how How long does it take to process a particular report Yes, it’s all there. This is a great news for 10G users, right ? I used to be one of them working with many different IT organizations and were craving for this, but it’s here now with 11G! How Can I Access to the Auditing Information? With the Fusion Middleware Auditing Framework, BI Publisher feed such information either to a log file or to a database. If you decided to get the data into the database then, of course you know, you can use BI Publisher to report and publish, or visualize the data to gain more insights. One thing though, in order to feed the data it requires a few extra steps, which I’ll cover it later.  Regardless of whether it’s the log file or the database to store the Auditing data, first, you need to enable the Auditing feature, which is not enabled as default. So, let’s take a look at how to enable it. How to Enable Auditing Feature? Here is a quick list of the steps: Enable Auditing related properties in BI Publisher configuration file Copy component_events.xml file to Fusion Middleware Audit Framework’s location Enable Auditing Policy with Fusion Middleware Control (Enterprise Manager) Restart WebLogic Server Enable Auditing related properties in BI Publisher configuration file Open xmlp-server-config.xml file, which is located under $BI_HOME/ user_projects/domains/bifoundation_domain/config/bipublisher/repository/Admin/Configuration directory. Set the following three properties values to ‘true’. AUDIT_ENABLED MONITORING_ENABLED AUDIT_JPS_INTEGRATION The ‘AUDIT_JPS_INTEGRATION’ is not in the file as default, so you need to add this. Here is an example of how it looks for the xmlp-server-config.xml file after the modification. <?xml version="1.0" encoding="UTF-8" standalone="no"?><xmlpConfigxmlns="http://xmlns.oracle.com/oxp/xmlp"> <property name="SAW_SERVER" value="adc6160510"/> <property name="SAW_SESSION_TIMEOUT" value="90"/> <property name="DEBUG_LEVEL" value="exception"/> <property name="SAW_PORT" value="7001"/> <property name="SAW_PASSWORD" value=""/> <property name="SAW_PROTOCOL" value="http"/> <property name="SAW_VERSION" value="v6"/> <property name="SAW_USERNAME" value=""/> <property name="SAW_URL_SUFFIX" value="analytics/saw.dll"/> <property name="MONITORING_ENABLED" value="true"/> <property name="MONITORING_DEFAULT_HISTORY_SIZE" value="30"/> <property name="AUDIT_ENABLED" value="true"/> <property name="JSESSION_RESET_DISABLED" value="true"/> <property name="SECURITY_MODEL" value="ORACLE_AS_JPS"/> <property name="AUDIT_JPS_INTEGRATION" value="true"/> </xmlpConfig>   Copy component_events.xml file to Audit Framework’s location There is a Audit related configuration file provided by BI Publisher that needs to be copied to the Audit Framework location. 1. Go to the following directory. $BI_HOME /oracle_common/modules/oracle.iau_11.1.1/components 2. Create a directory called ‘xmlpserver’ 3. Copy component_events.xml file from /user_projects/domains/bifoundation_domain/config/bipublisher/repository/Admin/Audit To the newly created ‘xmlpserver’ directory. Enable Auditing Policy with Fusion Middleware Control (EM) Now you can set a level of the auditing for each BI Publisher’s auditing type by using Fusion Middleware Control (a.k.a. Enterprise Manager). 1. Login to Fusion Middleware Control UI http://hostname:port/em (e.g. reporting.oracle.com:7001/em) 2. Access to Audit Policy configuration UI from the menu Under WebLogic Domain, right-click bifoundation_domain, select Security and then click Audit Policy.   3. Set Audit Level for BI Publisher. While you can select ‘Custom’ to set a customized level of Auditing for each component, I’m selecting ‘Medium’ for this exercise.   Restart WebLogic Server After all the above settings, now you need to restart the WebLogic Server instance in order to take those changes in effect. If you’re on Windows you can simply do this by selecting ‘Stop BI Servers’ and ‘Start BI Servers’ from the Start menu. If you’re on Linux then you can run ‘stopWebLogic.sh’ and ‘startWebLogic.sh’, which can be found under $BI_HOME/user_projects/domains/bifoundation_domain/bin Start Auditing! Now assuming that you have completed the above steps successfully, then from this point on any reporting activity should be audited and stored in the auditing log file, which can be found at $BI_HOME/user_projects/domains/bifoundation_domain/servers/AdminServer/logs/auditlogs/xmlpserver/audit.log And here is a sample of the log file: 2011-02-18 02:25:49.928 "" "ReportRendering" true - "82d4bdc47b99b33c:-7e3f334f:12e365c4d9c:-8000-0000000000000022,0" - - - - "bipublisher(11.1.1)" "ReportExecution" "200" "" "/Sample Lite/Published Reporting/Reports/Balance Letter.xdo" "pdf" "RTF Corp Styles" "en_US" - - - - - - - - - - - - - - 86608512 486989824 24517 169 - - - 2011-02-18 02:25:49.929 "steve.jobs" "ReportRequest" true - "82d4bdc47b99b33c:-7e3f334f:12e365c4d9c:-8000-0000000000000022,0" - - - - "bipublisher(11.1.1)" "ReportAccess" "200" "" "" "pdf" "RTF Corp Styles" - - - true - - - - - - - - - - - - - - - - - - 2011-02-18 03:25:49.554 "" "ReportDataProcess" true - "82d4bdc47b99b33c:-7e3f334f:12e365c4d9c:-8000-0000000000000022,0" - - - - "bipublisher(11.1.1)" "ReportExecution" "260" "" "/Sample Lite/Published Reporting/Reports/Balance Letter.xdo" - - - - - - - - - - - - - - - - - 34980200 554033152 - 134 - - - 2011-02-18 03:25:50.282 "" "ReportRendering" true - "82d4bdc47b99b33c:-7e3f334f:12e365c4d9c:-8000-0000000000000022,0" - - - - "bipublisher(11.1.1)" "ReportExecution" "263" "" "/Sample Lite/Published Reporting/Reports/Balance Letter.xdo" "pdf" "RTF Corp Styles" "en_US" - - - - - - - - - - - - - - 16158944 554033152 24517 503 - - - 2011-02-18 03:25:50.282 "steve.jobs" "ReportRequest" true - "82d4bdc47b99b33c:-7e3f334f:12e365c4d9c:-8000-0000000000000022,0" - - - - "bipublisher(11.1.1)" "ReportAccess" "263" "" "" "pdf" "RTF Corp Styles" - - - true - - - - - - - - - - - - - - - - - - 2011-02-18 03:30:00.448 "barack.obama" "UserLogin" true - "82d4bdc47b99b33c:-7e3f334f:12e365c4d9c:-8000-0000000000000406,0" - - - - "bipublisher(11.1.1)" "UserSession" "26" "" - - - - - - - - - - - - - - - - - - - - - - - - - From the above log file you can tell a user ‘steve.jobs’ was running some reports like ‘Balance Letter’ around afternoon on 2/18 and another user ‘barack.obama’ logged into the system at 3:30 on the same day. Yes, every login and log out will be recorded, and every report access will be recorded in this log file. Now, looking at this text file to understand what’s going on is pretty overwhelming. And accessing to this log file, which is located at the server’s file system where the BI Publisher/WebLogic Server are running, is another challenge in typical deployment scenarios. And that’s where the database storage option for the Auditing data  comes into a picture. I’ll talk about this tomorrow, so stay tuned!  

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• ASMLib

  - by wcoekaer

  Oracle ASMlib on Linux has been a topic of discussion a number of times since it was released way back when in 2004. There is a lot of confusion around it and certainly a lot of misinformation out there for no good reason. Let me try to give a bit of history around Oracle ASMLib. Oracle ASMLib was introduced at the time Oracle released Oracle Database 10g R1. 10gR1 introduced a very cool important new features called Oracle ASM (Automatic Storage Management). A very simplistic description would be that this is a very sophisticated volume manager for Oracle data. Give your devices directly to the ASM instance and we manage the storage for you, clustered, highly available, redundant, performance, etc, etc... We recommend using Oracle ASM for all database deployments, single instance or clustered (RAC). The ASM instance manages the storage and every Oracle server process opens and operates on the storage devices like it would open and operate on regular datafiles or raw devices. So by default since 10gR1 up to today, we do not interact differently with ASM managed block devices than we did before with a datafile being mapped to a raw device. All of this is without ASMLib, so ignore that one for now. Standard Oracle on any platform that we support (Linux, Windows, Solaris, AIX, ...) does it the exact same way. You start an ASM instance, it handles storage management, all the database instances use and open that storage and read/write from/to it. There are no extra pieces of software needed, including on Linux. ASM is fully functional and selfcontained without any other components. In order for the admin to provide a raw device to ASM or to the database, it has to have persistent device naming. If you booted up a server where a raw disk was named /dev/sdf and you give it to ASM (or even just creating a tablespace without asm on that device with datafile '/dev/sdf') and next time you boot up and that device is now /dev/sdg, you end up with an error. Just like you can't just change datafile names, you can't change device filenames without telling the database, or ASM. persistent device naming on Linux, especially back in those days ways to say it bluntly, a nightmare. In fact there were a number of issues (dating back to 2004) : Linux async IO wasn't pretty persistent device naming including permissions (had to be owned by oracle and the dba group) was very, very difficult to manage system resource usage in terms of open file descriptors So given the above, we tried to find a way to make this easier on the admins, in many ways, similar to why we started working on OCFS a few years earlier - how can we make life easier for the admins on Linux. A feature of Oracle ASM is the ability for third parties to write an extension using what's called ASMLib. It is possible for any third party OS or storage vendor to write a library using a specific Oracle defined interface that gets used by the ASM instance and by the database instance when available. This interface offered 2 components : Define an IO interface - allow any IO to the devices to go through ASMLib Define device discovery - implement an external way of discovering, labeling devices to provide to ASM and the Oracle database instance This is similar to a library that a number of companies have implemented over many years called libODM (Oracle Disk Manager). ODM was specified many years before we introduced ASM and allowed third party vendors to implement their own IO routines so that the database would use this library if installed and make use of the library open/read/write/close,.. routines instead of the standard OS interfaces. PolyServe back in the day used this to optimize their storage solution, Veritas used (and I believe still uses) this for their filesystem. It basically allowed, in particular, filesystem vendors to write libraries that could optimize access to their storage or filesystem.. so ASMLib was not something new, it was basically based on the same model. You have libodm for just database access, you have libasm for asm/database access. Since this library interface existed, we decided to do a reference implementation on Linux. We wrote an ASMLib for Linux that could be used on any Linux platform and other vendors could see how this worked and potentially implement their own solution. As I mentioned earlier, ASMLib and ODMLib are libraries for third party extensions. ASMLib for Linux, since it was a reference implementation implemented both interfaces, the storage discovery part and the IO part. There are 2 components : Oracle ASMLib - the userspace library with config tools (a shared object and some scripts) oracleasm.ko - a kernel module that implements the asm device for /dev/oracleasm/* The userspace library is a binary-only module since it links with and contains Oracle header files but is generic, we only have one asm library for the various Linux platforms. This library is opened by Oracle ASM and by Oracle database processes and this library interacts with the OS through the asm device (/dev/asm). It can install on Oracle Linux, on SuSE SLES, on Red Hat RHEL,.. The library itself doesn't actually care much about the OS version, the kernel module and device cares. The support tools are simple scripts that allow the admin to label devices and scan for disks and devices. This way you can say create an ASM disk label foo on, currently /dev/sdf... So if /dev/sdf disappears and next time is /dev/sdg, we just scan for the label foo and we discover it as /dev/sdg and life goes on without any worry. Also, when the database needs access to the device, we don't have to worry about file permissions or anything it will be taken care of. So it's a convenience thing. The kernel module oracleasm.ko is a Linux kernel module/device driver. It implements a device /dev/oracleasm/* and any and all IO goes through ASMLib - /dev/oracleasm. This kernel module is obviously a very specific Oracle related device driver but it was released under the GPL v2 so anyone could easily build it for their Linux distribution kernels. Advantages for using ASMLib : A good async IO interface for the database, the entire IO interface is based on an optimal ASYNC model for performance A single file descriptor per Oracle process, not one per device or datafile per process reducing # of open filehandles overhead Device scanning and labeling built-in so you do not have to worry about messing with udev or devlabel, permissions or the likes which can be very complex and error prone. Just like with OCFS and OCFS2, each kernel version (major or minor) has to get a new version of the device drivers. We started out building the oracleasm kernel module rpms for many distributions, SLES (in fact in the early days still even for this thing called United Linux) and RHEL. The driver didn't make sense to get pushed into upstream Linux because it's unique and specific to the Oracle database. As it takes a huge effort in terms of build infrastructure and QA and release management to build kernel modules for every architecture, every linux distribution and every major and minor version we worked with the vendors to get them to add this tiny kernel module to their infrastructure. (60k source code file). The folks at SuSE understood this was good for them and their customers and us and added it to SLES. So every build coming from SuSE for SLES contains the oracleasm.ko module. We weren't as successful with other vendors so for quite some time we continued to build it for RHEL and of course as we introduced Oracle Linux end of 2006 also for Oracle Linux. With Oracle Linux it became easy for us because we just added the code to our build system and as we churned out Oracle Linux kernels whether it was for a public release or for customers that needed a one off fix where they also used asmlib, we didn't have to do any extra work it was just all nicely integrated. With the introduction of Oracle Linux's Unbreakable Enterprise Kernel and our interest in being able to exploit ASMLib more, we started working on a very exciting project called Data Integrity. Oracle (Martin Petersen in particular) worked for many years with the T10 standards committee and storage vendors and implemented Linux kernel support for DIF/DIX, data protection in the Linux kernel, note to those that wonder, yes it's all in mainline Linux and under the GPL. This basically gave us all the features in the Linux kernel to checksum a data block, send it to the storage adapter, which can then validate that block and checksum in firmware before it sends it over the wire to the storage array, which can then do another checksum and to the actual DISK which does a final validation before writing the block to the physical media. So what was missing was the ability for a userspace application (read: Oracle RDBMS) to write a block which then has a checksum and validation all the way down to the disk. application to disk. Because we have ASMLib we had an entry into the Linux kernel and Martin added support in ASMLib (kernel driver + userspace) for this functionality. Now, this is all based on relatively current Linux kernels, the oracleasm kernel module depends on the main kernel to have support for it so we can make use of it. Thanks to UEK and us having the ability to ship a more modern, current version of the Linux kernel we were able to introduce this feature into ASMLib for Linux from Oracle. This combined with the fact that we build the asm kernel module when we build every single UEK kernel allowed us to continue improving ASMLib and provide it to our customers. So today, we (Oracle) provide Oracle ASMLib for Oracle Linux and in particular on the Unbreakable Enterprise Kernel. We did the build/testing/delivery of ASMLib for RHEL until RHEL5 but since RHEL6 decided that it was too much effort for us to also maintain all the build and test environments for RHEL and we did not have the ability to use the latest kernel features to introduce the Data Integrity features and we didn't want to end up with multiple versions of asmlib as maintained by us. SuSE SLES still builds and comes with the oracleasm module and they do all the work and RHAT it certainly welcome to do the same. They don't have to rebuild the userspace library, it's really about the kernel module. And finally to re-iterate a few important things : Oracle ASM does not in any way require ASMLib to function completely. ASMlib is a small set of extensions, in particular to make device management easier but there are no extra features exposed through Oracle ASM with ASMLib enabled or disabled. Often customers confuse ASMLib with ASM. again, ASM exists on every Oracle supported OS and on every supported Linux OS, SLES, RHEL, OL withoutASMLib Oracle ASMLib userspace is available for OTN and the kernel module is shipped along with OL/UEK for every build and by SuSE for SLES for every of their builds ASMLib kernel module was built by us for RHEL4 and RHEL5 but we do not build it for RHEL6, nor for the OL6 RHCK kernel. Only for UEK ASMLib for Linux is/was a reference implementation for any third party vendor to be able to offer, if they want to, their own version for their own OS or storage ASMLib as provided by Oracle for Linux continues to be enhanced and evolve and for the kernel module we use UEK as the base OS kernel hope this helps.

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• Sorting Algorithms

  - by MarkPearl

  General Every time I go back to university I find myself wading through sorting algorithms and their implementation in C++. Up to now I haven’t really appreciated their true value. However as I discovered this last week with Dictionaries in C# – having a knowledge of some basic programming principles can greatly improve the performance of a system and make one think twice about how to tackle a problem. I’m going to cover briefly in this post the following: Selection Sort Insertion Sort Shellsort Quicksort Mergesort Heapsort (not complete) Selection Sort Array based selection sort is a simple approach to sorting an unsorted array. Simply put, it repeats two basic steps to achieve a sorted collection. It starts with a collection of data and repeatedly parses it, each time sorting out one element and reducing the size of the next iteration of parsed data by one. So the first iteration would go something like this… Go through the entire array of data and find the lowest value Place the value at the front of the array The second iteration would go something like this… Go through the array from position two (position one has already been sorted with the smallest value) and find the next lowest value in the array. Place the value at the second position in the array This process would be completed until the entire array had been sorted. A positive about selection sort is that it does not make many item movements. In fact, in a worst case scenario every items is only moved once. Selection sort is however a comparison intensive sort. If you had 10 items in a collection, just to parse the collection you would have 10+9+8+7+6+5+4+3+2=54 comparisons to sort regardless of how sorted the collection was to start with. If you think about it, if you applied selection sort to a collection already sorted, you would still perform relatively the same number of iterations as if it was not sorted at all. Many of the following algorithms try and reduce the number of comparisons if the list is already sorted – leaving one with a best case and worst case scenario for comparisons. Likewise different approaches have different levels of item movement. Depending on what is more expensive, one may give priority to one approach compared to another based on what is more expensive, a comparison or a item move. Insertion Sort Insertion sort tries to reduce the number of key comparisons it performs compared to selection sort by not “doing anything” if things are sorted. Assume you had an collection of numbers in the following order… 10 18 25 30 23 17 45 35 There are 8 elements in the list. If we were to start at the front of the list – 10 18 25 & 30 are already sorted. Element 5 (23) however is smaller than element 4 (30) and so needs to be repositioned. We do this by copying the value at element 5 to a temporary holder, and then begin shifting the elements before it up one. So… Element 5 would be copied to a temporary holder 10 18 25 30 23 17 45 35 – T 23 Element 4 would shift to Element 5 10 18 25 30 30 17 45 35 – T 23 Element 3 would shift to Element 4 10 18 25 25 30 17 45 35 – T 23 Element 2 (18) is smaller than the temporary holder so we put the temporary holder value into Element 3. 10 18 23 25 30 17 45 35 – T 23   We now have a sorted list up to element 6. And so we would repeat the same process by moving element 6 to a temporary value and then shifting everything up by one from element 2 to element 5. As you can see, one major setback for this technique is the shifting values up one – this is because up to now we have been considering the collection to be an array. If however the collection was a linked list, we would not need to shift values up, but merely remove the link from the unsorted value and “reinsert” it in a sorted position. Which would reduce the number of transactions performed on the collection. So.. Insertion sort seems to perform better than selection sort – however an implementation is slightly more complicated. This is typical with most sorting algorithms – generally, greater performance leads to greater complexity. Also, insertion sort performs better if a collection of data is already sorted. If for instance you were handed a sorted collection of size n, then only n number of comparisons would need to be performed to verify that it is sorted. It’s important to note that insertion sort (array based) performs a number item moves – every time an item is “out of place” several items before it get shifted up. Shellsort – Diminishing Increment Sort So up to now we have covered Selection Sort & Insertion Sort. Selection Sort makes many comparisons and insertion sort (with an array) has the potential of making many item movements. Shellsort is an approach that takes the normal insertion sort and tries to reduce the number of item movements. In Shellsort, elements in a collection are viewed as sub-collections of a particular size. Each sub-collection is sorted so that the elements that are far apart move closer to their final position. Suppose we had a collection of 15 elements… 10 20 15 45 36 48 7 60 18 50 2 19 43 30 55 First we may view the collection as 7 sub-collections and sort each sublist, lets say at intervals of 7 10 60 55 – 20 18 – 15 50 – 45 2 – 36 19 – 48 43 – 7 30 10 55 60 – 18 20 – 15 50 – 2 45 – 19 36 – 43 48 – 7 30 (Sorted) We then sort each sublist at a smaller inter – lets say 4 10 55 60 18 – 20 15 50 2 – 45 19 36 43 – 48 7 30 10 18 55 60 – 2 15 20 50 – 19 36 43 45 – 7 30 48 (Sorted) We then sort elements at a distance of 1 (i.e. we apply a normal insertion sort) 10 18 55 60 2 15 20 50 19 36 43 45 7 30 48 2 7 10 15 18 19 20 30 36 43 45 48 50 55 (Sorted) The important thing with shellsort is deciding on the increment sequence of each sub-collection. From what I can tell, there isn’t any definitive method and depending on the order of your elements, different increment sequences may perform better than others. There are however certain increment sequences that you may want to avoid. An even based increment sequence (e.g. 2 4 8 16 32 …) should typically be avoided because it does not allow for even elements to be compared with odd elements until the final sort phase – which in a way would negate many of the benefits of using sub-collections. The performance on the number of comparisons and item movements of Shellsort is hard to determine, however it is considered to be considerably better than the normal insertion sort. Quicksort Quicksort uses a divide and conquer approach to sort a collection of items. The collection is divided into two sub-collections – and the two sub-collections are sorted and combined into one list in such a way that the combined list is sorted. The algorithm is in general pseudo code below… Divide the collection into two sub-collections Quicksort the lower sub-collection Quicksort the upper sub-collection Combine the lower & upper sub-collection together As hinted at above, quicksort uses recursion in its implementation. The real trick with quicksort is to get the lower and upper sub-collections to be of equal size. The size of a sub-collection is determined by what value the pivot is. Once a pivot is determined, one would partition to sub-collections and then repeat the process on each sub collection until you reach the base case. With quicksort, the work is done when dividing the sub-collections into lower & upper collections. The actual combining of the lower & upper sub-collections at the end is relatively simple since every element in the lower sub-collection is smaller than the smallest element in the upper sub-collection. Mergesort With quicksort, the average-case complexity was O(nlog2n) however the worst case complexity was still O(N*N). Mergesort improves on quicksort by always having a complexity of O(nlog2n) regardless of the best or worst case. So how does it do this? Mergesort makes use of the divide and conquer approach to partition a collection into two sub-collections. It then sorts each sub-collection and combines the sorted sub-collections into one sorted collection. The general algorithm for mergesort is as follows… Divide the collection into two sub-collections Mergesort the first sub-collection Mergesort the second sub-collection Merge the first sub-collection and the second sub-collection As you can see.. it still pretty much looks like quicksort – so lets see where it differs… Firstly, mergesort differs from quicksort in how it partitions the sub-collections. Instead of having a pivot – merge sort partitions each sub-collection based on size so that the first and second sub-collection of relatively the same size. This dividing keeps getting repeated until the sub-collections are the size of a single element. If a sub-collection is one element in size – it is now sorted! So the trick is how do we put all these sub-collections together so that they maintain their sorted order. Sorted sub-collections are merged into a sorted collection by comparing the elements of the sub-collection and then adjusting the sorted collection. Lets have a look at a few examples… Assume 2 sub-collections with 1 element each 10 & 20 Compare the first element of the first sub-collection with the first element of the second sub-collection. Take the smallest of the two and place it as the first element in the sorted collection. In this scenario 10 is smaller than 20 so 10 is taken from sub-collection 1 leaving that sub-collection empty, which means by default the next smallest element is in sub-collection 2 (20). So the sorted collection would be 10 20 Lets assume 2 sub-collections with 2 elements each 10 20 & 15 19 So… again we would Compare 10 with 15 – 10 is the winner so we add it to our sorted collection (10) leaving us with 20 & 15 19 Compare 20 with 15 – 15 is the winner so we add it to our sorted collection (10 15) leaving us with 20 & 19 Compare 20 with 19 – 19 is the winner so we add it to our sorted collection (10 15 19) leaving us with 20 & _ 20 is by default the winner so our sorted collection is 10 15 19 20. Make sense? Heapsort (still needs to be completed) So by now I am tired of sorting algorithms and trying to remember why they were so important. I think every year I go through this stuff I wonder to myself why are we made to learn about selection sort and insertion sort if they are so bad – why didn’t we just skip to Mergesort & Quicksort. I guess the only explanation I have for this is that sometimes you learn things so that you can implement them in future – and other times you learn things so that you know it isn’t the best way of implementing things and that you don’t need to implement it in future. Anyhow… luckily this is going to be the last one of my sorts for today. The first step in heapsort is to convert a collection of data into a heap. After the data is converted into a heap, sorting begins… So what is the definition of a heap? If we have to convert a collection of data into a heap, how do we know when it is a heap and when it is not? The definition of a heap is as follows: A heap is a list in which each element contains a key, such that the key in the element at position k in the list is at least as large as the key in the element at position 2k +1 (if it exists) and 2k + 2 (if it exists). Does that make sense? At first glance I’m thinking what the heck??? But then after re-reading my notes I see that we are doing something different – up to now we have really looked at data as an array or sequential collection of data that we need to sort – a heap represents data in a slightly different way – although the data is stored in a sequential collection, for a sequential collection of data to be in a valid heap – it is “semi sorted”. Let me try and explain a bit further with an example… Example 1 of Potential Heap Data Assume we had a collection of numbers as follows 1[1] 2[2] 3[3] 4[4] 5[5] 6[6] For this to be a valid heap element with value of 1 at position [1] needs to be greater or equal to the element at position [3] (2k +1) and position [4] (2k +2). So in the above example, the collection of numbers is not in a valid heap. Example 2 of Potential Heap Data Lets look at another collection of numbers as follows 6[1] 5[2] 4[3] 3[4] 2[5] 1[6] Is this a valid heap? Well… element with the value 6 at position 1 must be greater or equal to the element at position [3] and position [4]. Is 6 > 4 and 6 > 3? Yes it is. Lets look at element 5 as position 2. It must be greater than the values at [4] & [5]. Is 5 > 3 and 5 > 2? Yes it is. If you continued to examine this second collection of data you would find that it is in a valid heap based on the definition of a heap.

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• Microsoft Declares the Future of ASP.NET is Web API

  - by sbwalker

  Sitting on a plane on my way home from Tech Ed 2012 in Orlando, I thought it would be a good time to jot down some key takeaways from this year’s conference. Some of these items I have known since the Microsoft MVP Summit which occurred in Redmond in late February ( but due to NDA restrictions I could not share them with the developer community at large ) and some of them are a result of insightful conversations with a wide variety of industry insiders and Microsoft employees at the conference. First, let’s travel back in time 4 years to the Microsoft MVP Summit in 2008. Microsoft was facing some heat from market newcomer Ruby on Rails and responded with a new web development framework of its own, ASP.NET MVC. At the Summit they estimated that MVC would only be applicable for ~10% of all new web development projects. Based on that prediction I questioned why they were investing such considerable resources for such a relative edge case, but my guess is that they felt it was an important edge case at the time as some of the more vocal .NET evangelists as well as some very high profile start-ups ( ie. Twitter ) had publicly announced their intent to use Rails. Microsoft made a lot of noise about MVC. In fact, they focused so much of their messaging and marketing hype around MVC that it appeared that WebForms was essentially dead. Yes, it may have been true that Microsoft continued to invest in WebForms, but from an outside perspective it really appeared that MVC was the only framework getting any real attention. As a result, MVC started to gain market share. An inside source at Microsoft told me that MVC usage has grown at a rate of about 5% per year and now sits at ~30%. Essentially by focusing so much marketing effort on MVC, Microsoft actually created a larger market demand for it.  This is because in the Microsoft ecosystem there is somewhat of a bandwagon mentality amongst developers. If Microsoft spends a lot of time talking about a specific technology, developers get the perception that it must be really important. So rather than choosing the right tool for the job, they often choose the tool with the most marketing hype and then try to sell it to the customer. In 2010, I blogged about the fact that MVC did not make any business sense for the DotNetNuke platform. This was because our ecosystem relied on third party extensions which were dependent on the WebForms model. If we migrated the core to MVC it would mean that all of the third party extensions would no longer be compatible, which would be an irresponsible business decision for us to make at the expense of our users and customers. However, this did not stop the debate from continuing to occur in our ecosystem. Clearly some developers had drunk Microsoft’s Kool-Aid about MVC and were of the mindset, to paraphrase an old Scottish saying, “If its not MVC, it’s crap”. Now, this is a rather ignorant position to take as most of the benefits of MVC can be achieved in WebForms with solid architecture and responsible coding practices. Clean separation of concerns, unit testing, and direct control over page output are all possible in the WebForms model – it just requires diligence and discipline. So over the past few years some horror stories have begun to bubble to the surface of software development projects focused on ground-up rewrites of web applications for the sole purpose of migrating from WebForms to MVC. These large scale rewrites were typically initiated by engineering teams with only a single argument driving the business decision, that Microsoft was promoting MVC as “the future”. These ill-fated rewrites offered no benefit to end users or customers and in fact resulted in a less stable, less scalable and more complicated systems – basically taking one step forward and two full steps back. A case in point is the announcement earlier this week that a popular open source .NET CMS provider has decided to pull the plug on their new MVC product which has been under active development for more than 18 months and revert back to WebForms. The availability of multiple server-side development models has deeply fragmented the Microsoft developer community. Some folks like to compare it to the age-old VB vs. C# language debate. However, the VB vs. C# language debate was ultimately more of a religious war because at least the two dominant programming languages were compatible with one another and could be used interchangeably. The issue with WebForms vs. MVC is much more challenging. This is because the messaging from Microsoft has positioned the two solutions as being incompatible with one another and as a result web developers feel like they are forced to choose one path or another. Yes, it is true that it has always been technically possible to use WebForms and MVC in the same project, but the tooling support has always made this feel “dirty”. The fragmentation has also made it difficult to attract newcomers as the perceived barrier to entry for learning ASP.NET has become higher. As a result many new software developers entering the market are gravitating to environments where the development model seems more simple and intuitive ( ie. PHP or Ruby ). At the same time that the Web Platform team was busy promoting ASP.NET MVC, the Microsoft Office team has been promoting Sharepoint as a platform for building internal enterprise web applications. Sharepoint has great penetration in the enterprise and over time has been enhanced with improved extensibility capabilities for software developers. But, like many other mature enterprise ASP.NET web applications, it is built on the WebForms development model. Similar to DotNetNuke, Sharepoint leverages a rich third party ecosystem for both generic web controls and more specialized WebParts – both of which rely on WebForms. So basically this resulted in a situation where the Web Platform group had headed off in one direction and the Office team had gone in another direction, and the end customer was stuck in the middle trying to figure out what to do with their existing investments in Microsoft technology. It really emphasized the perception that the left hand was not speaking to the right hand, as strategically speaking there did not seem to be any high level plan from Microsoft to ensure consistency and continuity across the different product lines. With the introduction of ASP.NET MVC, it also made some of the third party control vendors scratch their heads, and wonder what the heck Microsoft was thinking. The original value proposition of ASP.NET over Classic ASP was the ability for web developers to emulate the highly productive desktop development model by using abstract components for creating rich, interactive web interfaces. Web control vendors like Telerik, Infragistics, DevExpress, and ComponentArt had all built sizable businesses offering powerful user interface components to WebForms developers. And even after MVC was introduced these vendors continued to improve their products, offering greater productivity and a superior user experience via AJAX to what was possible in MVC. And since many developers were comfortable and satisfied with these third party solutions, the demand remained strong and the third party web control market continued to prosper despite the availability of MVC. While all of this was going on in the Microsoft ecosystem, there has also been a fundamental shift in the general software development industry. Driven by the explosion of Internet-enabled devices, the focus has now centered on service-oriented architecture (SOA). Service-oriented architecture is all about defining a public API for your product that any client can consume; whether it’s a native application running on a smart phone or tablet, a web browser taking advantage of HTML5 and Javascript, or a rich desktop application running on a PC. REST-based services which utilize the less verbose characteristics of JSON as a transport mechanism, have become the preferred approach over older, more bloated SOAP-based techniques. SOA also has the benefit of producing a cross-platform API, as every major technology stack is able to interact with standard REST-based web services. And for web applications, more and more developers are turning to robust Javascript libraries like JQuery and Knockout for browser-based client-side development techniques for calling web services and rendering content to end users. In fact, traditional server-side page rendering has largely fallen out of favor, resulting in decreased demand for server-side frameworks like Ruby on Rails, WebForms, and (gasp) MVC. In response to these new industry trends, Microsoft did what it always does – it immediately poured some resources into developing a solution which will ensure they remain relevant and competitive in the web space. This work culminated in a new framework which was branded as Web API. It is convention-based and designed to embrace native HTTP standards without copious layers of abstraction. This framework is designed to be the ultimate replacement for both the REST aspects of WCF and ASP.NET MVC Web Services. And since it was developed out of band with a dependency only on ASP.NET 4.0, it means that it can be used immediately in a variety of production scenarios. So at Tech Ed 2012 it was made abundantly clear in numerous sessions that Microsoft views Web API as the “Future of ASP.NET”. In fact, one Microsoft PM even went as far as to say that if we look 3-4 years into the future, that all ASP.NET web applications will be developed using the Web API approach. This is a fairly bold prediction and clearly telegraphs where Microsoft plans to allocate its resources going forward. Currently Web API is being delivered as part of the MVC4 package, but this is only temporary for the sake of convenience. It also sounds like there are still internal discussions going on in terms of how to brand the various aspects of ASP.NET going forward – perhaps the moniker of “ASP.NET Web Stack” coined a couple years ago by Scott Hanselman and utilized as part of the open source release of ASP.NET bits on Codeplex a few months back will eventually stick. Web API is being positioned as the unification of ASP.NET – the glue that is able to pull this fragmented mess back together again. The  “One ASP.NET” strategy will promote the use of all frameworks - WebForms, MVC, and Web API, even within the same web project. Basically the message is utilize the appropriate aspects of each framework to solve your business problems. Instead of navigating developers to a fork in the road, the plan is to educate them that “hybrid” applications are a great strategy for delivering solutions to customers. In addition, the service-oriented approach coupled with client-side development promoted by Web API can effectively be used in both WebForms and MVC applications. So this means it is also relevant to application platforms like DotNetNuke and Sharepoint, which means that it starts to create a unified development strategy across all ASP.NET product lines once again. And so what about MVC? There have actually been rumors floated that MVC has reached a stage of maturity where, similar to WebForms, it will be treated more as a maintenance product line going forward ( MVC4 may in fact be the last significant iteration of this framework ). This may sound alarming to some folks who have recently adopted MVC but it really shouldn’t, as both WebForms and MVC will continue to play a vital role in delivering solutions to customers. They will just not be the primary area where Microsoft is spending the majority of its R&D resources. That distinction will obviously go to Web API. And when the question comes up of why not enhance MVC to make it work with Web API, you must take a step back and look at this from the higher level to see that it really makes no sense. MVC is a server-side page compositing framework; whereas, Web API promotes client-side page compositing with a heavy focus on web services. In order to make MVC work well with Web API, would require a complete rewrite of MVC and at the end of the day, there would be no upgrade path for existing MVC applications. So it really does not make much business sense. So what does this have to do with DotNetNuke? Well, around 8-12 months ago we recognized the software industry trends towards web services and client-side development. We decided to utilize a “hybrid” model which would provide compatibility for existing modules while at the same time provide a bridge for developers who wanted to utilize more modern web techniques. Customers who like the productivity and familiarity of WebForms can continue to build custom modules using the traditional approach. However, in DotNetNuke 6.2 we also introduced a new Service Framework which is actually built on top of MVC2 ( we chose to leverage MVC because it had the most intuitive, light-weight REST implementation in the .NET stack ). The Services Framework allowed us to build some rich interactive features in DotNetNuke 6.2, including the Messaging and Notification Center and Activity Feed. But based on where we know Microsoft is heading, it makes sense for the next major version of DotNetNuke ( which is expected to be released in Q4 2012 ) to migrate from MVC2 to Web API. This will likely result in some breaking changes in the Services Framework but we feel it is the best approach for ensuring the platform remains highly modern and relevant. The fact that our development strategy is perfectly aligned with the “One ASP.NET” strategy from Microsoft means that our customers and developer community can be confident in their current and future investments in the DotNetNuke platform.

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• CodePlex Daily Summary for Saturday, November 17, 2012

  CodePlex Daily Summary for Saturday, November 17, 2012Popular ReleasesPaint.NET PSD Plugin: 2.2.0: Changes: Layer group visibility is now applied to all layers within the group. This greatly improves the visual fidelity of complex PSD files that have hidden layer groups. Layer group names are prefixed so that users can get an indication of the layer group hierarchy. (Paint.NET has a flat list of layers, so the hierarchy is flattened out on load.) The progress bar now reports status when saving PSD files, instead of showing an indeterminate rolling bar. Performance improvement of 1...Water Entity for SunBurn: Sunburn Water Entity For 2.0.1.8 (Deffered Only): Sunburn water entity for Sunburn 2.0.1.8 for deffered rendering only, forward water is not working yet. You need to download water normal maps, from Sunburn Reflection/Refraction example from Here.CRM 2011 Visual Ribbon Editor: Visual Ribbon Editor (1.3.1116.7): [IMPROVED] Detailed error message descriptions for FaultException [FIX] Fixed bug in rule CrmOfflineAccessStateRule which had incorrect State attribute name [FIX] Fixed bug in rule EntityPropertyRule which was missing PropertyValue attribute [FIX] Current connection information was not displayed in status bar while refreshing list of entitiesSuper Metroid Randomizer: Super Metroid Randomizer v5: v5 -Added command line functionality for automation purposes. -Implented Krankdud's change to randomize the Etecoon's item. NOTE: this version will not accept seeds from a previous version. The seed format has changed by necessity. v4 -Started putting version numbers at the top of the form. -Added a warning when suitless Maridia is required in a parsed seed. v3 -Changed seed to only generate filename-legal characters. Using old seeds will still work exactly the same. -Files can now be saved...Caliburn Micro: WPF, Silverlight, WP7 and WinRT/Metro made easy.: Caliburn.Micro v1.4: Changes This version includes many bug fixes across all platforms, improvements to nuget support and...the biggest news of all...full support for both WinRT and WP8. Download Contents Debug and Release Assemblies Samples Readme.txt License.txt Packages Available on Nuget Caliburn.Micro – The full framework compiled into an assembly. Caliburn.Micro.Start - Includes Caliburn.Micro plus a starting bootstrapper, view model and view. Caliburn.Micro.Container – The Caliburn.Micro invers...DirectX Tool Kit: November 15, 2012: November 15, 2012 Added support for WIC2 when available on Windows 8 and Windows 7 with KB 2670838 Cleaned up warning level 4 warningsDotNetNuke® Community Edition CMS: 06.02.05: Major Highlights Updated the system so that it supports nested folders in the App_Code folder Updated the Global Error Handling so that when errors within the global.asax handler happen, they are caught and shown in a page displaying the original HTTP error code Fixed issue that stopped users from specifying Link URLs that open on a new window Security FixesFixed issue in the Member Directory module that could show members to non authenticated users Fixed issue in the Lists modul...xUnit.net Contrib: xunitcontrib-resharper 0.7 (RS 7.1, 6.1.1): xunitcontrib release 0.6.1 (ReSharper runner) This release provides a test runner plugin for Resharper 7.1 RTM and 6.1.1, targetting all versions of xUnit.net. (See the xUnit.net project to download xUnit.net itself.) This release drops 7.0 support and targets the latest revisions of the last two major versions of ReSharper (namely 7.0 and 6.1.1). Copies of the plugin that support previous verions of ReSharper can be downloaded from this release. Also note that all builds work against ALL ...MVC Bootstrap: MVC Boostrap 0.5.6: A small demo site, based on the default ASP.NET MVC 3 project template, showing off some of the features of MVC Bootstrap. Added features to the Membership provider, a "lock out" feature to help fight brute force hacking of accounts. After a set number of log in attempts, the account is locked for a set time. If you download and use this project, please give some feedback, good or bad!Home Access Plus+: v8.4: This release only contains fixes for the 97576 release, you can download the v8.3 release files which aren't in this release from 97576 Changes: Fixed: Setup.aspx wrong jquery reference Fixed: Issue with loading the user's photo Changed: The JSON Urls to use a number of a date rather than a string Added: Code to hopefully, finally, fix the AD Browser not working some times File Changes: ~/bin/hap.ad.dll ~/bin/hap.web.dll ~/bin/hap.web.configuration.dll ~/bin/hap.web.livetiles.dl...OnTopReplica: Release 3.4: Update to the 3 version with major fixes and improvements. Compatible with Windows 8. Now runs (and requires) .NET Framework v.4.0. Added relative mode for region selection (allows the user to select regions as margins from the borders of the thumbnail, useful for windows which have a variable size but fixed size controls, like video players). Improved window seeking when restoring cloned thumbnail or cloning a window by title or by class. Improved settings persistence. Improved co...DotSpatial: DotSpatial 1.4: This is a Minor Release. See the changes in the issue tracker. Minimal -- includes DotSpatial core and essential extensions Extended -- includes debugging symbols and additional extensions Tutorials are available. Just want to run the software? End user (non-programmer) version available branded as MapWindow Want to add your own feature? Develop a plugin, using the template and contribute to the extension feed (you can also write extensions that you distribute in other ways). Components ...WinRT XAML Toolkit: WinRT XAML Toolkit - 1.3.5: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features Attachable Behaviors AwaitableUI extensions Controls Converters Debugging helpers Extension methods Imaging helpers IO helpers VisualTree helpers Samples Recent changes Docum...AcDown?????: AcDown????? v4.3: ??●AcDown??????????、??、??、???????。????，????，?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????，??????、????????????????。 ● AcDown??????????????????，????????????????????????????。 ● AcDown???????C#??，????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ???? 32??64? ???Linux ????(1)????????Windows XP???，????????.NET Framework 2.0???(x86)，?????"?????????"??? (2)???????????Linux???，????????Mono?? ??2...????: ???? 1.0: ????Unicode IVS Add-in for Microsoft Office: Unicode IVS Add-in for Microsoft Office: Unicode IVS Add-in for Microsoft Office ??? ?????、Unicode IVS?????????????????Unicode IVS???????????????。??、??????????????、?????????????????????????????。Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.74: fix for issue #18836 - sometimes throws null-reference errors in ActivationObject.AnalyzeScope method. add back the Context object's 8-parameter constructor, since someone has code that's using it. throw a low-pri warning if an expression statement is == or ===; warn that the developer may have meant an assignment (=). if window.XXXX or window"XXXX" is encountered, add XXXX (as long as it's a valid JavaScript identifier) to the known globals so subsequent references to XXXX won't throw ...???????: Monitor 2012-11-11: This is the first releasehttpclient?????????: httpclient??????? 1.0: httpclient??????? （1）?????????? （2）????????? （3）??2012-11-06??，???????。VidCoder: 1.4.5 Beta: Removed the old Advanced user interface and moved x264 preset/profile/tune there instead. The functionality is still available through editing the options string. Added ability to specify the H.264 level. Added ability to choose VidCoder's interface language. If you are interested in translating, we can get VidCoder in your language! Updated WPF text rendering to use the better Display mode. Updated HandBrake core to SVN 5045. Removed logic that forced the .m4v extension in certain ...New Projects40Fingers Page Language module for DotNetNuke: DotNetNuke module that allows you to overrule the language a specific page, without using any other localization solutions. Brought to you by 40FINGERSAnonymous Interfaces (by Stephen Cleary): A fluent API for dynamically creating an anonymous type implementing a specific interface.Asynk: Asynk is a framework/application that allows existing applications to easily be extended with an offloaded asynchronous worker layer. Asynk is developed using C#.BizTalkWCFOperationPromoteEncoder: If you seen the BizTalk error: " An action mapping was defined but BTS.Operation was not found in the Message context ", When you use the BizTalk WCF-Customer, bLaugh Plugin for Windows Live Writer: The bLaugh Plugin for Windows Live Writer provides a quick and easy way to find and insert bLaugh (www.blaugh.com) comics into a blog post.CaptureWebPage: Code Between The Lines @ http://www.codebetweenthelines.com Capture an Entire Web Page in a C# Console Application Sample application that fixes most problems.CF-Soft: this is my workspace to study C# programming.Cloud Backup Scheduler: Desktop utility to auto schedule online backups with popular cloud services. Cloud Giraffe: Cloud Giraffe is a library which provides easy collection and analysis of Windows Azure Diagnostics data.dbscript: dbscript is a simple scripting language for DBAs, devs, and others who have need to routinely deliver the results of SQL queries in Excel spreadsheet form.Drill: Drill is the Dependency Resolution and Instance Location Layer, an abstraction to DI containers, service locators and the like facilitating loose coupling.Drzewa decyzyjne WPF: Praca inzE-Commerce Gado: E commerce voltado para o mercado bovinoELearningTutorial: A list of tutorialsElmas Kitap: Kitapliginizi düzenleyebileceginiz bir program.Epi Info iOS Companion: iPad and iPhone companion for Epi Info 7.FreeBlokus: A simple version of Blokus Duo.g1: test GGCStatus: Global Gift Card by We Solve IT. Server Status ApplicationGiveGraph: Social Managed Resources Distribution SystemGlobal String Formatter: The Global String Formatter library allows developers to deal with conditional string formatting in an elegant fashion. Developers specify a predicate and a corresponding string output function for each case of the formatting. The library plays well with DI frameworks.HTWKAidStation: The HTWKAidStation shows schedules and the menu of local mensae in Leipzig, Germany.JsViewEngine - a ASP.NET View Engine using JsRender on both client and server: An ASP.NET View Engine that specializes in sharing partial views between client and server.Kexp.ShoutcastRunner: ShoutcastRunner is a quick and simple Windows service that runs the SHOUTcast DNAS 1.x mp3 server and provides some extra features. MDrive - Controlling Precision Electric Motors: This project demonstrates how to control MDrive(r) precision electric motors from Schneider Electric.MyNet Project: MyNet is an undergraduate project developed in the context of the Cloud Data Management cours at Grenoble INP.Passwords Thief: Sometimes you need to see what is behind asteriks in password edit box. It will help you to resolve this problem. Pet Shop Web: Projeto para gerenciamento de Pet Shop Desenvolvido em ASP.NET com Framework 4.0primeiros passos: aRCVersion: A smart tool to modify version information in RC file.recycling20: Recycling 2.0replaceSID: replaceSID replaces an SID in a SDDL fileshmapcha: Cool toolSMC (Social Media Connector): Social Media APIs are developed to provide Join-In Game providers to access Social Media Portal. Textline Processor: Textline processor is a utility to execute C# codes dynamically on each line of texts, and get output to replace lines in the text. treadmill project: Treadmill ProjectTriathlon Checklist: Triathlon Checklist is a Windows Phone application for triathletes. Download it for free: http://bit.ly/TriathlonChecklistwarhamer40kListBuilder: projet personnel de geston de liste d'armée pour le jeux warhammer 40.000.Wonder: WonderWP7GBAEmulator: A C# GBA Emulator For Windows Phone 7WPF Message Box: WPF Message Box is a simple and free message box for WPF using MVVM pattern. Image, buttons, message, and caption can be set.????: ??????·???????????????

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• Down Tools Week Cometh: Kissing Goodbye to CVs/Resumes and Cover Letters

  - by Bart Read

  I haven't blogged about what I'm doing in my (not so new) temporary role as Red Gate's technical recruiter, mostly because it's been routine, business as usual stuff, and because I've been trying to understand the role by doing it. I think now though the time has come to get a little more radical, so I'm going to tell you why I want to largely eliminate CVs/resumes and cover letters from the application process for some of our technical roles, and why I think that might be a good thing for candidates (and for us). I have a terrible confession to make, or at least it's a terrible confession for a recruiter: I don't really like CV sifting, or reading cover letters, and, unless I've misread the mood around here, neither does anybody else. It's dull, it's time-consuming, and it's somewhat soul destroying because, when all is said and done, you're being paid to be incredibly judgemental about people based on relatively little information. I feel like I've dirtied myself by saying that - I mean, after all, it's a core part of my job - but it sucks, it really does. (And, of course, the truth is I'm still a software engineer at heart, and I'm always looking for ways to do things better.) On the flip side, I've never met anyone who likes writing their CV. It takes hours and hours of faffing around and massaging it into shape, and the whole process is beset by a gnawing anxiety, frustration, and insecurity. All you really want is a chance to demonstrate your skills - not just talk about them - and how do you do that in a CV or cover letter? Often the best candidates will include samples of their work (a portfolio, screenshots, links to websites, product downloads, etc.), but sometimes this isn't possible, or may not be appropriate, or you just don't think you're allowed because of what your school/university careers service has told you (more commonly an issue with grads, obviously). And what are we actually trying to find out about people with all of this? I think the common criteria are actually pretty basic: Smart Gets things done (thanks for these two Joel) Not an a55hole* (sorry, have to get around Simple Talk's swear filter - and thanks to Professor Robert I. Sutton for this one) *Of course, everyone has off days, and I don't honestly think we're too worried about somebody being a bit grumpy every now and again. We can do a bit better than this in the context of the roles I'm talking about: we can be more specific about what "gets things done" means, at least in part. For software engineers and interns, the non-exhaustive meaning of "gets things done" is: Excellent coder For test engineers, the non-exhaustive meaning of "gets things done" is: Good at finding problems in software Competent coder Team player, etc., to me, are covered by "not an a55hole". I don't expect people to be the life and soul of the party, or a wild extrovert - that's not what team player means, and it's not what "not an a55hole" means. Some of our best technical staff are quiet, introverted types, but they're still pleasant to work with. My problem is that I don't think the initial sift really helps us find out whether people are smart and get things done with any great efficacy. It's better than nothing, for sure, but it's not as good as it could be. It's also contentious, and potentially unfair/inequitable - if you want to get an idea of what I mean by this, check out the background information section at the bottom. Before I go any further, let's look at the Red Gate recruitment process for technical staff* as it stands now: (LOTS of) People apply for jobs. All these applications go through a brutal process of manual sifting, which eliminates between 75 and 90% of them, depending upon the role, and the time of year**. Depending upon the role, those who pass the sift will be sent an assessment or telescreened. For the purposes of this blog post I'm only interested in those that are sent some sort of programming assessment, or bug hunt. This means software engineers, test engineers, and software interns, which are the roles for which I receive the most applications. The telescreen tends to be reserved for project or product managers. Those that pass the assessment are invited in for first interview. This interview is mostly about assessing their technical skills***, although we're obviously on the look out for cultural fit red flags as well. If the first interview goes well we'll invite candidates back for a second interview. This is where team/cultural fit is really scoped out. We also use this interview to dive more deeply into certain areas of their skillset, and explore any concerns that may have come out of the first interview (these obviously won't have been serious or obvious enough to cause a rejection at that point, but are things we do need to look into before we'd consider making an offer). We might subsequently invite them in for lunch before we make them an offer. This tends to happen when we're recruiting somebody for a specific team and we'd like them to meet all the people they'll be working with directly. It's not an interview per se, but can prove pivotal if they don't gel with the team. Anyone who's made it this far will receive an offer from us. *We have a slightly quirky definition of "technical staff" as it relates to the technical recruiter role here. It includes software engineers, test engineers, software interns, user experience specialists, technical authors, project managers, product managers, and development managers, but does not include product support or information systems roles. **For example, the quality of graduate applicants overall noticeably drops as the academic year wears on, which is not to say that by now there aren't still stars in there, just that they're fewer and further between. ***Some organisations prefer to assess for team fit first, but I think assessing technical skills is a more effective initial filter - if they're the nicest person in the world, but can't cut a line of code they're not going to work out. Now, as I suggested in the title, Red Gate's Down Tools Week is upon us once again - next week in fact - and I had proposed as a project that we refactor and automate the first stage of marking our programming assessments. Marking assessments, and in fact organising the marking of them, is a somewhat time-consuming process, and we receive many assessment solutions that just don't make the cut, for whatever reason. Whilst I don't think it's possible to fully automate marking, I do think it ought to be possible to run a suite of automated tests over each candidate's solution to see whether or not it behaves correctly and, if it does, move on to a manual stage where we examine the code for structure, decomposition, style, readability, maintainability, etc. Obviously it's possible to use tools to generate potentially helpful metrics for some of these indices as well. This would obviously reduce the marking workload, and would provide candidates with quicker feedback about whether they've been successful - though I do wonder if waiting a tactful interval before sending a (nicely written) rejection might be wise. I duly scrawled out a picture of my ideal process, which looked like this: The problem is, as soon as I'd roughed it out, I realised that fundamentally it wasn't an ideal process at all, which explained the gnawing feeling of cognitive dissonance I'd been wrestling with all week, whilst I'd been trying to find time to do this. Here's what I mean. Automated assessment marking, and the associated infrastructure around that, makes it much easier for us to deal with large numbers of assessments. This means we can be much more permissive about who we send assessments out to or, in other words, we can give more candidates the opportunity to really demonstrate their skills to us. And this leads to a question: why not give everyone the opportunity to demonstrate their skills, to show that they're smart and can get things done? (Two or three of us even discussed this in the down tools week hustings earlier this week.) And isn't this a lot simpler than the alternative we'd been considering? (FYI, this was automated CV/cover letter sifting by some form of textual analysis to ideally eliminate the worst 50% or so of applications based on an analysis of the 20,000 or so historical applications we've received since 2007 - definitely not the basic keyword analysis beloved of recruitment agencies, since this would eliminate hardly anyone who was awful, but definitely would eliminate stellar Oxbridge candidates - #fail - or some nightmarishly complex Google-like system where we profile all our currently employees, only to realise that we're never going to get representative results because we don't have a statistically significant sample size in any given role - also #fail.) No, I think the new way is better. We let people self-select. We make them the masters (or mistresses) of their own destiny. We give applicants the power - we put their fate in their hands - by giving them the chance to demonstrate their skills, which is what they really want anyway, instead of requiring that they spend hours and hours creating a CV and cover letter that I'm going to evaluate for suitability, and make a value judgement about, in approximately 1 minute (give or take). It doesn't matter what university you attended, it doesn't matter if you had a bad year when you took your A-levels - here's your chance to shine, so take it and run with it. (As a side benefit, we cut the number of applications we have to sift by something like two thirds.) WIN! OK, yeah, sounds good, but will it actually work? That's an excellent question. My gut feeling is yes, and I'll justify why below (and hopefully have gone some way towards doing that above as well), but what I'm proposing here is really that we run an experiment for a period of time - probably a couple of months or so - and measure the outcomes we see: How many people apply? (Wouldn't be surprised or alarmed to see this cut by a factor of ten.) How many of them submit a good assessment? (More/less than at present?) How much overhead is there for us in dealing with these assessments compared to now? What are the success and failure rates at each interview stage compared to now? How many people are we hiring at the end of it compared to now? I think it'll work because I hypothesize that, amongst other things: It self-selects for people who really want to work at Red Gate which, at the moment, is something I have to try and assess based on their CV and cover letter - but if you're not that bothered about working here, why would you complete the assessment? Candidates who would submit a shoddy application probably won't feel motivated to do the assessment. Candidates who would demonstrate good attention to detail in their CV/cover letter will demonstrate good attention to detail in the assessment. In general, only the better candidates will complete and submit the assessment. Marking assessments is much less work so we'll be able to deal with any increase that we see (hopefully we will see). There are obviously other questions as well: Is plagiarism going to be a problem? Is there any way we can detect/discourage potential plagiarism? How do we assess candidates' education and experience? What about their ability to communicate in writing? Do we still want them to submit a CV afterwards if they pass assessment? Do we want to offer them the opportunity to tell us a bit about why they'd like the job when they submit their assessment? How does this affect our relationship with recruitment agencies we might use to hire for these roles? So, what's the objective for next week's Down Tools Week? Pretty simple really - we want to implement this process for the Graduate Software Engineer and Software Engineer positions that you can find on our website. I will be joined by a crack team of our best developers (Kevin Boyle, and new Red-Gater, Sam Blackburn), and recruiting hostess with the mostest Laura McQuillen, and hopefully a couple of others as well - if I can successfully twist more arms before Monday.* Hopefully by next Friday our experiment will be up and running, and we may have changed the way Red Gate recruits software engineers for good! Stay tuned and we'll let you know how it goes! *I'm going to play dirty by offering them beer and chocolate during meetings. Some background information: how agonising over the initial CV/cover letter sift helped lead us to bin it off entirely The other day I was agonising about the new university/good degree grade versus poor A-level results issue, and decided to canvas for other opinions to see if there was something I could do that was fairer than my current approach, which is almost always to reject. This generated quite an involved discussion on our Yammer site: I'm sure you can glean a pretty good impression of my own educational prejudices from that discussion as well, although I'm very open to changing my opinion - hopefully you've already figured that out from reading the rest of this post. Hopefully you can also trace a logical path from agonising about sifting to, "Uh, hang on, why on earth are we doing this anyway?!?" Technorati Tags: recruitment,hr,developers,testers,red gate,cv,resume,cover letter,assessment,sea change

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• C#/.NET Little Wonders: Interlocked CompareExchange()

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Two posts ago, I discussed the Interlocked Add(), Increment(), and Decrement() methods (here) for adding and subtracting values in a thread-safe, lightweight manner.  Then, last post I talked about the Interlocked Read() and Exchange() methods (here) for safely and efficiently reading and setting 32 or 64 bit values (or references).  This week, we’ll round out the discussion by talking about the Interlocked CompareExchange() method and how it can be put to use to exchange a value if the current value is what you expected it to be. Dirty reads can lead to bad results Many of the uses of Interlocked that we’ve explored so far have centered around either reading, setting, or adding values.  But what happens if you want to do something more complex such as setting a value based on the previous value in some manner? Perhaps you were creating an application that reads a current balance, applies a deposit, and then saves the new modified balance, where of course you’d want that to happen atomically.  If you read the balance, then go to save the new balance and between that time the previous balance has already changed, you’ll have an issue!  Think about it, if we read the current balance as $400, and we are applying a new deposit of $50.75, but meanwhile someone else deposits $200 and sets the total to $600, but then we write a total of $450.75 we’ve lost $200! Now, certainly for int and long values we can use Interlocked.Add() to handles these cases, and it works well for that.  But what if we want to work with doubles, for example?  Let’s say we wanted to add the numbers from 0 to 99,999 in parallel.  We could do this by spawning several parallel tasks to continuously add to a total: 1: double total = 0; 2:  3: Parallel.For(0, 10000, next => 4: { 5: total += next; 6: }); Were this run on one thread using a standard for loop, we’d expect an answer of 4,999,950,000 (the sum of all numbers from 0 to 99,999).  But when we run this in parallel as written above, we’ll likely get something far off.  The result of one of my runs, for example, was 1,281,880,740.  That is way off!  If this were banking software we’d be in big trouble with our clients.  So what happened?  The += operator is not atomic, it will read in the current value, add the result, then store it back into the total.  At any point in all of this another thread could read a “dirty” current total and accidentally “skip” our add.   So, to clean this up, we could use a lock to guarantee concurrency: 1: double total = 0.0; 2: object locker = new object(); 3:  4: Parallel.For(0, count, next => 5: { 6: lock (locker) 7: { 8: total += next; 9: } 10: }); Which will give us the correct result of 4,999,950,000.  One thing to note is that locking can be heavy, especially if the operation being locked over is trivial, or the life of the lock is a high percentage of the work being performed concurrently.  In the case above, the lock consumes pretty much all of the time of each parallel task – and the task being locked on is relatively trivial. Now, let me put in a disclaimer here before we go further: For most uses, lock is more than sufficient for your needs, and is often the simplest solution!    So, if lock is sufficient for most needs, why would we ever consider another solution?  The problem with locking is that it can suspend execution of your thread while it waits for the signal that the lock is free.  Moreover, if the operation being locked over is trivial, the lock can add a very high level of overhead.  This is why things like Interlocked.Increment() perform so well, instead of locking just to perform an increment, we perform the increment with an atomic, lockless method. As with all things performance related, it’s important to profile before jumping to the conclusion that you should optimize everything in your path.  If your profiling shows that locking is causing a high level of waiting in your application, then it’s time to consider lighter alternatives such as Interlocked. CompareExchange() – Exchange existing value if equal some value So let’s look at how we could use CompareExchange() to solve our problem above.  The general syntax of CompareExchange() is: T CompareExchange<T>(ref T location, T newValue, T expectedValue) If the value in location == expectedValue, then newValue is exchanged.  Either way, the value in location (before exchange) is returned. Actually, CompareExchange() is not one method, but a family of overloaded methods that can take int, long, float, double, pointers, or references.  It cannot take other value types (that is, can’t CompareExchange() two DateTime instances directly).  Also keep in mind that the version that takes any reference type (the generic overload) only checks for reference equality, it does not call any overridden Equals(). So how does this help us?  Well, we can grab the current total, and exchange the new value if total hasn’t changed.  This would look like this: 1: // grab the snapshot 2: double current = total; 3:  4: // if the total hasn’t changed since I grabbed the snapshot, then 5: // set it to the new total 6: Interlocked.CompareExchange(ref total, current + next, current); So what the code above says is: if the amount in total (1st arg) is the same as the amount in current (3rd arg), then set total to current + next (2nd arg).  This check and exchange pair is atomic (and thus thread-safe). This works if total is the same as our snapshot in current, but the problem, is what happens if they aren’t the same?  Well, we know that in either case we will get the previous value of total (before the exchange), back as a result.  Thus, we can test this against our snapshot to see if it was the value we expected: 1: // if the value returned is != current, then our snapshot must be out of date 2: // which means we didn't (and shouldn't) apply current + next 3: if (Interlocked.CompareExchange(ref total, current + next, current) != current) 4: { 5: // ooops, total was not equal to our snapshot in current, what should we do??? 6: } So what do we do if we fail?  That’s up to you and the problem you are trying to solve.  It’s possible you would decide to abort the whole transaction, or perhaps do a lightweight spin and try again.  Let’s try that: 1: double current = total; 2:  3: // make first attempt... 4: if (Interlocked.CompareExchange(ref total, current + i, current) != current) 5: { 6: // if we fail, go into a spin wait, spin, and try again until succeed 7: var spinner = new SpinWait(); 8:  9: do 10: { 11: spinner.SpinOnce(); 12: current = total; 13: } 14: while (Interlocked.CompareExchange(ref total, current + i, current) != current); 15: } 16:  This is not trivial code, but it illustrates a possible use of CompareExchange().  What we are doing is first checking to see if we succeed on the first try, and if so great!  If not, we create a SpinWait and then repeat the process of SpinOnce(), grab a fresh snapshot, and repeat until CompareExchnage() succeeds.  You may wonder why not a simple do-while here, and the reason it’s more efficient to only create the SpinWait until we absolutely know we need one, for optimal efficiency. Though not as simple (or maintainable) as a simple lock, this will perform better in many situations.  Comparing an unlocked (and wrong) version, a version using lock, and the Interlocked of the code, we get the following average times for multiple iterations of adding the sum of 100,000 numbers: 1: Unlocked money average time: 2.1 ms 2: Locked money average time: 5.1 ms 3: Interlocked money average time: 3 ms So the Interlocked.CompareExchange(), while heavier to code, came in lighter than the lock, offering a good compromise of safety and performance when we need to reduce contention. CompareExchange() - it’s not just for adding stuff… So that was one simple use of CompareExchange() in the context of adding double values -- which meant we couldn’t have used the simpler Interlocked.Add() -- but it has other uses as well. If you think about it, this really works anytime you want to create something new based on a current value without using a full lock.  For example, you could use it to create a simple lazy instantiation implementation.  In this case, we want to set the lazy instance only if the previous value was null: 1: public static class Lazy<T> where T : class, new() 2: { 3: private static T _instance; 4:  5: public static T Instance 6: { 7: get 8: { 9: // if current is null, we need to create new instance 10: if (_instance == null) 11: { 12: // attempt create, it will only set if previous was null 13: Interlocked.CompareExchange(ref _instance, new T(), (T)null); 14: } 15:  16: return _instance; 17: } 18: } 19: } So, if _instance == null, this will create a new T() and attempt to exchange it with _instance.  If _instance is not null, then it does nothing and we discard the new T() we created. This is a way to create lazy instances of a type where we are more concerned about locking overhead than creating an accidental duplicate which is not used.  In fact, the BCL implementation of Lazy<T> offers a similar thread-safety choice for Publication thread safety, where it will not guarantee only one instance was created, but it will guarantee that all readers get the same instance.  Another possible use would be in concurrent collections.  Let’s say, for example, that you are creating your own brand new super stack that uses a linked list paradigm and is “lock free”.  We could use Interlocked.CompareExchange() to be able to do a lockless Push() which could be more efficient in multi-threaded applications where several threads are pushing and popping on the stack concurrently. Yes, there are already concurrent collections in the BCL (in .NET 4.0 as part of the TPL), but it’s a fun exercise!  So let’s assume we have a node like this: 1: public sealed class Node<T> 2: { 3: // the data for this node 4: public T Data { get; set; } 5:  6: // the link to the next instance 7: internal Node<T> Next { get; set; } 8: } Then, perhaps, our stack’s Push() operation might look something like: 1: public sealed class SuperStack<T> 2: { 3: private volatile T _head; 4:  5: public void Push(T value) 6: { 7: var newNode = new Node<int> { Data = value, Next = _head }; 8:  9: if (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next) 10: { 11: var spinner = new SpinWait(); 12:  13: do 14: { 15: spinner.SpinOnce(); 16: newNode.Next = _head; 17: } 18: while (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next); 19: } 20: } 21:  22: // ... 23: } Notice a similar paradigm here as with adding our doubles before.  What we are doing is creating the new Node with the data to push, and with a Next value being the original node referenced by _head.  This will create our stack behavior (LIFO – Last In, First Out).  Now, we have to set _head to now refer to the newNode, but we must first make sure it hasn’t changed! So we check to see if _head has the same value we saved in our snapshot as newNode.Next, and if so, we set _head to newNode.  This is all done atomically, and the result is _head’s original value, as long as the original value was what we assumed it was with newNode.Next, then we are good and we set it without a lock!  If not, we SpinWait and try again. Once again, this is much lighter than locking in highly parallelized code with lots of contention.  If I compare the method above with a similar class using lock, I get the following results for pushing 100,000 items: 1: Locked SuperStack average time: 6 ms 2: Interlocked SuperStack average time: 4.5 ms So, once again, we can get more efficient than a lock, though there is the cost of added code complexity.  Fortunately for you, most of the concurrent collection you’d ever need are already created for you in the System.Collections.Concurrent (here) namespace – for more information, see my Little Wonders – The Concurent Collections Part 1 (here), Part 2 (here), and Part 3 (here). Summary We’ve seen before how the Interlocked class can be used to safely and efficiently add, increment, decrement, read, and exchange values in a multi-threaded environment.  In addition to these, Interlocked CompareExchange() can be used to perform more complex logic without the need of a lock when lock contention is a concern. The added efficiency, though, comes at the cost of more complex code.  As such, the standard lock is often sufficient for most thread-safety needs.  But if profiling indicates you spend a lot of time waiting for locks, or if you just need a lock for something simple such as an increment, decrement, read, exchange, etc., then consider using the Interlocked class’s methods to reduce wait. Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked,CompareExchange,threading,concurrency

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• Google and Bing Map APIs Compared

  - by SGWellens

  At one of the local golf courses I frequent, there is an open grass field next to the course. It is about eight acres in size and mowed regularly. It is permissible to hit golf balls there—you bring and shag our own balls. My golf colleagues and I spend hours there practicing, chatting and in general just wasting time. One of the guys brings Ginger, the amazing, incredible, wonder dog. Ginger is a Portuguese Pointer. She chases squirrels, begs for snacks and supervises us closely to make sure we don't misbehave.     Anyway, I decided to make a dedicated web page to measure distances on the field in yards using online mapping services. I started with Google maps and then did the same application with Bing maps. It is a good way to become familiar with the APIs. Here are images of the final two maps: Google:  Bing:   To start with online mapping services, you need to visit the respective websites and get a developers key. I pared the code down to the minimum to make it easier to compare the APIs. Google maps required this CSS (or it wouldn't work): <style type="text/css">     html     {         height: 100%;     }       body     {         height: 100%;         margin: 0;         padding: 0;     } Here is how the map scripts are included. Google requires the developer Key when loading the JavaScript, Bing requires it when the map object is created: Google: <script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key=XXXXXXX&libraries=geometry&sensor=false" > </script> Bing: <script  type="text/javascript" src="http://ecn.dev.virtualearth.net/mapcontrol/mapcontrol.ashx?v=7.0"> </script> Note: I use jQuery to manipulate the DOM elements which may be overkill, but I may add more stuff to this application and I didn't want to have to add it later. Plus, I really like jQuery. Here is how the maps are created: Common Code (the same for both Google and Bing Maps):     <script type="text/javascript">         var gTheMap;         var gMarker1;         var gMarker2;           $(document).ready(DocLoaded);           function DocLoaded()         {             // golf course coordinates             var StartLat = 44.924254;             var StartLng = -93.366859;               // what element to display the map in             var mapdiv = $("#map_div")[0];   Google:         // where on earth the map should display         var StartPoint = new google.maps.LatLng(StartLat, StartLng);           // create the map         gTheMap = new google.maps.Map(mapdiv,             {                 center: StartPoint,                 zoom: 18,                 mapTypeId: google.maps.MapTypeId.SATELLITE             });           // place two markers         marker1 = PlaceMarker(new google.maps.LatLng(StartLat, StartLng + .0001));         marker2 = PlaceMarker(new google.maps.LatLng(StartLat, StartLng - .0001));           DragEnd(null);     } Bing:         // where on earth the map should display         var StartPoint = new  Microsoft.Maps.Location(StartLat, StartLng);           // create the map         gTheMap = new Microsoft.Maps.Map(mapdiv,             {                 credentials: 'Asbsa_hzfHl69XF3wxBd_WbW0dLNTRUH3ZHQG9qcV5EFRLuWEaOP1hjWdZ0A0P17',                 center: StartPoint,                 zoom: 18,                 mapTypeId: Microsoft.Maps.MapTypeId.aerial             });             // place two markers         marker1 = PlaceMarker(new Microsoft.Maps.Location(StartLat, StartLng + .0001));         marker2 = PlaceMarker(new Microsoft.Maps.Location(StartLat, StartLng - .0001));           DragEnd(null);     } Note: In the Bing documentation, mapTypeId: was missing from the list of options even though the sample code included it. Note: When creating the Bing map, use the developer Key for the credentials property. I immediately place two markers/pins on the map which is simpler that creating them on the fly with mouse clicks (as I first tried). The markers/pins are draggable and I capture the DragEnd event to calculate and display the distance in yards and draw a line when the user finishes dragging. Here is the code to place a marker: Google: // ---- PlaceMarker ------------------------------------   function PlaceMarker(location) {     var marker = new google.maps.Marker(         {             position: location,             map: gTheMap,             draggable: true         });     marker.addListener('dragend', DragEnd);     return marker; }   Bing: // ---- PlaceMarker ------------------------------------   function PlaceMarker(location) {     var marker = new Microsoft.Maps.Pushpin(location,     {         draggable : true     });     Microsoft.Maps.Events.addHandler(marker, 'dragend', DragEnd);     gTheMap.entities.push(marker);     return marker; } Here is the code than runs when the user stops dragging a marker: Google: // ---- DragEnd -------------------------------------------   var gLine = null;   function DragEnd(Event) {     var meters = google.maps.geometry.spherical.computeDistanceBetween(marker1.position, marker2.position);     var yards = meters * 1.0936133;     $("#message").text(yards.toFixed(1) + ' yards');    // draw a line connecting the points     var Endpoints = [marker1.position, marker2.position];       if (gLine == null)     {         gLine = new google.maps.Polyline({             path: Endpoints,             strokeColor: "#FFFF00",             strokeOpacity: 1.0,             strokeWeight: 2,             map: gTheMap         });     }     else        gLine.setPath(Endpoints); } Bing: // ---- DragEnd -------------------------------------------   var gLine = null;   function DragEnd(Args) {    var Distance =  CalculateDistance(marker1._location, marker2._location);      $("#message").text(Distance.toFixed(1) + ' yards');       // draw a line connecting the points    var Endpoints = [marker1._location, marker2._location];           if (gLine == null)    {        gLine = new Microsoft.Maps.Polyline(Endpoints,            {                strokeColor: new Microsoft.Maps.Color(0xFF, 0xFF, 0xFF, 0),  // aRGB                strokeThickness : 2            });          gTheMap.entities.push(gLine);    }    else        gLine.setLocations(Endpoints);  }   Note: I couldn't find a function to calculate the distance between points in the Bing API, so I wrote my own (CalculateDistance). If you want to see the source for it, you can pick it off the web page. Note: I was able to verify the accuracy of the measurements by using the golf hole next to the field. I put a pin/marker on the center of the green, and then by zooming in, I was able to see the 150 markers on the fairway and put the other pin/marker on one of them. Final Notes: All in all, the APIs are very similar. Both made it easy to accomplish a lot with a minimum amount of code. In one aerial view, there are leaves on the tree, in the other, the trees are bare. I don't know which service has the newer data. Here are links to working pages: Bing Map Demo Google Map Demo I hope someone finds this useful. Steve Wellens   CodeProject

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• Google and Bing Map APIs Compared

  - by SGWellens

  At one of the local golf courses I frequent, there is an open grass field next to the course. It is about eight acres in size and mowed regularly. It is permissible to hit golf balls there—you bring and shag our own balls. My golf colleagues and I spend hours there practicing, chatting and in general just wasting time. One of the guys brings Ginger, the amazing, incredible, wonder dog. Ginger is a Hungarian Vizlas (or Hungarian pointer). She chases squirrels, begs for snacks and supervises us closely to make sure we don't misbehave. Anyway, I decided to make a dedicated web page to measure distances on the field in yards using online mapping services. I started with Google maps and then did the same application with Bing maps. It is a good way to become familiar with the APIs. Here are images of the final two maps: Google:  Bing:   To start with online mapping services, you need to visit the respective websites and get a developers key. I pared the code down to the minimum to make it easier to compare the APIs. Google maps required this CSS (or it wouldn't work): <style type="text/css">     html     {         height: 100%;     }       body     {         height: 100%;         margin: 0;         padding: 0;     } Here is how the map scripts are included. Google requires the developer Key when loading the JavaScript, Bing requires it when the map object is created: Google: <script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key=XXXXXXX&libraries=geometry&sensor=false" > </script> Bing: <script  type="text/javascript" src="http://ecn.dev.virtualearth.net/mapcontrol/mapcontrol.ashx?v=7.0"> </script> Note: I use jQuery to manipulate the DOM elements which may be overkill, but I may add more stuff to this application and I didn't want to have to add it later. Plus, I really like jQuery. Here is how the maps are created: Common Code (the same for both Google and Bing Maps):     <script type="text/javascript">         var gTheMap;         var gMarker1;         var gMarker2;           $(document).ready(DocLoaded);           function DocLoaded()         {             // golf course coordinates             var StartLat = 44.924254;             var StartLng = -93.366859;               // what element to display the map in             var mapdiv = $("#map_div")[0];   Google:         // where on earth the map should display         var StartPoint = new google.maps.LatLng(StartLat, StartLng);           // create the map         gTheMap = new google.maps.Map(mapdiv,             {                 center: StartPoint,                 zoom: 18,                 mapTypeId: google.maps.MapTypeId.SATELLITE             });           // place two markers         marker1 = PlaceMarker(new google.maps.LatLng(StartLat, StartLng + .0001));         marker2 = PlaceMarker(new google.maps.LatLng(StartLat, StartLng - .0001));           DragEnd(null);     } Bing:         // where on earth the map should display         var StartPoint = new  Microsoft.Maps.Location(StartLat, StartLng);           // create the map         gTheMap = new Microsoft.Maps.Map(mapdiv,             {                 credentials: 'XXXXXXXXXXXXXXXXXXX',                 center: StartPoint,                 zoom: 18,                 mapTypeId: Microsoft.Maps.MapTypeId.aerial             });           // place two markers         marker1 = PlaceMarker(new Microsoft.Maps.Location(StartLat, StartLng + .0001));         marker2 = PlaceMarker(new Microsoft.Maps.Location(StartLat, StartLng - .0001));           DragEnd(null);     } Note: In the Bing documentation, mapTypeId: was missing from the list of options even though the sample code included it. Note: When creating the Bing map, use the developer Key for the credentials property. I immediately place two markers/pins on the map which is simpler that creating them on the fly with mouse clicks (as I first tried). The markers/pins are draggable and I capture the DragEnd event to calculate and display the distance in yards and draw a line when the user finishes dragging. Here is the code to place a marker: Google: // ---- PlaceMarker ------------------------------------   function PlaceMarker(location) {     var marker = new google.maps.Marker(         {             position: location,             map: gTheMap,             draggable: true         });     marker.addListener('dragend', DragEnd);     return marker; } Bing: // ---- PlaceMarker ------------------------------------   function PlaceMarker(location) {     var marker = new Microsoft.Maps.Pushpin(location,     {         draggable : true     });     Microsoft.Maps.Events.addHandler(marker, 'dragend', DragEnd);     gTheMap.entities.push(marker);     return marker; } Here is the code than runs when the user stops dragging a marker: Google: // ---- DragEnd -------------------------------------------   var gLine = null;   function DragEnd(Event) {     var meters = google.maps.geometry.spherical.computeDistanceBetween(marker1.position, marker2.position);     var yards = meters * 1.0936133;     $("#message").text(yards.toFixed(1) + ' yards');    // draw a line connecting the points     var Endpoints = [marker1.position, marker2.position];       if (gLine == null)     {         gLine = new google.maps.Polyline({             path: Endpoints,             strokeColor: "#FFFF00",             strokeOpacity: 1.0,             strokeWeight: 2,             map: gTheMap         });     }     else        gLine.setPath(Endpoints); } Bing: // ---- DragEnd -------------------------------------------   var gLine = null;   function DragEnd(Args) {    var Distance =  CalculateDistance(marker1._location, marker2._location);      $("#message").text(Distance.toFixed(1) + ' yards');       // draw a line connecting the points    var Endpoints = [marker1._location, marker2._location];           if (gLine == null)    {        gLine = new Microsoft.Maps.Polyline(Endpoints,            {                strokeColor: new Microsoft.Maps.Color(0xFF, 0xFF, 0xFF, 0),  // aRGB                strokeThickness : 2            });          gTheMap.entities.push(gLine);    }    else        gLine.setLocations(Endpoints);  }  Note: I couldn't find a function to calculate the distance between points in the Bing API, so I wrote my own (CalculateDistance). If you want to see the source for it, you can pick it off the web page. Note: I was able to verify the accuracy of the measurements by using the golf hole next to the field. I put a pin/marker on the center of the green, and then by zooming in, I was able to see the 150 markers on the fairway and put the other pin/marker on one of them. Final Notes: All in all, the APIs are very similar. Both made it easy to accomplish a lot with a minimum amount of code. In one aerial view, there are leaves on the tree, in the other, the trees are bare. I don't know which service has the newer data. Here are links to working pages: Bing Map Demo Google Map Demo I hope someone finds this useful. Steve Wellens   CodeProject

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• How to count each digit in a range of integers?

  - by Carlos Gutiérrez

  Imagine you sell those metallic digits used to number houses, locker doors, hotel rooms, etc. You need to find how many of each digit to ship when your customer needs to number doors/houses: 1 to 100 51 to 300 1 to 2,000 with zeros to the left The obvious solution is to do a loop from the first to the last number, convert the counter to a string with or without zeros to the left, extract each digit and use it as an index to increment an array of 10 integers. I wonder if there is a better way to solve this, without having to loop through the entire integers range. Solutions in any language or pseudocode are welcome. Edit: Answers review John at CashCommons and Wayne Conrad comment that my current approach is good and fast enough. Let me use a silly analogy: If you were given the task of counting the squares in a chess board in less than 1 minute, you could finish the task by counting the squares one by one, but a better solution is to count the sides and do a multiplication, because you later may be asked to count the tiles in a building. Alex Reisner points to a very interesting mathematical law that, unfortunately, doesn’t seem to be relevant to this problem. Andres suggests the same algorithm I’m using, but extracting digits with %10 operations instead of substrings. John at CashCommons and phord propose pre-calculating the digits required and storing them in a lookup table or, for raw speed, an array. This could be a good solution if we had an absolute, unmovable, set in stone, maximum integer value. I’ve never seen one of those. High-Performance Mark and strainer computed the needed digits for various ranges. The result for one millon seems to indicate there is a proportion, but the results for other number show different proportions. strainer found some formulas that may be used to count digit for number which are a power of ten. Robert Harvey had a very interesting experience posting the question at MathOverflow. One of the math guys wrote a solution using mathematical notation. Aaronaught developed and tested a solution using mathematics. After posting it he reviewed the formulas originated from Math Overflow and found a flaw in it (point to Stackoverflow :). noahlavine developed an algorithm and presented it in pseudocode. A new solution After reading all the answers, and doing some experiments, I found that for a range of integer from 1 to 10n-1: For digits 1 to 9, n*10(n-1) pieces are needed For digit 0, if not using leading zeros, n*10n-1 - ((10n-1) / 9) are needed For digit 0, if using leading zeros, n*10n-1 - n are needed The first formula was found by strainer (and probably by others), and I found the other two by trial and error (but they may be included in other answers). For example, if n = 6, range is 1 to 999,999: For digits 1 to 9 we need 6*105 = 600,000 of each one For digit 0, without leading zeros, we need 6*105 – (106-1)/9 = 600,000 - 111,111 = 488,889 For digit 0, with leading zeros, we need 6*105 – 6 = 599,994 These numbers can be checked using High-Performance Mark results. Using these formulas, I improved the original algorithm. It still loops from the first to the last number in the range of integers, but, if it finds a number which is a power of ten, it uses the formulas to add to the digits count the quantity for a full range of 1 to 9 or 1 to 99 or 1 to 999 etc. Here's the algorithm in pseudocode: integer First,Last //First and last number in the range integer Number //Current number in the loop integer Power //Power is the n in 10^n in the formulas integer Nines //Nines is the resut of 10^n - 1, 10^5 - 1 = 99999 integer Prefix //First digits in a number. For 14,200, prefix is 142 array 0..9 Digits //Will hold the count for all the digits FOR Number = First TO Last CALL TallyDigitsForOneNumber WITH Number,1 //Tally the count of each digit //in the number, increment by 1 //Start of optimization. Comments are for Number = 1,000 and Last = 8,000. Power = Zeros at the end of number //For 1,000, Power = 3 IF Power 0 //The number ends in 0 00 000 etc Nines = 10^Power-1 //Nines = 10^3 - 1 = 1000 - 1 = 999 IF Number+Nines <= Last //If 1,000+999 < 8,000, add a full set Digits[0-9] += Power*10^(Power-1) //Add 3*10^(3-1) = 300 to digits 0 to 9 Digits[0] -= -Power //Adjust digit 0 (leading zeros formula) Prefix = First digits of Number //For 1000, prefix is 1 CALL TallyDigitsForOneNumber WITH Prefix,Nines //Tally the count of each //digit in prefix, //increment by 999 Number += Nines //Increment the loop counter 999 cycles ENDIF ENDIF //End of optimization ENDFOR SUBROUTINE TallyDigitsForOneNumber PARAMS Number,Count REPEAT Digits [ Number % 10 ] += Count Number = Number / 10 UNTIL Number = 0 For example, for range 786 to 3,021, the counter will be incremented: By 1 from 786 to 790 (5 cycles) By 9 from 790 to 799 (1 cycle) By 1 from 799 to 800 By 99 from 800 to 899 By 1 from 899 to 900 By 99 from 900 to 999 By 1 from 999 to 1000 By 999 from 1000 to 1999 By 1 from 1999 to 2000 By 999 from 2000 to 2999 By 1 from 2999 to 3000 By 1 from 3000 to 3010 (10 cycles) By 9 from 3010 to 3019 (1 cycle) By 1 from 3019 to 3021 (2 cycles) Total: 28 cycles Without optimization: 2,235 cycles Note that this algorithm solves the problem without leading zeros. To use it with leading zeros, I used a hack: If range 700 to 1,000 with leading zeros is needed, use the algorithm for 10,700 to 11,000 and then substract 1,000 - 700 = 300 from the count of digit 1. Benchmark and Source code I tested the original approach, the same approach using %10 and the new solution for some large ranges, with these results: Original 104.78 seconds With %10 83.66 With Powers of Ten 0.07 A screenshot of the benchmark application: If you would like to see the full source code or run the benchmark, use these links: Complete Source code (in Clarion): http://sca.mx/ftp/countdigits.txt Compilable project and win32 exe: http://sca.mx/ftp/countdigits.zip Accepted answer noahlavine solution may be correct, but l just couldn’t follow the pseudo code, I think there are some details missing or not completely explained. Aaronaught solution seems to be correct, but the code is just too complex for my taste. I accepted strainer’s answer, because his line of thought guided me to develop this new solution.

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• Does RVM "failover" to another ruby instance on error?

  - by JohnMetta

  Have a strange problem in that I have a Rake task that seems to be using multiple versions of Ruby. When one fails, it seems to try another one. Details MacBook running 10.6.5 rvm 1.1.0 Rubies: 1.8.7-p302, ree-1.8.7-2010.02, ruby-1.9.2-p0 Rake 0.8.7 Gem 1.3.7 Veewee (provisioning Virtual Machines using Opcode.com, Vagrant and Chef) I'm not entirely sure the specific details of the error matter, but since it might be an issue with Veewee itself. So, what I'm trying to do is build a new box base on a veewee definition. The command fails with an error about a missing method- but what's interesting is how it fails. Errors I managed to figure out that if I only have one Ruby installed with RVM, it just fails. If I have more than one Ruby install, it fails at the same place, but execution seems to continue in another interpreter. Here are two different clipped console outputs. I've clipped them for size. The full outputs of each error are available as a gist. One Ruby version installed Here is the command run when I only have a single version of Ruby (1.8.7) available in RVM boudica:veewee john$ rvm rake build['mettabox'] --trace rvm 1.1.0 by Wayne E. Seguin ([email protected]) [http://rvm.beginrescueend.com/] (in /Users/john/Work/veewee) ** Invoke build (first_time) ** Execute build … creating new harddrive rake aborted! undefined method `max_vdi_size' for #<VirtualBox::SystemProperties:0x102d6af80> /Users/john/.rvm/gems/ruby-1.8.7-p302/gems/virtualbox-0.8.3/lib/virtualbox/abstract_model/dirty.rb:172:in `method_missing' <------ stacktraces cut ----------> /Users/john/.rvm/gems/ruby-1.8.7-p302/gems/rake-0.8.7/bin/rake:31 /Users/john/.rvm/gems/ruby-1.8.7-p302@global/bin/rake:19:in `load' /Users/john/.rvm/gems/ruby-1.8.7-p302@global/bin/rake:19 Multiple Ruby Versions Here is the same command run with three versions of Ruby available in RVM. Prior to doing this, I used "rvm use 1.8.7." Again, I don't know how important the details of the specific errors are- what's interesting to me is that there are three separate errors- each with it's own stacktrace- and each in a different Ruby interpreter. Look at the bottom of each stacktrace and you'll see that they are all sourced from different interpreter locations- First ree-1.8.7, then ruby-1.8.7, then ruby-1.9.2: boudica:veewee john$ rvm rake build['mettabox'] --trace rvm 1.1.0 by Wayne E. Seguin ([email protected]) [http://rvm.beginrescueend.com/] (in /Users/john/Work/veewee) ** Invoke build (first_time) ** Execute build … creating new harddrive rake aborted! undefined method `max_vdi_size' for #<VirtualBox::SystemProperties:0x1059dd608> /Users/john/.rvm/gems/ree-1.8.7-2010.02/gems/virtualbox-0.8.3/lib/virtualbox/abstract_model/dirty.rb:172:in `method_missing' … /Users/john/.rvm/gems/ree-1.8.7-2010.02/gems/rake-0.8.7/bin/rake:31 /Users/john/.rvm/gems/ree-1.8.7-2010.02@global/bin/rake:19:in `load' /Users/john/.rvm/gems/ree-1.8.7-2010.02@global/bin/rake:19 (in /Users/john/Work/veewee) ** Invoke build (first_time) ** Execute build isofile ubuntu-10.04.1-server-amd64.iso is available ["a1b857f92eecaf9f0a31ecfc39dee906", "30b5c6fdddbfe7b397fe506400be698d"] [] Last good state: -1 Current step: 0 last good state -1 destroying machine+disks (re-)executing step 0-initial-a1b857f92eecaf9f0a31ecfc39dee906 VBoxManage: error: Machine settings file '/Users/john/VirtualBox VMs/mettabox/mettabox.vbox' already exists VBoxManage: error: Details: code VBOX_E_FILE_ERROR (0x80bb0004), component Machine, interface IMachine, callee nsISupports Context: "CreateMachine(bstrSettingsFile.raw(), name.raw(), osTypeId.raw(), Guid(id).toUtf16().raw(), FALSE , machine.asOutParam())" at line 247 of file VBoxManageMisc.cpp rake aborted! undefined method `memory_size=' for nil:NilClass /Users/john/Work/veewee/lib/veewee/session.rb:303:in `create_vm' /Users/john/Work/veewee/lib/veewee/session.rb:166:in `build' /Users/john/Work/veewee/lib/veewee/session.rb:560:in `transaction' /Users/john/Work/veewee/lib/veewee/session.rb:163:in `build' /Users/john/Work/veewee/Rakefile:87 /Users/john/.rvm/gems/ruby-1.8.7-p302/gems/rake-0.8.7/lib/rake.rb:636:in `call' /Users/john/.rvm/gems/ruby-1.8.7-p302/gems/rake-0.8.7/lib/rake.rb:636:in `execute' /Users/john/.rvm/gems/ruby-1.8.7-p302/gems/rake-0.8.7/lib/rake.rb:631:in `each' … /Users/john/.rvm/gems/ruby-1.8.7-p302/gems/rake-0.8.7/bin/rake:31 /Users/john/.rvm/gems/ruby-1.8.7-p302@global/bin/rake:19:in `load' /Users/john/.rvm/gems/ruby-1.8.7-p302@global/bin/rake:19 (in /Users/john/Work/veewee) ** Invoke build (first_time) ** Execute build isofile ubuntu-10.04.1-server-amd64.iso is available ["a9c4ab3257e1da3479c984eae9905c2a", "30b5c6fdddbfe7b397fe506400be698d"] [] Last good state: -1 Current step: 0 last good state -1 (re-)executing step 0-initial-a9c4ab3257e1da3479c984eae9905c2a VBoxManage: error: Machine settings file '/Users/john/VirtualBox VMs/mettabox/mettabox.vbox' already exists VBoxManage: error: Details: code VBOX_E_FILE_ERROR (0x80bb0004), component Machine, interface IMachine, callee nsISupports Context: "CreateMachine(bstrSettingsFile.raw(), name.raw(), osTypeId.raw(), Guid(id).toUtf16().raw(), FALSE , machine.asOutParam())" at line 247 of file VBoxManageMisc.cpp rake aborted! undefined method `memory_size=' for nil:NilClass /Users/john/Work/veewee/lib/veewee/session.rb:303:in `create_vm' /Users/john/Work/veewee/lib/veewee/session.rb:166:in `block in build' /Users/john/Work/veewee/lib/veewee/session.rb:560:in `transaction' /Users/john/Work/veewee/lib/veewee/session.rb:163:in `build' /Users/john/Work/veewee/Rakefile:87:in `block in <top (required)>' /Users/john/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/rake.rb:634:in `call' /Users/john/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/rake.rb:634:in `block in execute' … /Users/john/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/rake.rb:2013:in `top_level' /Users/john/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/rake.rb:1992:in `run' /Users/john/.rvm/rubies/ruby-1.9.2-p0/bin/rake:35:in `<main>' It isn't until we reach the last installed version of Ruby that execution halts. Discussion Does anyone have any idea what's going on here? Has anyone seen this "failover"-like behavior before? It seems strange to me that the first exception would not halt execution as it did with one interpreter, but I wonder if there are things happening when RVM is installed that we Ruby developers are not considering.

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• Trouble updating my datagrid in WPF

  - by wrigley06

  As the title indicates, I'm having trouble updating a datagrid in WPF. Basically what I'm trying to accomplish is a datagrid, that is connected to a SQL Server database, that updates automatically once a user enters information into a few textboxes and clicks a submit button. You'll notice that I have a command that joins two tables. The data from the Quote_Data table will be inserted by a different user at a later time. For now my only concern is getting the information from the textboxes and into the General_Info table, and from there into my datagrid. The code, which I'll include below compiles fine, but when I hit the submit button, nothing happens. This is the first application I've ever built working with a SQL Database so many of these concepts are new to me, which is why you'll probably look at my code and wonder what is he thinking. public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } public DataSet mds; // main data set (mds) private void Window_Loaded_1(object sender, RoutedEventArgs e) { try { string connectionString = Sqtm.Properties.Settings.Default.SqtmDbConnectionString; using (SqlConnection connection = new SqlConnection(connectionString)) { connection.Open(); //Merging tables General_Info and Quote_Data SqlCommand cmd = new SqlCommand("SELECT General_Info.Quote_ID, General_Info.Open_Quote, General_Info.Customer_Name," + "General_Info.OEM_Name, General_Info.Qty, General_Info.Quote_Num, General_Info.Fab_Drawing_Num, " + "General_Info.Rfq_Num, General_Info.Rev_Num, Quote_Data.MOA, Quote_Data.MOQ, " + "Quote_Data.Markup, Quote_Data.FOB, Quote_Data.Shipping_Method, Quote_Data.Freight, " + "Quote_Data.Vendor_Price, Unit_Price, Quote_Data.Difference, Quote_Data.Vendor_NRE_ET, " + "Quote_Data.NRE, Quote_Data.ET, Quote_Data.STI_NET, Quote_Data.Mfg_Time, Quote_Data.Delivery_Time, " + "Quote_Data.Mfg_Name, Quote_Data.Mfg_Location " + "FROM General_Info INNER JOIN dbo.Quote_Data ON General_Info.Quote_ID = Quote_Data.Quote_ID", connection); SqlDataAdapter da = new SqlDataAdapter(cmd); DataTable dt = new DataTable(); da.Fill(dt); MainGrid.ItemsSource = dt.DefaultView; mds = new DataSet(); da.Fill(mds, "General_Info"); MainGrid.DataContext = mds.Tables["General_Info"]; } } catch (Exception ex) { MessageBox.Show(ex.Message); } // renaming column names from the database so they are easier to read in the datagrid MainGrid.Columns[0].Header = "#"; MainGrid.Columns[1].Header = "Date"; MainGrid.Columns[2].Header = "Customer"; MainGrid.Columns[3].Header = "OEM"; MainGrid.Columns[4].Header = "Qty"; MainGrid.Columns[5].Header = "Quote Number"; MainGrid.Columns[6].Header = "Fab Drawing Num"; MainGrid.Columns[7].Header = "RFQ Number"; MainGrid.Columns[8].Header = "Rev Number"; MainGrid.Columns[9].Header = "MOA"; MainGrid.Columns[10].Header = "MOQ"; MainGrid.Columns[11].Header = "Markup"; MainGrid.Columns[12].Header = "FOB"; MainGrid.Columns[13].Header = "Shipping"; MainGrid.Columns[14].Header = "Freight"; MainGrid.Columns[15].Header = "Vendor Price"; MainGrid.Columns[16].Header = "Unit Price"; MainGrid.Columns[17].Header = "Difference"; MainGrid.Columns[18].Header = "Vendor NRE/ET"; MainGrid.Columns[19].Header = "NRE"; MainGrid.Columns[20].Header = "ET"; MainGrid.Columns[21].Header = "STINET"; MainGrid.Columns[22].Header = "Mfg. Time"; MainGrid.Columns[23].Header = "Delivery Time"; MainGrid.Columns[24].Header = "Manufacturer"; MainGrid.Columns[25].Header = "Mfg. Location"; } private void submitQuotebtn_Click(object sender, RoutedEventArgs e) { CustomerData newQuote = new CustomerData(); int quantity; quantity = Convert.ToInt32(quantityTxt.Text); string theDate = System.DateTime.Today.Date.ToString("d"); newQuote.OpenQuote = theDate; newQuote.CustomerName = customerNameTxt.Text; newQuote.OEMName = oemNameTxt.Text; newQuote.Qty = quantity; newQuote.QuoteNumber = quoteNumberTxt.Text; newQuote.FdNumber = fabDrawingNumberTxt.Text; newQuote.RfqNumber = rfqNumberTxt.Text; newQuote.RevNumber = revNumberTxt.Text; try { string insertConString = Sqtm.Properties.Settings.Default.SqtmDbConnectionString; using (SqlConnection insertConnection = new SqlConnection(insertConString)) { insertConnection.Open(); SqlDataAdapter adapter = new SqlDataAdapter(Sqtm.Properties.Settings.Default.SqtmDbConnectionString, insertConnection); SqlCommand updateCmd = new SqlCommand("UPDATE General_Info " + "Quote_ID = @Quote_ID, " + "Open_Quote = @Open_Quote, " + "OEM_Name = @OEM_Name, " + "Qty = @Qty, " + "Quote_Num = @Quote_Num, " + "Fab_Drawing_Num = @Fab_Drawing_Num, " + "Rfq_Num = @Rfq_Num, " + "Rev_Num = @Rev_Num " + "WHERE Quote_ID = @Quote_ID"); updateCmd.Connection = insertConnection; System.Data.SqlClient.SqlParameterCollection param = updateCmd.Parameters; // // Add new SqlParameters to the command. // param.AddWithValue("Open_Quote", newQuote.OpenQuote); param.AddWithValue("Customer_Name", newQuote.CustomerName); param.AddWithValue("OEM_Name", newQuote.OEMName); param.AddWithValue("Qty", newQuote.Qty); param.AddWithValue("Quote_Num", newQuote.QuoteNumber); param.AddWithValue("Fab_Drawing_Num", newQuote.FdNumber); param.AddWithValue("Rfq_Num", newQuote.RfqNumber); param.AddWithValue("Rev_Num", newQuote.RevNumber); adapter.UpdateCommand = updateCmd; adapter.Update(mds.Tables[0]); mds.AcceptChanges(); } } catch (Exception ex) { MessageBox.Show(ex.Message); } } Thanks in advance to anyone who can help, I really appreciate it, Andrew

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• Reverse engineering windows mobile live search CellID location awareness protocol (yikes)...

  - by Jean-Charles

  I wasn't sure of how to form the question so I apologize if the title is misleading. Additionally, you may want to get some coffee and take a seat for this one ... It's long. Basically, I'm trying to reverse engineer the protocol used by the Windows Mobile Live Search application to get location based on cellID. Before I go on, I am aware of other open source services (such as OpenCellID) but this is more for the sake of education and a bit for redundancy. According to the packets I captured, a POST request is made to ... mobile.search.live.com/positionlookupservice_1/service.aspx ... with a few specific headers (agent, content-length, etc) and no body. Once this goes through, the server sends back a 100-Continue response. At this point, the application submits this data (I chopped off the packet header): 00 00 00 01 00 00 00 05 55 54 ........UT 46 2d 38 05 65 6e 2d 55 53 05 65 6e 2d 55 53 01 F-8.en-US.en-US. 06 44 65 76 69 63 65 05 64 75 6d 6d 79 01 06 02 .Device.dummy... 50 4c 08 0e 52 65 76 65 72 73 65 47 65 6f 63 6f PL..ReverseGeoco 64 65 01 07 0b 47 50 53 43 68 69 70 49 6e 66 6f de...GPSChipInfo 01 20 06 09 43 65 6c 6c 54 6f 77 65 72 06 03 43 . ..CellTower..C 47 49 08 03 4d 43 43 b6 02 07 03 4d 4e 43 03 34 GI..MCC....MNC.4 31 30 08 03 4c 41 43 cf 36 08 02 43 49 fd 01 00 10..LAC.6..CI... 00 00 00 ... And receives this in response (packet and HTTP response headers chopped): 00 00 00 01 00 00 00 00 01 06 02 50 4c ...........PL 06 08 4c 6f 63 61 6c 69 74 79 06 08 4c 6f 63 61 ..Locality..Loca 74 69 6f 6e 07 03 4c 61 74 09 34 32 2e 33 37 35 tion..Lat.42.375 36 32 31 07 04 4c 6f 6e 67 0a 2d 37 31 2e 31 35 621..Long.-71.15 38 39 33 38 00 07 06 52 61 64 69 75 73 09 32 30 8938...Radius.20 30 30 2e 30 30 30 30 00 42 07 0c 4c 6f 63 61 6c 00.0000.B..Local 69 74 79 4e 61 6d 65 09 57 61 74 65 72 74 6f 77 ityName.Watertow 6e 07 16 41 64 6d 69 6e 69 73 74 72 61 74 69 76 n..Administrativ 65 41 72 65 61 4e 61 6d 65 0d 4d 61 73 73 61 63 eAreaName.Massac 68 75 73 65 74 74 73 07 10 50 6f 73 74 61 6c 43 husetts..PostalC 6f 64 65 4e 75 6d 62 65 72 05 30 32 34 37 32 07 odeNumber.02472. 0b 43 6f 75 6e 74 72 79 4e 61 6d 65 0d 55 6e 69 .CountryName.Uni 74 65 64 20 53 74 61 74 65 73 00 00 00 ted States... Now, here is what I've determined so far: All strings are prepended with one byte that is the decimal equivalent of their length. There seem to be three different casts that are used throughout the request and response. They show up as one byte before the length byte. I've concluded that the three types map out as follows: 0x06 - parent element (subsequent values are children, closed with 0x00) 0x07 - string 0x08 - int? Based on these determinations, here is what the request and response look like in a more readable manner (values surrounded by brackets denote length and values surrounded by parenthesis denote a cast): \0x00\0x00\0x00\0x01\0x00\0x00\0x00 [5]UTF-8 [5]en-US [5]en-US \0x01 [6]Device [5]dummy \0x01 (6)[2]PL (8)[14]ReverseGeocode\0x01 (7)[11]GPSChipInfo[1]\0x20 (6)[9]CellTower (6)[3]CGI (8)[3]MCC\0xB6\0x02 //310 (7)[3]MNC[3]410 //410 (8)[3]LAC\0xCF\0x36 //6991 (8)[2]CI\0xFD\0x01 //259 \0x00 \0x00 \0x00 \0x00 and.. \0x00\0x00\0x00\0x01\0x00\0x00\0x00 \0x00\0x01 (6)[2]PL (6)[8]Locality (6)[8]Location (7)[3]Lat[9]42.375621 (7)[4]Long[10]-71.158938 \0x00 (7)[6]Radius[9]2000.0000 \0x00 \0x42 //"B" ... Has to do with GSM (7)[12]LocalityName[9]Watertown (7)[22]AdministrativeAreaName[13]Massachusetts (7)[16]PostalCodeNumber[5]02472 (7)[11]CountryName[13]United States \0x00 \0x00\0x00 My analysis seems to work out pretty well except for a few things: The 0x01s throughout confuse me ... At first I thought they were some sort of base level element terminators but I'm not certain. I'm not sure the 7-byte header is, in fact, a seven byte header. I wonder if it's maybe 4 bytes and that the three remaining 0x00s are of some other significance. The trailing 0x00s. Why is it that there is only one on the request but two on the response? The type 8 cast mentioned above ... I can't seem to figure out how those values are being encoded. I added comments to those lines with what the values should correspond to. Any advice on these four points will be greatly appreciated. And yes, these packets were captured in Watertown, MA. :)

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• OpenGL render vs. own Phong Illumination Implementation

  - by Myx

  Hello: I have implemented a Phong Illumination Scheme using a camera that's centered at (0,0,0) and looking directly at the sphere primitive. The following are the relevant contents of the scene file that is used to view the scene using OpenGL as well as to render the scene using my own implementation: ambient 0 1 0 dir_light 1 1 1 -3 -4 -5 # A red sphere with 0.5 green ambiance, centered at (0,0,0) with radius 1 material 0 0.5 0 1 0 0 1 0 0 0 0 0 0 0 0 10 1 0 sphere 0 0 0 0 1 The resulting image produced by OpenGL. The image that my rendering application produces. As you can see, there are various differences between the two: The specular highlight on my image is smaller than the one in OpenGL. The diffuse surface seems to not diffuse in the correct way, resulting in the yellow region to be unneccessarily large in my image, whereas in OpenGL there's a nice dark green region closer to the bottom of the sphere The color produced by OpenGL is much darker than the one in my image. Those are the most prominent three differences that I see. The following is my implementation of the Phong illumination: R3Rgb Phong(R3Scene *scene, R3Ray *ray, R3Intersection *intersection) { R3Rgb radiance; if(intersection->hit == 0) { radiance = scene->background; return radiance; } R3Vector normal = intersection->normal; R3Rgb Kd = intersection->node->material->kd; R3Rgb Ks = intersection->node->material->ks; // obtain ambient term R3Rgb intensity_ambient = intersection->node->material->ka*scene->ambient; // obtain emissive term R3Rgb intensity_emission = intersection->node->material->emission; // for each light in the scene, obtain calculate the diffuse and specular terms R3Rgb intensity_diffuse(0,0,0,1); R3Rgb intensity_specular(0,0,0,1); for(unsigned int i = 0; i < scene->lights.size(); i++) { R3Light *light = scene->Light(i); R3Rgb light_color = LightIntensity(scene->Light(i), intersection->position); R3Vector light_vector = -LightDirection(scene->Light(i), intersection->position); // calculate diffuse reflection intensity_diffuse += Kd*normal.Dot(light_vector)*light_color; // calculate specular reflection R3Vector reflection_vector = 2.*normal.Dot(light_vector)*normal-light_vector; reflection_vector.Normalize(); R3Vector viewing_vector = ray->Start() - intersection->position; viewing_vector.Normalize(); double n = intersection->node->material->shininess; intensity_specular += Ks*pow(max(0.,viewing_vector.Dot(reflection_vector)),n)*light_color; } radiance = intensity_emission+intensity_ambient+intensity_diffuse+intensity_specular; return radiance; } Here are the related LightIntensity(...) and LightDirection(...) functions: R3Vector LightDirection(R3Light *light, R3Point position) { R3Vector light_direction; switch(light->type) { case R3_DIRECTIONAL_LIGHT: light_direction = light->direction; break; case R3_POINT_LIGHT: light_direction = position-light->position; break; case R3_SPOT_LIGHT: light_direction = position-light->position; break; } light_direction.Normalize(); return light_direction; } R3Rgb LightIntensity(R3Light *light, R3Point position) { R3Rgb light_intensity; double distance; double denominator; if(light->type != R3_DIRECTIONAL_LIGHT) { distance = (position-light->position).Length(); denominator = light->constant_attenuation + light->linear_attenuation*distance + light->quadratic_attenuation*distance*distance; } switch(light->type) { case R3_DIRECTIONAL_LIGHT: light_intensity = light->color; break; case R3_POINT_LIGHT: light_intensity = light->color/denominator; break; case R3_SPOT_LIGHT: R3Vector from_light_to_point = position - light->position; light_intensity = light->color*( pow(light->direction.Dot(from_light_to_point), light->angle_attenuation)); break; } return light_intensity; } I would greatly appreciate any suggestions as to any implementation errors that are apparent. I am wondering if the differences could be occurring simply because of the gamma values used for display by OpenGL and the default gamma value for my display. I also know that OpenGL (or at least tha parts that I was provided) can't cast shadows on objects. Not that this is relevant for the point in question, but it just leads me to wonder if it's simply display and capability differences between OpenGL and what I am trying to do. Thank you for your help.

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• How can I further optimize this color difference function?

  - by aLfa

  I have made this function to calculate color differences in the CIE Lab colorspace, but it lacks speed. Since I'm not a Java expert, I wonder if any Java guru around has some tips that can improve the speed here. The code is based on the matlab function mentioned in the comment block. /** * Compute the CIEDE2000 color-difference between the sample color with * CIELab coordinates 'sample' and a standard color with CIELab coordinates * 'std' * * Based on the article: * "The CIEDE2000 Color-Difference Formula: Implementation Notes, * Supplementary Test Data, and Mathematical Observations,", G. Sharma, * W. Wu, E. N. Dalal, submitted to Color Research and Application, * January 2004. * available at http://www.ece.rochester.edu/~gsharma/ciede2000/ */ public static double deltaE2000(double[] lab1, double[] lab2) { double L1 = lab1[0]; double a1 = lab1[1]; double b1 = lab1[2]; double L2 = lab2[0]; double a2 = lab2[1]; double b2 = lab2[2]; // Cab = sqrt(a^2 + b^2) double Cab1 = Math.sqrt(a1 * a1 + b1 * b1); double Cab2 = Math.sqrt(a2 * a2 + b2 * b2); // CabAvg = (Cab1 + Cab2) / 2 double CabAvg = (Cab1 + Cab2) / 2; // G = 1 + (1 - sqrt((CabAvg^7) / (CabAvg^7 + 25^7))) / 2 double CabAvg7 = Math.pow(CabAvg, 7); double G = 1 + (1 - Math.sqrt(CabAvg7 / (CabAvg7 + 6103515625.0))) / 2; // ap = G * a double ap1 = G * a1; double ap2 = G * a2; // Cp = sqrt(ap^2 + b^2) double Cp1 = Math.sqrt(ap1 * ap1 + b1 * b1); double Cp2 = Math.sqrt(ap2 * ap2 + b2 * b2); // CpProd = (Cp1 * Cp2) double CpProd = Cp1 * Cp2; // hp1 = atan2(b1, ap1) double hp1 = Math.atan2(b1, ap1); // ensure hue is between 0 and 2pi if (hp1 < 0) { // hp1 = hp1 + 2pi hp1 += 6.283185307179586476925286766559; } // hp2 = atan2(b2, ap2) double hp2 = Math.atan2(b2, ap2); // ensure hue is between 0 and 2pi if (hp2 < 0) { // hp2 = hp2 + 2pi hp2 += 6.283185307179586476925286766559; } // dL = L2 - L1 double dL = L2 - L1; // dC = Cp2 - Cp1 double dC = Cp2 - Cp1; // computation of hue difference double dhp = 0.0; // set hue difference to zero if the product of chromas is zero if (CpProd != 0) { // dhp = hp2 - hp1 dhp = hp2 - hp1; if (dhp > Math.PI) { // dhp = dhp - 2pi dhp -= 6.283185307179586476925286766559; } else if (dhp < -Math.PI) { // dhp = dhp + 2pi dhp += 6.283185307179586476925286766559; } } // dH = 2 * sqrt(CpProd) * sin(dhp / 2) double dH = 2 * Math.sqrt(CpProd) * Math.sin(dhp / 2); // weighting functions // Lp = (L1 + L2) / 2 - 50 double Lp = (L1 + L2) / 2 - 50; // Cp = (Cp1 + Cp2) / 2 double Cp = (Cp1 + Cp2) / 2; // average hue computation // hp = (hp1 + hp2) / 2 double hp = (hp1 + hp2) / 2; // identify positions for which abs hue diff exceeds 180 degrees if (Math.abs(hp1 - hp2) > Math.PI) { // hp = hp - pi hp -= Math.PI; } // ensure hue is between 0 and 2pi if (hp < 0) { // hp = hp + 2pi hp += 6.283185307179586476925286766559; } // LpSqr = Lp^2 double LpSqr = Lp * Lp; // Sl = 1 + 0.015 * LpSqr / sqrt(20 + LpSqr) double Sl = 1 + 0.015 * LpSqr / Math.sqrt(20 + LpSqr); // Sc = 1 + 0.045 * Cp double Sc = 1 + 0.045 * Cp; // T = 1 - 0.17 * cos(hp - pi / 6) + // + 0.24 * cos(2 * hp) + // + 0.32 * cos(3 * hp + pi / 30) - // - 0.20 * cos(4 * hp - 63 * pi / 180) double hphp = hp + hp; double T = 1 - 0.17 * Math.cos(hp - 0.52359877559829887307710723054658) + 0.24 * Math.cos(hphp) + 0.32 * Math.cos(hphp + hp + 0.10471975511965977461542144610932) - 0.20 * Math.cos(hphp + hphp - 1.0995574287564276334619251841478); // Sh = 1 + 0.015 * Cp * T double Sh = 1 + 0.015 * Cp * T; // deltaThetaRad = (pi / 3) * e^-(36 / (5 * pi) * hp - 11)^2 double powerBase = hp - 4.799655442984406; double deltaThetaRad = 1.0471975511965977461542144610932 * Math.exp(-5.25249016001879 * powerBase * powerBase); // Rc = 2 * sqrt((Cp^7) / (Cp^7 + 25^7)) double Cp7 = Math.pow(Cp, 7); double Rc = 2 * Math.sqrt(Cp7 / (Cp7 + 6103515625.0)); // RT = -sin(delthetarad) * Rc double RT = -Math.sin(deltaThetaRad) * Rc; // de00 = sqrt((dL / Sl)^2 + (dC / Sc)^2 + (dH / Sh)^2 + RT * (dC / Sc) * (dH / Sh)) double dLSl = dL / Sl; double dCSc = dC / Sc; double dHSh = dH / Sh; return Math.sqrt(dLSl * dLSl + dCSc * dCSc + dHSh * dHSh + RT * dCSc * dHSh); }

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• Cobol: science and fiction

  - by user847

  There are a few threads about the relevance of the Cobol programming language on this forum, e.g. this thread links to a collection of them. What I am interested in here is a frequently repeated claim based on a study by Gartner from 1997: that there were around 200 billion lines of code in active use at that time! I would like to ask some questions to verify or falsify a couple of related points. My goal is to understand if this statement has any truth to it or if it is totally unrealistic. I apologize in advance for being a little verbose in presenting my line of thought and my own opinion on the things I am not sure about, but I think it might help to put things in context and thus highlight any wrong assumptions and conclusions I have made. Sometimes, the "200 billion lines" number is accompanied by the added claim that this corresponded to 80% of all programming code in any language in active use. Other times, the 80% merely refer to so-called "business code" (or some other vague phrase hinting that the reader is not to count mainstream software, embedded systems or anything else where Cobol is practically non-existent). In the following I assume that the code does not include double-counting of multiple installations of the same software (since that is cheating!). In particular in the time prior to the y2k problem, it has been noted that a lot of Cobol code is already 20 to 30 years old. That would mean it was written in the late 60ies and 70ies. At that time, the market leader was IBM with the IBM/370 mainframe. IBM has put up a historical announcement on his website quoting prices and availability. According to the sheet, prices are about one million dollars for machines with up to half a megabyte of memory. Question 1: How many mainframes have actually been sold? I have not found any numbers for those times; the latest numbers are for the year 2000, again by Gartner. :^( I would guess that the actual number is in the hundreds or the low thousands; if the market size was 50 billion in 2000 and the market has grown exponentially like any other technology, it might have been merely a few billions back in 1970. Since the IBM/370 was sold for twenty years, twenty times a few thousand will result in a couple of ten-thousands of machines (and that is pretty optimistic)! Question 2: How large were the programs in lines of code? I don't know how many bytes of machine code result from one line of source code on that architecture. But since the IBM/370 was a 32-bit machine, any address access must have used 4 bytes plus instruction (2, maybe 3 bytes for that?). If you count in operating system and data for the program, how many lines of code would have fit into the main memory of half a megabyte? Question 3: Was there no standard software? Did every single machine sold run a unique hand-coded system without any standard software? Seriously, even if every machine was programmed from scratch without any reuse of legacy code (wait ... didn't that violate one of the claims we started from to begin with???) we might have O(50,000 l.o.c./machine) * O(20,000 machines) = O(1,000,000,000 l.o.c.). That is still far, far, far away from 200 billion! Am I missing something obvious here? Question 4: How many programmers did we need to write 200 billion lines of code? I am really not sure about this one, but if we take an average of 10 l.o.c. per day, we would need 55 million man-years to achieve this! In the time-frame of 20 to 30 years this would mean that there must have existed two to three million programmers constantly writing, testing, debugging and documenting code. That would be about as many programmers as we have in China today, wouldn't it? Question 5: What about the competition? So far, I have come up with two things here: 1) IBM had their own programming language, PL/I. Above I have assumed that the majority of code has been written exclusively using Cobol. However, all other things being equal I wonder if IBM marketing had really pushed their own development off the market in favor of Cobol on their machines. Was there really no relevant code base of PL/I? 2) Sometimes (also on this board in the thread quoted above) I come across the claim that the "200 billion lines of code" are simply invisible to anybody outside of "governments, banks ..." (and whatnot). Actually, the DoD had funded their own language in order to increase cost effectiveness and reduce the proliferation of programming language. This lead to their use of Ada. Would they really worry about having so many different programming languages if they had predominantly used Cobol? If there was any language running on "government and military" systems outside the perception of mainstream computing, wouldn't that language be Ada? I hope someone can point out any flaws in my assumptions and/or conclusions and shed some light on whether the above claim has any truth to it or not.

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• SetWindowHookEx and execution blocking

  - by Kalaz

  Hello, I just wonder... I mainly use .NET but now I started to investigate WINAPI calls. For example I am using this piece of code to hook to the API functions. It starts freezing, when I try to debug the application... using System; using System.Diagnostics; using System.Runtime.InteropServices; using System.Threading; using System.Windows.Forms; public class Keyboard { private const int WH_KEYBOARD_LL = 13; private const int WM_KEYDOWN = 0x0100; private static LowLevelKeyboardProc _proc = HookCallback; private static IntPtr _hookID = IntPtr.Zero; public static event Action<Keys,bool, bool> KeyDown; public static void Hook() { new Thread(new ThreadStart(()=> { _hookID = SetHook(_proc); Application.Run(); })).Start(); } public static void Unhook() { UnhookWindowsHookEx(_hookID); } private static IntPtr SetHook(LowLevelKeyboardProc proc) { using (Process curProcess = Process.GetCurrentProcess()) using (ProcessModule curModule = curProcess.MainModule) { return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0); } } private delegate IntPtr LowLevelKeyboardProc( int nCode, IntPtr wParam, IntPtr lParam); private static IntPtr HookCallback( int nCode, IntPtr wParam, IntPtr lParam) { if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN) { int vkCode = Marshal.ReadInt32(lParam); Keys k = (Keys) vkCode; if (KeyDown != null) { KeyDown.BeginInvoke(k, IsKeyPressed(VirtualKeyStates.VK_CONTROL), IsKeyPressed(VirtualKeyStates.VK_SHIFT),null,null); } } return CallNextHookEx(_hookID, nCode, wParam, lParam); } private static bool IsKeyPressed(VirtualKeyStates virtualKeyStates) { return (GetKeyState(virtualKeyStates) & (1 << 7))==128; } [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId); [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool UnhookWindowsHookEx(IntPtr hhk); [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam); [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr GetModuleHandle(string lpModuleName); [DllImport("user32.dll")] static extern short GetKeyState(VirtualKeyStates nVirtKey); } enum VirtualKeyStates : int { VK_LBUTTON = 0x01, VK_RBUTTON = 0x02, VK_CANCEL = 0x03, VK_MBUTTON = 0x04, // VK_XBUTTON1 = 0x05, VK_XBUTTON2 = 0x06, // VK_BACK = 0x08, VK_TAB = 0x09, // VK_CLEAR = 0x0C, VK_RETURN = 0x0D, // VK_SHIFT = 0x10, VK_CONTROL = 0x11, VK_MENU = 0x12, VK_PAUSE = 0x13, VK_CAPITAL = 0x14, // VK_KANA = 0x15, VK_HANGEUL = 0x15, /* old name - should be here for compatibility */ VK_HANGUL = 0x15, VK_JUNJA = 0x17, VK_FINAL = 0x18, VK_HANJA = 0x19, VK_KANJI = 0x19, // VK_ESCAPE = 0x1B, // VK_CONVERT = 0x1C, VK_NONCONVERT = 0x1D, VK_ACCEPT = 0x1E, VK_MODECHANGE = 0x1F, // VK_SPACE = 0x20, VK_PRIOR = 0x21, VK_NEXT = 0x22, VK_END = 0x23, VK_HOME = 0x24, VK_LEFT = 0x25, VK_UP = 0x26, VK_RIGHT = 0x27, VK_DOWN = 0x28, VK_SELECT = 0x29, VK_PRINT = 0x2A, VK_EXECUTE = 0x2B, VK_SNAPSHOT = 0x2C, VK_INSERT = 0x2D, VK_DELETE = 0x2E, VK_HELP = 0x2F, // VK_LWIN = 0x5B, VK_RWIN = 0x5C, VK_APPS = 0x5D, // VK_SLEEP = 0x5F, // VK_NUMPAD0 = 0x60, VK_NUMPAD1 = 0x61, VK_NUMPAD2 = 0x62, VK_NUMPAD3 = 0x63, VK_NUMPAD4 = 0x64, VK_NUMPAD5 = 0x65, VK_NUMPAD6 = 0x66, VK_NUMPAD7 = 0x67, VK_NUMPAD8 = 0x68, VK_NUMPAD9 = 0x69, VK_MULTIPLY = 0x6A, VK_ADD = 0x6B, VK_SEPARATOR = 0x6C, VK_SUBTRACT = 0x6D, VK_DECIMAL = 0x6E, VK_DIVIDE = 0x6F, VK_F1 = 0x70, VK_F2 = 0x71, VK_F3 = 0x72, VK_F4 = 0x73, VK_F5 = 0x74, VK_F6 = 0x75, VK_F7 = 0x76, VK_F8 = 0x77, VK_F9 = 0x78, VK_F10 = 0x79, VK_F11 = 0x7A, VK_F12 = 0x7B, VK_F13 = 0x7C, VK_F14 = 0x7D, VK_F15 = 0x7E, VK_F16 = 0x7F, VK_F17 = 0x80, VK_F18 = 0x81, VK_F19 = 0x82, VK_F20 = 0x83, VK_F21 = 0x84, VK_F22 = 0x85, VK_F23 = 0x86, VK_F24 = 0x87, // VK_NUMLOCK = 0x90, VK_SCROLL = 0x91, // VK_OEM_NEC_EQUAL = 0x92, // '=' key on numpad // VK_OEM_FJ_JISHO = 0x92, // 'Dictionary' key VK_OEM_FJ_MASSHOU = 0x93, // 'Unregister word' key VK_OEM_FJ_TOUROKU = 0x94, // 'Register word' key VK_OEM_FJ_LOYA = 0x95, // 'Left OYAYUBI' key VK_OEM_FJ_ROYA = 0x96, // 'Right OYAYUBI' key // VK_LSHIFT = 0xA0, VK_RSHIFT = 0xA1, VK_LCONTROL = 0xA2, VK_RCONTROL = 0xA3, VK_LMENU = 0xA4, VK_RMENU = 0xA5, // VK_BROWSER_BACK = 0xA6, VK_BROWSER_FORWARD = 0xA7, VK_BROWSER_REFRESH = 0xA8, VK_BROWSER_STOP = 0xA9, VK_BROWSER_SEARCH = 0xAA, VK_BROWSER_FAVORITES = 0xAB, VK_BROWSER_HOME = 0xAC, // VK_VOLUME_MUTE = 0xAD, VK_VOLUME_DOWN = 0xAE, VK_VOLUME_UP = 0xAF, VK_MEDIA_NEXT_TRACK = 0xB0, VK_MEDIA_PREV_TRACK = 0xB1, VK_MEDIA_STOP = 0xB2, VK_MEDIA_PLAY_PAUSE = 0xB3, VK_LAUNCH_MAIL = 0xB4, VK_LAUNCH_MEDIA_SELECT = 0xB5, VK_LAUNCH_APP1 = 0xB6, VK_LAUNCH_APP2 = 0xB7, // VK_OEM_1 = 0xBA, // ';:' for US VK_OEM_PLUS = 0xBB, // '+' any country VK_OEM_COMMA = 0xBC, // ',' any country VK_OEM_MINUS = 0xBD, // '-' any country VK_OEM_PERIOD = 0xBE, // '.' any country VK_OEM_2 = 0xBF, // '/?' for US VK_OEM_3 = 0xC0, // '`~' for US // VK_OEM_4 = 0xDB, // '[{' for US VK_OEM_5 = 0xDC, // '\|' for US VK_OEM_6 = 0xDD, // ']}' for US VK_OEM_7 = 0xDE, // ''"' for US VK_OEM_8 = 0xDF, // VK_OEM_AX = 0xE1, // 'AX' key on Japanese AX kbd VK_OEM_102 = 0xE2, // "<>" or "\|" on RT 102-key kbd. VK_ICO_HELP = 0xE3, // Help key on ICO VK_ICO_00 = 0xE4, // 00 key on ICO // VK_PROCESSKEY = 0xE5, // VK_ICO_CLEAR = 0xE6, // VK_PACKET = 0xE7, // VK_OEM_RESET = 0xE9, VK_OEM_JUMP = 0xEA, VK_OEM_PA1 = 0xEB, VK_OEM_PA2 = 0xEC, VK_OEM_PA3 = 0xED, VK_OEM_WSCTRL = 0xEE, VK_OEM_CUSEL = 0xEF, VK_OEM_ATTN = 0xF0, VK_OEM_FINISH = 0xF1, VK_OEM_COPY = 0xF2, VK_OEM_AUTO = 0xF3, VK_OEM_ENLW = 0xF4, VK_OEM_BACKTAB = 0xF5, // VK_ATTN = 0xF6, VK_CRSEL = 0xF7, VK_EXSEL = 0xF8, VK_EREOF = 0xF9, VK_PLAY = 0xFA, VK_ZOOM = 0xFB, VK_NONAME = 0xFC, VK_PA1 = 0xFD, VK_OEM_CLEAR = 0xFE } It works well even if you put messagebox into the event or something that blocks execution. But it gets bad if you try to put breakpoint into the event. Why? I mean event is not run in the same thread that the windows hook is. That means that It shouldn't block HookCallback. It does however... I would really like to know why is this happening. My theory is that Visual Studio when breaking execution temporarily stops all threads and that means that HookCallback is blocked... Is there any book or valuable resource that would explain concepts behind all of this threading?

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• Odd optimization problem under MSVC

  - by Goz

  I've seen this blog: http://igoro.com/archive/gallery-of-processor-cache-effects/ The "weirdness" in part 7 is what caught my interest. My first thought was "Thats just C# being weird". Its not I wrote the following C++ code. volatile int* p = (volatile int*)_aligned_malloc( sizeof( int ) * 8, 64 ); memset( (void*)p, 0, sizeof( int ) * 8 ); double dStart = t.GetTime(); for (int i = 0; i < 200000000; i++) { //p[0]++;p[1]++;p[2]++;p[3]++; // Option 1 //p[0]++;p[2]++;p[4]++;p[6]++; // Option 2 p[0]++;p[2]++; // Option 3 } double dTime = t.GetTime() - dStart; The timing I get on my 2.4 Ghz Core 2 Quad go as follows: Option 1 = ~8 cycles per loop. Option 2 = ~4 cycles per loop. Option 3 = ~6 cycles per loop. Now This is confusing. My reasoning behind the difference comes down to the cache write latency (3 cycles) on my chip and an assumption that the cache has a 128-bit write port (This is pure guess work on my part). On that basis in Option 1: It will increment p[0] (1 cycle) then increment p[2] (1 cycle) then it has to wait 1 cycle (for cache) then p[1] (1 cycle) then wait 1 cycle (for cache) then p[3] (1 cycle). Finally 2 cycles for increment and jump (Though its usually implemented as decrement and jump). This gives a total of 8 cycles. In Option 2: It can increment p[0] and p[4] in one cycle then increment p[2] and p[6] in another cycle. Then 2 cycles for subtract and jump. No waits needed on cache. Total 4 cycles. In option 3: It can increment p[0] then has to wait 2 cycles then increment p[2] then subtract and jump. The problem is if you set case 3 to increment p[0] and p[4] it STILL takes 6 cycles (which kinda blows my 128-bit read/write port out of the water). So ... can anyone tell me what the hell is going on here? Why DOES case 3 take longer? Also I'd love to know what I've got wrong in my thinking above, as i obviously have something wrong! Any ideas would be much appreciated! :) It'd also be interesting to see how GCC or any other compiler copes with it as well! Edit: Jerry Coffin's idea gave me some thoughts. I've done some more tests (on a different machine so forgive the change in timings) with and without nops and with different counts of nops case 2 - 0.46 00401ABD jne (401AB0h) 0 nops - 0.68 00401AB7 jne (401AB0h) 1 nop - 0.61 00401AB8 jne (401AB0h) 2 nops - 0.636 00401AB9 jne (401AB0h) 3 nops - 0.632 00401ABA jne (401AB0h) 4 nops - 0.66 00401ABB jne (401AB0h) 5 nops - 0.52 00401ABC jne (401AB0h) 6 nops - 0.46 00401ABD jne (401AB0h) 7 nops - 0.46 00401ABE jne (401AB0h) 8 nops - 0.46 00401ABF jne (401AB0h) 9 nops - 0.55 00401AC0 jne (401AB0h) I've included the jump statetements so you can see that the source and destination are in one cache line. You can also see that we start to get a difference when we are 13 bytes or more apart. Until we hit 16 ... then it all goes wrong. So Jerry isn't right (though his suggestion DOES help a bit), however something IS going on. I'm more and more intrigued to try and figure out what it is now. It does appear to be more some sort of memory alignment oddity rather than some sort of instruction throughput oddity. Anyone want to explain this for an inquisitive mind? :D Edit 3: Interjay has a point on the unrolling that blows the previous edit out of the water. With an unrolled loop the performance does not improve. You need to add a nop in to make the gap between jump source and destination the same as for my good nop count above. Performance still sucks. Its interesting that I need 6 nops to improve performance though. I wonder how many nops the processor can issue per cycle? If its 3 then that account for the cache write latency ... But, if thats it, why is the latency occurring? Curiouser and curiouser ...

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• System.ServiceModel.Channels.MessageHeader Error

  - by user220511

  I'm trying to get the following to work on my machine but I get an error (Cannot create an instance of the abstract class or interface 'System.ServiceModel.Channels.MessageHeader') using System; using System.IO; using System.Reflection; namespace com.mycompanyname.business { /// /// Summary description for SessionCreateRQClient. /// class SessionCreateRQClient { /// /// The main entry point. /// [STAThread] static void Main(string[] args) { try { // Set user information, including security credentials and the IPCC. string username = "user"; string password = "password"; string ipcc = "IPCC"; string domain = "DEFAULT"; string temp = Environment.GetEnvironmentVariable("tmp"); // Get temp directory string PropsFileName = temp + "/session.properties"; // Define dir and file name DateTime dt = DateTime.UtcNow; string tstamp = dt.ToString("s") + "Z"; //Create the message header and provide the conversation ID. MessageHeader msgHeader = new MessageHeader(); msgHeader.ConversationId = "TestSession"; // Set the ConversationId From from = new From(); PartyId fromPartyId = new PartyId(); PartyId[] fromPartyIdArr = new PartyId[1]; fromPartyId.Value = "WebServiceClient"; fromPartyIdArr[0] = fromPartyId; from.PartyId = fromPartyIdArr; msgHeader.From = from; To to = new To(); PartyId toPartyId = new PartyId(); PartyId[] toPartyIdArr = new PartyId[1]; toPartyId.Value = "WebServiceSupplier"; toPartyIdArr[0] = toPartyId; to.PartyId = toPartyIdArr; msgHeader.To = to; //Add the value for eb:CPAId, which is the IPCC. //Add the value for the action code of this Web service, SessionCreateRQ. msgHeader.CPAId = ipcc; msgHeader.Action = "SessionCreateRQ"; Service service = new Service(); service.Value = "SessionCreate"; msgHeader.Service = service; MessageData msgData = new MessageData(); msgData.MessageId = "mid:[email protected]"; msgData.Timestamp = tstamp; msgHeader.MessageData = msgData; Security security = new Security(); SecurityUsernameToken securityUserToken = new SecurityUsernameToken(); securityUserToken.Username = username; securityUserToken.Password = password; securityUserToken.Organization = ipcc; securityUserToken.Domain = domain; security.UsernameToken = securityUserToken; SessionCreateRQ req = new SessionCreateRQ(); SessionCreateRQPOS pos = new SessionCreateRQPOS(); SessionCreateRQPOSSource source = new SessionCreateRQPOSSource(); source.PseudoCityCode = ipcc; pos.Source = source; req.POS = pos; SessionCreateRQService serviceObj = new SessionCreateRQService(); serviceObj.MessageHeaderValue = msgHeader; serviceObj.SecurityValue = security; SessionCreateRS resp = serviceObj.SessionCreateRQ(req); // Send the request if (resp.Errors != null && resp.Errors.Error != null) { Console.WriteLine("Error : " + resp.Errors.Error.ErrorInfo.Message); } else { msgHeader = serviceObj.MessageHeaderValue; security = serviceObj.SecurityValue; Console.WriteLine("**********************************************"); Console.WriteLine("Response of SessionCreateRQ service"); Console.WriteLine("BinarySecurityToken returned : " + security.BinarySecurityToken); Console.WriteLine("**********************************************"); string ConvIdLine = "convid="+msgHeader.ConversationId; // ConversationId to a string string TokenLine = "securitytoken="+security.BinarySecurityToken; // BinarySecurityToken to a string string ipccLine = "ipcc="+ipcc; // IPCC to a string File.Delete(PropsFileName); // Clean up TextWriter tw = new StreamWriter(PropsFileName); // Create & open the file tw.WriteLine(DateTime.Now); // Write the date for reference tw.WriteLine(TokenLine); // Write the BinarySecurityToken tw.WriteLine(ConvIdLine); // Write the ConversationId tw.WriteLine(ipccLine); // Write the IPCC tw.Close(); //Console.Read(); } } catch(Exception e) { Console.WriteLine("Exception Message : " + e.Message ); Console.WriteLine("Exception Stack Trace : " + e.StackTrace); Console.Read(); } } } } I have added the reference System.ServiceModel and the lines: using System.ServiceModel; using System.ServiceModel.Channels; but I continue to get that error when trying to compile -- "Cannot create an instance of the abstract class or interface 'System.ServiceModel.Channels.MessageHeader'" I am using Microsoft Visual Studio 2008 Version 9.0.21022.8 RTM Microsoft .NET Framework Version 3.5 SP1 Professional Edition Is there another reference I have to add? Or a dll to move over? I wonder was the code above written for Framework 2.0 only? Thanks for your help.

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• Is multithreading the right way to go for my case?

  - by Julien Lebosquain

  Hello, I'm currently designing a multi-client / server application. I'm using plain good old sockets because WCF or similar technology is not what I need. Let me explain: it isn't the classical case of a client simply calling a service; all clients can 'interact' with each other by sending a packet to the server, which will then do some action, and possible re-dispatch an answer message to one or more clients. Although doable with WCF, the application will get pretty complex with hundreds of different messages. For each connected client, I'm of course using asynchronous methods to send and receive bytes. I've got the messages fully working, everything's fine. Except that for each line of code I'm writing, my head just burns because of multithreading issues. Since there could be around 200 clients connected at the same time, I chose to go the fully multithreaded way: each received message on a socket is immediately processed on the thread pool thread it was received, not on a single consumer thread. Since each client can interact with other clients, and indirectly with shared objects on the server, I must protect almost every object that is mutable. I first went with a ReaderWriterLockSlim for each resource that must be protected, but quickly noticed that there are more writes overall than reads in the server application, and switched to the well-known Monitor to simplify the code. So far, so good. Each resource is protected, I have helper classes that I must use to get a lock and its protected resource, so I can't use an object without getting a lock. Moreover, each client has its own lock that is entered as soon as a packet is received from its socket. It's done to prevent other clients from making changes to the state of this client while it has some messages being processed, which is something that will happen frequently. Now, I don't just need to protect resources from concurrent accesses. I must keep every client in sync with the server for some collections I have. One tricky part that I'm currently struggling with is the following: I have a collection of clients. Each client has its own unique ID. When a client connects, it must receive the IDs of every connected client, and each one of them must be notified of the newcomer's ID. When a client disconnects, every other client must know it so that its ID is no longer valid for them. Every client must always have, at a given time, the same clients collection as the server so that I can assume that everybody knows everybody. This way if I'm sending a message to client #1 telling "Client #2 has done something", I know that it will always be correctly interpreted: Client 1 will never wonder "but who is Client 2 anyway?". My first attempt for handling the connection of a new client (let's call it X) was this pseudo-code (remember that newClient is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("newClient with id X has connected"); } } clients.Add(newClient); newClient.Send("the list of other clients"); } Now imagine that in the same time, another client has sent a packet that translates into a message that must be broadcasted to every connected client, the pseudo-code will be something like this (remember that the current client - let's call it Y - is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("something"); } } } An obvious deadlock occurs here: on one thread X is locked, the clients lock has been entered, started looping through the clients, and at one moment must get Y's lock... which is already acquired on the second thread, itself waiting for the clients collection lock to be released! This is not the only case like this in the server application. There are other collections which must be kept in sync with the clients, some properties on a client can be changed by another one, etc. I tried other types of locks, lock-free mechanisms and a bunch of other things. Either there were obvious deadlocks when I'm using too much locks for safety, or obvious race conditions otherwise. When I finally find a good middle point between the two, it usually comes with very subtle race conditions / dead locks and other multi-threading issues... my head hurts very quickly since for any single line of code I'm writing I have to review almost the whole application to ensure everything will behave correctly with any number of threads. So here's my final question: how would you resolve this specific case, the general case, and more importantly: aren't I going the wrong way here? I have little problems with the .NET framework, C#, simple concurrency or algorithms in general. Still, I'm lost here. I know I could use only one thread processing the incoming requests and everything will be fine. However, that won't scale well at all with more clients... But I'm thinking more and more to go this simple way. What do you think? Thanks in advance to you, StackOverflow people which have taken the time to read this huge question. I really had to explain the whole context if I want to get some help.

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• Accessing local variable doesn't improve performance

  - by NicMagnier

  The short version Why is this code: var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; More performant than this one? var index = Math.floor(ref_index) * 4; The long version This week, the author of Impact js published an article about some rendering issue: http://www.phoboslab.org/log/2012/09/drawing-pixels-is-hard In the article there was the source of a function to scale an image by accessing pixels in the canvas. I wanted to suggest some traditional ways to optimize this kind of code so that the scaling would be shorter at loading time. But after testing it my result was most of the time worst that the original function. Guessing this was the JavaScript engine that was doing some smart optimization I tried to understand a bit more what was going on so I did a bunch of test. But my results are quite confusing and I would need some help to understand what's going on. I have a test page here: http://www.mx981.com/stuff/resize_bench/test.html jsPerf: http://jsperf.com/local-variable-due-to-the-scope-lookup To start the test, click the picture and the results will appear in the console. There are three different versions: The original code: for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; var indexScaled = (y * widthScaled + x) * 4; scaledPixels.data[ indexScaled ] = origPixels.data[ index ]; scaledPixels.data[ indexScaled+1 ] = origPixels.data[ index+1 ]; scaledPixels.data[ indexScaled+2 ] = origPixels.data[ index+2 ]; scaledPixels.data[ indexScaled+3 ] = origPixels.data[ index+3 ]; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance One of my attempt to optimize it: var ref_index = 0; var ref_indexScaled = 0 var ref_step = 1 / scale; for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = Math.floor(ref_index) * 4; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+1 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+2 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+3 ]; ref_index+= ref_step; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance The same optimized code but with recalculating the index variable each time (Hybrid) var ref_index = 0; var ref_indexScaled = 0 var ref_step = 1 / scale; for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+1 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+2 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+3 ]; ref_index+= ref_step; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance The only difference in the two last one is the calculation of the 'index' variable. And to my surprise the optimized version is slower in most browsers (except opera). Results of personal testing (not the jsPerf tests): Opera Original: 8668ms Optimized: 932ms Hybrid: 8696ms Chrome Original: 139ms Optimized: 145ms Hybrid: 136ms Safari Original: 433ms Optimized: 853ms Hybrid: 451ms Firefox Original: 343ms Optimized: 422ms Hybrid: 350ms After digging around, it seems an usual good practice is to access mainly local variable due to the scope lookup. Because The optimized version only call one local variable it should be faster that the Hybrid code which call multiple variable and object in addition to the various operation involved. So why the "optimized" version is slower? I thought that it might be because some JavaScript engine don't optimize the Optimized version because it is not hot enough but after using --trace-opt in chrome, it seems all version are properly compiled by V8. At this point I am a bit clueless and wonder if somebody would know what is going on? I did also some more test cases in this page: http://www.mx981.com/stuff/resize_bench/index.html

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