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  • How to Easily Put a Windows PC into Kiosk Mode With Assigned Access

    - by Chris Hoffman
    Windows 8.1′s Assigned Access feature allows you to easily lock a Windows PC to a single application, such as a web browser. This feature makes it easy for anyone to configure Windows 8.1 devices as point-of-sale or other kiosk systems. In the past, setting up a Windows PC in kiosk mode involved much more work, requiring the use of third-party software, group policy, or Linux distributions designed around kiosk mode. Assigned Access is available on Windows 8.1 RT, Windows 8.1 Professional, and Windows 8.1 Enterprise. The standard edition of Windows 8.1 doesn’t support Assigned Access. Create a User Account for Assigned Access Rather than turn your entire computer into a locked-down kiosk system, Assigned Access allows you to create a separate user account that can only launch a single app — such as a web browser. To set this up, you must be logged into Windows as a user with administrator permissions. First, open the PC settings app — swipe in from the right or press Windows Key + C to open the charms bar, tap Settings, and tap Change PC settings. In the PC settings app, select Accounts and select Other accounts. Use the Add an account button to create a new Windows account. Select  the “Sign in without a Microsoft account” option and select Local account to create a local user account. You could also create a Microsoft account, but you may not want to do this if you just want a locked-down account with only browser access. If you need to install apps from the Windows Store to use in Assigned Access mode, you’ll have to set up a Microsoft account instead of a local account. A local account will still allow you access to the preinstalled apps, such as Internet Explorer. You may want to create a user account with a blank password. This would make it simple for anyone to access kiosk mode, even if the system becomes locked or needs to be rebooted. The account will be created as a standard user account with limited permissions. Leave it as a standard user account — don’t make it an administrator account. Set Up Assigned Access Once you’ve created an account, you’ll first need to sign into it. If you don’t, you’ll see a “This account has no apps” message when trying to enable Assigned Access. Go back to the welcome screen, log in to the new account you created, and allow Windows to go through the first-time account setup process. If you want to use a non-default app in kiosk mode, install it while logged in as that user account. Once you’re done, log out of the other account, log back in as your administrator account, and go back to the Other accounts screen. Click the Set up an account for assigned access option to continue. Select the user account you created and select the app you want to limit the account to. For a web-based kiosk, this can be a web browser such as the Modern version of Internet Explorer. Businesses can also create their own Modern apps and set them to run in kiosk mode in this way. Note that Microsoft’s documentation says “web browsers are not good choices for assigned access” because they require more permissions than average Modern (or “Windows Store”) apps. However, if you want to provide a kiosk for web-browsing, using Assigned Access is a much better option than using Guest Mode and offering up a full Windows desktop. When you’re done, restart your PC and log in as the Assigned Access account. Windows will automatically open the app you chose and won’t allow a user to leave that app. Standard Windows 8 features like the charms bar, app switcher, and Start screen won’t appear. Pressing the Windows key once will do nothing. To sign out of Assigned Access mode, press the Windows key five times — quickly — while signed in. You’ll be sent back to the standard login screen. The account will actually still be logged in and the app will remain running — this method just “locks” the screen and allows another user to log in. Automatically Log Into Assigned Access Whenever your Windows device boots, you can log into the Assigned Access account and turn it into a kiosk system. While this isn’t ideal for all kiosk systems, you may want the device to automatically launch the specific app when it boots without requiring any login process. To do so, you’ll just need to have Windows automatically log into the Assigned Access account when it boots. This option is hidden and not available in the standard Control Panel. You’ll need to use the hidden netplwiz Control Panel tool to set up automatic login on boot. If you didn’t create a password for the user account, leave the Password field empty while configuring this. Security Considerations If you’re using this feature to turn a Windows 8.1 system into a kiosk and leaving it open to the public, remember to consider security. Anyone could come up to the system, press the Windows key five times, and try to log into your standard administrator user account. Ensure the administrator user account has a strong password so people won’t be able to get past the kiosk system’s limitations and tamper with the system. Even Windows 8′s detractors have to admit that it’s an ideal system for a touch-screen kiosk device, running either a browser or another specific application. Assigned Access finally makes this easy to set up on Windows systems in the real world — no IT experience, third-party software, or Linux distributions necessary.     

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  • Process.Start() and ShellExecute() fails with URLs on Windows 8

    - by Rick Strahl
    Since I installed Windows 8 I've noticed that a number of my applications appear to have problems opening URLs. That is when I click on a link inside of a Windows application, either nothing happens or there's an error that occurs. It's happening both to my own applications and a host of Windows applications I'm running. At first I thought this was an issue with my default browser (Chrome) but after switching the default browser to a few others and experimenting a bit I noticed that the errors occur - oddly enough - only when I run an application as an Administrator. I also tried switching to FireFox and Opera as my default browser and saw exactly the same behavior. The scenario for this is a bit bizarre: Running on Windows 8 Call Process.Start() (or ShellExecute() in Win32 API) with a URL or an HTML file Run 'As Administrator' (works fine under non-elevated user account!) or with UAC off A browser other than Internet Explorer is set as your Default Web Browser Talk about a weird scenario: Something that doesn't work when you run as an Administrator which is supposed to have rights to everything on the system! Instead running under an Admin account - either elevated with a User Account Control prompt or even when running as a full Administrator fails. It appears that this problem does not occur for everyone, but when I looked for a solution to this, I saw quite a few posts in relation to this with no clear resolutions. I have three Windows 8 machines running here in the office and all three of them showed this behavior. Lest you think this is just a programmer's problem - this can affect any software running on your system that needs to run under administrative rights. Try it out Now, in order for this next example to fail, any browser but Internet Explorer has to be your default browser and even then it may not fail depending on how you installed your browser. To see if this is a problem create a small Console application and call Process.Start() with a URL in it:namespace Win8ShellBugConsole { class Program { static void Main(string[] args) { Console.WriteLine("Launching Url..."); Process.Start("http://microsoft.com"); Console.Write("Press any key to continue..."); Console.ReadKey(); Console.WriteLine("\r\n\r\nLaunching image..."); Process.Start(Path.GetFullPath(@"..\..\sailbig.jpg")); Console.Write("Press any key to continue..."); Console.ReadKey(); } } } Compile this code. Then execute the code from Explorer (not from Visual Studio because that may change the permissions). If you simply run the EXE and you're not running as an administrator, you'll see the Web page pop up in the browser as well as the image loading. Now run the same thing with Run As Administrator: Now when you run it you get a nice error when Process.Start() is fired: The same happens if you are running with User Account Control off altogether - ie. you are running as a full admin account. Now if you comment out the URL in the code above and just fire the image display - that works just fine in any user mode. As does opening any other local file type or even starting a new EXE locally (ie. Process.Start("c:\windows\notepad.exe"). All that works, EXCEPT for URLs. The code above uses Process.Start() in .NET but the same happens in Win32 Applications that use the ShellExecute API. In some of my older Fox apps ShellExecute returns an error code of 31 - which is No Shell Association found. What's the Deal? It turns out the problem has to do with the way browsers are registering themselves on Windows. Internet Explorer - being a built-in application in Windows 8 - apparently does this correctly, but other browsers possibly don't or at least didn't at the time I installed them. So even Chrome, which continually updates itself, has a recent version that apparently has this registration issue fixed, I was unable to simply set IE as my default browser then use Chrome to 'Set as Default Browser'. It still didn't work. Neither did using the Set Program Associations dialog which lets you assign what extensions are mapped to by a given application. Each application provides a set of extension/moniker mappings that it supports and this dialog lets you associate them on a system wide basis. This also did not work for Chrome or any of the other browsers at first. However, after repeated retries here eventually I did manage to get FireFox to work, but not any of the others. What Works? Reinstall the Browser In the end I decided on the hard core pull the plug solution: Totally uninstall and re-install Chrome in this case. And lo and behold, after reinstall everything was working fine. Now even removing the association for Chrome, switching to IE as the default browser and then back to Chrome works. But, even though the version of Chrome I was running before uninstalling and reinstalling is the same as I'm running now after the reinstall now it works. Of course I had to find out the hard way, before Richard commented with a note regarding what the issue is with Chrome at least: http://code.google.com/p/chromium/issues/detail?id=156400 As expected the issue is a registration issue - with keys not being registered at the machine level. Reading this I'm still not sure why this should be a problem - an elevated account still runs under the same user account (ie. I'm still rickstrahl even if I Run As Administrator), so why shouldn't an app be able to read my Current User registry hive? And also that doesn't quite explain why if I register the extensions using Run As Administrator in Chrome when using Set as Default Browser). But in the end it works… Not so fast It's now a couple of days later and still there are some oddball problems although this time they appear to be purely Chrome issues. After the reinstall Chrome seems to pop up properly with ShellExecute() calls both in regular user and Admin mode. However, it now looks like Chrome is actually running two completely separate user profiles for each. For example, when I run Visual Studio in Admin mode and go to View in browser, Chrome complains that it was installed in Admin mode and can't launch (WTF?). Then you retry a few times later and it ends up working. When launched that way some of the plug-ins installed don't show up with the effect that sometimes they're visible sometimes they're not. Also Chrome seems to loose my configuration and Google sign in between sessions now, presumably when switching user modes. Add-ins installed in admin mode don't show up in user mode and vice versa. Ah, this is lovely. Did I mention that I freaking hate UAC precisely because of this kind of bullshit. You can never tell exactly what account your app is running under, and apparently apps also have a hard time trying to put data into the right place that works for both scenarios. And as my recent post on using Windows Live accounts shows it's yet another level of abstraction ontop of the underlying system identity that can cause all sort of small side effect headaches like this. Hopefully, most of you are skirting this issue altogether - having installed more recent versions of your favorite browsers. If not, hopefully this post will take you straight to reinstallation to fix this annoying issue.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Windows  .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • CodePlex Daily Summary for Monday, July 01, 2013

    CodePlex Daily Summary for Monday, July 01, 2013Popular ReleasesQuickMon: Version 2.10.3: Mainly just a service release - no major changes. Toolbar buttons on main and config window can now be re-arrange (using ALT key) Added property to disable corrective scriptsDotNetNuke® IFrame: IFrame 04.05.00: New DNN6/7 Manifest file and Azure Compatibility.VidCoder: 1.5.2 Beta: Fixed crash on presets with an invalid bitrate.Roadkill - .NET Wiki engine: Roadkill v1.7: New features in 1.7: New file manager: Multiple file uploads Drag and drop uploads Delete folders (admins only) Delete files (admins only) (Experimental) Syntaxhighlighting custom variable (using https://github.com/alexgorbatchev/SyntaxHighlighter) - use [[[code lang=c#|your code here]]] (Experimental) MathJax custom variable - use [[[Mathjax]]] and $$your tex$$ on the page. Improved black bar theme Site speed improvements for Javascript/CSS files - now just two files files ea...Download Sharepoint Solution package: Release 4: version updated for SP2013WinRT XAML Toolkit: WinRT XAML Toolkit - 1.5: WinRT XAML Toolkit based on the Windows 8.0 and 8.1 Preview SDKs. Do not download the source code from here if you are looking for latest updates! You can 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 Composition library for visual tree rende...Gardens Point LEX: Gardens Point LEX version 1.2.1: The main distribution is a zip file. This contains the binary executable, documentation, source code and the examples. ChangesVersion 1.2.1 has new facilities for defining and manipulating character classes. These changes make the construction of large Unicode character classes more convenient. The runtime code for performing automaton backup has been re-implemented, and is now faster for scanners that need backup. Source CodeThe distribution contains a complete VS2010 project for the appli...ZXMAK2: Version 2.7.5.7: - fix TZX emulation (Bruce Lee, Zynaps) - fix ATM 16 colors for border - add memory module PROFI 512K; add PROFI V03 rom image; fix PROFI 3.XX configTwitter image Downloader: Twitter Image Downloader 2 with Installer: Application file with Install shield and Dot Net 4.0 redistributableUltimate Music Tagger: Ultimate Music Tagger 1.0.0.0: First release of Ultimate Music TaggerBlackJumboDog: Ver5.9.2: 2013.06.28 Ver5.9.2 (1) ??????????(????SMTP?????)?????????? (2) HTTPS???????????Outlook 2013 Add-In: Configuration Form: This new version includes the following changes: - Refactored code a bit. - Removing configuration from main form to gain more space to display items. - Moved configuration to separate form. You can click the little "gear" icon to access the configuration form (still very simple). - Added option to show past day appointments from the selected day (previous in time, that is). - Added some tooltips. You will have to uninstall the previous version (add/remove programs) if you had installed it ...Terminals: Version 3.0 - Release: Changes since version 2.0:Choose 100% portable or installed version Removed connection warning when running RDP 8 (Windows 8) client Fixed Active directory search Extended Active directory search by LDAP filters Fixed single instance mode when running on Windows Terminal server Merged usage of Tags and Groups Added columns sorting option in tables No UAC prompts on Windows 7 Completely new file persistence data layer New MS SQL persistence layer (Store data in SQL database)...NuGet: NuGet 2.6: Released June 26, 2013. Release notes: http://docs.nuget.org/docs/release-notes/nuget-2.6Python Tools for Visual Studio: 2.0 Beta: We’re pleased to announce the release of Python Tools for Visual Studio 2.0 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 CPython/IronPython, Edit/Intellisense/Debug/Profile, Cloud, HPC, IPython, and cross platform debugging support. For a quick overview of the general IDE experience, please watch this video: http://www.youtube.com/watch?v=TuewiStN...Player Framework by Microsoft: Player Framework for Windows 8 and WP8 (v1.3 beta): Preview: New MPEG DASH adaptive streaming plugin for Windows Azure Media Services Preview: New Ultraviolet CFF plugin. Preview: New WP7 version with WP8 compatibility. (source code only) Source code is now available via CodePlex Git Misc bug fixes and improvements: WP8 only: Added optional fullscreen and mute buttons to default xaml JS only: protecting currentTime from returning infinity. Some videos would cause currentTime to be infinity which could cause errors in plugins expectin...AssaultCube Reloaded: 2.5.8: SERVER OWNERS: note that the default maprot has changed once again. Linux has Ubuntu 11.10 32-bit precompiled binaries and Ubuntu 10.10 64-bit precompiled binaries, but you can compile your own as it also contains the source. If you are using Mac or other operating systems, please wait while we continue to try to package for those OSes. Or better yet, try to compile it. If it fails, download a virtual machine. The server pack is ready for both Windows and Linux, but you might need to compi...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.95: update parser to allow for CSS3 calc( function to nest. add recognition of -pponly (Preprocess-Only) switch in AjaxMinManifestTask build task. Fix crashing bug in EXE when processing a manifest file using the -xml switch and an error message needs to be displayed (like a missing input file). Create separate Clean and Bundle build tasks for working with manifest files (AjaxMinManifestCleanTask and AjaxMinBundleTask). Removed the IsCleanOperation from AjaxMinManifestTask -- use AjaxMinMan...VG-Ripper & PG-Ripper: VG-Ripper 2.9.44: changes NEW: Added Support for "ImgChili.net" links FIXED: Auto UpdaterDocument.Editor: 2013.25: What's new for Document.Editor 2013.25: Improved Spell Check support Improved User Interface Minor Bug Fix's, improvements and speed upsNew ProjectsAerCloud.net Client - Java, Linux & Windows: This project source code provides a step by step guide for using AerCloud.net Framework as a Service API. For more information please visit http://www.aercloudAmiClient – Asterisk Manager Interface (AMI) client based on the Rx Framework: Asterisk Manager Interface (AMI) client based on the Rx Frameworkbaidupan: cdcddddC#??????: C#??????ImageHelper: imagehelperIP switcher: IP switcher is a simple tool for switching settings, and store presets, on networkadapters.MastersProject: A MS project with a goal of creating a fully Code Contracts verified physics engine and a relatively simple game that uses it.Multiplatform card game: Example multipatform project.PhoneTools: A collection of tools designed to help developers create beautiful Windows Phone 8 apps.rodidexter: lllSharePoint 2013 List Item Encryption: This coding exercise project enables you to encrypt/decrypt list item text field in the browser using industry standard algorithms.tvaSoft: simulation, rotor dynamics, Finite Element Analisys, FEM, ODE, torsional vibration, flexural vibrationX3DML Project: X3DML is an xml-based markup language that defines rules for modeling 3D scenes from a tag-based document. It may be usefull in 3D web design and VR.zhuang-tfs: zhuang tfs

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  • SPARC T3-1 Record Results Running JD Edwards EnterpriseOne Day in the Life Benchmark with Added Batch Component

    - by Brian
    Using Oracle's SPARC T3-1 server for the application tier and Oracle's SPARC Enterprise M3000 server for the database tier, a world record result was produced running the Oracle's JD Edwards EnterpriseOne applications Day in the Life benchmark run concurrently with a batch workload. The SPARC T3-1 server based result has 25% better performance than the IBM Power 750 POWER7 server even though the IBM result did not include running a batch component. The SPARC T3-1 server based result has 25% better space/performance than the IBM Power 750 POWER7 server as measured by the online component. The SPARC T3-1 server based result is 5x faster than the x86-based IBM x3650 M2 server system when executing the online component of the JD Edwards EnterpriseOne 9.0.1 Day in the Life benchmark. The IBM result did not include a batch component. The SPARC T3-1 server based result has 2.5x better space/performance than the x86-based IBM x3650 M2 server as measured by the online component. The combination of SPARC T3-1 and SPARC Enterprise M3000 servers delivered a Day in the Life benchmark result of 5000 online users with 0.875 seconds of average transaction response time running concurrently with 19 Universal Batch Engine (UBE) processes at 10 UBEs/minute. The solution exercises various JD Edwards EnterpriseOne applications while running Oracle WebLogic Server 11g Release 1 and Oracle Web Tier Utilities 11g HTTP server in Oracle Solaris Containers, together with the Oracle Database 11g Release 2. The SPARC T3-1 server showed that it could handle the additional workload of batch processing while maintaining the same number of online users for the JD Edwards EnterpriseOne Day in the Life benchmark. This was accomplished with minimal loss in response time. JD Edwards EnterpriseOne 9.0.1 takes advantage of the large number of compute threads available in the SPARC T3-1 server at the application tier and achieves excellent response times. The SPARC T3-1 server consolidates the application/web tier of the JD Edwards EnterpriseOne 9.0.1 application using Oracle Solaris Containers. Containers provide flexibility, easier maintenance and better CPU utilization of the server leaving processing capacity for additional growth. A number of Oracle advanced technology and features were used to obtain this result: Oracle Solaris 10, Oracle Solaris Containers, Oracle Java Hotspot Server VM, Oracle WebLogic Server 11g Release 1, Oracle Web Tier Utilities 11g, Oracle Database 11g Release 2, the SPARC T3 and SPARC64 VII+ based servers. This is the first published result running both online and batch workload concurrently on the JD Enterprise Application server. No published results are available from IBM running the online component together with a batch workload. The 9.0.1 version of the benchmark saw some minor performance improvements relative to 9.0. When comparing between 9.0.1 and 9.0 results, the reader should take this into account when the difference between results is small. Performance Landscape JD Edwards EnterpriseOne Day in the Life Benchmark Online with Batch Workload This is the first publication on the Day in the Life benchmark run concurrently with batch jobs. The batch workload was provided by Oracle's Universal Batch Engine. System RackUnits Online Users Resp Time (sec) BatchConcur(# of UBEs) BatchRate(UBEs/m) Version SPARC T3-1, 1xSPARC T3 (1.65 GHz), Solaris 10 M3000, 1xSPARC64 VII+ (2.86 GHz), Solaris 10 4 5000 0.88 19 10 9.0.1 Resp Time (sec) — Response time of online jobs reported in seconds Batch Concur (# of UBEs) — Batch concurrency presented in the number of UBEs Batch Rate (UBEs/m) — Batch transaction rate in UBEs/minute. JD Edwards EnterpriseOne Day in the Life Benchmark Online Workload Only These results are for the Day in the Life benchmark. They are run without any batch workload. System RackUnits Online Users ResponseTime (sec) Version SPARC T3-1, 1xSPARC T3 (1.65 GHz), Solaris 10 M3000, 1xSPARC64 VII (2.75 GHz), Solaris 10 4 5000 0.52 9.0.1 IBM Power 750, 1xPOWER7 (3.55 GHz), IBM i7.1 4 4000 0.61 9.0 IBM x3650M2, 2xIntel X5570 (2.93 GHz), OVM 2 1000 0.29 9.0 IBM result from http://www-03.ibm.com/systems/i/advantages/oracle/, IBM used WebSphere Configuration Summary Hardware Configuration: 1 x SPARC T3-1 server 1 x 1.65 GHz SPARC T3 128 GB memory 16 x 300 GB 10000 RPM SAS 1 x Sun Flash Accelerator F20 PCIe Card, 92 GB 1 x 10 GbE NIC 1 x SPARC Enterprise M3000 server 1 x 2.86 SPARC64 VII+ 64 GB memory 1 x 10 GbE NIC 2 x StorageTek 2540 + 2501 Software Configuration: JD Edwards EnterpriseOne 9.0.1 with Tools 8.98.3.3 Oracle Database 11g Release 2 Oracle 11g WebLogic server 11g Release 1 version 10.3.2 Oracle Web Tier Utilities 11g Oracle Solaris 10 9/10 Mercury LoadRunner 9.10 with Oracle Day in the Life kit for JD Edwards EnterpriseOne 9.0.1 Oracle’s Universal Batch Engine - Short UBEs and Long UBEs Benchmark Description JD Edwards EnterpriseOne is an integrated applications suite of Enterprise Resource Planning (ERP) software. Oracle offers 70 JD Edwards EnterpriseOne application modules to support a diverse set of business operations. Oracle's Day in the Life (DIL) kit is a suite of scripts that exercises most common transactions of JD Edwards EnterpriseOne applications, including business processes such as payroll, sales order, purchase order, work order, and other manufacturing processes, such as ship confirmation. These are labeled by industry acronyms such as SCM, CRM, HCM, SRM and FMS. The kit's scripts execute transactions typical of a mid-sized manufacturing company. The workload consists of online transactions and the UBE workload of 15 short and 4 long UBEs. LoadRunner runs the DIL workload, collects the user’s transactions response times and reports the key metric of Combined Weighted Average Transaction Response time. The UBE processes workload runs from the JD Enterprise Application server. Oracle's UBE processes come as three flavors: Short UBEs < 1 minute engage in Business Report and Summary Analysis, Mid UBEs > 1 minute create a large report of Account, Balance, and Full Address, Long UBEs > 2 minutes simulate Payroll, Sales Order, night only jobs. The UBE workload generates large numbers of PDF files reports and log files. The UBE Queues are categorized as the QBATCHD, a single threaded queue for large UBEs, and the QPROCESS queue for short UBEs run concurrently. One of the Oracle Solaris Containers ran 4 Long UBEs, while another Container ran 15 short UBEs concurrently. The mixed size UBEs ran concurrently from the SPARC T3-1 server with the 5000 online users driven by the LoadRunner. Oracle’s UBE process performance metric is Number of Maximum Concurrent UBE processes at transaction rate, UBEs/minute. Key Points and Best Practices Two JD Edwards EnterpriseOne Application Servers and two Oracle Fusion Middleware WebLogic Servers 11g R1 coupled with two Oracle Fusion Middleware 11g Web Tier HTTP Server instances on the SPARC T3-1 server were hosted in four separate Oracle Solaris Containers to demonstrate consolidation of multiple application and web servers. See Also SPARC T3-1 oracle.com SPARC Enterprise M3000 oracle.com Oracle Solaris oracle.com JD Edwards EnterpriseOne oracle.com Oracle Database 11g Release 2 Enterprise Edition oracle.com Disclosure Statement Copyright 2011, Oracle and/or its affiliates. All rights reserved. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners. Results as of 6/27/2011.

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  • Beginner Geek: How to Use Bookmarklets on Any Device

    - by Chris Hoffman
    Web browser bookmarklets allow you to perform actions on the current page with just a click or tap. They’re a lightweight alternative to browser extensions. They even work on mobile browsers that don’t support traditional extensions. To use bookmarklets, all you need is a web browser that supports bookmarks — that’s it! Bookmarklets Explained Web pages you view in your browser use JavaScript code. That’s why web pages aren’t just static documents anymore — they’re dynamic. A bookmarklet is a normal bookmark with a piece of JavaScript code instead of a web address. When you click or tap the bookmarklet, it will execute the JavaScript code on the current page instead of loading a different page, as most bookmarks do. Bookmarklets can be used to do something to a web page with a single click. For example, you’ll find bookmarklets associated with web services like Twitter, Facebook, Google+, LinkedIn, Pocket, and LastPass. When you click the bookmarklet, it will run code that lets you easily share the current page with that service. Bookmarklets don’t just have to be  associated with web services. A bookmarklet you click could modify the appearance of the page, stripping away most of the junk and giving you a clean “reading mode.” It could alter fonts, remove images, or insert other content. It can access anything the web page could access. For example, you could use a bookmarklet to reveal a password that just appears as ******* on the page. Unlike browser extensions, bookmarklets don’t run in the background and bog down your browser. They don’t do anything at all until you click them. Because they just use the standard bookmark system, they can also be used in mobile browsers where you couldn’t run extensions. For example, you could install the Pocket bookmarklet in Safari on an iPad and get an “Add to Pocket” option in Safari. Safari doesn’t offer browsing extensions and Apple’s iOS doesn’t offer a “Share” feature like Android and Windows 8 do, so this is the only way to get this direct integration. You could even use the LastPass bookmarklets in Safari on an iPad to integrate LastPass with the Safari web browser. Where to Find Bookmarklets If you’re looking for a bookmarklet for a particular service, you’ll generally find the bookmarklet on that service’s site. Websites like Twitter, Facebook, and Pocket host pages where they provide bookmarklets along with browser extensions. Bookmarklets aren’t like programs. They’re really just a piece of text that you can put in a bookmarklet, so you don’t have to download them a specific site. You can get them from practically anywhere — installing them just involves copying a bit of text off of a web page. For example, you can just search the web for “reveal password bookmarklet” if you wanted a bookmarklet that will reveal passwords. We’ve covered many of the must-have bookmarklets — and our readers have chimed in too — so take a look at our lists for more examples. How to Install a Bookmarklet Bookmarklets are simple to install. When you hover over a bookmarklet on a web page, you’ll see its address begins with “javascript:”. If you have your web browser’s bookmark or favorites toolbar visible, the easiest way to install a bookmarklet is with drag-and-drop. Press Ctrl+Shift+B to show your bookmarks toolbar if you’re using Chrome or Internet Explorer. In Firefox, right-click the toolbar and click Bookmarks Toolbar. Just drag and drop this link to your bookmark toolbar. The bookmarklet is now installed. You can also install bookmarklets manually. Select the bookmarklet’s code and copy it to your clipboard. If the bookmarklet is a link, right-click or long-press the link and copy its address to your clipboard. Open your browser’s bookmarks manager, add a bookmark, and paste the JavaScript code directly into the address box. Give your bookmarklet a name and save it. How to Use a Bookmarklet Bookmarklets are easiest to use if you have your browser’s bookmarks toolbar enabled. Just click the bookmarklet and your browser will run it on the current page. If you don’t have a bookmarks toolbar — such as on Safari on an iPad or another mobile browser — just open your browser’s bookmarks pane and tap or click the bookmark. In mobile Chrome, you’ll need to launch the bookmarklet from the location bar. Open the web page you want to run the bookmarklet on, tap your location bar, and start searching for the name of the bookmarklet. Tap the bookmarklet’s name to run it on the current page. Note that the bookmarklet only appears here because we have it saved as a bookmark in Chrome. You’ll need to add the bookmarklet to your browser’s bookmarks before you can use it in this way. The location bar approach may also be necessary in other browsers. The trick is loading the bookmark so that it will be associated with your current tab. You can’t just open your bookmarks in a separate browser tab and run the bookmarklet from there — it will run on that other browser tab. Bookmarklets are powerful and flexible. While they’re not as flashy as browser extensions, they’re much more lightweight and allow you to get extension-like features in more limited mobile browsers.

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  • Charms and the App Bar

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

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  • Tailoring the Oracle Fusion Applications User Interface with Oracle Composer

    - by mvaughan
    By Killian Evers, Oracle Applications User Experience Changing the user interface (UI) is one of the most common modifications customers perform to Oracle Fusion Applications. Typically, customers add or remove a field based on their needs. Oracle makes the process of tailoring easier for customers, and reduces the burden for their IT staff, which you can read about on the Usable Apps website or in an earlier VoX post.This is the first in a series of posts that will talk about the tools that Oracle has provided for tailoring with its family of composers. These tools are designed for business systems analysts, and they allow employees other than IT staff to make changes in an upgrade-safe and patch-friendly manner. Let’s take a deep dive into one of these composers, the Oracle Composer. Oracle Composer allows business users to modify existing UIs after they have been deployed and are in use. It is an integral component of our SaaS offering. Using Oracle Composer, users can control:     •    Who sees the changes     •    When the changes are made     •    What changes are made Change for me, change for you, change for all of youOne of the most powerful aspects of Oracle Composer is its flexibility. Oracle uses Oracle Composer to make changes for a user or group of users – those who see the changes. A user of Oracle Fusion Applications can make changes to the user interface at runtime via Oracle Composer, and these changes will remain every time they log into the system. For example, they can rearrange certain objects on a page, add and remove designated content, and save queries.Business systems analysts can make changes to Oracle Fusion Application UIs for groups of users or all users. Oracle’s Fusion Middleware Metadata Services (MDS) stores these changes and retrieves them at runtime, merging customizations with the base metadata and revealing the final experience to the end user. A tailored application can have multiple customization layers, and some layers can be specific to certain Fusion Applications. Some examples of customization layers are: site, organization, country, or role. Customization layers are applied in a specific order of precedence on top of the base application metadata. This image illustrates how customization layers are applied.What time is it?Users make changes to UIs at design time, runtime, and design time at runtime. Design time changes are typically made by application developers using an integrated development environment, or IDE, such as Oracle JDeveloper. Once made, these changes are then deployed to managed servers by application administrators. Oracle Composer covers the other two areas: Runtime changes and design time at runtime changes. When we say users are making changes at runtime, we mean that the changes are made within the running application and take effect immediately in the running application. A prime example of this ability is users who make changes to their running application that only affect the UIs they see. What is new with Oracle Composer is the last area: Design time at runtime.  A business systems analyst can make changes to the UIs at runtime but does not have to make those changes immediately to the application. These changes are stored as metadata, separate from the base application definitions. Customizations made at runtime can be saved in a sandbox so that the changes can be isolated and validated before being published into an environment, without the need to redeploy the application. What can I do?Oracle Composer can be run in one of two modes. Depending on which mode is chosen, you may have different capabilities available for changing the UIs. The first mode is view mode, the most common default mode for most pages. This is the mode that is used for personalizations or user customizations. Users can access this mode via the Personalization link (see below) in the global region on Oracle Fusion Applications pages. In this mode, you can rearrange components on a page with drag-and-drop, collapse or expand components, add approved external content, and change the overall layout of a page. However, all of the changes made this way are exclusive to that particular user.The second mode, edit mode, is typically made available to select users with access privileges to edit page content. We call these folks business systems analysts. This mode is used to make UI changes for groups of users. Users with appropriate privileges can access the edit mode of Oracle Composer via the Administration menu (see below) in the global region on Oracle Fusion Applications pages. In edit mode, users can also add components, delete components, and edit component properties. While in edit mode in Oracle Composer, there are two views that assist the business systems analyst with making UI changes: Design View and Source View (see below). Design View, the default view, is a WYSIWYG rendering of the page and its content. The business systems analyst can perform these actions: Add content – including custom content like a portlet displaying news or stock quotes, or predefined content delivered from Oracle Fusion Applications (including ADF components and task flows) Rearrange content – performed via drag-and-drop on the page or by using the actions menu of a component or portlet to move content around Edit component properties and parameters – for specific components, control the visual properties such as text or display labels, or parameters such as RSS feeds Hide or show components – hidden components can be re-shown Delete components Change page layout – users can select from eight pre-defined layouts Edit page properties – create or edit a page’s parameters and display properties Reset page customizations – remove edits made to the page in the current layer and/or reset the page to a previous state. Detailed information on each of these capabilities and the additional actions not covered in the list above can be found in the Oracle® Fusion Middleware Developer's Guide for Oracle WebCenter.This image shows what the screen looks like in Design View.Source View, the second option in the edit mode of Oracle Composer, provides a WYSIWYG and a hierarchical rendering of page components in a component navigator. In Source View, users can access and modify properties of components that are not otherwise selectable in Design View. For example, many ADF Faces components can be edited only in Source View. Users can also edit components within a task flow. This image shows what the screen looks like in Source View.Detailed information on Source View can be found in the Oracle® Fusion Middleware Developer's Guide for Oracle WebCenter.Oracle Composer enables any application or portal to be customized or personalized after it has been deployed and is in use. It is designed to be extremely easy to use so that both business systems analysts and users can edit Oracle Fusion Applications pages with a few clicks of the mouse. Oracle Composer runs in all modern browsers and provides a rich, dynamic way to edit JSF application and portal pages.From the editor: The next post in this series about composers will be on Data Composer. You can also catch Killian speaking about extensibility at OpenWorld 2012 and in her Faces of Fusion video.

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  • Responsive Inline Elements with Twitter Bootstrap

    - by MightyZot
    Originally posted on: http://geekswithblogs.net/MightyZot/archive/2013/11/12/responsive-inline-elements-with-twitter-bootstrap.aspxTwitter Boostrap is a responsive css platform created by some dudes affiliated with Twitter and since supported and maintained by an open source following. I absolutely love the new version of this css toolkit. They rebuilt it with a mobile first strategy and it’s very easy to layout pages once you get the hang of it. Using a css / javascript framework like bootstrap is certainly much easier than coding your layout by hand. And, you get a “leg up” when it comes to adding responsive features to your site. Bootstrap includes column layout classes that let you specify size and placement based upon the viewport width. In addition, there are a handful of responsive helpers to hide and show content based upon the user’s device size. Most notably, the visible-xs, visible-sm, visible-md, and visible-lg classes let you show content for devices corresponding to those sizes (they are listed in the bootstrap docs.) hidden-xs, hidden-sm, hidden-md, and hidden-lg let you hide content for devices with those respective sizes. These helpers work great for showing and hiding block elements. Unfortunately, there isn’t a provision yet in Twitter Bootstrap (as of the time of this writing) for inline elements. We are using the navbar classes to create a navigation bar at the top of our website, www.crowdit.com. When you shrink the width of the screen to tablet or phone size, the tools in the navbar are turned into a drop down menu, and a button appears on the right side of the navbar. This is great! But, we wanted different content to display based upon whether the items were on the navbar versus when they were in the dropdown menu. The visible-?? and hidden-?? classes make this easy for images and block elements. In our case, we wanted our anchors to show different text depending upon whether they’re in the navbar, or in the dropdown. span is inherently inline and it can be a block element. My first approach was to create two anchors for each options, one set visible when the navbar is on a desktop or laptop with a wide display and another set visible when the elements converted to a dropdown menu. That works fine with the visible-?? and hidden-?? classes, but it just doesn’t seem that clean to me. I put up with that for about a week…last night I created the following classes to augment the block-based classes provided by bootstrap. .cdt-hidden-xs, .cdt-hidden-sm, .cdt-hidden-md, .cdt-hidden-lg {     display: inline !important; } @media (max-width:767px) {     .cdt-hidden-xs, .cdt-hidden-sm.cdt-hidden-xs, .cdt-hidden-md.cdt-hidden-xs, .cdt-hidden-lg.cdt-hidden-xs {         display: none !important;     } } @media (min-width:768px) and (max-width:991px) {     .cdt-hidden-xs.cdt-hidden-sm, .cdt-hidden-sm, .cdt-hidden-md.cdt-hidden-sm, .cdt-hidden-lg.cdt-hidden-sm {         display: none !important;     } } @media (min-width:992px) and (max-width:1199px) {     .cdt-hidden-xs.cdt-hidden-md, .cdt-hidden-sm.cdt-hidden-md, .cdt-hidden-md, .cdt-hidden-lg.cdt-hidden-md {         display: none !important;     } } @media (min-width:1200px) {     .cdt-hidden-xs.cdt-hidden-lg, .cdt-hidden-sm.cdt-hidden-lg, .cdt-hidden-md.cdt-hidden-lg, .cdt-hidden-lg {         display: none !important;     } } .cdt-visible-xs, .cdt-visible-sm, .cdt-visible-md, .cdt-visible-lg {     display: none !important; } @media (max-width:767px) {     .cdt-visible-xs, .cdt-visible-sm.cdt-visible-xs, .cdt-visible-md.cdt-visible-xs, .cdt-visible-lg.cdt-visible-xs {         display: inline !important;     } } @media (min-width:768px) and (max-width:991px) {     .cdt-visible-xs.cdt-visible-sm, .cdt-visible-sm, .cdt-visible-md.cdt-visible-sm, .cdt-visible-lg.cdt-visible-sm {         display: inline !important;     } } @media (min-width:992px) and (max-width:1199px) {     .cdt-visible-xs.cdt-visible-md, .cdt-visible-sm.cdt-visible-md, .cdt-visible-md, .cdt-visible-lg.cdt-visible-md {         display: inline !important;     } } @media (min-width:1200px) {     .cdt-visible-xs.cdt-visible-lg, .cdt-visible-sm.cdt-visible-lg, .cdt-visible-md.cdt-visible-lg, .cdt-visible-lg {         display: inline !important;     } } I created these by looking at the example provided by bootstrap and consolidating the styles. “cdt” is just a prefix that I’m using to distinguish these classes from the block-based classes in bootstrap. You are welcome to change the prefix to whatever feels right for you. These classes can be applied to spans in textual content to hide and show text based upon the browser width. Applying the styles is simple… <span class=”cdt-visible-xs”>This text is visible in extra small</span> <span class=”cdt-visible-sm”>This text is visible in small</span> Why would you want to do this? Here are a couple of examples, shown in screen shots. This is the CrowdIt navbar on larger displays. Notice how the text is two line and certain words are capitalized? Now, check this out! Here is a screen shot showing the dropdown menu that’s displayed when the browser window is tablet or phone sized. The markup to make this happen is quite simple…take a look. <li>     <a href="@Url.Action("what-is-crowdit","home")" title="Learn about what CrowdIt can do for your Small Business">         <span class="cdt-hidden-xs">WHAT<br /><small>is CrowdIt?</small></span>         <span class="cdt-visible-xs">What is CrowdIt?</span>     </a> </li> There is a single anchor tag in this example and only the spans change visibility based on browser width. I left them separate for readability and because I wanted to use the small tag; however, you could just as easily hide the “WHAT” and the br tag on small displays and replace them with “What “, consolidating this even further to text containing a single span. <span class=”cdt-hidden-xs”>WHAT<br /></span><span class=”cdt-visible-xs”>What </span>is CrowdIt? You might be a master of css and have a better method of handling this problem. If so, I’d love to hear about your solution…leave me some feedback! You’ll be entered into a drawing for a chance to win an autographed picture of ME! Yay!

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  • Help me solve my problem with NPR Media Player

    - by Calcipher
    First of, let me apologize for this getting a bit technical. Several weeks ago, I found that while using NPR's media player (e.g. click on 'Listen to the Show' - this is what I've been using as a test) the stream would suddenly halt after a minute or three. I could not get the stream to restart without reloading the page. Now, I assumed this was an issue with NPR's player and Linux (or just a bug in their stuff in general) so I began to dig, the following is what I have tried to date (please note, the tldr; option is to skip to the latest thing as I think I know what is causing the problem). Note: All testing has been done, for consistency purposes, on a clean install of Chromium with no pluggins running. My machine is Ubuntu 10.10x64. First thing I always try, I disabled all firewall stuff on the system (UFW, default deny all, allow ssh). No change, firewall back up for all additional tests unless otherwise noted. In any case, UFW is stateful, so connections it started on a non-specified on different ports will continue to work. I deleted my ~/.macromeda and ~/.adobe folders, restarted (just to be sure) and tried. Program still froze. I decided the problem might be with my install of flash, so I purged the version I had (and the home folders again). I installed the x64 version of flash from a PPA. This had no effect. I decided that the problem might be with the version of flash, so I purged the x64 version and installed the standard x32 version that comes with Ubuntu. No luck. Back to the x64 version for consistency, I decided to set up a 64-bit mini 'clone' of my system in VirtualBox. I was able to run the media player with no problem. I rsynced (in archive mode) my home directory from my real machine to the virtual machine (with bridged networking, so it was fully visible on the network). I also used a few tricks to install ALL of the same software (and repositories) from the real machine to the virtual machine. I was still able to listen to the player. I decided that the problem was with my install (after all, it had gone through two major version upgrades). As I have /home/ on a separate partition it was easy to reinstall and use the same trick from #6 to have my system up and running again within about an hour. I continue to have issues with the NPR Media Player. By this point the weekend had come. At work, I use a wired connection while at home I use a wireless connection. For some reason I forgot that I was having problems and used the NPR Media Player over the weekend. Low and behold it worked just fine at home on wireless (note: for various reasons, I could not test this on wired at home). Following from #6, I decided that the problem was either something with the network at work or still something with my account. As the latter was easier to test, I created a new account on my system and used that at work. The Media Player worked. At a loss, I decided to watch the traffic with tshark (the text based brother of wireshark) - X's to protect the innocent, I am the XXX.24.200.XXX: sudo tshark -i eth0 -p -t a -R "ip.addr == XXX.24.200.XXX && ip.addr == XXX.166.98.XXX" As you would expect, there were tons and tons of packets, but each and every time the player froze, this is what I got 08:42:20.679200 XXX.166.98.XXX - XXX.24.200.XXX TCP macromedia-fcs 56371 [PSH, ACK] Seq=817686 Ack=6 Win=65535 Len=1448 TSV=495713325 TSER=396467 08:42:20.718602 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396475 TSER=495713325 08:42:21.050183 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713362 TSER=396475 08:42:21.050221 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396508 TSER=495713362 08:42:21.680548 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713425 TSER=396508 08:42:21.680605 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396571 TSER=495713425 08:42:22.910354 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713548 TSER=396571 08:42:22.910400 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396694 TSER=495713548 08:42:25.340458 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713791 TSER=396694 08:42:25.340517 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396937 TSER=495713791 08:42:30.170698 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495714274 TSER=396937 08:42:30.170746 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=397420 TSER=495714274 08:42:39.801738 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495715237 TSER=397420 08:42:39.801784 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=398383 TSER=495715237 08:42:59.032648 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495717160 TSER=398383 08:42:59.032696 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=400306 TSER=495717160 08:43:00.267721 XXX.24.200.XXX - XXX.166.98.XXX TCP 56371 macromedia-fcs [FIN, ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=400430 TSER=495717160 08:43:00.267827 XXX.24.200.XXX - XXX.166.98.XXX TCP 56371 macromedia-fcs [RST, ACK] Seq=7 Ack=819134 Win=65535 Len=0 TSV=400430 TSER=495717160 So, as you can see, my machine is sending out a ZeroWindow packet (which I think means some buffer or another filled up) which causes the Media Player to halt (unfortunately, terminally - no controls on it really do anything anymore). Any ideas, at all, what would cause this? Why only on eth0 under my main account?

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  • Scripting Language Sessions at Oracle OpenWorld and MySQL Connect, 2012

    - by cj
    This posts highlights some great scripting language sessions coming up at the Oracle OpenWorld and MySQL Connect conferences. These events are happening in San Francisco from the end of September. You can search for other interesting conference sessions in the Content Catalog. Also check out what is happening at JavaOne in that event's Content Catalog (I haven't included sessions from it in this post.) To find the timeslots and locations of each session, click their respective link and check the "Session Schedule" box on the top right. GEN8431 - General Session: What’s New in Oracle Database Application Development This general session takes a look at what’s been new in the last year in Oracle Database application development tools using the latest generation of database technology. Topics range from Oracle SQL Developer and Oracle Application Express to Java and PHP. (Thomas Kyte - Architect, Oracle) BOF9858 - Meet the Developers of Database Access Services (OCI, ODBC, DRCP, PHP, Python) This session is your opportunity to meet in person the Oracle developers who have built Oracle Database access tools and products such as the Oracle Call Interface (OCI), Oracle C++ Call Interface (OCCI), and Open Database Connectivity (ODBC) drivers; Transparent Application Failover (TAF); Oracle Database Instant Client; Database Resident Connection Pool (DRCP); Oracle Net Services, and so on. The team also works with those who develop the PHP, Ruby, Python, and Perl adapters for Oracle Database. Come discuss with them the features you like, your pains, and new product enhancements in the latest database technology. CON8506 - Syndication and Consolidation: Oracle Database Driver for MySQL Applications This technical session presents a new Oracle Database driver that enables you to run MySQL applications (written in PHP, Perl, C, C++, and so on) against Oracle Database with almost no code change. Use cases for such a driver include application syndication such as interoperability across a relationship database management system, application migration, and database consolidation. In addition, the session covers enhancements in database technology that enable and simplify the migration of third-party databases and applications to and consolidation with Oracle Database. Attend this session to learn more and see a live demo. (Srinath Krishnaswamy - Director, Software Development, Oracle. Kuassi Mensah - Director Product Management, Oracle. Mohammad Lari - Principal Technical Staff, Oracle ) CON9167 - Current State of PHP and MySQL Together, PHP and MySQL power large parts of the Web. The developers of both technologies continue to enhance their software to ensure that developers can be satisfied despite all their changing and growing needs. This session presents an overview of changes in PHP 5.4, which was released earlier this year and shows you various new MySQL-related features available for PHP, from transparent client-side caching to direct support for scaling and high-availability needs. (Johannes Schlüter - SoftwareDeveloper, Oracle) CON8983 - Sharding with PHP and MySQL In deploying MySQL, scale-out techniques can be used to scale out reads, but for scaling out writes, other techniques have to be used. To distribute writes over a cluster, it is necessary to shard the database and store the shards on separate servers. This session provides a brief introduction to traditional MySQL scale-out techniques in preparation for a discussion on the different sharding techniques that can be used with MySQL server and how they can be implemented with PHP. You will learn about static and dynamic sharding schemes, their advantages and drawbacks, techniques for locating and moving shards, and techniques for resharding. (Mats Kindahl - Senior Principal Software Developer, Oracle) CON9268 - Developing Python Applications with MySQL Utilities and MySQL Connector/Python This session discusses MySQL Connector/Python and the MySQL Utilities component of MySQL Workbench and explains how to write MySQL applications in Python. It includes in-depth explanations of the features of MySQL Connector/Python and the MySQL Utilities library, along with example code to illustrate the concepts. Those interested in learning how to expand or build their own utilities and connector features will benefit from the tips and tricks from the experts. This session also provides an opportunity to meet directly with the engineers and provide feedback on your issues and priorities. You can learn what exists today and influence future developments. (Geert Vanderkelen - Software Developer, Oracle) BOF9141 - MySQL Utilities and MySQL Connector/Python: Python Developers, Unite! Come to this lively discussion of the MySQL Utilities component of MySQL Workbench and MySQL Connector/Python. It includes in-depth explanations of the features and dives into the code for those interested in learning how to expand or build their own utilities and connector features. This is an audience-driven session, so put on your best Python shirt and let’s talk about MySQL Utilities and MySQL Connector/Python. (Geert Vanderkelen - Software Developer, Oracle. Charles Bell - Senior Software Developer, Oracle) CON3290 - Integrating Oracle Database with a Social Network Facebook, Flickr, YouTube, Google Maps. There are many social network sites, each with their own APIs for sharing data with them. Most developers do not realize that Oracle Database has base tools for communicating with these sites, enabling all manner of information, including multimedia, to be passed back and forth between the sites. This technical presentation goes through the methods in PL/SQL for connecting to, and then sending and retrieving, all types of data between these sites. (Marcelle Kratochvil - CTO, Piction) CON3291 - Storing and Tuning Unstructured Data and Multimedia in Oracle Database Database administrators need to learn new skills and techniques when the decision is made in their organization to let Oracle Database manage its unstructured data. They will face new scalability challenges. A single row in a table can become larger than a whole database. This presentation covers the techniques a DBA needs for managing the large volume of data in a standard Oracle Database instance. (Marcelle Kratochvil - CTO, Piction) CON3292 - Using PHP, Perl, Visual Basic, Ruby, and Python for Multimedia in Oracle Database These five programming languages are just some of the most popular ones in use at the moment in the marketplace. This presentation details how you can use them to access and retrieve multimedia from Oracle Database. It covers programming techniques and methods for achieving faster development against Oracle Database. (Marcelle Kratochvil - CTO, Piction) UGF5181 - Building Real-World Oracle DBA Tools in Perl Perl is not normally associated with building mission-critical application or DBA tools. Learn why Perl could be a good choice for building your next killer DBA app. This session draws on real-world experience of building DBA tools in Perl, showing the framework and architecture needed to deal with portability, efficiency, and maintainability. Topics include Perl frameworks; Which Comprehensive Perl Archive Network (CPAN) modules are good to use; Perl and CPAN module licensing; Perl and Oracle connectivity; Compiling and deploying your app; An example of what is possible with Perl. (Arjen Visser - CEO & CTO, Dbvisit Software Limited) CON3153 - Perl: A DBA’s and Developer’s Best (Forgotten) Friend This session reintroduces Perl as a language of choice for many solutions for DBAs and developers. Discover what makes Perl so successful and why it is so versatile in our day-to-day lives. Perl can automate all those manual tasks and is truly platform-independent. Perl may not be in the limelight the way other languages are, but it is a remarkable language, it is still very current with ongoing development, and it has amazing online resources. Learn what makes Perl so great (including CPAN), get an introduction to Perl language syntax, find out what you can use Perl for, hear how Oracle uses Perl, discover the best way to learn Perl, and take away a small Perl project challenge. (Arjen Visser - CEO & CTO, Dbvisit Software Limited) CON10332 - Oracle RightNow CX Cloud Service’s Connect PHP API: Intro, What’s New, and Roadmap Connect PHP is a public API that enables developers to build solutions with the Oracle RightNow CX Cloud Service platform. This API is used primarily by developers working within the Oracle RightNow Customer Portal Cloud Service framework who are looking to gain access to data and services hosted by the Oracle RightNow CX Cloud Service platform through a backward-compatible API. Connect for PHP leverages the same data model and services as the Connect Web Services for SOAP API. Come to this session to get an introduction and learn what’s new and what’s coming up. (Mark Rhoads - Senior Principal Applications Engineer, Oracle. Mark Ericson - Sr. Principle Product Manager, Oracle) CON10330 - Oracle RightNow CX Cloud Service APIs and Frameworks Overview Oracle RightNow CX Cloud Service APIs are available in the following areas: desktop UI, Web services, customer portal, PHP, and knowledge. These frameworks provide access to Oracle RightNow CX Cloud Service’s Connect Common Object Model and custom objects. This session provides a broad overview of capabilities in all these areas. (Mark Ericson - Sr. Principle Product Manager, Oracle)

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  • Changing an HTML Form's Target with jQuery

    - by Rick Strahl
    This is a question that comes up quite frequently: I have a form with several submit or link buttons and one or more of the buttons needs to open a new Window. How do I get several buttons to all post to the right window? If you're building ASP.NET forms you probably know that by default the Web Forms engine sends button clicks back to the server as a POST operation. A server form has a <form> tag which expands to this: <form method="post" action="default.aspx" id="form1"> Now you CAN change the target of the form and point it to a different window or frame, but the problem with that is that it still affects ALL submissions of the current form. If you multiple buttons/links and they need to go to different target windows/frames you can't do it easily through the <form runat="server"> tag. Although this discussion uses ASP.NET WebForms as an example, realistically this is a general HTML problem although likely more common in WebForms due to the single form metaphor it uses. In ASP.NET MVC for example you'd have more options by breaking out each button into separate forms with its own distinct target tag. However, even with that option it's not always possible to break up forms - for example if multiple targets are required but all targets require the same form data to the be posted. A common scenario here is that you might have a button (or link) that you click where you still want some server code to fire but at the end of the request you actually want to display the content in a new window. A common operation where this happens is report generation: You click a button and the server generates a report say in PDF format and you then want to display the PDF result in a new window without killing the content in the current window. Assuming you have other buttons on the same Page that need to post to base window how do you get the button click to go to a new window? Can't  you just use a LinkButton or other Link Control? At first glance you might think an easy way to do this is to use an ASP.NET LinkButton to do this - after all a LinkButton creates a hyper link that CAN accept a target and it also posts back to the server, right? However, there's no Target property, although you can set the target HTML attribute easily enough. Code like this looks reasonable: <asp:LinkButton runat="server" ID="btnNewTarget" Text="New Target" target="_blank" OnClick="bnNewTarget_Click" /> But if you try this you'll find that it doesn't work. Why? Because ASP.NET creates postbacks with JavaScript code that operates on the current window/frame: <a id="btnNewTarget" target="_blank" href="javascript:__doPostBack(&#39;btnNewTarget&#39;,&#39;&#39;)">New Target</a> What happens with a target tag is that before the JavaScript actually executes a new window is opened and the focus shifts to the new window. The new window of course is empty and has no __doPostBack() function nor access to the old document. So when you click the link a new window opens but the window remains blank without content - no server postback actually occurs. Natch that idea. Setting the Form Target for a Button Control or LinkButton So, in order to send Postback link controls and buttons to another window/frame, both require that the target of the form gets changed dynamically when the button or link is clicked. Luckily this is rather easy to do however using a little bit of script code and jQuery. Imagine you have two buttons like this that should go to another window: <asp:LinkButton runat="server" ID="btnNewTarget" Text="New Target" OnClick="ClickHandler" /> <asp:Button runat="server" ID="btnButtonNewTarget" Text="New Target Button" OnClick="ClickHandler" /> ClickHandler in this case is any routine that generates the output you want to display in the new window. Generally this output will not come from the current page markup but is generated externally - like a PDF report or some report generated by another application component or tool. The output generally will be either generated by hand or something that was generated to disk to be displayed with Response.Redirect() or Response.TransmitFile() etc. Here's the dummy handler that just generates some HTML by hand and displays it: protected void ClickHandler(object sender, EventArgs e) { // Perform some operation that generates HTML or Redirects somewhere else Response.Write("Some custom output would be generated here (PDF, non-Page HTML etc.)"); // Make sure this response doesn't display the page content // Call Response.End() or Response.Redirect() Response.End(); } To route this oh so sophisticated output to an alternate window for both the LinkButton and Button Controls, you can use the following simple script code: <script type="text/javascript"> $("#btnButtonNewTarget,#btnNewTarget").click(function () { $("form").attr("target", "_blank"); }); </script> So why does this work where the target attribute did not? The difference here is that the script fires BEFORE the target is changed to the new window. When you put a target attribute on a link or form the target is changed as the very first thing before the link actually executes. IOW, the link literally executes in the new window when it's done this way. By attaching a click handler, though we're not navigating yet so all the operations the script code performs (ie. __doPostBack()) and the collection of Form variables to post to the server all occurs in the current page. By changing the target from within script code the target change fires as part of the form submission process which means it runs in the correct context of the current page. IOW - the input for the POST is from the current page, but the output is routed to a new window/frame. Just what we want in this scenario. Voila you can dynamically route output to the appropriate window.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  HTML  jQuery  

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  • My Code Kata–A Solution Kata

    - by Glav
    There are many developers and coders out there who like to do code Kata’s to keep their coding ability up to scratch and to practice their skills. I think it is a good idea. While I like the concept, I find them dead boring and of minimal purpose. Yes, they serve to hone your skills but that’s about it. They are often quite abstract, in that they usually focus on a small problem set requiring specific solutions. It is fair enough as that is how they are designed but again, I find them quite boring. What I personally like to do is go for something a little larger and a little more fun. It takes a little more time and is not as easily executed as a kata though, but it services the same purposes from a practice perspective and allows me to continue to solve some problems that are not directly part of the initial goal. This means I can cover a broader learning range and have a bit more fun. If I am lucky, sometimes they even end up being useful tools. With that in mind, I thought I’d share my current ‘kata’. It is not really a code kata as it is too big. I prefer to think of it as a ‘solution kata’. The code is on bitbucket here. What I wanted to do was create a kind of simplistic virtual world where I can create a player, or a class, stuff it into the world, and see if it survives, and can navigate its way to the exit. Requirements were pretty simple: Must be able to define a map to describe the world using simple X,Y co-ordinates. Z co-ordinates as well if you feel like getting clever. Should have the concept of entrances, exists, solid blocks, and potentially other materials (again if you want to get clever). A coder should be able to easily write a class which will act as an inhabitant of the world. An inhabitant will receive stimulus from the world in the form of surrounding environment and be able to make a decision on action which it passes back to the ‘world’ for processing. At a minimum, an inhabitant will have sight and speed characteristics which determine how far they can ‘see’ in the world, and how fast they can move. Coders who write a really bad ‘inhabitant’ should not adversely affect the rest of world. Should allow multiple inhabitants in the world. So that was the solution I set out to act as a practice solution and a little bit of fun. It had some interesting problems to solve and I figured, if it turned out ok, I could potentially use this as a ‘developer test’ for interviews. Ask a potential coder to write a class for an inhabitant. Show the coder the map they will navigate, but also mention that we will use their code to navigate a map they have not yet seen and a little more complex. I have been playing with solution for a short time now and have it working in basic concepts. Below is a screen shot using a very basic console visualiser that shows the map, boundaries, blocks, entrance, exit and players/inhabitants. The yellow asterisks ‘*’ are the players, green ‘O’ the entrance, purple ‘^’ the exit, maroon/browny ‘#’ are solid blocks. The players can move around at different speeds, knock into each others, and make directional movement decisions based on what they see and who is around them. It has been quite fun to write and it is also quite fun to develop different players to inject into the world. The code below shows a really simple implementation of an inhabitant that can work out what to do based on stimulus from the world. It is pretty simple and just tries to move in some direction if there is nothing blocking the path. public class TestPlayer:LivingEntity { public TestPlayer() { Name = "Beta Boy"; LifeKey = Guid.NewGuid(); } public override ActionResult DecideActionToPerform(EcoDev.Core.Common.Actions.ActionContext actionContext) { try { var action = new MovementAction(); // move forward if we can if (actionContext.Position.ForwardFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.ForwardFacingPositions[0])) { action.DirectionToMove = MovementDirection.Forward; return action; } } if (actionContext.Position.LeftFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.LeftFacingPositions[0])) { action.DirectionToMove = MovementDirection.Left; return action; } } if (actionContext.Position.RearFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.RearFacingPositions[0])) { action.DirectionToMove = MovementDirection.Back; return action; } } if (actionContext.Position.RightFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.RightFacingPositions[0])) { action.DirectionToMove = MovementDirection.Right; return action; } } return action; } catch (Exception ex) { World.WriteDebugInformation("Player: "+ Name, string.Format("Player Generated exception: {0}",ex.Message)); throw ex; } } private bool CheckAccessibilityOfMapBlock(MapBlock block) { if (block == null || block.Accessibility == MapBlockAccessibility.AllowEntry || block.Accessibility == MapBlockAccessibility.AllowExit || block.Accessibility == MapBlockAccessibility.AllowPotentialEntry) { return true; } return false; } } It is simple and it seems to work well. The world implementation itself decides the stimulus context that is passed to he inhabitant to make an action decision. All movement is carried out on separate threads and timed appropriately to be as fair as possible and to cater for additional skills such as speed, and eventually maybe stamina, strength, with actions like fighting. It is pretty fun to make up random maps and see how your inhabitant does. You can download the code from here. Along the way I have played with parallel extensions to make the compute intensive stuff spread across all cores, had to heavily factor in visibility of methods and properties so design of classes was paramount, work out movement algorithms that play fairly in the world and properly favour the players with higher abilities, as well as a host of other issues. So that is my ‘solution kata’. If I keep going with it, I may develop a web interface for it where people can upload assemblies and watch their player within a web browser visualiser and maybe even a map designer. What do you do to keep the fires burning?

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  • How to Achieve OC4J RMI Load Balancing

    - by fip
    This is an old, Oracle SOA and OC4J 10G topic. In fact this is not even a SOA topic per se. Questions of RMI load balancing arise when you developed custom web applications accessing human tasks running off a remote SOA 10G cluster. Having returned from a customer who faced challenges with OC4J RMI load balancing, I felt there is still some confusions in the field how OC4J RMI load balancing work. Hence I decide to dust off an old tech note that I wrote a few years back and share it with the general public. Here is the tech note: Overview A typical use case in Oracle SOA is that you are building web based, custom human tasks UI that will interact with the task services housed in a remote BPEL 10G cluster. Or, in a more generic way, you are just building a web based application in Java that needs to interact with the EJBs in a remote OC4J cluster. In either case, you are talking to an OC4J cluster as RMI client. Then immediately you must ask yourself the following questions: 1. How do I make sure that the web application, as an RMI client, even distribute its load against all the nodes in the remote OC4J cluster? 2. How do I make sure that the web application, as an RMI client, is resilient to the node failures in the remote OC4J cluster, so that in the unlikely case when one of the remote OC4J nodes fail, my web application will continue to function? That is the topic of how to achieve load balancing with OC4J RMI client. Solutions You need to configure and code RMI load balancing in two places: 1. Provider URL can be specified with a comma separated list of URLs, so that the initial lookup will land to one of the available URLs. 2. Choose a proper value for the oracle.j2ee.rmi.loadBalance property, which, along side with the PROVIDER_URL property, is one of the JNDI properties passed to the JNDI lookup.(http://docs.oracle.com/cd/B31017_01/web.1013/b28958/rmi.htm#BABDGFBI) More details below: About the PROVIDER_URL The JNDI property java.name.provider.url's job is, when the client looks up for a new context at the very first time in the client session, to provide a list of RMI context The value of the JNDI property java.name.provider.url goes by the format of a single URL, or a comma separate list of URLs. A single URL. For example: opmn:ormi://host1:6003:oc4j_instance1/appName1 A comma separated list of multiple URLs. For examples:  opmn:ormi://host1:6003:oc4j_instanc1/appName, opmn:ormi://host2:6003:oc4j_instance1/appName, opmn:ormi://host3:6003:oc4j_instance1/appName When the client looks up for a new Context the very first time in the client session, it sends a query against the OPMN referenced by the provider URL. The OPMN host and port specifies the destination of such query, and the OC4J instance name and appName are actually the “where clause” of the query. When the PROVIDER URL reference a single OPMN server Let's consider the case when the provider url only reference a single OPMN server of the destination cluster. In this case, that single OPMN server receives the query and returns a list of the qualified Contexts from all OC4Js within the cluster, even though there is a single OPMN server in the provider URL. A context represent a particular starting point at a particular server for subsequent object lookup. For example, if the URL is opmn:ormi://host1:6003:oc4j_instance1/appName, then, OPMN will return the following contexts: appName on oc4j_instance1 on host1 appName on oc4j_instance1 on host2, appName on oc4j_instance1 on host3,  (provided that host1, host2, host3 are all in the same cluster) Please note that One OPMN will be sufficient to find the list of all contexts from the entire cluster that satisfy the JNDI lookup query. You can do an experiment by shutting down appName on host1, and observe that OPMN on host1 will still be able to return you appname on host2 and appName on host3. When the PROVIDER URL reference a comma separated list of multiple OPMN servers When the JNDI propery java.naming.provider.url references a comma separated list of multiple URLs, the lookup will return the exact same things as with the single OPMN server: a list of qualified Contexts from the cluster. The purpose of having multiple OPMN servers is to provide high availability in the initial context creation, such that if OPMN at host1 is unavailable, client will try the lookup via OPMN on host2, and so on. After the initial lookup returns and cache a list of contexts, the JNDI URL(s) are no longer used in the same client session. That explains why removing the 3rd URL from the list of JNDI URLs will not stop the client from getting the EJB on the 3rd server. About the oracle.j2ee.rmi.loadBalance Property After the client acquires the list of contexts, it will cache it at the client side as “list of available RMI contexts”.  This list includes all the servers in the destination cluster. This list will stay in the cache until the client session (JVM) ends. The RMI load balancing against the destination cluster is happening at the client side, as the client is switching between the members of the list. Whether and how often the client will fresh the Context from the list of Context is based on the value of the  oracle.j2ee.rmi.loadBalance. The documentation at http://docs.oracle.com/cd/B31017_01/web.1013/b28958/rmi.htm#BABDGFBI list all the available values for the oracle.j2ee.rmi.loadBalance. Value Description client If specified, the client interacts with the OC4J process that was initially chosen at the first lookup for the entire conversation. context Used for a Web client (servlet or JSP) that will access EJBs in a clustered OC4J environment. If specified, a new Context object for a randomly-selected OC4J instance will be returned each time InitialContext() is invoked. lookup Used for a standalone client that will access EJBs in a clustered OC4J environment. If specified, a new Context object for a randomly-selected OC4J instance will be created each time the client calls Context.lookup(). Please note the regardless of the setting of oracle.j2ee.rmi.loadBalance property, the “refresh” only occurs at the client. The client can only choose from the "list of available context" that was returned and cached from the very first lookup. That is, the client will merely get a new Context object from the “list of available RMI contexts” from the cache at the client side. The client will NOT go to the OPMN server again to get the list. That also implies that if you are adding a node to the server cluster AFTER the client’s initial lookup, the client would not know it because neither the server nor the client will initiate a refresh of the “list of available servers” to reflect the new node. About High Availability (i.e. Resilience Against Node Failure of Remote OC4J Cluster) What we have discussed above is about load balancing. Let's also discuss high availability. This is how the High Availability works in RMI: when the client use the context but get an exception such as socket is closed, it knows that the server referenced by that Context is problematic and will try to get another unused Context from the “list of available contexts”. Again, this list is the list that was returned and cached at the very first lookup in the entire client session.

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  • C#: LINQ vs foreach - Round 1.

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

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  • SSIS: Deploying OLAP cubes using C# script tasks and AMO

    - by DrJohn
    As part of the continuing series on Building dynamic OLAP data marts on-the-fly, this blog entry will focus on how to automate the deployment of OLAP cubes using SQL Server Integration Services (SSIS) and Analysis Services Management Objects (AMO). OLAP cube deployment is usually done using the Analysis Services Deployment Wizard. However, this option was dismissed for a variety of reasons. Firstly, invoking external processes from SSIS is fraught with problems as (a) it is not always possible to ensure SSIS waits for the external program to terminate; (b) we cannot log the outcome properly and (c) it is not always possible to control the server's configuration to ensure the executable works correctly. Another reason for rejecting the Deployment Wizard is that it requires the 'answers' to be written into four XML files. These XML files record the three things we need to change: the name of the server, the name of the OLAP database and the connection string to the data mart. Although it would be reasonably straight forward to change the content of the XML files programmatically, this adds another set of complication and level of obscurity to the overall process. When I first investigated the possibility of using C# to deploy a cube, I was surprised to find that there are no other blog entries about the topic. I can only assume everyone else is happy with the Deployment Wizard! SSIS "forgets" assembly references If you build your script task from scratch, you will have to remember how to overcome one of the major annoyances of working with SSIS script tasks: the forgetful nature of SSIS when it comes to assembly references. Basically, you can go through the process of adding an assembly reference using the Add Reference dialog, but when you close the script window, SSIS "forgets" the assembly reference so the script will not compile. After repeating the operation several times, you will find that SSIS only remembers the assembly reference when you specifically press the Save All icon in the script window. This problem is not unique to the AMO assembly and has certainly been a "feature" since SQL Server 2005, so I am not amazed it is still present in SQL Server 2008 R2! Sample Package So let's take a look at the sample SSIS package I have provided which can be downloaded from here: DeployOlapCubeExample.zip  Below is a screenshot after a successful run. Connection Managers The package has three connection managers: AsDatabaseDefinitionFile is a file connection manager pointing to the .asdatabase file you wish to deploy. Note that this can be found in the bin directory of you OLAP database project once you have clicked the "Build" button in Visual Studio TargetOlapServerCS is an Analysis Services connection manager which identifies both the deployment server and the target database name. SourceDataMart is an OLEDB connection manager pointing to the data mart which is to act as the source of data for your cube. This will be used to replace the connection string found in your .asdatabase file Once you have configured the connection managers, the sample should run and deploy your OLAP database in a few seconds. Of course, in a production environment, these connection managers would be associated with package configurations or set at runtime. When you run the sample, you should see that the script logs its activity to the output screen (see screenshot above). If you configure logging for the package, then these messages will also appear in your SSIS logging. Sample Code Walkthrough Next let's walk through the code. The first step is to parse the connection string provided by the TargetOlapServerCS connection manager and obtain the name of both the target OLAP server and also the name of the OLAP database. Note that the target database does not have to exist to be referenced in an AS connection manager, so I am using this as a convenient way to define both properties. We now connect to the server and check for the existence of the OLAP database. If it exists, we drop the database so we can re-deploy. svr.Connect(olapServerName); if (svr.Connected) { // Drop the OLAP database if it already exists Database db = svr.Databases.FindByName(olapDatabaseName); if (db != null) { db.Drop(); } // rest of script } Next we start building the XMLA command that will actually perform the deployment. Basically this is a small chuck of XML which we need to wrap around the large .asdatabase file generated by the Visual Studio build process. // Start generating the main part of the XMLA command XmlDocument xmlaCommand = new XmlDocument(); xmlaCommand.LoadXml(string.Format("<Batch Transaction='false' xmlns='http://schemas.microsoft.com/analysisservices/2003/engine'><Alter AllowCreate='true' ObjectExpansion='ExpandFull'><Object><DatabaseID>{0}</DatabaseID></Object><ObjectDefinition/></Alter></Batch>", olapDatabaseName));  Next we need to merge two XML files which we can do by simply using setting the InnerXml property of the ObjectDefinition node as follows: // load OLAP Database definition from .asdatabase file identified by connection manager XmlDocument olapCubeDef = new XmlDocument(); olapCubeDef.Load(Dts.Connections["AsDatabaseDefinitionFile"].ConnectionString); // merge the two XML files by obtain a reference to the ObjectDefinition node oaRootNode.InnerXml = olapCubeDef.InnerXml;   One hurdle I had to overcome was removing detritus from the .asdabase file left by the Visual Studio build. Through an iterative process, I found I needed to remove several nodes as they caused the deployment to fail. The XMLA error message read "Cannot set read-only node: CreatedTimestamp" or similar. In comparing the XMLA generated with by the Deployment Wizard with that generated by my code, these read-only nodes were missing, so clearly I just needed to strip them out. This was easily achieved using XPath to find the relevant XML nodes, of which I show one example below: foreach (XmlNode node in rootNode.SelectNodes("//ns1:CreatedTimestamp", nsManager)) { node.ParentNode.RemoveChild(node); } Now we need to change the database name in both the ID and Name nodes using code such as: XmlNode databaseID = xmlaCommand.SelectSingleNode("//ns1:Database/ns1:ID", nsManager); if (databaseID != null) databaseID.InnerText = olapDatabaseName; Finally we need to change the connection string to point at the relevant data mart. Again this is easily achieved using XPath to search for the relevant nodes and then replace the content of the node with the new name or connection string. XmlNode connectionStringNode = xmlaCommand.SelectSingleNode("//ns1:DataSources/ns1:DataSource/ns1:ConnectionString", nsManager); if (connectionStringNode != null) { connectionStringNode.InnerText = Dts.Connections["SourceDataMart"].ConnectionString; } Finally we need to perform the deployment using the Execute XMLA command and check the returned XmlaResultCollection for errors before setting the Dts.TaskResult. XmlaResultCollection oResults = svr.Execute(xmlaCommand.InnerXml);  // check for errors during deployment foreach (Microsoft.AnalysisServices.XmlaResult oResult in oResults) { foreach (Microsoft.AnalysisServices.XmlaMessage oMessage in oResult.Messages) { if ((oMessage.GetType().Name == "XmlaError")) { FireError(oMessage.Description); HadError = true; } } } If you are not familiar with XML programming, all this may all seem a bit daunting, but perceiver as the sample code is pretty short. If you would like the script to process the OLAP database, simply uncomment the lines in the vicinity of Process method. Of course, you can extend the script to perform your own custom processing and to even synchronize the database to a front-end server. Personally, I like to keep the deployment and processing separate as the code can become overly complex for support staff.If you want to know more, come see my session at the forthcoming SQLBits conference.

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  • Beginner’s Guide to Flock, the Social Media Browser

    - by Asian Angel
    Are you wanting a browser that can work as a social hub from the first moment that you start it up? If you love the idea of a browser that is ready to go out of the box then join us as we look at Flock. During the Install Process When you are installing Flock there are two install windows that you should watch for. The first one lets you choose between the “Express Setup & Custom Setup”. We recommend the “Custom Setup”. Once you have selected the “Custom Setup” you can choose which of the following options will enabled. Notice the “anonymous usage statistics” option at the bottom…you can choose to leave this enabled or disable it based on your comfort level. The First Look When you start Flock up for the first time it will open with three tabs. All three are of interest…especially if this is your first time using Flock. With the first tab you can jump right into “logging in/activating” favorite social services within Flock. This page is set to display each time that you open Flock unless you deselect the option in the lower left corner. The second tab provides a very nice overview of Flock and its’ built-in social management power. The third and final page can be considered a “Personal Page”. You can make some changes to the content displayed for quick and easy access and/or monitoring “Twitter Search, Favorite Feeds, Favorite Media, Friend Activity, & Favorite Sites”. Use the “Widget Menu” in the upper left corner to select the “Personal Page Components” that you would like to use. In the upper right corner there is a built-in “Search Bar” and buttons for “Posting to Your Blog & Uploading Media”. To help personalize the “My World Page” just a bit more you can even change the text to your name or whatever best suits your needs. The Flock Toolbar The “Flock Toolbar” is full of social account management goodness. In order from left to right the buttons are: My World (Homepage), Open People Sidebar, Open Media Bar, Open Feeds Sidebar, Webmail, Open Favorites Sidebar, Open Accounts and Services Sidebar, Open Web Clipboard Sidebar, Open Blog Editor, & Open Photo Uploader. The buttons will be “highlighted” with a blue background to help indicate which area you are in. The first area will display a listing of people that you are watching/following at the services shown here. Clicking on the “Media Bar Button” will display the following “Media Slider Bar” above your “Tab Bar”. Notice that there is a built-in “Search Bar” on the right side. Any photos, etc. clicked on will be opened in the currently focused tab below the “Media Bar”. Here is a listing of the “Media Streams” available for viewing. By default Flock will come with a small selection of pre-subscribed RSS Feeds. You can easily unsubscribe, rearrange, add custom folders, or non-categorized feeds as desired. RSS Feeds subscribed to here can be viewed combined together as a single feed (clickable links) in the “My World Page”. or can be viewed individually in a new tab. Very nice! Next on the “Flock Toolbar is the “Webmail Button”. You can set up access to your favorite “Yahoo!, Gmail, & AOL Mail” accounts from here. The “Favorites Sidebar” combines your “Browser History & Bookmarks” into one convenient location. The “Accounts and Services Sidebar” gives you quick and easy access to get logged into your favorite social accounts. Clicking on any of the links will open that particular service’s login page in a new tab. Want to store items such as photos, links, and text to add into a blog post or tweet later on? Just drag and drop them into the “Web Clipboard Sidebar” for later access. Clicking on the “Blog Editor Button” will open up a separate blogging window to compose your posts in. If you have not logged into or set up an account yet in Flock you will see the following message window. The “Blogging Window”…nice, simple, and straightforward. If you are not already logged into your photo account(s) then you will see the following message window when you click on the “Photo Uploader Button”. Clicking “OK” will open the “Accounts and Services Sidebar” with compatible photo services highlighted in a light yellow color. Log in to your favorite service to start uploading all those great images. After Setting Up Here is what our browser looked like after setting up some of our favorite services. The Twitter feed is certainly looking nice and easy to read through… Some tweaking in the “RSS Feeds Sidebar” makes for a perfect reading experience. Keeping up with our e-mail is certainly easy to do too. A look back at the “Accounts and Services Sidebar” shows that all of our accounts are actively logged in (green dot on the right side). Going back to our “My World Page” you can see how nice everything looks for monitoring our “Friend Activity & Favorite Feeds”. Moving on to regular browsing everything is looking very good… Flock is a perfect choice for anyone wanting a browser and social hub all built into a single app. Conclusion Anyone who loves keeping up with their favorite social services while browsing will find using Flock to be a wonderful experience. You literally get the best of both worlds with this browser. Links Download Flock The Official Flock Extensions Homepage The Official Flock Toolbar Homepage Similar Articles Productive Geek Tips Add Color Coding to Windows 7 Media Center Program GuideAdd Social Bookmarking (Digg This!) Links to your Wordpress BlogHow to use an ISO image on Ubuntu LinuxAdvertise on How-To GeekFixing When Windows Media Player Library Won’t Let You Add Files TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Have Fun Editing Photo Editing with Citrify Outlook Connector Upgrade Error Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause

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  • SQL SERVER – Core Concepts – Elasticity, Scalability and ACID Properties – Exploring NuoDB an Elastically Scalable Database System

    - by pinaldave
    I have been recently exploring Elasticity and Scalability attributes of databases. You can see that in my earlier blog posts about NuoDB where I wanted to look at Elasticity and Scalability concepts. The concepts are very interesting, and intriguing as well. I have discussed these concepts with my friend Joyti M and together we have come up with this interesting read. The goal of this article is to answer following simple questions What is Elasticity? What is Scalability? How ACID properties vary from NOSQL Concepts? What are the prevailing problems in the current database system architectures? Why is NuoDB  an innovative and welcome change in database paradigm? Elasticity This word’s original form is used in many different ways and honestly it does do a decent job in holding things together over the years as a person grows and contracts. Within the tech world, and specifically related to software systems (database, application servers), it has come to mean a few things - allow stretching of resources without reaching the breaking point (on demand). What are resources in this context? Resources are the usual suspects – RAM/CPU/IO/Bandwidth in the form of a container (a process or bunch of processes combined as modules). When it is about increasing resources the simplest idea which comes to mind is the addition of another container. Another container means adding a brand new physical node. When it is about adding a new node there are two questions which comes to mind. 1) Can we add another node to our software system? 2) If yes, does adding new node cause downtime for the system? Let us assume we have added new node, let us see what the new needs of the system are when a new node is added. Balancing incoming requests to multiple nodes Synchronization of a shared state across multiple nodes Identification of “downstate” and resolution action to bring it to “upstate” Well, adding a new node has its advantages as well. Here are few of the positive points Throughput can increase nearly horizontally across the node throughout the system Response times of application will increase as in-between layer interactions will be improved Now, Let us put the above concepts in the perspective of a Database. When we mention the term “running out of resources” or “application is bound to resources” the resources can be CPU, Memory or Bandwidth. The regular approach to “gain scalability” in the database is to look around for bottlenecks and increase the bottlenecked resource. When we have memory as a bottleneck we look at the data buffers, locks, query plans or indexes. After a point even this is not enough as there needs to be an efficient way of managing such large workload on a “single machine” across memory and CPU bound (right kind of scheduling)  workload. We next move on to either read/write separation of the workload or functionality-based sharing so that we still have control of the individual. But this requires lots of planning and change in client systems in terms of knowing where to go/update/read and for reporting applications to “aggregate the data” in an intelligent way. What we ideally need is an intelligent layer which allows us to do these things without us getting into managing, monitoring and distributing the workload. Scalability In the context of database/applications, scalability means three main things Ability to handle normal loads without pressure E.g. X users at the Y utilization of resources (CPU, Memory, Bandwidth) on the Z kind of hardware (4 processor, 32 GB machine with 15000 RPM SATA drives and 1 GHz Network switch) with T throughput Ability to scale up to expected peak load which is greater than normal load with acceptable response times Ability to provide acceptable response times across the system E.g. Response time in S milliseconds (or agreed upon unit of measure) – 90% of the time The Issue – Need of Scale In normal cases one can plan for the load testing to test out normal, peak, and stress scenarios to ensure specific hardware meets the needs. With help from Hardware and Software partners and best practices, bottlenecks can be identified and requisite resources added to the system. Unfortunately this vertical scale is expensive and difficult to achieve and most of the operational people need the ability to scale horizontally. This helps in getting better throughput as there are physical limits in terms of adding resources (Memory, CPU, Bandwidth and Storage) indefinitely. Today we have different options to achieve scalability: Read & Write Separation The idea here is to do actual writes to one store and configure slaves receiving the latest data with acceptable delays. Slaves can be used for balancing out reads. We can also explore functional separation or sharing as well. We can separate data operations by a specific identifier (e.g. region, year, month) and consolidate it for reporting purposes. For functional separation the major disadvantage is when schema changes or workload pattern changes. As the requirement grows one still needs to deal with scale need in manual ways by providing an abstraction in the middle tier code. Using NOSQL solutions The idea is to flatten out the structures in general to keep all values which are retrieved together at the same store and provide flexible schema. The issue with the stores is that they are compromising on mostly consistency (no ACID guarantees) and one has to use NON-SQL dialect to work with the store. The other major issue is about education with NOSQL solutions. Would one really want to make these compromises on the ability to connect and retrieve in simple SQL manner and learn other skill sets? Or for that matter give up on ACID guarantee and start dealing with consistency issues? Hybrid Deployment – Mac, Linux, Cloud, and Windows One of the challenges today that we see across On-premise vs Cloud infrastructure is a difference in abilities. Take for example SQL Azure – it is wonderful in its concepts of throttling (as it is shared deployment) of resources and ability to scale using federation. However, the same abilities are not available on premise. This is not a mistake, mind you – but a compromise of the sweet spot of workloads, customer requirements and operational SLAs which can be supported by the team. In today’s world it is imperative that databases are available across operating systems – which are a commodity and used by developers of all hues. An Ideal Database Ability List A system which allows a linear scale of the system (increase in throughput with reasonable response time) with the addition of resources A system which does not compromise on the ACID guarantees and require developers to learn new paradigms A system which does not force fit a new way interacting with database by learning Non-SQL dialect A system which does not force fit its mechanisms for providing availability across its various modules. Well NuoDB is the first database which has all of the above abilities and much more. In future articles I will cover my hands-on experience with it. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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

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

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  • Prevent your Silverlight XAP file from caching in your browser.

    - by mbcrump
    If you work with Silverlight daily then you have run into this problem. Your XAP file has been cached in your browser and you have to empty your browser cache to resolve it. If your using Google Chrome then you typically do the following: Go to Options –> Clear Browsing History –> Empty the Cache and finally click Clear Browsing data. As you can see, this is a lot of unnecessary steps. It is even worse when you have a customer that says, “I can’t see the new features you just implemented!” and you realize it’s a cached xap problem.  I have been struggling with a way to prevent my XAP file from caching inside of a browser for a while now and decided to implement the following solution. If the Visual Studio Debugger is attached then add a unique query string to the source param to force the XAP file to be refreshed. If the Visual Studio Debugger is not attached then add the source param as Visual Studio generates it. This is also in case I forget to remove the above code in my production environment. I want the ASP.NET code to be inline with my .ASPX page. (I do not want a separate code behind .cs page or .vb page attached to the .aspx page.) Below is an example of the hosting code generated when you create a new Silverlight project. As a quick refresher, the hard coded param name = “source” specifies the location of your XAP file.  <form id="form1" runat="server" style="height:100%"> <div id="silverlightControlHost"> <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> <param name="source" value="ClientBin/SilverlightApplication2.xap"/> <param name="onError" value="onSilverlightError" /> <param name="background" value="white" /> <param name="minRuntimeVersion" value="4.0.50826.0" /> <param name="autoUpgrade" value="true" /> <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none"> <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/> </a> </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe></div> </form> We are going to use a little bit of inline ASP.NET to generate the param name = source dynamically to prevent the XAP file from caching. Lets look at the completed solution: <form id="form1" runat="server" style="height:100%"> <div id="silverlightControlHost"> <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> <% string strSourceFile = @"ClientBin/SilverlightApplication2.xap"; string param; if (System.Diagnostics.Debugger.IsAttached) //Debugger Attached - Refresh the XAP file. param = "<param name=\"source\" value=\"" + strSourceFile + "?" + DateTime.Now.Ticks + "\" />"; else { //Production Mode param = "<param name=\"source\" value=\"" + strSourceFile + "\" />"; } Response.Write(param); %> <param name="onError" value="onSilverlightError" /> <param name="background" value="white" /> <param name="minRuntimeVersion" value="4.0.50826.0" /> <param name="autoUpgrade" value="true" /> <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none"> <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/> </a> </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe></div> </form> We add the location to our XAP file to strSourceFile and if the debugger is attached then it will append DateTime.Now.Ticks to the XAP file source and force the browser to download the .XAP. If you view the page source of your Silverlight Application then you can verify it worked properly by looking at the param name = “source” tag as shown below. <param name="source" value="ClientBin/SilverlightApplication2.xap?634299001187160148" /> If the debugger is not attached then it will use the standard source tag as shown below. <param name="source" value="ClientBin/SilverlightApplication2.xap"/> At this point you may be asking, How do I prevent my XAP file from being cached on my production app? Well, you have two easy options: 1) I really don’t recommend this approach but you can force the XAP to be refreshed everytime with the following code snippet.  <param name="source" value="ClientBin/SilverlightApplication2.xap?<%=Guid.NewGuid().ToString() %>"/> NOTE: You could also substitute the “Guid.NewGuid().ToString() for anything that create a random field. (I used DateTime.Now.Ticks earlier). 2) Another solution that I like even better involves checking the XAP Creation Date and appending it to the param name = source. This method was described by Lars Holm Jenson. <% string strSourceFile = @"ClientBin/SilverlightApplication2.xap"; string param; if (System.Diagnostics.Debugger.IsAttached) param = "<param name=\"source\" value=\"" + strSourceFile + "\" />"; else { string xappath = HttpContext.Current.Server.MapPath(@"") + @"\" + strSourceFile; DateTime xapCreationDate = System.IO.File.GetLastWriteTime(xappath); param = "<param name=\"source\" value=\"" + strSourceFile + "?ignore=" + xapCreationDate.ToString() + "\" />"; } Response.Write(param); %> As you can see, this problem has been solved. It will work with all web browsers and stubborn proxy servers that are caching your .XAP. If you enjoyed this article then check out my blog for others like this. You may also want to subscribe to my blog or follow me on Twitter.   Subscribe to my feed

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  • Anatomy of a .NET Assembly - PE Headers

    - by Simon Cooper
    Today, I'll be starting a look at what exactly is inside a .NET assembly - how the metadata and IL is stored, how Windows knows how to load it, and what all those bytes are actually doing. First of all, we need to understand the PE file format. PE files .NET assemblies are built on top of the PE (Portable Executable) file format that is used for all Windows executables and dlls, which itself is built on top of the MSDOS executable file format. The reason for this is that when .NET 1 was released, it wasn't a built-in part of the operating system like it is nowadays. Prior to Windows XP, .NET executables had to load like any other executable, had to execute native code to start the CLR to read & execute the rest of the file. However, starting with Windows XP, the operating system loader knows natively how to deal with .NET assemblies, rendering most of this legacy code & structure unnecessary. It still is part of the spec, and so is part of every .NET assembly. The result of this is that there are a lot of structure values in the assembly that simply aren't meaningful in a .NET assembly, as they refer to features that aren't needed. These are either set to zero or to certain pre-defined values, specified in the CLR spec. There are also several fields that specify the size of other datastructures in the file, which I will generally be glossing over in this initial post. Structure of a PE file Most of a PE file is split up into separate sections; each section stores different types of data. For instance, the .text section stores all the executable code; .rsrc stores unmanaged resources, .debug contains debugging information, and so on. Each section has a section header associated with it; this specifies whether the section is executable, read-only or read/write, whether it can be cached... When an exe or dll is loaded, each section can be mapped into a different location in memory as the OS loader sees fit. In order to reliably address a particular location within a file, most file offsets are specified using a Relative Virtual Address (RVA). This specifies the offset from the start of each section, rather than the offset within the executable file on disk, so the various sections can be moved around in memory without breaking anything. The mapping from RVA to file offset is done using the section headers, which specify the range of RVAs which are valid within that section. For example, if the .rsrc section header specifies that the base RVA is 0x4000, and the section starts at file offset 0xa00, then an RVA of 0x401d (offset 0x1d within the .rsrc section) corresponds to a file offset of 0xa1d. Because each section has its own base RVA, each valid RVA has a one-to-one mapping with a particular file offset. PE headers As I said above, most of the header information isn't relevant to .NET assemblies. To help show what's going on, I've created a diagram identifying all the various parts of the first 512 bytes of a .NET executable assembly. I've highlighted the relevant bytes that I will refer to in this post: Bear in mind that all numbers are stored in the assembly in little-endian format; the hex number 0x0123 will appear as 23 01 in the diagram. The first 64 bytes of every file is the DOS header. This starts with the magic number 'MZ' (0x4D, 0x5A in hex), identifying this file as an executable file of some sort (an .exe or .dll). Most of the rest of this header is zeroed out. The important part of this header is at offset 0x3C - this contains the file offset of the PE signature (0x80). Between the DOS header & PE signature is the DOS stub - this is a stub program that simply prints out 'This program cannot be run in DOS mode.\r\n' to the console. I will be having a closer look at this stub later on. The PE signature starts at offset 0x80, with the magic number 'PE\0\0' (0x50, 0x45, 0x00, 0x00), identifying this file as a PE executable, followed by the PE file header (also known as the COFF header). The relevant field in this header is in the last two bytes, and it specifies whether the file is an executable or a dll; bit 0x2000 is set for a dll. Next up is the PE standard fields, which start with a magic number of 0x010b for x86 and AnyCPU assemblies, and 0x20b for x64 assemblies. Most of the rest of the fields are to do with the CLR loader stub, which I will be covering in a later post. After the PE standard fields comes the NT-specific fields; again, most of these are not relevant for .NET assemblies. The one that is is the highlighted Subsystem field, and specifies if this is a GUI or console app - 0x20 for a GUI app, 0x30 for a console app. Data directories & section headers After the PE and COFF headers come the data directories; each directory specifies the RVA (first 4 bytes) and size (next 4 bytes) of various important parts of the executable. The only relevant ones are the 2nd (Import table), 13th (Import Address table), and 15th (CLI header). The Import and Import Address table are only used by the startup stub, so we will look at those later on. The 15th points to the CLI header, where the CLR-specific metadata begins. After the data directories comes the section headers; one for each section in the file. Each header starts with the section's ASCII name, null-padded to 8 bytes. Again, most of each header is irrelevant, but I've highlighted the base RVA and file offset in each header. In the diagram, you can see the following sections: .text: base RVA 0x2000, file offset 0x200 .rsrc: base RVA 0x4000, file offset 0xa00 .reloc: base RVA 0x6000, file offset 0x1000 The .text section contains all the CLR metadata and code, and so is by far the largest in .NET assemblies. The .rsrc section contains the data you see in the Details page in the right-click file properties page, but is otherwise unused. The .reloc section contains address relocations, which we will look at when we study the CLR startup stub. What about the CLR? As you can see, most of the first 512 bytes of an assembly are largely irrelevant to the CLR, and only a few bytes specify needed things like the bitness (AnyCPU/x86 or x64), whether this is an exe or dll, and the type of app this is. There are some bytes that I haven't covered that affect the layout of the file (eg. the file alignment, which determines where in a file each section can start). These values are pretty much constant in most .NET assemblies, and don't affect the CLR data directly. Conclusion To summarize, the important data in the first 512 bytes of a file is: DOS header. This contains a pointer to the PE signature. DOS stub, which we'll be looking at in a later post. PE signature PE file header (aka COFF header). This specifies whether the file is an exe or a dll. PE standard fields. This specifies whether the file is AnyCPU/32bit or 64bit. PE NT-specific fields. This specifies what type of app this is, if it is an app. Data directories. The 15th entry (at offset 0x168) contains the RVA and size of the CLI header inside the .text section. Section headers. These are used to map between RVA and file offset. The important one is .text, which is where all the CLR data is stored. In my next post, we'll start looking at the metadata used by the CLR directly, which is all inside the .text section.

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

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

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  • Elegance, thy Name is jQuery

    - by SGWellens
    So, I'm browsing though some questions over on the Stack Overflow website and I found a good jQuery question just a few minutes old. Here is a link to it. It was a tough question; I knew that by answering it, I could learn new stuff and reinforce what I already knew: Reading is good, doing is better. Maybe I could help someone in the process too. I cut and pasted the HTML from the question into my Visual Studio IDE and went back to Stack Overflow to reread the question. Dang, someone had already answered it! And it was a great answer. I never even had a chance to start analyzing the issue. Now I know what a one-legged man feels like in an ass-kicking contest. Nevertheless, since the question and answer were so interesting, I decided to dissect them and learn as much as possible. The HTML consisted of some divs separated by h3 headings.  Note the elements are laid out sequentially with no programmatic grouping: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div></form></body>  The requirement was to wrap a div around each h3 heading and the subsequent divs grouping them into sections. Why? I don't know, I suppose if you screen-scrapped some HTML from another site, you might want to reformat it before displaying it on your own. Anyways… Here is the marvelously, succinct posted answer: $('.heading').each(function(){ $(this).nextUntil('.heading').andSelf().wrapAll('<div class="section">');}); I was familiar with all the parts except for nextUntil and andSelf. But, I'll analyze the whole answer for completeness. I'll do this by rewriting the posted answer in a different style and adding a boat-load of comments: function Test(){ // $Sections is a jQuery object and it will contain three elements var $Sections = $('.heading'); // use each to iterate over each of the three elements $Sections.each(function () { // $this is a jquery object containing the current element // being iterated var $this = $(this); // nextUntil gets the following sibling elements until it reaches // an element with the CSS class 'heading' // andSelf adds in the source element (this) to the collection $this = $this.nextUntil('.heading').andSelf(); // wrap the elements with a div $this.wrapAll('<div class="section" >'); });}  The code here doesn't look nearly as concise and elegant as the original answer. However, unless you and your staff are jQuery masters, during development it really helps to work through algorithms step by step. You can step through this code in the debugger and examine the jQuery objects to make sure one step is working before proceeding on to the next. It's much easier to debug and troubleshoot when each logical coding step is a separate line of code. Note: You may think the original code runs much faster than this version. However, the time difference is trivial: Not enough to worry about: Less than 1 millisecond (tested in IE and FF). Note: You may want to jam everything into one line because it results in less traffic being sent to the client. That is true. However, most Internet servers now compress HTML and JavaScript by stripping out comments and white space (go to Bing or Google and view the source). This feature should be enabled on your server: Let the server compress your code, you don't need to do it. Free Career Advice: Creating maintainable code is Job One—Maximum Priority—The Prime Directive. If you find yourself suddenly transferred to customer support, it may be that the code you are writing is not as readable as it could be and not as readable as it should be. Moving on… I created a CSS class to enhance the results: .section{ background-color: yellow; border: 2px solid black; margin: 5px;} Here is the rendered output before:   …and after the jQuery code runs.   Pretty Cool! But, while playing with this code, the logic of nextUntil began to bother me: What happens in the last section? What stops elements from being collected since there are no more elements with the .heading class? The answer is nothing.  In this case it stopped collecting elements because it was at the end of the page.  But what if there were additional HTML elements? I added an anchor tag and another div to the HTML: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div><a>this is a link</a><div>unrelated div</div> </form></body> The code as-is will include both the anchor and the unrelated div. This isn't what we want.   My first attempt to correct this used the filter parameter of the nextUntil function: nextUntil('.heading', 'div')  This will only collect div elements. But it merely skipped the anchor tag and it still collected the unrelated div:   The problem is we need a way to tell the nextUntil function when to stop. CSS selectors to the rescue! nextUntil('.heading, a')  This tells nextUntil to stop collecting elements when it gets to an element with a .heading class OR when it gets to an anchor tag. In this case it solved the problem. FYI: The comma operator in a CSS selector allows multiple criteria.   Bingo! One final note, we could have broken the code down even more: We could have replaced the andSelf function here: $this = $this.nextUntil('.heading, a').andSelf(); With this: // get all the following siblings and then add the current item$this = $this.nextUntil('.heading, a');$this.add(this);  But in this case, the andSelf function reads real nice. In my opinion. Here's a link to a jsFiddle if you want to play with it. I hope someone finds this useful Steve Wellens CodeProject

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  • Cost Comparison Hard Disk Drive to Solid State Drive on Price per Gigabyte - dispelling a myth!

    - by tonyrogerson
    It is often said that Hard Disk Drive storage is significantly cheaper per GiByte than Solid State Devices – this is wholly inaccurate within the database space. People need to look at the cost of the complete solution and not just a single component part in isolation to what is really required to meet the business requirement. Buying a single Hitachi Ultrastar 600GB 3.5” SAS 15Krpm hard disk drive will cost approximately £239.60 (http://scan.co.uk, 22nd March 2012) compared to an OCZ 600GB Z-Drive R4 CM84 PCIe costing £2,316.54 (http://scan.co.uk, 22nd March 2012); I’ve not included FusionIO ioDrive because there is no public pricing available for it – something I never understand and personally when companies do this I immediately think what are they hiding, luckily in FusionIO’s case the product is proven though is expensive compared to OCZ enterprise offerings. On the face of it the single 15Krpm hard disk has a price per GB of £0.39, the SSD £3.86; this is what you will see in the press and this is what sales people will use in comparing the two technologies – do not be fooled by this bullshit people! What is the requirement? The requirement is the database will have a static size of 400GB kept static through archiving so growth and trim will balance the database size, the client requires resilience, there will be several hundred call centre staff querying the database where queries will read a small amount of data but there will be no hot spot in the data so the randomness will come across the entire 400GB of the database, estimates predict that the IOps required will be approximately 4,000IOps at peak times, because it’s a call centre system the IO latency is important and must remain below 5ms per IO. The balance between read and write is 70% read, 30% write. The requirement is now defined and we have three of the most important pieces of the puzzle – space required, estimated IOps and maximum latency per IO. Something to consider with regard SQL Server; write activity requires synchronous IO to the storage media specifically the transaction log; that means the write thread will wait until the IO is completed and hardened off until the thread can continue execution, the requirement has stated that 30% of the system activity will be write so we can expect a high amount of synchronous activity. The hardware solution needs to be defined; two possible solutions: hard disk or solid state based; the real question now is how many hard disks are required to achieve the IO throughput, the latency and resilience, ditto for the solid state. Hard Drive solution On a test on an HP DL380, P410i controller using IOMeter against a single 15Krpm 146GB SAS drive, the throughput given on a transfer size of 8KiB against a 40GiB file on a freshly formatted disk where the partition is the only partition on the disk thus the 40GiB file is on the outer edge of the drive so more sectors can be read before head movement is required: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 3,733 IOps at an average latency of 34.06ms (34 MiB/s). The same test was done on the same disk but the test file was 130GiB: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 528 IOps at an average latency of 217.49ms (4 MiB/s). From the result it is clear random performance gets worse as the disk fills up – I’m currently writing an article on short stroking which will cover this in detail. Given the work load is random in nature looking at the random performance of the single drive when only 40 GiB of the 146 GB is used gives near the IOps required but the latency is way out. Luckily I have tested 6 x 15Krpm 146GB SAS 15Krpm drives in a RAID 0 using the same test methodology, for the same test above on a 130 GiB for each drive added the performance boost is near linear, for each drive added throughput goes up by 5 MiB/sec, IOps by 700 IOps and latency reducing nearly 50% per drive added (172 ms, 94 ms, 65 ms, 47 ms, 37 ms, 30 ms). This is because the same 130GiB is spread out more as you add drives 130 / 1, 130 / 2, 130 / 3 etc. so implicit short stroking is occurring because there is less file on each drive so less head movement required. The best latency is still 30 ms but we have the IOps required now, but that’s on a 130GiB file and not the 400GiB we need. Some reality check here: a) the drive randomness is more likely to be 50/50 and not a full 100% but the above has highlighted the effect randomness has on the drive and the more a drive fills with data the worse the effect. For argument sake let us assume that for the given workload we need 8 disks to do the job, for resilience reasons we will need 16 because we need to RAID 1+0 them in order to get the throughput and the resilience, RAID 5 would degrade performance. Cost for hard drives: 16 x £239.60 = £3,833.60 For the hard drives we will need disk controllers and a separate external disk array because the likelihood is that the server itself won’t take the drives, a quick spec off DELL for a PowerVault MD1220 which gives the dual pathing with 16 disks 146GB 15Krpm 2.5” disks is priced at £7,438.00, note its probably more once we had two controller cards to sit in the server in, racking etc. Minimum cost taking the DELL quote as an example is therefore: {Cost of Hardware} / {Storage Required} £7,438.60 / 400 = £18.595 per GB £18.59 per GiB is a far cry from the £0.39 we had been told by the salesman and the myth. Yes, the storage array is composed of 16 x 146 disks in RAID 10 (therefore 8 usable) giving an effective usable storage availability of 1168GB but the actual storage requirement is only 400 and the extra disks have had to be purchased to get the  IOps up. Solid State Drive solution A single card significantly exceeds the IOps and latency required, for resilience two will be required. ( £2,316.54 * 2 ) / 400 = £11.58 per GB With the SSD solution only two PCIe sockets are required, no external disk units, no additional controllers, no redundant controllers etc. Conclusion I hope by showing you an example that the myth that hard disk drives are cheaper per GiB than Solid State has now been dispelled - £11.58 per GB for SSD compared to £18.59 for Hard Disk. I’ve not even touched on the running costs, compare the costs of running 18 hard disks, that’s a lot of heat and power compared to two PCIe cards!Just a quick note: I've left a fair amount of information out due to this being a blog! If in doubt, email me :)I'll also deal with the myth that SSD's wear out at a later date as well - that's just way over done still, yes, 5 years ago, but now - no.

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  • A Good Developer is So Hard to Find

    - by James Michael Hare
    Let me start out by saying I want to damn the writers of the Toughest Developer Puzzle Ever – 2. It is eating every last shred of my free time! But as I've been churning through each puzzle and marvelling at the brain teasers and trivia within, I began to think about interviewing developers and why it seems to be so hard to find good ones.  The problem is, it seems like no matter how hard we try to find the perfect way to separate the chaff from the wheat, inevitably someone will get hired who falls far short of expectations or someone will get passed over for missing a piece of trivia or a tricky brain teaser that could have been an excellent team member.   In shops that are primarily software-producing businesses or other heavily IT-oriented businesses (Microsoft, Amazon, etc) there often exists a much tighter bond between HR and the hiring development staff because development is their life-blood. Unfortunately, many of us work in places where IT is viewed as a cost or just a means to an end. In these shops, too often, HR and development staff may work against each other due to differences in opinion as to what a good developer is or what one is worth.  It seems that if you ask two different people what makes a good developer, often you will get three different opinions.   With the exception of those shops that are purely development-centric (you guys have it much easier!), most other shops have management who have very little knowledge about the development process.  Their view can often be that development is simply a skill that one learns and then once aquired, that developer can produce widgets as good as the next like workers on an assembly-line floor.  On the other side, you have many developers that feel that software development is an art unto itself and that the ability to create the most pure design or know the most obscure of keywords or write the shortest-possible obfuscated piece of code is a good coder.  So is it a skill?  An Art?  Or something entirely in between?   Saying that software is merely a skill and one just needs to learn the syntax and tools would be akin to saying anyone who knows English and can use Word can write a 300 page book that is accurate, meaningful, and stays true to the point.  This just isn't so.  It takes more than mere skill to take words and form a sentence, join those sentences into paragraphs, and those paragraphs into a document.  I've interviewed candidates who could answer obscure syntax and keyword questions and once they were hired could not code effectively at all.  So development must be more than a skill.   But on the other end, we have art.  Is development an art?  Is our end result to produce art?  I can marvel at a piece of code -- see it as concise and beautiful -- and yet that code most perform some stated function with accuracy and efficiency and maintainability.  None of these three things have anything to do with art, per se.  Art is beauty for its own sake and is a wonderful thing.  But if you apply that same though to development it just doesn't hold.  I've had developers tell me that all that matters is the end result and how you code it is entirely part of the art and I couldn't disagree more.  Yes, the end result, the accuracy, is the prime criteria to be met.  But if code is not maintainable and efficient, it would be just as useless as a beautiful car that breaks down once a week or that gets 2 miles to the gallon.  Yes, it may work in that it moves you from point A to point B and is pretty as hell, but if it can't be maintained or is not efficient, it's not a good solution.  So development must be something less than art.   In the end, I think I feel like development is a matter of craftsmanship.  We use our tools and we use our skills and set about to construct something that satisfies a purpose and yet is also elegant and efficient.  There is skill involved, and there is an art, but really it boils down to being able to craft code.  Crafting code is far more than writing code.  Anyone can write code if they know the syntax, but so few people can actually craft code that solves a purpose and craft it well.  So this is what I want to find, I want to find code craftsman!  But how?   I used to ask coding-trivia questions a long time ago and many people still fall back on this.  The thought is that if you ask the candidate some piece of coding trivia and they know the answer it must follow that they can craft good code.  For example:   What C++ keyword can be applied to a class/struct field to allow it to be changed even from a const-instance of that class/struct?  (answer: mutable)   So what do we prove if a candidate can answer this?  Only that they know what mutable means.  One would hope that this would infer that they'd know how to use it, and more importantly when and if it should ever be used!  But it rarely does!  The problem with triva questions is that you will either: Approve a really good developer who knows what some obscure keyword is (good) Reject a really good developer who never needed to use that keyword or is too inexperienced to know how to use it (bad) Approve a really bad developer who googled "C++ Interview Questions" and studied like hell but can't craft (very bad) Many HR departments love these kind of tests because they are short and easy to defend if a legal issue arrises on hiring decisions.  After all it's easy to say a person wasn't hired because they scored 30 out of 100 on some trivia test.  But unfortunately, you've eliminated a large part of your potential developer pool and possibly hired a few duds.  There are times I've hired candidates who knew every trivia question I could throw out them and couldn't craft.  And then there are times I've interviewed candidates who failed all my trivia but who I took a chance on who were my best finds ever.    So if not trivia, then what?  Brain teasers?  The thought is, these type of questions measure the thinking power of a candidate.  The problem is, once again, you will either: Approve a good candidate who has never heard the problem and can solve it (good) Reject a good candidate who just happens not to see the "catch" because they're nervous or it may be really obscure (bad) Approve a candidate who has studied enough interview brain teasers (once again, you can google em) to recognize the "catch" or knows the answer already (bad). Once again, you're eliminating good candidates and possibly accepting bad candidates.  In these cases, I think testing someone with brain teasers only tests their ability to answer brain teasers, not the ability to craft code. So how do we measure someone's ability to craft code?  Here's a novel idea: have them code!  Give them a computer and a compiler, or a whiteboard and a pen, or paper and pencil and have them construct a piece of code.  It just makes sense that if we're going to hire someone to code we should actually watch them code.  When they're done, we can judge them on several criteria: Correctness - does the candidate's solution accurately solve the problem proposed? Accuracy - is the candidate's solution reasonably syntactically correct? Efficiency - did the candidate write or use the more efficient data structures or algorithms for the job? Maintainability - was the candidate's code free of obfuscation and clever tricks that diminish readability? Persona - are they eager and willing or aloof and egotistical?  Will they work well within your team? It may sound simple, or it may sound crazy, but when I'm looking to hire a developer, I want to see them actually develop well-crafted code.

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  • CLR Version issues with CorBindRuntimeEx

    - by Rick Strahl
    I’m working on an older FoxPro application that’s using .NET Interop and this app loads its own copy of the .NET runtime through some of our own tools (wwDotNetBridge). This all works fine and it’s fairly straightforward to load and host the runtime and then make calls against it. I’m writing this up for myself mostly because I’ve been bitten by these issues repeatedly and spend 15 minutes each However, things get tricky when calling specific versions of the .NET runtime since .NET 4.0 has shipped. Basically we need to be able to support both .NET 2.0 and 4.0 and we’re currently doing it with the same assembly – a .NET 2.0 assembly that is the AppDomain entry point. This works as .NET 4.0 can easily host .NET 2.0 assemblies and the functionality in the 2.0 assembly provides all the features we need to call .NET 4.0 assemblies via Reflection. In wwDotnetBridge we provide a load flag that allows specification of the runtime version to use. Something like this: do wwDotNetBridge LOCAL loBridge as wwDotNetBridge loBridge = CreateObject("wwDotNetBridge","v4.0.30319") and this works just fine in most cases.  If I specify V4 internally that gets fixed up to a whole version number like “v4.0.30319” which is then actually used to host the .NET runtime. Specifically the ClrVersion setting is handled in this Win32 DLL code that handles loading the runtime for me: /// Starts up the CLR and creates a Default AppDomain DWORD WINAPI ClrLoad(char *ErrorMessage, DWORD *dwErrorSize) { if (spDefAppDomain) return 1; //Retrieve a pointer to the ICorRuntimeHost interface HRESULT hr = CorBindToRuntimeEx( ClrVersion, //Retrieve latest version by default L"wks", //Request a WorkStation build of the CLR STARTUP_LOADER_OPTIMIZATION_MULTI_DOMAIN | STARTUP_CONCURRENT_GC, CLSID_CorRuntimeHost, IID_ICorRuntimeHost, (void**)&spRuntimeHost ); if (FAILED(hr)) { *dwErrorSize = SetError(hr,ErrorMessage); return hr; } //Start the CLR hr = spRuntimeHost->Start(); if (FAILED(hr)) return hr; CComPtr<IUnknown> pUnk; WCHAR domainId[50]; swprintf(domainId,L"%s_%i",L"wwDotNetBridge",GetTickCount()); hr = spRuntimeHost->CreateDomain(domainId,NULL,&pUnk); hr = pUnk->QueryInterface(&spDefAppDomain.p); if (FAILED(hr)) return hr; return 1; } CorBindToRuntimeEx allows for a specific .NET version string to be supplied which is what I’m doing via an API call from the FoxPro code. The behavior of CorBindToRuntimeEx is a bit finicky however. The documentation states that NULL should load the latest version of the .NET runtime available on the machine – but it actually doesn’t. As far as I can see – regardless of runtime overrides even in the .config file – NULL will always load .NET 2.0 even if 4.0 is installed. <supportedRuntime> .config File Settings Things get even more unpredictable once you start adding runtime overrides into the application’s .config file. In my scenario working inside of Visual FoxPro this would be VFP9.exe.config in the FoxPro installation folder (not the current folder). If I have a specific runtime override in the .config file like this: <?xml version="1.0"?> <configuration> <startup> <supportedRuntime version="v2.0.50727" /> </startup> </configuration> Not surprisingly with this I can load a .NET 2.0  runtime, but I will not be able to load Version 4.0 of the .NET runtime even if I explicitly specify it in my call to ClrLoad. Worse I don’t get an error – it will just go ahead and hand me a V2 version of the runtime and assume that’s what I wanted. Yuck! However, if I set the supported runtime to V4 in the .config file: <?xml version="1.0"?> <configuration> <startup> <supportedRuntime version="v4.0.30319" /> </startup> </configuration> Then I can load both V4 and V2 of the runtime. Specifying NULL however will STILL only give me V2 of the runtime. Again this seems pretty inconsistent. If you’re hosting runtimes make sure you check which version of the runtime is actually loading first to ensure you get the one you’re looking for. If the wrong version loads – say 2.0 and you want 4.0 - and you then proceed to load 4.0 assemblies they will all fail to load due to version mismatches. This is how all of this started – I had a bunch of assemblies that weren’t loading and it took a while to figure out that the host was running the wrong version of the CLR and therefore caused the assemblies loading to fail. Arrggh! <supportedRuntime> and Debugger Version <supportedRuntime> also affects the use of the .NET debugger when attached to the target application. Whichever runtime is specified in the key is the version of the debugger that fires up. This can have some interesting side effects. If you load a .NET 2.0 assembly but <supportedRuntime> points at V4.0 (or vice versa) the debugger will never fire because it can only debug in the appropriate runtime version. This has bitten me on several occasions where code runs just fine but the debugger will just breeze by breakpoints without notice. The default version for the debugger is the latest version installed on the system if <supportedRuntime> is not set. Summary Besides all the hassels, I’m thankful I can build a .NET 2.0 assembly and have it host .NET 4.0 and call .NET 4.0 code. This way we’re able to ship a single assembly that provides functionality that supports both .NET 2 and 4 without having to have separate DLLs for both which would be a deployment and update nightmare. The MSDN documentation does point at newer hosting API’s specifically for .NET 4.0 which are way more complicated and even less documented but that doesn’t help here because the runtime needs to be able to host both .NET 4.0 and 2.0. Not pleased about that – the new APIs look way more complex and of course they’re not available with older versions of the runtime installed which in our case makes them useless to me in this scenario where I have to support .NET 2.0 hosting (to provide greater ‘built-in’ platform support). Once you know the behavior above, it’s manageable. However, it’s quite easy to get tripped up here because there are multiple combinations that can really screw up behaviors.© Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  FoxPro  

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