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  • CodePlex Daily Summary for Sunday, April 04, 2010

    CodePlex Daily Summary for Sunday, April 04, 2010New ProjectsAcervo 2 - Gerenciador de coleções: Acervo 2 is a web application developed in ASP.NET 3.5 with Entity Framework, Coolite UI web controls and MySQL database that helps to catalog and ...AssemblyInfo Editor: AssemblyInfo Editor is a small Visual Studio 2010 extension I developed for my personal use mainly for automatically incrementing AssemblyVersion a...CommLine: It's a Command Line Interpreter. At the moment, it's a beta version, so I wait for developers that wanna help meFlowgraph Viewer: The flowgraph viewer enables users to view, build and share flowgraphs for the Crysis-franchise. It's built on Silverlight4, using MEF and Mvvmlight.Hash Calculator: WPF Windows 7 program to compute SHA1 & MD5 hash functions.MediaRSS library for .NET: This is a small set of libraries that allow you to create, read, and write MediaRSS files. By leveraging the syndication model object in .NET this...MEF Visualizer Tool: Helps to see what is going on inside the CompositionContainerone framework for developing asp.net project more elegent、flexible、and testable: if you are familiar with jsf、cdi、scoped javabean and work under asp.net, you may want to support aop and max flexibility and testability , all of ...Picasa Manager: A Silverlight Out Of Browser Application that Helps you manage your PicasaWeb albums in the easyest way possible.SharePhone: Windows Phone 7 library for connecting to SharePoint 2007/2010. Lets you work with SPWeb, SPList, reading/writing strong typed list items, user ...Silverlight Resource Extension: Silverlight Resource Extension. Extension silverlight project for use ResX resources and localize satellite dll.Silverlight Streamgraph: Streamgraph component for SilverlightTFTP Server: Managed TFTP server implementation, written in C#. Supports: - IPv4 and IPv6 - correct retry behavior. - TFTP options: block size, transfer size, a...Virtual UserGroup Video Helpers: This is a project that holds all the tools used by the C4MVC Virtual Usergroup. Tools written in C# and Powershell to automate, Live Meeting, Expr...xBlog: xBlog is a project to build a simple and extensible Blog Engine based on xml and linqXmlCodeEditor: XmlCodeEditor is a Silverlight 4 control based on RichTextControl that creates coloring and intellisense similar to the one in Visual Studio for ed...Zinc Launcher: Zinc Launcher is a simple Windows Media Center plugin that launches Zinc and attempts to manage the windows as seamlessly as possible. In addition ...New ReleasesAcervo 2 - Gerenciador de coleções: Acervo 2 - v1.0: Arquivos para implantação do sistema Acervo2 Aplicação web Web service Smart ClientAssemblyInfo Editor: Beta 1: Initial release of Assembly Info Editor. At this point, it is feature-complete and is relatively stable. There are undoubtedly some bugs to work o...Box2D.XNA: Box2D.XNA r70 Source Code and Solution: This version is synced to changeset 44697. This represents our official port of the C Box2D up to r70 on the Google Code project. With this versi...Boxee Launcher: Boxee Launcher Release 1.0.1.2: Will now stop Media Center playback before launching BoxeeBoxee Launcher: Boxee Launcher Release 1.0.1.3: Added a background window that attempts to display over the desktop and taskbar, and below Boxee and Media Center so that the desktop and taskbar a...CommLine: Beta Version 0.1: First Beta Of the AppCommLine: Source v0.1 Beta: Source Code C of 0.1 beta versionEncrypted Notes: Encrypted Notes 1.6.2: This is the latest version of Encrypted Notes (1.6.2), with general changes and improved randomness for the key generator. It has an installer that...Hash Calculator: HashCalculator: HashCalculator 1.0Hash Calculator: HashCalculator Source code: HashCalculator 1.0Hulu Launcher: Hulu Launcher 1.0.1.3: Added a background window that attempts to display over the desktop and taskbar, and below Hulu and Media Center so that the desktop and taskbar ar...Hulu Launcher: Hulu Launcher Release 1.0.1.2: Hulu Launcher will now stop playback in Media Center before launching Hulu Desktop.Innovative Games: 4.3 - Sprite Effects: Source code download for chapter 4.3 - "Sprite Effects"MediaRSS library for .NET: 0.1: Alpha release. Majority of MediaRSS spec is supported. A small set of unit test / sample code are included. A lightly tested CustomFormatter object...MEF Visualizer Tool: MEF Visualizer Tool 0.1: Help to see what going on in side CompositionContainer Container = new CompositionContainer( new AggregateCatalog( ...Ncqrs Framework - A CQRS framework for .NET: Ncqrs with sample application: This is the first release of the Ncqrs Framework. It contains the Ncqrs source code and a runnable sample application. All the code in this release...Rubik Cube's 3D Silverlight 3.0 Animated Solution: Rubik Cube 3D with Animated Solution: This project is a realization of Silverlight 3.0 Rubik Cube 3D with Animated Solution. The Solution is available for 3x3x3 cube, other features are...Scrabler: scrabler release 0.6.2.5: fixed a bug that werent executed some scriptsSharePhone: SharePhone: Initial release with basic functionality: Open SharePoint webs and subwebs Retrieve lists on SPWeb objects Read metadata/properties on lists ...SharePhone: SharePhone v.1.0.1: Fixed a bug that prevented saving list items to SharePointSharePoint Labs: SPLab4001A-FRA-Level100: SPLab4001A-FRA-Level100 This SharePoint Lab will teach you the first best practice you should apply when writing code with the SharePoint API. Lab ...Silverlight Resource Extension: ResourceExtension (alpha): Alpha version is not stable. Only for review.Silverlight Streamgraph: Port from processing.org: A port from the processing.org streamgraph. Code-heavy with very little XAML involved at this point.Theocratic Ministry School System: TMSS - Ver 1.1.1: What’s New! Added Menu Options 2010 Schedule Access 2007 Runtime There are still many uncompleted items so this is still a conceptual release....Theocratic Ministry School System: TMSS - Ver 1.1.2: Fixed the Schedule Import. Need needs to be tested. Click import button and make sure you can get the 2010 Schedule from the internet.thinktecture Starter STS (Community Edition): StarterSTS v1.0 RTW: Version 1.0 RTWTribe.Cache: Tribe.Cache Alpha - 0.2.0.0: Tribe.Cache Alpha - 0.2.0.0 - Now has sliding and absolute expiration on cache entries. Functional Alpha Release - But do not use in productionTwitterVB - A .NET Twitter Library: TwitterVB-2.3.1: This is mostly a minor release that adds br.st URL shortening to the menu (API key from http://br.st required)Virtu: Virtu 0.8.1: Source Requirements.NET Framework 3.5 with Service Pack 1 Visual Studio 2008 with Service Pack 1, or Visual C# 2008 Express Edition with Service Pa...Visual Studio DSite: Advanced C++ Calculator: An advanced visual c 2008 calculator that can do all your basic operations, plus some advanced mathematical functions. Source Code Only.xnaWebcam: xnaWebcam 0.3: xnaWebcam 0.3 Version 0.3: -ResolutionSet: 400x300 (Default), 800x600, 1024x720 -Settings Window got Icon -Settings Window Changes -DevConsole.cs ...Most Popular ProjectsRawrWBFS ManagerMicrosoft SQL Server Product Samples: DatabaseASP.NET Ajax LibrarySilverlight ToolkitAJAX Control ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesDotNetNuke® Community EditionMost Active ProjectsGraffiti CMSnopCommerce. Open Source online shop e-commerce solution.RawrFacebook Developer ToolkitjQuery Library for SharePoint Web ServicesLINQ to TwitterBlogEngine.NETN2 CMSBase Class LibrariesFarseer Physics Engine

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  • Virus that tries to brute force attack Active Directory users (in alphabetical order)?

    - by Nate Pinchot
    Users started complaining about slow network speed so I fired up Wireshark. Did some checking and found many PCs sending packets similar to the following: (screenshot) http://imgur.com/45VlI.png I blurred out the text for the username, computer name and domain name (since it matches the internet domain name). Computers are spamming the Active Directory servers trying to brute force hack passwords. It will start with Administrator and go down the list of users in alphabetical order. Physically going to the PC finds no one anywhere near it and this behavior is spread across the network so it appears to be a virus of some sort. Scanning computers which have been caught spamming the server with Malwarebytes, Super Antispyware and BitDefender (this is the antivirus the client has) yields no results. This is an enterprise network with about 2500 PCs so doing a rebuild is not a favorable option. My next step is to contact BitDefender to see what help they can provide. Has anybody seen anything like this or have any ideas what it could possibly be?

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  • "Agile Principles, Patterns, and Practices in C#": Is this just a .NET-translation of the popular Uncle Bob book?

    - by Louis Rhys
    I found this book sold on Amazon Agile Principles, Patterns, and Practices in C#, written by Robert C Martin and Micah Martin. Is it merely a .NET port of the older, more popular Agile Software Development, Principles, Patterns, and Practices? Or is it just a new book trying to take advantage of the other book's popularity? If I am a .NET developer who hasn't read either book, which one would you recommend?

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  • An increase to 3 Gig of RAM slows down Ubuntu 10.04 LTS

    - by williepabon
    I have Ubuntu 10.04 running from an external hard drive (installed on an enclosure) connected via USB port. Like a month or so ago, I increased RAM on my pc from 2 Gigs to 3 Gigs. This resulted on extremely long boot times and slow application loads. While I was understanding the nature of my problem, I posted various threads on this forum ( Questions # 188417, 188801), where I was advised to gather speed tests, and other info on my machine. I was also suggested that I might have problems with the RAM installed. Initially, I did not consider that possibility because: 1) I did a memory test with a diagnostic program from DELL (My pc is from Dell) 2) My pc works fine with Windows XP (the default OS), no problems with memory 3) My pc works fine when booting with Ubuntu 10.10 memory stick, no speed problems 4) My pc works fine when booting with Ubuntu 11.10 memory stick, no speed problems Anyway, I performed the memory tests suggested. But before doing it, and to check out any possibility of hardware issues on the hard drive, I did the following: (1) purchased a new hard drive enclosure and moved my hard drive to it, (2) purchased a new USB cable and used it to connect my hard drive/enclosure setup to a different USB port on my pc. Then, I performed speed tests with 1 Gig, 2 Gigs and 3 Gigs of RAM with my Ubuntu 10.04 OS. Ubuntu 10.04 worked well when booted with 1 Gig or 2 Gigs of RAM. When I increased to 3 Gigs, it slowed down to a crawl. I can't understand the relationship between an increase of 1 Gig and the effect it has in Ubuntu 10.04. This doesn't happen with Ubuntu 10.10 and 11.10. Unfortunately for me, Ubuntu 10.04 is my principal work operating system. So, I need a solution for this. Hardware and system information: DELL Precision 670 2 internal SATA Hard drives Audigy 2 ZS audio system Factory OS: Windows XP Professional SP3 NVidia 8400 GTS video card More info: williepabon@WP-WrkStation:~$ uname -a Linux WP-WrkStation 2.6.32-38-generic #83-Ubuntu SMP Wed Jan 4 11:13:04 UTC 2012 i686 GNU/Linux williepabon@WP-WrkStation:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 10.04.4 LTS Release: 10.04 Codename: lucid Speed test with the 3 Gigs of RAM installed: williepabon@WP-WrkStation:~$ sudo hdparm -tT /dev/sdc [sudo] password for williepabon: /dev/sdc: Timing cached reads: 84 MB in 2.00 seconds = 41.96 MB/sec Timing buffered disk reads: 4 MB in 3.81 seconds = 1.05 MB/sec This is a very slow transfer rate from a hard drive. I will really appreciate a solution or a work around for this problem. I know that that there are users that have Ubuntu 10.04 with 3 Gigs or more of RAM and they don't have this problem. Same question asked on Launchpad for reference.

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  • First time using Java Web Start in Ubuntu - Fatal Launch Exception

    - by MountainX
    I've been using Ubuntu for a while and Java Web Start applications have never "just worked" in the current or any prior version, so I ignored them until now. However, now I have a need to get them working in Firefox. When I am on a page like this: http://www.oracle.com/technetwork/java/demos-nojavascript-137100.html I want to be able to click on the demos as suggested and have them run. I'm running Ubuntu 11.10 with Gnome 3 and/or Linux Mint 12 (64 bit) with OpenJDK 6, OpenJDK 7 and Sun Java 6. My default is currently: /usr/lib/jvm/java-6-openjdk/jre/bin/java $ whereis javaws javaws: /usr/bin/javaws /etc/alternatives/javaws - /usr/lib/jvm/java-6-openjdk/jre/bin/javaws Here's the error I get when I try to run a Java Web Start application: net.sourceforge.jnlp.LaunchException: Fatal: Initialization Error: Could not initialize application. at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:776) at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:552) at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:887) Caused by: net.sourceforge.jnlp.LaunchException: Fatal: Initialization Error: A fatal error occurred while trying to verify jars. at net.sourceforge.jnlp.runtime.JNLPClassLoader.initializeResources(JNLPClassLoader.java:448) at net.sourceforge.jnlp.runtime.JNLPClassLoader.<init>(JNLPClassLoader.java:176) at net.sourceforge.jnlp.runtime.JNLPClassLoader.getInstance(JNLPClassLoader.java:295) at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:767) ... 2 more Caused by: net.sourceforge.jnlp.LaunchException: Fatal: Initialization Error: A fatal error occurred while trying to verify jars. at net.sourceforge.jnlp.runtime.JNLPClassLoader.initializeResources(JNLPClassLoader.java:448) at net.sourceforge.jnlp.runtime.JNLPClassLoader.<init>(JNLPClassLoader.java:176) at net.sourceforge.jnlp.runtime.JNLPClassLoader.getInstance(JNLPClassLoader.java:295) at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:767) at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:552) at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:887) Here's another example: http://docs.oracle.com/javase/tutorial/uiswing/events/keylistener.html net.sourceforge.jnlp.LaunchException: Fatal: Read Error: Could not read or parse the JNLP file. at net.sourceforge.jnlp.Launcher.fromUrl(Launcher.java:491) at net.sourceforge.jnlp.Launcher.launch(Launcher.java:283) at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:199) at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:51) at java.security.AccessController.doPrivileged(Native Method) at net.sourceforge.jnlp.runtime.Boot.main(Boot.java:165) Caused by: java.io.IOException: port out of range:-2147483648 at net.sourceforge.jnlp.JNLPFile.openURL(JNLPFile.java:255) at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:185) at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:162) at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:148) at net.sourceforge.jnlp.Launcher.fromUrl(Launcher.java:477) ... 5 more Caused by: java.io.IOException: port out of range:-2147483648 at net.sourceforge.jnlp.JNLPFile.openURL(JNLPFile.java:255) at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:185) at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:162) at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:148) at net.sourceforge.jnlp.Launcher.fromUrl(Launcher.java:477) at net.sourceforge.jnlp.Launcher.launch(Launcher.java:283) at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:199) at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:51) at java.security.AccessController.doPrivileged(Native Method) at net.sourceforge.jnlp.runtime.Boot.main(Boot.java:165)

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  • JMX Based Monitoring - Part Four - Business App Server Monitoring

    - by Anthony Shorten
    In the last blog entry I talked about the Oracle Utilities Application Framework V4 feature for monitoring and managing aspects of the Web Application Server using JMX. In this blog entry I am going to discuss a similar new feature that allows JMX to be used for management and monitoring the Oracle Utilities business application server component. This feature is primarily focussed on performance tracking of the product. In first release of Oracle Utilities Customer Care And Billing (V1.x I am talking about), we used to use Oracle Tuxedo as part of the architecture. In Oracle Utilities Application Framework V2.0 and above, we removed Tuxedo from the architecture. One of the features that some customers used within Tuxedo was the performance tracking ability. The idea was that you enabled performance logging on the individual Tuxedo servers and then used a utility named txrpt to produce a performance report. This report would list every service called, the number of times it was called and the average response time. When I worked a performance consultant, I used this report to identify badly performing services and also gauge the overall performance characteristics of a site. When Tuxedo was removed from the architecture this information was also lost. While you can get some information from access.log and some Mbeans supplied by the Web Application Server it was not at the same granularity as txrpt or as useful. I am happy to say we have not only reintroduced this facility in Oracle Utilities Application Framework but it is now accessible via JMX and also we have added more detail into the performance tracking. Most of this new design was working with customers around the world to make sure we introduced a new feature that not only satisfied their performance tracking needs but allowed for finer grained performance analysis. As with the Web Application Server, the Business Application Server JMX monitoring is enabled by specifying a JMX port number in RMI Port number for JMX Business and initial credentials in the JMX Enablement System User ID and JMX Enablement System Password configuration options. These options are available using the configureEnv[.sh] -a utility. These credentials are shared across the Web Application Server and Business Application Server for authorization purposes. Once this is information is supplied a number of configuration files are built (by the initialSetup[.sh] utility) to configure the facility: spl.properties - contains the JMX URL, the security configuration and the mbeans that are enabled. For example, on my demonstration machine: spl.runtime.management.rmi.port=6750 spl.runtime.management.connector.url.default=service:jmx:rmi:///jndi/rmi://localhost:6750/oracle/ouaf/ejbAppConnector jmx.remote.x.password.file=scripts/ouaf.jmx.password.file jmx.remote.x.access.file=scripts/ouaf.jmx.access.file ouaf.jmx.com.splwg.ejb.service.management.PerformanceStatistics=enabled ouaf.jmx.* files - contain the userid and password. The default configuration uses the JMX default configuration. You can use additional security features by altering the spl.properties file manually or using a custom template. For more security options see JMX Security for more details. Once it has been configured and the changes reflected in the product using the initialSetup[.sh] utility the JMX facility can be used. For illustrative purposes I will use jconsole but any JSR160 complaint browser or client can be used (with the appropriate configuration). Once you start jconsole (ensure that splenviron[.sh] is executed prior to execution to set the environment variables or for remote connection, ensure java is in your path and jconsole.jar in your classpath) you specify the URL in the spl.runtime.management.connnector.url.default entry. For example: You are then able to track performance of the product using the PerformanceStatistics Mbean. The attributes of the PerformanceStatistics Mbean are counts of each object type. This is where this facility differs from txrpt. The information that is collected includes the following: The Service Type is captured so you can filter the results in terms of the type of service. For maintenance type services you can even see the transaction type (ADD, CHANGE etc) so you can see the performance of updates against read transactions. The Minimum and Maximum are also collected to give you an idea of the spread of performance. The last call is recorded. The date, time and user of the last call are recorded to give you an idea of the timeliness of the data. The Mbean maintains a set of counters per Service Type to give you a summary of the types of transactions being executed. This gives you an overall picture of the types of transactions and volumes at your site. There are a number of interesting operations that can also be performed: reset - This resets the statistics back to zero. This is an important operation. For example, txrpt is restricted to collecting statistics per hour, which is ok for most people. But what if you wanted to be more granular? This operation allows to set the collection period to anything you wish. The statistics collected will represent values since the last restart or last reset. completeExecutionDump - This is the operation that produces a CSV in memory to allow extraction of the data. All the statistics are extracted (see the Server Administration Guide for a full list). This can be then loaded into a database, a tool or simply into your favourite spreadsheet for analysis. Here is an extract of an execution dump from my demonstration environment to give you an idea of the format: ServiceName, ServiceType, MinTime, MaxTime, Avg Time, # of Calls, Latest Time, Latest Date, Latest User ... CFLZLOUL, EXECUTE_LIST, 15.0, 64.0, 22.2, 10, 16.0, 2009-12-16::11-25-36-932, ASHORTEN CILBBLLP, READ, 106.0, 1184.0, 466.3333333333333, 6, 106.0, 2009-12-16::11-39-01-645, BOBAMA CILBBLLP, DELETE, 70.0, 146.0, 108.0, 2, 70.0, 2009-12-15::12-53-58-280, BPAYS CILBBLLP, ADD, 860.0, 4903.0, 2243.5, 8, 860.0, 2009-12-16::17-54-23-862, LELLISON CILBBLLP, CHANGE, 112.0, 3410.0, 815.1666666666666, 12, 112.0, 2009-12-16::11-40-01-103, ASHORTEN CILBCBAL, EXECUTE_LIST, 8.0, 84.0, 26.0, 22, 23.0, 2009-12-16::17-54-01-643, LJACKMAN InitializeUserInfoService, READ_SYSTEM, 49.0, 962.0, 70.83777777777777, 450, 63.0, 2010-02-25::11-21-21-667, ASHORTEN InitializeUserService, READ_SYSTEM, 130.0, 2835.0, 234.85777777777778, 450, 216.0, 2010-02-25::11-21-21-446, ASHORTEN MenuLoginService, READ_SYSTEM, 530.0, 1186.0, 703.3333333333334, 9, 530.0, 2009-12-16::16-39-31-172, ASHORTEN NavigationOptionDescriptionService, READ_SYSTEM, 2.0, 7.0, 4.0, 8, 2.0, 2009-12-21::09-46-46-892, ASHORTEN ... There are other operations and attributes available. Refer to the Server Administration Guide provided with your product to understand the full et of operations and attributes. This is one of the many features I am proud that we implemented as it allows flexible monitoring of the performance of the product.

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  • My laptop causes the wireless router to stop working

    - by Pier
    hello all, it's happening something strange to my wireless connection. The wireless connection works fine with all the devices at home, except with my laptop (Toshiba satellite, WIN 7 64): as I start it, the wireless network shuts off and the connection disappears also for the other devices. I can use internet only plugging the laptop with an ethernet cable, and I have to shut off the wireless card, to allow the other people in the house to use the wireless connection. I tried to update the firmware (it is a D-Link DIR 615) but it's up to date, and reconfigure the router, but all indicates that the problem is caused by my laptop. I'm currently doing an antivirus scanning, but the computer seems to be clean. Any suggestion?

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  • Configure Windows Firewall for SQL Server 2008 Database Engine in Windows Server 2008 R2

    I have installed SQL Server 2008 Developer Edition on Windows Server 2008 R2 and I am unable to get connect to SQL Server 2008 Instance from SQL Server 2008 Management Studio which is installed on another remote server. As I am new to Windows Server 2008 R2 it would be great if you can let me know the step by step approach to enable the default port of SQL Server 2008 in Windows Firewall for user connectivity.

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  • Improving CSS With .LESS

    Improve your CSS skills using .LESS, a free, open-source port of Ruby's LESS library. LESS (and .LESS, by extension) is a parser that allows web developers to create style sheets using new and improved language features, including variables, operations, mix-ins, and nested rules.

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  • How do I install an HP home-use printer on Windows Home Server (Windows Server 2003)

    - by Rob Allen
    I have an HP DeskJet F4210 printer that I would like to share on my network via Windows Home Server. Unfortunately, the driver installation checks for supported OS's, detects Home Server as Windows Server 2003 and exits. The driver install supports WinXP, W2k, Vista, and Win98SE. In theory, drivers for XP or Windows 2000 should work fine with Home Server. When using the "Install Printer" tool in Home Server I am only able to select .inf files (there are serveral on the install media) but the driver folders for XP and 2000 have .sys and .dll files. How can I bypass HP's short-sighted install program and get this printer up and running on Home server? I'll be happy with basic print functionality and will save the task of enabling scanning for another time.

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  • So…is it a Seek or a Scan?

    - by Paul White
    You’re probably most familiar with the terms ‘Seek’ and ‘Scan’ from the graphical plans produced by SQL Server Management Studio (SSMS).  The image to the left shows the most common ones, with the three types of scan at the top, followed by four types of seek.  You might look to the SSMS tool-tip descriptions to explain the differences between them: Not hugely helpful are they?  Both mention scans and ranges (nothing about seeks) and the Index Seek description implies that it will not scan the index entirely (which isn’t necessarily true). Recall also yesterday’s post where we saw two Clustered Index Seek operations doing very different things.  The first Seek performed 63 single-row seeking operations; and the second performed a ‘Range Scan’ (more on those later in this post).  I hope you agree that those were two very different operations, and perhaps you are wondering why there aren’t different graphical plan icons for Range Scans and Seeks?  I have often wondered about that, and the first person to mention it after yesterday’s post was Erin Stellato (twitter | blog): Before we go on to make sense of all this, let’s look at another example of how SQL Server confusingly mixes the terms ‘Scan’ and ‘Seek’ in different contexts.  The diagram below shows a very simple heap table with two columns, one of which is the non-clustered Primary Key, and the other has a non-unique non-clustered index defined on it.  The right hand side of the diagram shows a simple query, it’s associated query plan, and a couple of extracts from the SSMS tool-tip and Properties windows. Notice the ‘scan direction’ entry in the Properties window snippet.  Is this a seek or a scan?  The different references to Scans and Seeks are even more pronounced in the XML plan output that the graphical plan is based on.  This fragment is what lies behind the single Index Seek icon shown above: You’ll find the same confusing references to Seeks and Scans throughout the product and its documentation. Making Sense of Seeks Let’s forget all about scans for a moment, and think purely about seeks.  Loosely speaking, a seek is the process of navigating an index B-tree to find a particular index record, most often at the leaf level.  A seek starts at the root and navigates down through the levels of the index to find the point of interest: Singleton Lookups The simplest sort of seek predicate performs this traversal to find (at most) a single record.  This is the case when we search for a single value using a unique index and an equality predicate.  It should be readily apparent that this type of search will either find one record, or none at all.  This operation is known as a singleton lookup.  Given the example table from before, the following query is an example of a singleton lookup seek: Sadly, there’s nothing in the graphical plan or XML output to show that this is a singleton lookup – you have to infer it from the fact that this is a single-value equality seek on a unique index.  The other common examples of a singleton lookup are bookmark lookups – both the RID and Key Lookup forms are singleton lookups (an RID lookup finds a single record in a heap from the unique row locator, and a Key Lookup does much the same thing on a clustered table).  If you happen to run your query with STATISTICS IO ON, you will notice that ‘Scan Count’ is always zero for a singleton lookup. Range Scans The other type of seek predicate is a ‘seek plus range scan’, which I will refer to simply as a range scan.  The seek operation makes an initial descent into the index structure to find the first leaf row that qualifies, and then performs a range scan (either backwards or forwards in the index) until it reaches the end of the scan range. The ability of a range scan to proceed in either direction comes about because index pages at the same level are connected by a doubly-linked list – each page has a pointer to the previous page (in logical key order) as well as a pointer to the following page.  The doubly-linked list is represented by the green and red dotted arrows in the index diagram presented earlier.  One subtle (but important) point is that the notion of a ‘forward’ or ‘backward’ scan applies to the logical key order defined when the index was built.  In the present case, the non-clustered primary key index was created as follows: CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col ASC) ) ; Notice that the primary key index specifies an ascending sort order for the single key column.  This means that a forward scan of the index will retrieve keys in ascending order, while a backward scan would retrieve keys in descending key order.  If the index had been created instead on key_col DESC, a forward scan would retrieve keys in descending order, and a backward scan would return keys in ascending order. A range scan seek predicate may have a Start condition, an End condition, or both.  Where one is missing, the scan starts (or ends) at one extreme end of the index, depending on the scan direction.  Some examples might help clarify that: the following diagram shows four queries, each of which performs a single seek against a column holding every integer from 1 to 100 inclusive.  The results from each query are shown in the blue columns, and relevant attributes from the Properties window appear on the right: Query 1 specifies that all key_col values less than 5 should be returned in ascending order.  The query plan achieves this by seeking to the start of the index leaf (there is no explicit starting value) and scanning forward until the End condition (key_col < 5) is no longer satisfied (SQL Server knows it can stop looking as soon as it finds a key_col value that isn’t less than 5 because all later index entries are guaranteed to sort higher). Query 2 asks for key_col values greater than 95, in descending order.  SQL Server returns these results by seeking to the end of the index, and scanning backwards (in descending key order) until it comes across a row that isn’t greater than 95.  Sharp-eyed readers may notice that the end-of-scan condition is shown as a Start range value.  This is a bug in the XML show plan which bubbles up to the Properties window – when a backward scan is performed, the roles of the Start and End values are reversed, but the plan does not reflect that.  Oh well. Query 3 looks for key_col values that are greater than or equal to 10, and less than 15, in ascending order.  This time, SQL Server seeks to the first index record that matches the Start condition (key_col >= 10) and then scans forward through the leaf pages until the End condition (key_col < 15) is no longer met. Query 4 performs much the same sort of operation as Query 3, but requests the output in descending order.  Again, we have to mentally reverse the Start and End conditions because of the bug, but otherwise the process is the same as always: SQL Server finds the highest-sorting record that meets the condition ‘key_col < 25’ and scans backward until ‘key_col >= 20’ is no longer true. One final point to note: seek operations always have the Ordered: True attribute.  This means that the operator always produces rows in a sorted order, either ascending or descending depending on how the index was defined, and whether the scan part of the operation is forward or backward.  You cannot rely on this sort order in your queries of course (you must always specify an ORDER BY clause if order is important) but SQL Server can make use of the sort order internally.  In the four queries above, the query optimizer was able to avoid an explicit Sort operator to honour the ORDER BY clause, for example. Multiple Seek Predicates As we saw yesterday, a single index seek plan operator can contain one or more seek predicates.  These seek predicates can either be all singleton seeks or all range scans – SQL Server does not mix them.  For example, you might expect the following query to contain two seek predicates, a singleton seek to find the single record in the unique index where key_col = 10, and a range scan to find the key_col values between 15 and 20: SELECT key_col FROM dbo.Example WHERE key_col = 10 OR key_col BETWEEN 15 AND 20 ORDER BY key_col ASC ; In fact, SQL Server transforms the singleton seek (key_col = 10) to the equivalent range scan, Start:[key_col >= 10], End:[key_col <= 10].  This allows both range scans to be evaluated by a single seek operator.  To be clear, this query results in two range scans: one from 10 to 10, and one from 15 to 20. Final Thoughts That’s it for today – tomorrow we’ll look at monitoring singleton lookups and range scans, and I’ll show you a seek on a heap table. Yes, a seek.  On a heap.  Not an index! If you would like to run the queries in this post for yourself, there’s a script below.  Thanks for reading! IF OBJECT_ID(N'dbo.Example', N'U') IS NOT NULL BEGIN DROP TABLE dbo.Example; END ; -- Test table is a heap -- Non-clustered primary key on 'key_col' CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ; -- Non-unique non-clustered index on the 'data' column CREATE NONCLUSTERED INDEX [IX dbo.Example data] ON dbo.Example (data) ; -- Add 100 rows INSERT dbo.Example WITH (TABLOCKX) ( key_col, data ) SELECT key_col = V.number, data = V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 100 ; -- ================ -- Singleton lookup -- ================ ; -- Single value equality seek in a unique index -- Scan count = 0 when STATISTIS IO is ON -- Check the XML SHOWPLAN SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col = 32 ; -- =========== -- Range Scans -- =========== ; -- Query 1 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col <= 5 ORDER BY E.key_col ASC ; -- Query 2 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col > 95 ORDER BY E.key_col DESC ; -- Query 3 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col >= 10 AND E.key_col < 15 ORDER BY E.key_col ASC ; -- Query 4 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col >= 20 AND E.key_col < 25 ORDER BY E.key_col DESC ; -- Final query (singleton + range = 2 range scans) SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col = 10 OR E.key_col BETWEEN 15 AND 20 ORDER BY E.key_col ASC ; -- === TIDY UP === DROP TABLE dbo.Example; © 2011 Paul White email: [email protected] twitter: @SQL_Kiwi

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  • Syncing Data with a Server using Silverlight and HTTP Polling Duplex

    - by dwahlin
    Many applications have the need to stay in-sync with data provided by a service. Although web applications typically rely on standard polling techniques to check if data has changed, Silverlight provides several interesting options for keeping an application in-sync that rely on server “push” technologies. A few years back I wrote several blog posts covering different “push” technologies available in Silverlight that rely on sockets or HTTP Polling Duplex. We recently had a project that looked like it could benefit from pushing data from a server to one or more clients so I thought I’d revisit the subject and provide some updates to the original code posted. If you’ve worked with AJAX before in Web applications then you know that until browsers fully support web sockets or other duplex (bi-directional communication) technologies that it’s difficult to keep applications in-sync with a server without relying on polling. The problem with polling is that you have to check for changes on the server on a timed-basis which can often be wasteful and take up unnecessary resources. With server “push” technologies, data can be pushed from the server to the client as it changes. Once the data is received, the client can update the user interface as appropriate. Using “push” technologies allows the client to listen for changes from the data but stay 100% focused on client activities as opposed to worrying about polling and asking the server if anything has changed. Silverlight provides several options for pushing data from a server to a client including sockets, TCP bindings and HTTP Polling Duplex.  Each has its own strengths and weaknesses as far as performance and setup work with HTTP Polling Duplex arguably being the easiest to setup and get going.  In this article I’ll demonstrate how HTTP Polling Duplex can be used in Silverlight 4 applications to push data and show how you can create a WCF server that provides an HTTP Polling Duplex binding that a Silverlight client can consume.   What is HTTP Polling Duplex? Technologies that allow data to be pushed from a server to a client rely on duplex functionality. Duplex (or bi-directional) communication allows data to be passed in both directions.  A client can call a service and the server can call the client. HTTP Polling Duplex (as its name implies) allows a server to communicate with a client without forcing the client to constantly poll the server. It has the benefit of being able to run on port 80 making setup a breeze compared to the other options which require specific ports to be used and cross-domain policy files to be exposed on port 943 (as with sockets and TCP bindings). Having said that, if you’re looking for the best speed possible then sockets and TCP bindings are the way to go. But, they’re not the only game in town when it comes to duplex communication. The first time I heard about HTTP Polling Duplex (initially available in Silverlight 2) I wasn’t exactly sure how it was any better than standard polling used in AJAX applications. I read the Silverlight SDK, looked at various resources and generally found the following definition unhelpful as far as understanding the actual benefits that HTTP Polling Duplex provided: "The Silverlight client periodically polls the service on the network layer, and checks for any new messages that the service wants to send on the callback channel. The service queues all messages sent on the client callback channel and delivers them to the client when the client polls the service." Although the previous definition explained the overall process, it sounded as if standard polling was used. Fortunately, Microsoft’s Scott Guthrie provided me with a more clear definition several years back that explains the benefits provided by HTTP Polling Duplex quite well (used with his permission): "The [HTTP Polling Duplex] duplex support does use polling in the background to implement notifications – although the way it does it is different than manual polling. It initiates a network request, and then the request is effectively “put to sleep” waiting for the server to respond (it doesn’t come back immediately). The server then keeps the connection open but not active until it has something to send back (or the connection times out after 90 seconds – at which point the duplex client will connect again and wait). This way you are avoiding hitting the server repeatedly – but still get an immediate response when there is data to send." After hearing Scott’s definition the light bulb went on and it all made sense. A client makes a request to a server to check for changes, but instead of the request returning immediately, it parks itself on the server and waits for data. It’s kind of like waiting to pick up a pizza at the store. Instead of calling the store over and over to check the status, you sit in the store and wait until the pizza (the request data) is ready. Once it’s ready you take it back home (to the client). This technique provides a lot of efficiency gains over standard polling techniques even though it does use some polling of its own as a request is initially made from a client to a server. So how do you implement HTTP Polling Duplex in your Silverlight applications? Let’s take a look at the process by starting with the server. Creating an HTTP Polling Duplex WCF Service Creating a WCF service that exposes an HTTP Polling Duplex binding is straightforward as far as coding goes. Add some one way operations into an interface, create a client callback interface and you’re ready to go. The most challenging part comes into play when configuring the service to properly support the necessary binding and that’s more of a cut and paste operation once you know the configuration code to use. To create an HTTP Polling Duplex service you’ll need to expose server-side and client-side interfaces and reference the System.ServiceModel.PollingDuplex assembly (located at C:\Program Files (x86)\Microsoft SDKs\Silverlight\v4.0\Libraries\Server on my machine) in the server project. For the demo application I upgraded a basketball simulation service to support the latest polling duplex assemblies. The service simulates a simple basketball game using a Game class and pushes information about the game such as score, fouls, shots and more to the client as the game changes over time. Before jumping too far into the game push service, it’s important to discuss two interfaces used by the service to communicate in a bi-directional manner. The first is called IGameStreamService and defines the methods/operations that the client can call on the server (see Listing 1). The second is IGameStreamClient which defines the callback methods that a server can use to communicate with a client (see Listing 2).   [ServiceContract(Namespace = "Silverlight", CallbackContract = typeof(IGameStreamClient))] public interface IGameStreamService { [OperationContract(IsOneWay = true)] void GetTeamData(); } Listing 1. The IGameStreamService interface defines server operations that can be called on the server.   [ServiceContract] public interface IGameStreamClient { [OperationContract(IsOneWay = true)] void ReceiveTeamData(List<Team> teamData); [OperationContract(IsOneWay = true, AsyncPattern=true)] IAsyncResult BeginReceiveGameData(GameData gameData, AsyncCallback callback, object state); void EndReceiveGameData(IAsyncResult result); } Listing 2. The IGameStreamClient interfaces defines client operations that a server can call.   The IGameStreamService interface is decorated with the standard ServiceContract attribute but also contains a value for the CallbackContract property.  This property is used to define the interface that the client will expose (IGameStreamClient in this example) and use to receive data pushed from the service. Notice that each OperationContract attribute in both interfaces sets the IsOneWay property to true. This means that the operation can be called and passed data as appropriate, however, no data will be passed back. Instead, data will be pushed back to the client as it’s available.  Looking through the IGameStreamService interface you can see that the client can request team data whereas the IGameStreamClient interface allows team and game data to be received by the client. One interesting point about the IGameStreamClient interface is the inclusion of the AsyncPattern property on the BeginReceiveGameData operation. I initially created this operation as a standard one way operation and it worked most of the time. However, as I disconnected clients and reconnected new ones game data wasn’t being passed properly. After researching the problem more I realized that because the service could take up to 7 seconds to return game data, things were getting hung up. By setting the AsyncPattern property to true on the BeginReceivedGameData operation and providing a corresponding EndReceiveGameData operation I was able to get around this problem and get everything running properly. I’ll provide more details on the implementation of these two methods later in this post. Once the interfaces were created I moved on to the game service class. The first order of business was to create a class that implemented the IGameStreamService interface. Since the service can be used by multiple clients wanting game data I added the ServiceBehavior attribute to the class definition so that I could set its InstanceContextMode to InstanceContextMode.Single (in effect creating a Singleton service object). Listing 3 shows the game service class as well as its fields and constructor.   [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single)] public class GameStreamService : IGameStreamService { object _Key = new object(); Game _Game = null; Timer _Timer = null; Random _Random = null; Dictionary<string, IGameStreamClient> _ClientCallbacks = new Dictionary<string, IGameStreamClient>(); static AsyncCallback _ReceiveGameDataCompleted = new AsyncCallback(ReceiveGameDataCompleted); public GameStreamService() { _Game = new Game(); _Timer = new Timer { Enabled = false, Interval = 2000, AutoReset = true }; _Timer.Elapsed += new ElapsedEventHandler(_Timer_Elapsed); _Timer.Start(); _Random = new Random(); }} Listing 3. The GameStreamService implements the IGameStreamService interface which defines a callback contract that allows the service class to push data back to the client. By implementing the IGameStreamService interface, GameStreamService must supply a GetTeamData() method which is responsible for supplying information about the teams that are playing as well as individual players.  GetTeamData() also acts as a client subscription method that tracks clients wanting to receive game data.  Listing 4 shows the GetTeamData() method. public void GetTeamData() { //Get client callback channel var context = OperationContext.Current; var sessionID = context.SessionId; var currClient = context.GetCallbackChannel<IGameStreamClient>(); context.Channel.Faulted += Disconnect; context.Channel.Closed += Disconnect; IGameStreamClient client; if (!_ClientCallbacks.TryGetValue(sessionID, out client)) { lock (_Key) { _ClientCallbacks[sessionID] = currClient; } } currClient.ReceiveTeamData(_Game.GetTeamData()); //Start timer which when fired sends updated score information to client if (!_Timer.Enabled) { _Timer.Enabled = true; } } Listing 4. The GetTeamData() method subscribes a given client to the game service and returns. The key the line of code in the GetTeamData() method is the call to GetCallbackChannel<IGameStreamClient>().  This method is responsible for accessing the calling client’s callback channel. The callback channel is defined by the IGameStreamClient interface shown earlier in Listing 2 and used by the server to communicate with the client. Before passing team data back to the client, GetTeamData() grabs the client’s session ID and checks if it already exists in the _ClientCallbacks dictionary object used to track clients wanting callbacks from the server. If the client doesn’t exist it adds it into the collection. It then pushes team data from the Game class back to the client by calling ReceiveTeamData().  Since the service simulates a basketball game, a timer is then started if it’s not already enabled which is then used to randomly send data to the client. When the timer fires, game data is pushed down to the client. Listing 5 shows the _Timer_Elapsed() method that is called when the timer fires as well as the SendGameData() method used to send data to the client. void _Timer_Elapsed(object sender, ElapsedEventArgs e) { int interval = _Random.Next(3000, 7000); lock (_Key) { _Timer.Interval = interval; _Timer.Enabled = false; } SendGameData(_Game.GetGameData()); } private void SendGameData(GameData gameData) { var cbs = _ClientCallbacks.Where(cb => ((IContextChannel)cb.Value).State == CommunicationState.Opened); for (int i = 0; i < cbs.Count(); i++) { var cb = cbs.ElementAt(i).Value; try { cb.BeginReceiveGameData(gameData, _ReceiveGameDataCompleted, cb); } catch (TimeoutException texp) { //Log timeout error } catch (CommunicationException cexp) { //Log communication error } } lock (_Key) _Timer.Enabled = true; } private static void ReceiveGameDataCompleted(IAsyncResult result) { try { ((IGameStreamClient)(result.AsyncState)).EndReceiveGameData(result); } catch (CommunicationException) { // empty } catch (TimeoutException) { // empty } } LIsting 5. _Timer_Elapsed is used to simulate time in a basketball game. When _Timer_Elapsed() fires the SendGameData() method is called which iterates through the clients wanting to be notified of changes. As each client is identified, their respective BeginReceiveGameData() method is called which ultimately pushes game data down to the client. Recall that this method was defined in the client callback interface named IGameStreamClient shown earlier in Listing 2. Notice that BeginReceiveGameData() accepts _ReceiveGameDataCompleted as its second parameter (an AsyncCallback delegate defined in the service class) and passes the client callback as the third parameter. The initial version of the sample application had a standard ReceiveGameData() method in the client callback interface. However, sometimes the client callbacks would work properly and sometimes they wouldn’t which was a little baffling at first glance. After some investigation I realized that I needed to implement an asynchronous pattern for client callbacks to work properly since 3 – 7 second delays are occurring as a result of the timer. Once I added the BeginReceiveGameData() and ReceiveGameDataCompleted() methods everything worked properly since each call was handled in an asynchronous manner. The final task that had to be completed to get the server working properly with HTTP Polling Duplex was adding configuration code into web.config. In the interest of brevity I won’t post all of the code here since the sample application includes everything you need. However, Listing 6 shows the key configuration code to handle creating a custom binding named pollingDuplexBinding and associate it with the service’s endpoint.   <bindings> <customBinding> <binding name="pollingDuplexBinding"> <binaryMessageEncoding /> <pollingDuplex maxPendingSessions="2147483647" maxPendingMessagesPerSession="2147483647" inactivityTimeout="02:00:00" serverPollTimeout="00:05:00"/> <httpTransport /> </binding> </customBinding> </bindings> <services> <service name="GameService.GameStreamService" behaviorConfiguration="GameStreamServiceBehavior"> <endpoint address="" binding="customBinding" bindingConfiguration="pollingDuplexBinding" contract="GameService.IGameStreamService"/> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services>   Listing 6. Configuring an HTTP Polling Duplex binding in web.config and associating an endpoint with it. Calling the Service and Receiving “Pushed” Data Calling the service and handling data that is pushed from the server is a simple and straightforward process in Silverlight. Since the service is configured with a MEX endpoint and exposes a WSDL file, you can right-click on the Silverlight project and select the standard Add Service Reference item. After the web service proxy is created you may notice that the ServiceReferences.ClientConfig file only contains an empty configuration element instead of the normal configuration elements created when creating a standard WCF proxy. You can certainly update the file if you want to read from it at runtime but for the sample application I fed the service URI directly to the service proxy as shown next: var address = new EndpointAddress("http://localhost.:5661/GameStreamService.svc"); var binding = new PollingDuplexHttpBinding(); _Proxy = new GameStreamServiceClient(binding, address); _Proxy.ReceiveTeamDataReceived += _Proxy_ReceiveTeamDataReceived; _Proxy.ReceiveGameDataReceived += _Proxy_ReceiveGameDataReceived; _Proxy.GetTeamDataAsync(); This code creates the proxy and passes the endpoint address and binding to use to its constructor. It then wires the different receive events to callback methods and calls GetTeamDataAsync().  Calling GetTeamDataAsync() causes the server to store the client in the server-side dictionary collection mentioned earlier so that it can receive data that is pushed.  As the server-side timer fires and game data is pushed to the client, the user interface is updated as shown in Listing 7. Listing 8 shows the _Proxy_ReceiveGameDataReceived() method responsible for handling the data and calling UpdateGameData() to process it.   Listing 7. The Silverlight interface. Game data is pushed from the server to the client using HTTP Polling Duplex. void _Proxy_ReceiveGameDataReceived(object sender, ReceiveGameDataReceivedEventArgs e) { UpdateGameData(e.gameData); } private void UpdateGameData(GameData gameData) { //Update Score this.tbTeam1Score.Text = gameData.Team1Score.ToString(); this.tbTeam2Score.Text = gameData.Team2Score.ToString(); //Update ball visibility if (gameData.Action != ActionsEnum.Foul) { if (tbTeam1.Text == gameData.TeamOnOffense) { AnimateBall(this.BB1, this.BB2); } else //Team 2 { AnimateBall(this.BB2, this.BB1); } } if (this.lbActions.Items.Count > 9) this.lbActions.Items.Clear(); this.lbActions.Items.Add(gameData.LastAction); if (this.lbActions.Visibility == Visibility.Collapsed) this.lbActions.Visibility = Visibility.Visible; } private void AnimateBall(Image onBall, Image offBall) { this.FadeIn.Stop(); Storyboard.SetTarget(this.FadeInAnimation, onBall); Storyboard.SetTarget(this.FadeOutAnimation, offBall); this.FadeIn.Begin(); } Listing 8. As the server pushes game data, the client’s _Proxy_ReceiveGameDataReceived() method is called to process the data. In a real-life application I’d go with a ViewModel class to handle retrieving team data, setup data bindings and handle data that is pushed from the server. However, for the sample application I wanted to focus on HTTP Polling Duplex and keep things as simple as possible.   Summary Silverlight supports three options when duplex communication is required in an application including TCP bindins, sockets and HTTP Polling Duplex. In this post you’ve seen how HTTP Polling Duplex interfaces can be created and implemented on the server as well as how they can be consumed by a Silverlight client. HTTP Polling Duplex provides a nice way to “push” data from a server while still allowing the data to flow over port 80 or another port of your choice.   Sample Application Download

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  • Best way to automatically synchronize files between Linux and Windows

    - by Gregory
    My first choice was rsync but it caused some issues and is too manual. My second choice, currently under evaluation is Unison. Are there any other good options for bi-directional auto-syncing? The synching tool cannot add it's own files to the directories to be synched. Which removes CVS/SVN as a choice. Plus they are too manual. The requirements are user-level program on both sides, no root account access available. Only scanning on linux. On windows it could be a virtual drive/path. Very fast and efficient like rsync. Some other requirements include: machines are not on the same network, files cannot fall into the wrong hands, nor can they be handled by 3rd parties, this pretty much excludes all online storage sites.

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  • eBay Leads Mobile Commerce

    - by David Dorf
    For the first time, more smartphones where shipped than PCs. This important milestone helps reinforce that retailers need a strong mobile commerce strategy. IDC reported that for the 4th quarter of 2010, manufacturers shipped 100.9 million devices versus 92.1 million PCs shipped. One early adopter for the retail industry is eBay, the popular online auction and shopping site. In July 2008 they released their first mobile app and have increased investments ever since. In 2002 they bought PayPal for use with its online channel, but its becoming a force in the mobile world as well. In June 2010 they acquired RedLaser, the popular barcode scanning mobile app. Both pieces of technology enhance the mobile experience, and are available to other retailers as well. More recently, in December 2010 they acquired Critical Path Software, the developer of their eBay, StubHub, and Shopping.com mobile applications. Taking their mobile development in-house was a clear signal that mobile commerce is important to their strategy. Pop on over the eBay Inc's mobile commerce stats page to see just how well they are doing. You can use the animated map to see where people are using the app on any given day, and you can compare sales of the different categories. eBay's hottest category is Cars & Trucks, garnering 16.5% of the total $2B (yes, billion) in mobile sales in 2010. To understand why that category is so large, let's look at the top 10 most expensive cars sold on eBay mobile in 2010: $240,001 Mercedes-Benz: SLR McLaren $209,888 Lamborghini: Gallardo $208,500 Ferrari: 430 $199,900 Lamborghini: Gallardo $189,000 Lamborghini: Murcielago $185,000 Ferrari: 430 $175,000 Porsche: 911 $170,000 Ferrari: 550 $160,000 Bentley: Continental, GT $159,900 Lamborghini: Gallardo eBay claims they sell 3-4 Ferraris on their mobile app each month. Yes, mobile commerce is not limited to small items. While I would wait to get home and fire up the PC, the current generation that has grown up with mobile phones has no issue satisfying their impulses. Dave Sikora of Digby told me he's seen people buy furniture sets, mattresses, and diamonds via their mobile phones. I guess mobile commerce is rapidly becoming the norm.

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  • bradford persistent agent login not coming up.

    - by alex
    Wired connection. Desktop. It downloads and installs fine but at the point where the login is supposed to pop up. Nothing happens. Bradford says I have normal network access and it never shows it scanning. It just installs and does nothing. I have all of the updates and everything Bradford needs. And I've used the internet at this dorm before witb this computer. Tried reinstalling.disabling my firewall. Any advice would be appreciated

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  • Microsoft Test Manager error in displaying test steps caused by malware

    - by terje
    Sometimes the tool is blamed for errors which are not the fault of the tool – this is one such story.  It was however, not so easy to get to the bottom of it, so I hope sharing this story can help some others. One of our test developers started to get this message inside the test steps part of a test case in the MTM. saying “Could not load file or assembly ‘0 bytes from System, Version=4.0.0.0,……..” The same error came up inside Visual Studio when we opened a test case there. Then we noted a similar error on another piece of software – this error: A System.BadImageFormatException, and same message as above, but just for framework 2.0. We found this  description which pointed to a malware problem (See bottom of that post), that is a fake anti-spyware program called “Additional Guard”.  We checked the computer in question using Malwarebytes Anti-Malware tool.  It found and cleaned out 753 registry keys!!  After this cleanup operation the error was gone.  This is a great tool !  The “Additional Guard” program had been inadvertently installed, and then uninstalled afterwards, but the corrupted keys were of course not removed.  We also noted that this computer had full corporate virus scanning and malware protection, but still this nasty little thing still slipped through. Technorati Tags: Malware,BadImageFormatException,Microsoft Test Manager,Malwarebytes

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  • Cloud9 + vmware server

    - by Vigrond
    I recently bought a Chromebook to allow me to travel and work easily. My work likes to use VMWare images for our environments. I would like to run these on a server somewhere and hook them up to Cloud9 IDE so I can program fairly easily with my Chromebook What would be the easiest way to set this environment up? Can you say, take a VMWare image, "run" it on a linux server and hook up secure access to it through a given port?

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  • What sources do spammers use to get email addresses?

    - by Andrew Grimm
    From what sources do email spammers get their addresses? Wikipedia mentions the following: Harvesting email addresses from publicly available sources. This includes web pages (web crawling), usenet posts, mailing list archives, DNS and WHOIS records Guessing email addresses (directory harvest attack) Asking people for their emails for one purpose, such as jokes of the day, and selling the email addresses elsewhere Getting access to people's address books (which Quechup utilized) Scanning an infected computer for email addresses. Are there any other techniques used? Are any of the techniques above now obsolete?

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  • Netbook Review: HP Mini 311

    With an HD display and an HDMI port, HP's $400 netbook is all about the video -- at least until we try it and find that an 11.6- rather than the usual 10.1-inch screen is irresistible for everyday productivity, too.

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  • Netbook Review: HP Mini 311

    With an HD display and an HDMI port, HP's $400 netbook is all about the video -- at least until we try it and find that an 11.6- rather than the usual 10.1-inch screen is irresistible for everyday productivity, too.

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  • Flash Technology Can Revolutionize your IT Infrastructure

    - by kimberly.billings
    A recent article in the Data Center Journal written by Mark Teter outlines how flash is becoming a disruptive technology in the data center and how it will soon replace HDDs in the storage hierarchy. As Teter explains, the drivers behind this trend are lower cost/performance and power savings; flash is over 100x faster for reads than the fastest HDD, and while it is expensive, it can produce dramatic reductions in the cost of performance as measured in Input/Outputs per second (IOPS). What's more, flash consumes 1/5th the power of HDD, so it's faster AND greener. Teter writes, "when appropriately used, flash turns the current economics of IT performance on its head. That's disruptive." Exadata Smart Flash Cache in the Sun Oracle Database Machine makes intelligent use of flash storage to deliver extreme performance for OLTP and mixed workloads. It intelligently caches data from the Oracle Database replacing slow mechanical I/O operations to disk with very rapid flash memory operations. Exadata Smart Flash Cache is the fundamental technology of the Sun Oracle Database Machine that enables the processing of up to 1 million random I/O operations per second (IOPS), and the scanning of data within Exadata storage at up to 50 GB/second. Are you incorporating flash into your storage strategy? Let us know! Read more: "Flash technology can revolutionize your IT infrastructure", The Data Center Journal, March 30, 2010. Exadata Smart Flash Cache and the Sun Oracle Database Machine white paper var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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  • Python PyBluez loses Bluetooth connection after a while

    - by Travis G.
    I am using Python to write a simple serial Bluetooth script that sends information about my computer stats periodically. The receiving device is a Sparkfun BlueSmirf Silver. The problem is that, after the script runs for a few minutes, it stops sending packets to the receiver and fails with the error: (11, 'Resource temporarily unavailable') Noticing that this inevitably happens, I added some code to automatically try to reopen the connection. However, then I get: Could not connect: (16, 'Device or resource busy') Am I doing something wrong with the connection? Do I need to occasionally reopen the socket? I'm not sure how to recover from this type of error. I understand that sometimes the port will be busy and a write operation is deferred to avoid blocking other processes, but I wouldn't expect the connection to fail so regularly. Any thoughts? Here is the script: import psutil import serial import string import time import bluetooth sampleTime = 1 numSamples = 5 lastTemp = 0 TEMP_CHAR = 't' USAGE_CHAR = 'u' SENSOR_NAME = 'TC0D' #gauges = serial.Serial() #gauges.port = '/dev/rfcomm0' #gauges.baudrate = 9600 #gauges.parity = 'N' #gauges.writeTimeout = 0 #gauges.open() filename = '/sys/bus/platform/devices/applesmc.768/temp2_input' def parseSensorsOutputLinux(output): return int(round(float(output) / 1000)) def connect(): while(True): try: gaugeSocket = bluetooth.BluetoothSocket(bluetooth.RFCOMM) gaugeSocket.connect(('00:06:66:42:22:96', 1)) break; except bluetooth.btcommon.BluetoothError as error: print "Could not connect: ", error, "; Retrying in 5s..." time.sleep(5) return gaugeSocket; gaugeSocket = connect() while(1): usage = psutil.cpu_percent(interval=sampleTime) sensorFile = open(filename) temp = parseSensorsOutputLinux(sensorFile.read()) try: #gauges.write(USAGE_CHAR) gaugeSocket.send(USAGE_CHAR) #gauges.write(chr(int(usage))) #write the first byte gaugeSocket.send(chr(int(usage))) #print("Wrote usage: " + str(int(usage))) #gauges.write(TEMP_CHAR) gaugeSocket.send(TEMP_CHAR) #gauges.write(chr(temp)) gaugeSocket.send(chr(temp)) #print("Wrote temp: " + str(temp)) except bluetooth.btcommon.BluetoothError as error: print "Caught BluetoothError: ", error time.sleep(5) gaugeSocket = connect() pass gaugeSocket.close() EDIT: I should add that this code connects fine after I power-cycle the receiver and start the script. However, it fails after the first exception until I restart the receiver. P.S. This is related to my recent question, Why is /dev/rfcomm0 giving PySerial problems?, but that was more about PySerial specifically with rfcomm0. Here I am asking about general rfcomm etiquette.

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  • Are there netcat-like tools for Windows which are not quarantined as malware?

    - by Matthew Murdoch
    I used to use netcat for Windows to help track down network connectivity issues. However these days my anti-virus software (Symantec - but I understand others display similar behaviour) quarantines netcat.exe as malware. Are there any alternative applications which provide at least the following functionality: can connect to an open TCP socket and send data to it which is typed on the console can open and listen on a TCP socket and print received data to the console ? I don't need the 'advanced' features (which are possibly the reason for the quarantining) such as port scanning or remote execution.

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  • Quickie Guide Getting Java Embedded Running on Raspberry Pi

    - by hinkmond
    Gary C. and I did a Bay Area Java User Group presentation of how to get Java Embedded running on a RPi. See: here. But, if you want the Quickie Guide on how to get Java up and running on the RPi, then follow these steps (which I'm doing right now as we speak, since I got my RPi in the mail on Monday. Woo-hoo!!!). So, follow along at home as I do the same steps here on my board... 1. Download the Win32DiskImager if you are on Windows, or use dd on a Linux PC: https://launchpad.net/win32-image-writer/0.6/0.6/+download/win32diskimager-binary.zip 2. Download the RPi Debian Wheezy image from here: http://files.velocix.com/c1410/images/debian/7/2012-08-08-wheezy-armel/2012-08-08-wheezy-armel.zip 3. Insert a blank 4GB SD Card into your Windows or Linux PC. 4. Use either Win32DiskImager or Linux dd to burn the unzipped image from #2 to the SD Card. 5. Insert the SD Card into your RPi. Connect an Ethernet cable to your RPi to your network. Connect the RPi Power Adapter. 6. The RPi will boot onto your network. Find its IP address using Windows Wireshark or Linux: sudo tcpdump -vv -ieth0 port 67 and port 68 7. ssh to your RPi: ssh <ip_addr_rpi> -l pi <Password: "raspberry"> 8. Download Java SE Embedded: http://www.oracle.com/technetwork/java/embedded/downloads/javase/index.html NOTE: First click accept, then choose the first bundle in the list: ARMv6/7 Linux - Headless EABI, VFP, SoftFP ABI, Little Endian - ejre-7u6-fcs-b24-linux-arm-vfp-client_headless-10_aug_2012.tar.gz 9. scp the bundle from #8 to your RPi: scp <ejre-bundle> pi@<ip_addr_rpi> 10. mkdir /usr/local, untar the bundle from #9 and rename (move) the ejre1.7.0_06 directory to /usr/local/java That's it! You are ready to roll with Java Embedded on your RPi. Hinkmond

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