case statement - Page 178

What are the pitfalls of hardlinked files on my desktop PC?

- by MountainX

All the identical-content files on my PC are now hardlinked. (My data is completely de-duplicated. It is a consequence of the way I copied my data from my old computer.) What pitfalls do I need to be aware of now that certain actions on one file could silently affect a number of other files? I know that deleting the file I'm working on is not a problem (assuming I deleted it on purpose). It doesn't affect any of the other hardlinked files and I don't see that the delete action would lead to unexpected side effects. Moving or renaming the file is not a problem. I don't see any unexpected consequences. I don't think copying hardlinked files is a problem, but I'm not as confident about any unexpected consequences in this regard. What I have seen is that making a copy (to the same disk) of a hardlinked file with cp keeps the copy hardlinked (i.e., inode number doesn't change in the copy). Copying to another filesystem obviously breaks the hardlink. (I guess one pitfall is forgetting this fact, given that my PC has 3 hard disks.) Changing permissions does affect all linked files. So far this has proven handy. (I made a large number of the hardlinked files read-only.) None of the operations above seem to produce any major unexpected consequences. However, as was pointed out to me by Daniel Beck in a comment, editing or modifying a file can sometimes be a problem. It depends on the tool and maybe the type of edit. (For example, editing small text files using sed seems to always break the link while using nano doesn't.) This introduces the chance that editing one file could affect all the hardlinked files (i.e., alter the original inode). My proposed solution to this is to make all hardlinked files read-only (and that is already mostly the case). If I can't do that for some files, I will unlink those particular files. Is there any problem with this read-only approach? I'm assuming that if I go to edit a file and find it to be read-only, I'll remember to unlink that filename while making it writable. So one pitfall might be forgetting this rule. In that case, I'll have to rely on my backups. Am I correct in the above statements? And what else do I need to know? BTW, I'm running Kubuntu 12.04. I'm also using btrfs. (I have 2 SSD's and 1 HDD in the PC. I will also be adding an external USB HDD. I'm also connected to a network and I mount some NFS shares. I don't assume any of these last bits are relevant to the question, but I'm adding them just in case.) BTW, since I have more than one drive (with separate file systems), to unlink any file all I have to do is copy it to another drive, then move it back. However, using sed also works (in my testing). Here's my script: sed -i 's/$.$/\1/' file1 Surprisingly, this even unlinks zero byte files. In my testing it also appears to work on non-text files without any special options. (But I understand that the --binary option might be needed on Windows, MS-DOS and Cygwin.) However, copying to another disk and moving back may be the best way to unlink. For my use-case, unlink command doesn't really "unlink", rather it "removes".

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More Animation - Self Dismissing Dialogs

- by Duncan Mills

In my earlier articles on animation, I discussed various slide, grow and flip transitions for items and containers. In this article I want to discuss a fade animation and specifically the use of fades and auto-dismissal for informational dialogs. If you use a Mac, you may be familiar with Growl as a notification system, and the nice way that messages that are informational just fade out after a few seconds. So in this blog entry I wanted to discuss how we could make an ADF popup behave in the same way. This can be an effective way of communicating information to the user without "getting in the way" with modal alerts. This of course, has been done before, but everything I've seen previously requires something like JQuery to be in the mix when we don't really need it to be. The solution I've put together is nice and generic and will work with either <af:panelWindow> or <af:dialog> as a the child of the popup. In terms of usage it's pretty simple to use we just need to ensure that the popup itself has clientComponent is set to true and includes the animation JavaScript (animateFadingPopup) on a popupOpened event: <af:popup id="pop1" clientComponent="true"> <af:panelWindow title="A Fading Message..."> ... </af:panelWindow> <af:clientListener method="animateFadingPopup" type="popupOpened"/> </af:popup> The popup can be invoked in the normal way using showPopupBehavior or JavaScript, no special code is required there. As a further twist you can include an additional clientAttribute called preFadeDelay to define a delay before the fade itself starts (the default is 5 seconds) . To set the delay to just 2 seconds for example: <af:popup ...> ... <af:clientAttribute name="preFadeDelay" value="2"/> <af:clientListener method="animateFadingPopup" type="popupOpened"/> </af:popup> The Animation Styles As before, we have a couple of CSS Styles which define the animation, I've put these into the skin in my case, and, as in the other articles, I've only defined the transitions for WebKit browsers (Chrome, Safari) at the moment. In this case, the fade is timed at 5 seconds in duration. .popupFadeReset { opacity: 1; } .popupFadeAnimate { opacity: 0; -webkit-transition: opacity 5s ease-in-out; } As you can see here, we are achieving the fade by simply setting the CSS opacity property. The JavaScript The final part of the puzzle is, of course, the JavaScript, there are four functions, these are generic (apart from the Style names which, if you've changed above, you'll need to reflect here): The initial function invoked from the popupOpened event, animateFadingPopup which starts a timer and provides the initial delay before we start to fade the popup. The function that applies the fade animation to the popup - initiatePopupFade. The callback function - closeFadedPopup used to reset the style class and correctly hide the popup so that it can be invoked again and again. A utility function - findFadeContainer, which is responsible for locating the correct child component of the popup to actually apply the style to. Function - animateFadingPopup This function, as stated is the one hooked up to the popupOpened event via a clientListener. Because of when the code is called it does not actually matter how you launch the popup, or if the popup is re-used from multiple places. All usages will get the fade behavior. /** * Client listener which will kick off the animation to fade the dialog and register * a callback to correctly reset the popup once the animation is complete * @param event */ function animateFadingPopup(event) { var fadePopup = event.getSource(); var fadeCandidate = false; //Ensure that the popup is initially Opaque //This handles the situation where the user has dismissed //the popup whilst it was in the process of fading var fadeContainer = findFadeContainer(fadePopup); if (fadeContainer != null) { fadeCandidate = true; fadeContainer.setStyleClass("popupFadeReset"); } //Only continue if we can actually fade this popup if (fadeCandidate) { //See if a delay has been specified var waitTimeSeconds = event.getSource().getProperty('preFadeDelay'); //Default to 5 seconds if not supplied if (waitTimeSeconds == undefined) { waitTimeSeconds = 5; } // Now call the fade after the specified time var fadeFunction = function () { initiatePopupFade(fadePopup); }; var fadeDelayTimer = setTimeout(fadeFunction, (waitTimeSeconds * 1000)); } } The things to note about this function is the initial check that we have to do to ensure that the container is currently visible and reset it's style to ensure that it is. This is to handle the situation where the popup has begun the fade, and yet the user has still explicitly dismissed the popup before it's complete and in doing so has prevented the callback function (described later) from executing. In this particular situation the initial display of the dialog will be (apparently) missing it's normal animation but at least it becomes visible to the user (and most users will probably not notice this difference in any case). You'll notice that the style that we apply to reset the opacity - popupFadeReset, is not applied to the popup component itself but rather the dialog or panelWindow within it. More about that in the description of the next function findFadeContainer(). Finally, assuming that we have a suitable candidate for fading, a JavaScript timer is started using the specified preFadeDelay wait time (or 5 seconds if that was not supplied). When this timer expires then the main animation styleclass will be applied using the initiatePopupFade() function Function - findFadeContainer As a component, the <af:popup> does not support styleClass attribute, so we can't apply the animation style directly. Instead we have to look for the container within the popup which defines the window object that can have a style attached. This is achieved by the following code: /** * The thing we actually fade will be the only child * of the popup assuming that this is a dialog or window * @param popup * @return the component, or null if this is not valid for fading */ function findFadeContainer(popup) { var children = popup.getDescendantComponents(); var fadeContainer = children[0]; if (fadeContainer != undefined) { var compType = fadeContainer.getComponentType(); if (compType == "oracle.adf.RichPanelWindow" || compType == "oracle.adf.RichDialog") { return fadeContainer; } } return null; } So what we do here is to grab the first child component of the popup and check its type. Here I decided to limit the fade behaviour to only <af:dialog> and <af:panelWindow>. This was deliberate. If we apply the fade to say an <af:noteWindow> you would see the text inside the balloon fade, but the balloon itself would hang around until the fade animation was over and then hide. It would of course be possible to make the code smarter to walk up the DOM tree to find the correct <div> to apply the style to in order to hide the whole balloon, however, that means that this JavaScript would then need to have knowledge of the generated DOM structure, something which may change from release to release, and certainly something to avoid. So, all in all, I think that this is an OK restriction and frankly it's windows and dialogs that I wanted to fade anyway, not balloons and menus. You could of course extend this technique and handle the other types should you really want to. One thing to note here is the selection of the first (children[0]) child of the popup. It does not matter if there are non-visible children such as clientListener before the <af:dialog> or <af:panelWindow> within the popup, they are not included in this array, so picking the first element in this way seems to be fine, no matter what the underlying ordering is within the JSF source. If you wanted a super-robust version of the code you might want to iterate through the children array of the popup to check for the right type, again it's up to you. Function - initiatePopupFade On to the actual fading. This is actually very simple and at it's heart, just the application of the popupFadeAnimate style to the correct component and then registering a callback to execute once the fade is done. /** * Function which will kick off the animation to fade the dialog and register * a callback to correctly reset the popup once the animation is complete * @param popup the popup we are animating */ function initiatePopupFade(popup) { //Only continue if the popup has not already been dismissed if (popup.isPopupVisible()) { //The skin styles that define the animation var fadeoutAnimationStyle = "popupFadeAnimate"; var fadeAnimationResetStyle = "popupFadeReset"; var fadeContainer = findFadeContainer(popup); if (fadeContainer != null) { var fadeContainerReal = AdfAgent.AGENT.getElementById(fadeContainer.getClientId()); //Define the callback this will correctly reset the popup once it's disappeared var fadeCallbackFunction = function (event) { closeFadedPopup(popup, fadeContainer, fadeAnimationResetStyle); event.target.removeEventListener("webkitTransitionEnd", fadeCallbackFunction); }; //Initiate the fade fadeContainer.setStyleClass(fadeoutAnimationStyle); //Register the callback to execute once fade is done fadeContainerReal.addEventListener("webkitTransitionEnd", fadeCallbackFunction, false); } } } I've added some extra checks here though. First of all we only start the whole process if the popup is still visible. It may be that the user has closed the popup before the delay timer has finished so there is no need to start animating in that case. Again we use the findFadeContainer() function to locate the correct component to apply the style to, and additionally we grab the DOM id that represents that container. This physical ID is required for the registration of the callback function. The closeFadedPopup() call is then registered on the callback so as to correctly close the now transparent (but still there) popup. Function - closeFadedPopup The final function just cleans things up: /** * Callback function to correctly cancel and reset the style in the popup * @param popup id of the popup so we can close it properly * @param contatiner the window / dialog within the popup to actually style * @param resetStyle the syle that sets the opacity back to solid */ function closeFadedPopup(popup, container, resetStyle) { container.setStyleClass(resetStyle); popup.cancel(); } First of all we reset the style to make the popup contents opaque again and then we cancel the popup. This will ensure that any of your user code that is waiting for a popup cancelled event will actually get the event, additionally if you have done this as a modal window / dialog it will ensure that the glasspane is dismissed and you can interact with the UI again. What's Next? There are several ways in which this technique could be used, I've been working on a popup here, but you could apply the same approach to in-line messages. As this code (in the popup case) is generic it will make s pretty nice declarative component and maybe, if I get time, I'll look at constructing a formal Growl component using a combination of this technique, and active data push. Also, I'm sure the above code can be improved a little too. Specifically things like registering a popup cancelled listener to handle the style reset so that we don't loose the subtle animation that takes place when the popup is opened in that situation where the user has closed the in-fade dialog.

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Prepping a conference

- by Laurent Bugnion

I have had the chance to talk at many conferences these past few years, and came up with a way to prepare them which works really well for me. Most importantly, it would make it quite easy to overcome an emergency (for example if my laptop would suddenly lose data). The whole code as well as the slides and other documents are in the cloud. I also use source control for my demos, so that I always have the latest and the greatest, but also a history of changes I made to my demos. Finally I have a system of code snippets which works great, and I often had very positive remarks from the audience regarding that. Putting everything in the cloud The one thing I used to be the most scared of was a sudden crash of my laptop, and being unable to restore in time for a conference. Most conferences ask speakers to send slides a few days (or weeks…) in advance, but let's face it, we all have last minute changes to our talks and I always come in the conference with updated slides that I pass to the management team. The answer to that dilemma used to be working off memory sticks, and that worked not bad. However last year I started putting all the documents relating to a conference in a DropBox folder, and that works great too. Obviously DropBox works only if you have connectivity, so if I for instance update slides while on an international flight, I cannot save to the cloud. The obvious answer to that is to backup everything on a memory stick… but I have to admit, I have been trusting my luck and working off my laptop HD and then synching everything to the cloud after landing. Of course on some US national flights you get WiFi on board, so in that case it is even simpler :) Usually after the conference is done, I remove the files from DropBox and copy them to their "final destination". They are backed up from there to BackBlaze, the great online backup service I am using routinely (I currently have about 90GB of data in BackBlaze). Outlining the presentations I like to have a written outline of my presentations written somewhere. I keep it simple, just write the various sections of the presentation with timing. I guess it is a remnant of the time when I was a private pilot, and using checklists for flight preparation. For example: Demo about designability 15' (0:37) Switch to Blend Open MainPage.xaml Create a DataTemplate ... Here I can immediately see during the presentation if I am taking too much time for my demo (0:37 is where I need to be when I am done with this section of the presentation, and 15' is the time that this particular section takes). I keep these sections reasonable, I don't detail every step of the preparation. Typically I have one such section for every 10-15 minutes of my talks. Yes, I am timing my presentations. I keep adjusting these numbers when I rehearse, and this really helps to feel more confident during the presentations. This is especially important for presentations that are long, like my MIX11 demo which clocked at 57 minutes (I had a lot of stuff to show…). Such presentations are risky, because if anything goes wrong, you will have to cut stuff, so the answer to that is: Rehearse, rehearse and when you're done rehearsing, rehearse a little more. I also have a "Preparation" section where I outline what I need to do before a presentation. For instance: Preparation Reboot in VHD Make sure MSN and Twitter are not running. Open VS10 and load demo Open Blend and load demo Run the WP7 emulator ... I typically start preparing my laptop an hour before the talk, starting everything I need to start and then putting my laptop to sleep. Saving and printing the outline, Timing Printing is a real problem because it is really hard to find a printer at most conference venues, and also quite hard in hotels. To solve that, I simply write everything in OneNote (synched to the cloud, now you start to know what I like ;) and then I print it to a PDF (I use CutePDFWriter) that I save to my Kindle. During the presentation, I read the outline off the Kindle (I mostly just need a quick check to see how I am timing). For timing during the presentation, I use the free tool ChronoGPS on my Windows Phone 7, but of course any phone these days has a clock/chrono application. In some conferences, they even have timers that the presenters can see, but they tend to count down and I prefer to count up… so I just use my own :) Source control for demos For demos, I create a separate folder and use Mercurial as source control. Mercurial has the huge advantage (over SVN or TFS) to work offline too, so I can commit while on a plane, and all the history is saved. Then when I have connectivity I push everything to the cloud (I am using the fantastic Trunksapp.com for my private repositories). Here too the obvious downside is the risk of losing my last changes if my laptop crashes before I can push to the cloud, and here too the obvious answer would be to work from a memory stick… though I have to admit I didn't do that lately (except when I was writing Silverlight 4 Unleashed, where I was really paranoid…) And code snippets? I am one of these presenters who hates to type in front of an audience. I can type really fast (writing two books has this advantage, it really teaches you to touch type and be fast at it) but in the context of an audience, on a stage where it is often damn cold (an issue I had a lot in past conferences, air conditioning can freeze your fingers and make it really hard to type), it doesn't work as well. I don't know for you, but I really dislike seeing a presentation where the speaker uses the backspace key more often than others ;) To solve that, I like to have my code ready in snippets, and drag them to the screen. Then I can spend time explaining each code snippet, while highlighting portions of the code (always highlight what you talk about, the audience often doesn't even see the cursor and doesn't know where you are on the screen!) Over the years I have used various solutions for code snippets, and now I have one which works really well… if you take a few precautions! I use the Visual Studio Toolbox. Preparing the code snippets You can store code snippets in the Toolbox for anything, XAML, C# etc. I arrange the snippets in the order in which I need them, which is a great way to remember what comes next in the presentation. I also separate them by topic, to make it easier to find them, for example when I switch to the slides and then back to the code. Remember that no matter how experienced you are, you will feel more nervous on stage than while you are preparing, so any way to make it easier for you is going to be beneficial to the audience. To store a code snippet, I do the following: Open the final demo that you want to show to the audience in Visual Studio. In your code, select a snippet of code that you want to explain in particular. Make sure that the Visual Studio Toolbox is open (menu View, Toolbox or Ctrl-Alt-X). Drag the selected snippet from the code window to the toolbox. (if needed) drag the snippet to the correct location (for example between two other code snippets so that you can access it as you speak through the demo). Right click on the snippet and select Rename Item from the context menu. Select a meaningful name. For me I use the following conventions: If it is a method, I use the method's name. If it is not a whole method, I use a descriptive name. If it is the content of a method (i.e. the body only, without the method's signature), I use "-> MethodName". This reminds me during the presentation that this is only the body, and that I need to insert that into an existing signature. This is the case, for instance, when I use Visual Studio to automatically generate the members of an interface’s implementation; then I only need to insert my snippet inside the generated method body. Saving the snippets This is the most important!! It happened to me a few times that VS10 lost its settings. When that happens, the snippets are lost too! Yeah that really sucks, especially (as it happened once) when this is the case about an hour before a talk… Stress and sweat follows, not good conditions to start a talk in front of an audience believe me. Thankfully, saving snippets is really easy with the following steps: Select the menu Tools, Import and Export Settings. Select Export selected environment settings and press Next. Uncheck All Settings. Then expand General Settings and select Toolbox (only!). Press Next. Select your source control folder and save under a meaningful name (for instance Snippets.vssettings). Commit to source control and push to the cloud. By the way, this also has the advantage of applying source control to the snippets file (which is an XML file), so you get history for free on that file! Reimporting the snippets If VS loses its settings and you need to reimport the snippets, this can be done super easily and very fast. Make sure that the Toolbox is empty. When you import snippets, they are merged with existing ones, they do not replace the content of the Toolbox. Unless merging is really what you want, make sure that your Toolbox is clean before you import, it is really easier. Select the menu Tools, Import and Export Settings. Select Import selected environment settings and press Next. Select No, just import new settings and press Next. Press Browse and select the Snippets.vssettings file. Press Finish. Et voila, all your snippets appear again in the Toolbox. Whew, the worst was averted and you can start your demo without sweating! (I had to do that once literally 5 minutes before the start of a demo, while my laptop was already hooked to the projector, and it went just fine). What about special tools? When using special tools (for example beta versions of tools you have an early access to), or a special configuration of your laptop, things can get tricky because you cannot really be sure that you will get a laptop with the same tools and the same configuration at the conference. To solve that, I use the following precautions: I make my demos from a Virtual Hard Disk. The great John Papa made a very easy-to-follow web page where he explains how to create a VHD and install Win7 to it. This gives you the full power of your laptop (as fast as booting from the metal). For me, I have a basic configuration that I saved on a USB harddrive (Win7 plus drivers, basic settings for desktop, folder options, taskbar etc) and Visual Studio 2010 SP1 on it. When preparing, I start by copying this "basis VHD" to my laptop. I install additional tools and configurations. I save the VHD back to the USB harddrive in a different folder. This would allow me to reinstall my demo environment quite fast, for example in case of harddrive failure. Replace the harddrive, copy the VHD to it, configure the BCD and you can start. Unfortunately this only works if the laptop itself still works. In the worst case of total failure, my security is to back all the installers up: The installers I use are synched on all my laptops and backed up to BackBlaze. If the worst happens and my laptop is absolutely broken, I can download the installer from BackBlaze and install on another laptop. This of course takes some time, and if that happens 5 minutes before a presentation, well… I don't have an answer to that, except of course crossing my fingers. Still, all that gives me additional security. Conclusion Remember folks, talking to an audience, large or small, will make you nervous. Just ask Scott Hanselman :) The goal here is to create the best possible conditions for you, and to create an environment where everything is saved and easy to restore, where everything is well known and provides you with additional confidence. The cooler you feel before the presentation (and during ;)), the better your presentation will be. Here too, the goal is to provide the best user experience you can have, which in turn will make it more enjoyable for your audience! Happy presenting :) Laurent Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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Part 2–Load Testing In The Cloud

- by Tarun Arora

Welcome to Part 2, In Part 1 we discussed the advantages of creating a Test Rig in the cloud, the Azure edge and the Test Rig Topology we want to get to. In Part 2, Let’s start by understanding the components of Azure we’ll be making use of followed by manually putting them together to create the test rig, so… let’s get down dirty start setting up the Test Rig. What Components of Azure will I be using for building the Test Rig in the Cloud? To run the Test Agents we’ll make use of Windows Azure Compute and to enable communication between Test Controller and Test Agents we’ll make use of Windows Azure Connect. Azure Connect The Test Controller is on premise and the Test Agents are in the cloud (How will they talk?). To enable communication between the two, we’ll make use of Windows Azure Connect. With Windows Azure Connect, you can use a simple user interface to configure IPsec protected connections between computers or virtual machines (VMs) in your organization’s network, and roles running in Windows Azure. With this you can now join Windows Azure role instances to your domain, so that you can use your existing methods for domain authentication, name resolution, or other domain-wide maintenance actions. For more details refer to an overview of Windows Azure connect. A very useful video explaining everything you wanted to know about Windows Azure connect. Azure Compute Windows Azure compute provides developers a platform to host and manage applications in Microsoft’s data centres across the globe. A Windows Azure application is built from one or more components called ‘roles.’ Roles come in three different types: Web role, Worker role, and Virtual Machine (VM) role, we’ll be using the Worker role to set up the Test Agents. A very nice blog post discussing the difference between the 3 role types. Developers are free to use the .NET framework or other software that runs on Windows with the Worker role or Web role. Developers can also create applications using languages such as PHP and Java. More on Windows Azure Compute. Each Windows Azure compute instance represents a virtual server... Virtual Machine Size CPU Cores Memory Cost Per Hour Extra Small Shared 768 MB $0.04 Small 1 1.75 GB $0.12 Medium 2 3.50 GB $0.24 Large 4 7.00 GB $0.48 Extra Large 8 14.00 GB $0.96 You might want to review the Windows Azure Pricing FAQ. Let’s Get Started building the Test Rig… Configuration Machine Role Comments VM – 1 Domain Controller for Playpit.com On Premise VM – 2 TFS, Test Controller On Premise VM – 3 Test Agent Cloud In this blog post I would assume that you have the domain, Team Foundation Server and Test Controller Installed and set up already. If not, please refer to the TFS 2010 Installation Guide and this walkthrough on MSDN to set up your Test Controller. You can also download a preconfigured TFS 2010 VM from Brian Keller's blog, Brian also has some great hands on Labs on TFS 2010 that you may want to explore. I. Lets start building VM – 3: The Test Agent Download the Windows Azure SDK and Tools Open Visual Studio and create a new Windows Azure Project using the Cloud Template Choose the Worker Role for reasons explained in the earlier post The WorkerRole.cs implements the Run() and OnStart() methods, no code changes required. You should be able to compile the project and run it in the compute emulator (The compute emulator should have been installed as part of the Windows Azure Toolkit) on your local machine. We will only be making changes to WindowsAzureProject, open ServiceDefinition.csdef. Ensure that the vmsize is small (remember the cost chart above). Import the “Connect” module. I am importing the Connect module because I need to join the Worker role VM to the Playpit domain. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WorkerRole name="WorkerRole1" vmsize="Small"> <Imports> <Import moduleName="Diagnostics" /> <Import moduleName="Connect"/> </Imports> </WorkerRole> </ServiceDefinition> Go to the ServiceConfiguration.Cloud.cscfg and note that settings with key ‘Microsoft.WindowsAzure.Plugins.Connect.%%%%’ have been added to the configuration file. This is because you decided to import the connect module. See the config below. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*"> <Role name="WorkerRole1"> <Instances count="1" /> <ConfigurationSettings> <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.ActivationToken" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Refresh" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.WaitForConnectivity" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Upgrade" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.EnableDomainJoin" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainFQDN" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainControllerFQDN" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainAccountName" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainPassword" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainOU" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Administrators" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainSiteName" value="" /> </ConfigurationSettings> </Role> </ServiceConfiguration> Let’s go step by step and understand all the highlighted parameters and where you can find the values for them. osFamily – By default this is set to 1 (Windows Server 2008 SP2). Change this to 2 if you want the Windows Server 2008 R2 operating system. The Advantage of using osFamily = “2” is that you get Powershell 2.0 rather than Powershell 1.0. In Powershell 2.0 you could simply use “powershell -ExecutionPolicy Unrestricted ./myscript.ps1” and it will work while in Powershell 1.0 you will have to change the registry key by including the following in your command file “reg add HKLM\Software\Microsoft\PowerShell\1\ShellIds\Microsoft.PowerShell /v ExecutionPolicy /d Unrestricted /f” before you can execute any power shell. The other reason you might want to move to os2 is if you wanted IIS 7.5. Activation Token – To enable communication between the on premise machine and the Windows Azure Worker role VM both need to have the same token. Log on to Windows Azure Management Portal, click on Connect, click on Get Activation Token, this should give you the activation token, copy the activation token to the clipboard and paste it in the configuration file. Note – Later in the blog I’ll be showing you how to install connect on the on premise machine. EnableDomainJoin – Set the value to true, ofcourse we want to join the on windows azure worker role VM to the domain. DomainFQDN, DomainControllerFQDN, DomainAccountName, DomainPassword, DomainOU, Administrators – This information is specific to your domain. I have extracted this information from the ‘service manager’ and ‘Active Directory Users and Computers’. Also, i created a new Domain-OU namely ‘CloudInstances’ so all my cloud instances joined to my domain show up here, this is optional. You can encrypt the DomainPassword – refer to the instructions here. Or hold fire, I’ll be covering that when i come to certificates and encryption in the coming section. Now once you have filled all this information up, the configuration file should look something like below, <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="2" osVersion="*"> <Role name="WorkerRole1"> <Instances count="1" /> <ConfigurationSettings> <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.ActivationToken" value="45f55fea-f194-4fbc-b36e-25604faac784" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Refresh" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.WaitForConnectivity" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Upgrade" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.EnableDomainJoin" value="true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainFQDN" value="play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainControllerFQDN" value="WIN-KUDQMQFGQOL.play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainAccountName" value="playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainPassword" value="************************" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainOU" value="OU=CloudInstances, DC=Play, DC=Pit, DC=com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Administrators" value="Playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainSiteName" value="" /> </ConfigurationSettings> </Role> </ServiceConfiguration> Next we will be enabling the Remote Desktop module in to the ServiceDefinition.csdef, we could make changes manually or allow a beautiful wizard to help us make changes. I prefer the second option. So right click on the Windows Azure project and choose Publish Now once you get the publish wizard, if you haven’t already you would be asked to import your Windows Azure subscription, this is simply the Msdn subscription activation key xml. Once you have done click Next to go to the Settings page and check ‘Enable Remote Desktop for all roles’. As soon as you do that you get another pop up asking you the details for the user that you would be logging in with (make sure you enter a reasonable expiry date, you do not want the user account to expire today). Notice the more information tag at the bottom, click that to get access to the certificate section. See screen shot below. From the drop down select the option to create a new certificate In the pop up window enter the friendly name for your certificate. In my case I entered ‘WAC – Test Rig’ and click ok. This will create a new certificate for you. Click on the view button to see the certificate details. Do you see the Thumbprint, this is the value that will go in the config file (very important). Now click on the Copy to File button to copy the certificate, we will need to import the certificate to the windows Azure Management portal later. So, make sure you save it a safe location. Click Finish and enter details of the user you would like to create with permissions for remote desktop access, once you have entered the details on the ‘Remote desktop configuration’ screen click on Ok. From the Publish Windows Azure Wizard screen press Cancel. Cancel because we don’t want to publish the role just yet and Yes because we want to save all the changes in the config file. Now if you go to the ServiceDefinition.csdef file you will see that the RemoteAccess and RemoteForwarder roles have been imported for you. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WorkerRole name="WorkerRole1" vmsize="Small"> <Imports> <Import moduleName="Diagnostics" /> <Import moduleName="Connect" /> <Import moduleName="RemoteAccess" /> <Import moduleName="RemoteForwarder" /> </Imports> </WorkerRole> </ServiceDefinition> Now go to the ServiceConfiguration.Cloud.cscfg file and you see a whole bunch for setting “Microsoft.WindowsAzure.Plugins.RemoteAccess.%%%” values added for you. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="2" osVersion="*"> <Role name="WorkerRole1"> <Instances count="1" /> <ConfigurationSettings> <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.ActivationToken" value="45f55fea-f194-4fbc-b36e-25604faac784" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Refresh" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.WaitForConnectivity" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Upgrade" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.EnableDomainJoin" value="true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainFQDN" value="play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainControllerFQDN" value="WIN-KUDQMQFGQOL.play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainAccountName" value="playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainPassword" value="************************" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainOU" value="OU=CloudInstances, DC=Play, DC=Pit, DC=com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Administrators" value="Playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainSiteName" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.Enabled" value="true" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountUsername" value="Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountEncryptedPassword" value="MIIBnQYJKoZIhvcNAQcDoIIBjjCCAYoCAQAxggFOMIIBSgIBADAyMB4xHDAaBgNVBAMME1dpbmRvd 3MgQXp1cmUgVG9vbHMCEGa+B46voeO5T305N7TSG9QwDQYJKoZIhvcNAQEBBQAEggEABg4ol5Xol66Ip6QKLbAPWdmD4ae ADZ7aKj6fg4D+ATr0DXBllZHG5Umwf+84Sj2nsPeCyrg3ZDQuxrfhSbdnJwuChKV6ukXdGjX0hlowJu/4dfH4jTJC7sBWS AKaEFU7CxvqYEAL1Hf9VPL5fW6HZVmq1z+qmm4ecGKSTOJ20Fptb463wcXgR8CWGa+1w9xqJ7UmmfGeGeCHQ4QGW0IDSBU6ccg vzF2ug8/FY60K1vrWaCYOhKkxD3YBs8U9X/kOB0yQm2Git0d5tFlIPCBT2AC57bgsAYncXfHvPesI0qs7VZyghk8LVa9g5IqaM Cp6cQ7rmY/dLsKBMkDcdBHuCTAzBgkqhkiG9w0BBwEwFAYIKoZIhvcNAwcECDRVifSXbA43gBApNrp40L1VTVZ1iGag+3O1" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountExpiration" value="2012-11-27T23:59:59.0000000+00:00" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteForwarder.Enabled" value="true" /> </ConfigurationSettings> <Certificates> <Certificate name="Microsoft.WindowsAzure.Plugins.RemoteAccess.PasswordEncryption" thumbprint="AA23016CF0BDFC344400B5B82706B608B92E4217" thumbprintAlgorithm="sha1" /> </Certificates> </Role> </ServiceConfiguration> Okay let’s look at them one at a time, Enabled - Yes, we would like to enable Remote Access. AccountUserName – This is the user name you entered while you were on the publish windows azure role screen, as detailed above. AccountEncrytedPassword – Try and decode that, the certificate is used to encrypt the password you specified for the user account. Remember earlier i said, either use the instructions or wait and i’ll be showing you encryption, now the user account i am using for rdp has the same password as my domain password, so i can simply copy the value of the AccountEncryptedPassword to the DomainPassword as well. AccountExpiration – This is the expiration as you specified in the wizard earlier, make sure your account does not expire today. Remote Forwarder – Check out the documentation, below is how I understand it, -- One role in an application that implements a remote desktop connection must import the RemoteForwarder module. The two modules work together to enable the remote desktop connections to role instances. -- If you have multiple roles defined in the service model, it does not matter which role you add the RemoteForwarder module to, but you must add it to only one of the role definitions. Certificate – Remember the certificate thumbprint from the wizard, the on premise machine and windows azure role machine that need to speak to each other must have the same thumbprint. More on that when we install Windows Azure connect Endpoints on the on premise machine. As i said earlier, in this blog post, I’ll be showing you the manual process so i won’t be scripting any star up tasks to install the test agent or register the test agent with the TFS Server. I’ll be showing you all this cool stuff in the next blog post, that’s because it’s important to understand the manual side of it, it becomes easier for you to troubleshoot in case something fails. Having said that, the changes we have made are sufficient to spin up the Windows Azure Worker Role aka Test Agent VM, have it connected with the play.pit.com domain and have remote access enabled on it. Before we deploy the Test Agent VM we need to set up Windows Azure Connect on the TFS Server. II. Windows Azure Connect: Setting up Connect on VM – 2 i.e. TFS & Test Controller Glad you made it so far, now to enable communication between the on premise TFS/Test Controller and Azure-ed Test Agent we need to enable communication. We have set up the Azure connect module in the Test Agent configuration, now the connect end points need to be enabled on the on premise machines, let’s have a look at how we can do this. Log on to VM – 2 running the TFS Server and Test Controller Log on to the Windows Azure Management Portal and click on Virtual Network Click on Virtual Network, if you already have a subscription you should see the below screen shot, if not, you would be asked to complete the subscription first Click on Install Local Endpoints from the top left on the panel and you get a url appended with a token id in it, remember the token i showed you earlier, in theory the token you get here should match the token you added to the Test Agent config file. Copy the url to the clip board and paste it in IE explorer (important, the installation at present only works out of IE and you need to have cookies enabled in order to complete the installation). As stated in the pop up, you can NOT download and run the software later, you need to run it as is, since it contains a token. Once the installation completes you should see the Windows Azure connect icon in the system tray. Right click the Azure Connect icon, choose Diagnostics and refer to this link for diagnostic detail terminology. NOTE – Unfortunately I could not see the Windows Azure connect icon in the system tray, a bit of binging with Google revealed that the azure connect icon is only shown when the ‘Windows Azure Connect Endpoint’ Service is started. So go to services.msc and make sure that the service is started, if not start it, unfortunately again, the service did not start for me on a manual start and i realised that one of the dependant services was disabled, you can look at the service dependencies and start them and then start windows azure connect. Bottom line, you need to start Windows Azure connect service before you can proceed. Please refer here on MSDN for more on Troubleshooting Windows Azure connect. (Follow the next step as well) Now go back to the Windows Azure Management Portal and from Groups and Roles create a new group, lets call it ‘Test Rig’. Make sure you add the VM – 2 (the TFS Server VM where you just installed the endpoint). Now if you go back to the Azure Connect icon in the system tray and click ‘Refresh Policy’ you will notice that the disconnected status of the icon should change to ready for connection. III. Importing Certificate in to Windows Azure Management Portal But before that you need to import the certificate you created in Step I in to the Windows Azure Management Portal. Log on to the Windows Azure Management Portal and click on ‘Hosted Services, Storage Accounts & CDN’ and then ‘Management Certificates’ followed by Add Certificates as shown in the screen shot below Browse to the location where you saved the certificate earlier, remember… Refer to Step I in case you forgot. Now you should be able to see the imported certificate here, make sure the thumbprint of the certificate matches the one you inserted in the config files IV. Publish Windows Azure Worker Role aka Test Agent Having completed I, II and III, you are ready to publish the Test Agent VM – 3 to the cloud. Go to Visual Studio and right click the Windows Azure project and select Publish. Verify the infomration in the wizard, from the advanced settings tab, you can also enabled capture of intellitrace or profiling information. Click Next and Click Publish! From the view menu bar select the Windows Azure Activity Log window. Now you should be able to see the deployment progress in real time. In the Windows Azure Management Portal, you should also be able to see the progress of creation of a new Worker Role. Once the deployment is complete you should be able to RDP (go to run prompt type mstsc and in the pop up the machine name) in to the Test Agent Worker Role VM from the Playpit network using the domain admin user account. In case you are unable to log in to the Test Agent using the domain admin user account it means the process of joining the Test Agent to the domain has failed! But the good news is, because you imported the connect module, you can connect to the Test Agent machine using Windows Azure Management Portal and troubleshoot the reason for failure, you will be able to log in with the user name and password you specified in the config file for the keys ‘RemoteAccess.AccountUsername, RemoteAccess.EncryptedPassword (just that enter the password unencrypted)’, fix it or manually join the machine to the domain. Once you have managed to Join the Test Agent VM to the Domain move to the next step. So, log in to the Test Agent Worker Role VM with the Playpit Domain Administrator and verify that you can log in, the machine is connected to the domain and the connect service is successfully running. If yes, give your self a pat on the back, you are 80% mission accomplished! Go to the Windows Azure Management Portal and click on Virtual Network, click on Groups and Roles and click on Test Rig, click Edit Group, the edit the Test Rig group you created earlier. In the Connect to section, click on Add to select the worker role you have just deployed. Also, check the ‘Allow connections between endpoints in the group’ with this you will enable to communication between test controller and test agents and test agents/test agents. Click Save. Now, you are ready to deploy the Test Agent software on the Worker Role Test Agent VM and configure it to work with the Test Controller. V. Configuring VM – 3: Installing Test Agent and Associating Test Agent to Controller Log in to the Worker Role Test Agent VM that you have just successfully deployed, make sure you log in with the domain administrator account. Download the All Agents software from MSDN, ‘en_visual_studio_agents_2010_x86_x64_dvd_509679.iso’, extract the iso and navigate to where you have extracted the iso. In my case, i have extracted the iso to “C:\Resources\Temp\VsAgentSetup”. Open the Test Agent folder and double click on setup.exe. Once you have installed the Test Agent you should reach the configuration window. If you face any issues installing TFS Test Agent on the VM, refer to the walkthrough on MSDN. Once you have successfully installed the Test Agent software you will need to configure the test agent. Right click the test agent configuration tool and run as a different user. i.e. an Administrator. This is really to run the configuration wizard with elevated privileges (you might have UAC block something's otherwise). In the run options, you can select ‘service’ you do not need to run the agent as interactive un less you are running coded UI tests. I have specified the domain administrator to connect to the TFS Test Controller. In real life, i would never do that, i would create a separate test user service account for this purpose. But for the blog post, we are using the most powerful user so that any policies or restrictions don’t block you. Click the Apply Settings button and you should be all green! If not, the summary usually gives helpful error messages that you can resolve and proceed. As per my experience, you may run in to either a permission or a firewall blocking communication issue. And now the moment of truth! Go to VM –2 open up Visual Studio and from the Test Menu select Manage Test Controller Mission Accomplished! You should be able to see the Test Agent that you have just configured here, VI. Creating and Running Load Tests on your brand new Azure-ed Test Rig I have various blog posts on Performance Testing with Visual Studio Ultimate, you can follow the links and videos below, Blog Posts: - Part 1 – Performance Testing using Visual Studio 2010 Ultimate - Part 2 – Performance Testing using Visual Studio 2010 Ultimate - Part 3 – Performance Testing using Visual Studio 2010 Ultimate Videos: - Test Tools Configuration & Settings in Visual Studio - Why & How to Record Web Performance Tests in Visual Studio Ultimate - Goal Driven Load Testing using Visual Studio Ultimate Now that you have created your load tests, there is one last change you need to make before you can run the tests on your Azure Test Rig, create a new Test settings file, and change the Test Execution method to ‘Remote Execution’ and select the test controller you have configured the Worker Role Test Agent against in our case VM – 2 So, go on, fire off a test run and see the results of the test being executed on the Azur-ed Test Rig. Review and What’s next? A quick recap of the benefits of running the Test Rig in the cloud and what i will be covering in the next blog post AND I would love to hear your feedback! Advantages Utilizing the power of Azure compute to run a heavy virtual user load. Benefiting from the Azure flexibility, destroy Test Agents when not in use, takes < 25 minutes to spin up a new Test Agent. Most important test Network Latency, (network latency and speed of connection are two different things – usually network latency is very hard to test), by placing the Test Agents in Microsoft Data centres around the globe, one can actually test the lag in transferring the bytes not because of a slow connection but because the page has been requested from the other side of the globe. Next Steps The process of spinning up the Test Agents in windows Azure is not 100% automated. I am working on the Worker process and power shell scripts to make the role deployment, unattended install of test agent software and registration of the test agent to the test controller automated. In the next blog post I will show you how to make the complete process unattended and automated. Remember to subscribe to http://feeds.feedburner.com/TarunArora. Hope you enjoyed this post, I would love to hear your feedback! If you have any recommendations on things that I should consider or any questions or feedback, feel free to leave a comment. See you in Part III. Share this post : CodeProject

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C#/.NET Little Wonders: The Useful But Overlooked Sets

- by James Michael Hare

Once again we consider some of the lesser known classes and keywords of C#. Today we will be looking at two set implementations in the System.Collections.Generic namespace: HashSet<T> and SortedSet<T>. Even though most people think of sets as mathematical constructs, they are actually very useful classes that can be used to help make your application more performant if used appropriately. A Background From Math In mathematical terms, a set is an unordered collection of unique items. In other words, the set {2,3,5} is identical to the set {3,5,2}. In addition, the set {2, 2, 4, 1} would be invalid because it would have a duplicate item (2). In addition, you can perform set arithmetic on sets such as: Intersections: The intersection of two sets is the collection of elements common to both. Example: The intersection of {1,2,5} and {2,4,9} is the set {2}. Unions: The union of two sets is the collection of unique items present in either or both set. Example: The union of {1,2,5} and {2,4,9} is {1,2,4,5,9}. Differences: The difference of two sets is the removal of all items from the first set that are common between the sets. Example: The difference of {1,2,5} and {2,4,9} is {1,5}. Supersets: One set is a superset of a second set if it contains all elements that are in the second set. Example: The set {1,2,5} is a superset of {1,5}. Subsets: One set is a subset of a second set if all the elements of that set are contained in the first set. Example: The set {1,5} is a subset of {1,2,5}. If We’re Not Doing Math, Why Do We Care? Now, you may be thinking: why bother with the set classes in C# if you have no need for mathematical set manipulation? The answer is simple: they are extremely efficient ways to determine ownership in a collection. For example, let’s say you are designing an order system that tracks the price of a particular equity, and once it reaches a certain point will trigger an order. Now, since there’s tens of thousands of equities on the markets, you don’t want to track market data for every ticker as that would be a waste of time and processing power for symbols you don’t have orders for. Thus, we just want to subscribe to the stock symbol for an equity order only if it is a symbol we are not already subscribed to. Every time a new order comes in, we will check the list of subscriptions to see if the new order’s stock symbol is in that list. If it is, great, we already have that market data feed! If not, then and only then should we subscribe to the feed for that symbol. So far so good, we have a collection of symbols and we want to see if a symbol is present in that collection and if not, add it. This really is the essence of set processing, but for the sake of comparison, let’s say you do a list instead: 1: // class that handles are order processing service 2: public sealed class OrderProcessor 3: { 4: // contains list of all symbols we are currently subscribed to 5: private readonly List<string> _subscriptions = new List<string>(); 6: 7: ... 8: } Now whenever you are adding a new order, it would look something like: 1: public PlaceOrderResponse PlaceOrder(Order newOrder) 2: { 3: // do some validation, of course... 4: 5: // check to see if already subscribed, if not add a subscription 6: if (!_subscriptions.Contains(newOrder.Symbol)) 7: { 8: // add the symbol to the list 9: _subscriptions.Add(newOrder.Symbol); 10: 11: // do whatever magic is needed to start a subscription for the symbol 12: } 13: 14: // place the order logic! 15: } What’s wrong with this? In short: performance! Finding an item inside a List<T> is a linear - O(n) – operation, which is not a very performant way to find if an item exists in a collection. (I used to teach algorithms and data structures in my spare time at a local university, and when you began talking about big-O notation you could immediately begin to see eyes glossing over as if it was pure, useless theory that would not apply in the real world, but I did and still do believe it is something worth understanding well to make the best choices in computer science). Let’s think about this: a linear operation means that as the number of items increases, the time that it takes to perform the operation tends to increase in a linear fashion. Put crudely, this means if you double the collection size, you might expect the operation to take something like the order of twice as long. Linear operations tend to be bad for performance because they mean that to perform some operation on a collection, you must potentially “visit” every item in the collection. Consider finding an item in a List<T>: if you want to see if the list has an item, you must potentially check every item in the list before you find it or determine it’s not found. Now, we could of course sort our list and then perform a binary search on it, but sorting is typically a linear-logarithmic complexity – O(n * log n) - and could involve temporary storage. So performing a sort after each add would probably add more time. As an alternative, we could use a SortedList<TKey, TValue> which sorts the list on every Add(), but this has a similar level of complexity to move the items and also requires a key and value, and in our case the key is the value. This is why sets tend to be the best choice for this type of processing: they don’t rely on separate keys and values for ordering – so they save space – and they typically don’t care about ordering – so they tend to be extremely performant. The .NET BCL (Base Class Library) has had the HashSet<T> since .NET 3.5, but at that time it did not implement the ISet<T> interface. As of .NET 4.0, HashSet<T> implements ISet<T> and a new set, the SortedSet<T> was added that gives you a set with ordering. HashSet<T> – For Unordered Storage of Sets When used right, HashSet<T> is a beautiful collection, you can think of it as a simplified Dictionary<T,T>. That is, a Dictionary where the TKey and TValue refer to the same object. This is really an oversimplification, but logically it makes sense. I’ve actually seen people code a Dictionary<T,T> where they store the same thing in the key and the value, and that’s just inefficient because of the extra storage to hold both the key and the value. As it’s name implies, the HashSet<T> uses a hashing algorithm to find the items in the set, which means it does take up some additional space, but it has lightning fast lookups! Compare the times below between HashSet<T> and List<T>: Operation HashSet<T> List<T> Add() O(1) O(1) at end O(n) in middle Remove() O(1) O(n) Contains() O(1) O(n) Now, these times are amortized and represent the typical case. In the very worst case, the operations could be linear if they involve a resizing of the collection – but this is true for both the List and HashSet so that’s a less of an issue when comparing the two. The key thing to note is that in the general case, HashSet is constant time for adds, removes, and contains! This means that no matter how large the collection is, it takes roughly the exact same amount of time to find an item or determine if it’s not in the collection. Compare this to the List where almost any add or remove must rearrange potentially all the elements! And to find an item in the list (if unsorted) you must search every item in the List. So as you can see, if you want to create an unordered collection and have very fast lookup and manipulation, the HashSet is a great collection. And since HashSet<T> implements ICollection<T> and IEnumerable<T>, it supports nearly all the same basic operations as the List<T> and can use the System.Linq extension methods as well. All we have to do to switch from a List<T> to a HashSet<T> is change our declaration. Since List and HashSet support many of the same members, chances are we won’t need to change much else. 1: public sealed class OrderProcessor 2: { 3: private readonly HashSet<string> _subscriptions = new HashSet<string>(); 4: 5: // ... 6: 7: public PlaceOrderResponse PlaceOrder(Order newOrder) 8: { 9: // do some validation, of course... 10: 11: // check to see if already subscribed, if not add a subscription 12: if (!_subscriptions.Contains(newOrder.Symbol)) 13: { 14: // add the symbol to the list 15: _subscriptions.Add(newOrder.Symbol); 16: 17: // do whatever magic is needed to start a subscription for the symbol 18: } 19: 20: // place the order logic! 21: } 22: 23: // ... 24: } 25: Notice, we didn’t change any code other than the declaration for _subscriptions to be a HashSet<T>. Thus, we can pick up the performance improvements in this case with minimal code changes. SortedSet<T> – Ordered Storage of Sets Just like HashSet<T> is logically similar to Dictionary<T,T>, the SortedSet<T> is logically similar to the SortedDictionary<T,T>. The SortedSet can be used when you want to do set operations on a collection, but you want to maintain that collection in sorted order. Now, this is not necessarily mathematically relevant, but if your collection needs do include order, this is the set to use. So the SortedSet seems to be implemented as a binary tree (possibly a red-black tree) internally. Since binary trees are dynamic structures and non-contiguous (unlike List and SortedList) this means that inserts and deletes do not involve rearranging elements, or changing the linking of the nodes. There is some overhead in keeping the nodes in order, but it is much smaller than a contiguous storage collection like a List<T>. Let’s compare the three: Operation HashSet<T> SortedSet<T> List<T> Add() O(1) O(log n) O(1) at end O(n) in middle Remove() O(1) O(log n) O(n) Contains() O(1) O(log n) O(n) The MSDN documentation seems to indicate that operations on SortedSet are O(1), but this seems to be inconsistent with its implementation and seems to be a documentation error. There’s actually a separate MSDN document (here) on SortedSet that indicates that it is, in fact, logarithmic in complexity. Let’s put it in layman’s terms: logarithmic means you can double the collection size and typically you only add a single extra “visit” to an item in the collection. Take that in contrast to List<T>’s linear operation where if you double the size of the collection you double the “visits” to items in the collection. This is very good performance! It’s still not as performant as HashSet<T> where it always just visits one item (amortized), but for the addition of sorting this is a good thing. Consider the following table, now this is just illustrative data of the relative complexities, but it’s enough to get the point: Collection Size O(1) Visits O(log n) Visits O(n) Visits 1 1 1 1 10 1 4 10 100 1 7 100 1000 1 10 1000 Notice that the logarithmic – O(log n) – visit count goes up very slowly compare to the linear – O(n) – visit count. This is because since the list is sorted, it can do one check in the middle of the list, determine which half of the collection the data is in, and discard the other half (binary search). So, if you need your set to be sorted, you can use the SortedSet<T> just like the HashSet<T> and gain sorting for a small performance hit, but it’s still faster than a List<T>. Unique Set Operations Now, if you do want to perform more set-like operations, both implementations of ISet<T> support the following, which play back towards the mathematical set operations described before: IntersectWith() – Performs the set intersection of two sets. Modifies the current set so that it only contains elements also in the second set. UnionWith() – Performs a set union of two sets. Modifies the current set so it contains all elements present both in the current set and the second set. ExceptWith() – Performs a set difference of two sets. Modifies the current set so that it removes all elements present in the second set. IsSupersetOf() – Checks if the current set is a superset of the second set. IsSubsetOf() – Checks if the current set is a subset of the second set. For more information on the set operations themselves, see the MSDN description of ISet<T> (here). What Sets Don’t Do Don’t get me wrong, sets are not silver bullets. You don’t really want to use a set when you want separate key to value lookups, that’s what the IDictionary implementations are best for. Also sets don’t store temporal add-order. That is, if you are adding items to the end of a list all the time, your list is ordered in terms of when items were added to it. This is something the sets don’t do naturally (though you could use a SortedSet with an IComparer with a DateTime but that’s overkill) but List<T> can. Also, List<T> allows indexing which is a blazingly fast way to iterate through items in the collection. Iterating over all the items in a List<T> is generally much, much faster than iterating over a set. Summary Sets are an excellent tool for maintaining a lookup table where the item is both the key and the value. In addition, if you have need for the mathematical set operations, the C# sets support those as well. The HashSet<T> is the set of choice if you want the fastest possible lookups but don’t care about order. In contrast the SortedSet<T> will give you a sorted collection at a slight reduction in performance. Technorati Tags: C#,.Net,Little Wonders,BlackRabbitCoder,ISet,HashSet,SortedSet

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simple and reliable centralized logging inside Amazon VPC

- by Nakedible

I need to set up centralized logging for a set of servers (10-20) in an Amazon VPC. The logging should be as to not lose any log messages in case any single server goes offline - or in the case that an entire availability zone goes offline. It should also tolerate packet loss and other normal network conditions without losing or duplicating messages. It should store the messages durably, at the minimum on two different EBS volumes in two availability zones, but S3 is a good place as well. It should also be realtime so that the messages arrive within seconds of their generation to two different availability zones. I also need to sync logfiles not generated via syslog, so a syslog-only centralized logging solution would not fulfill all the needs, although I guess that limitation could be worked around. I have already reviewed a few solutions, and I will list them here: Flume to Flume to S3: I could set up two logservers as Flume hosts which would store log messages either locally or in S3, and configure all the servers with Flume to send all messages to both servers, using the end-to-end reliability options. That way the loss of a single server shouldn't cause lost messages and all messages would arrive in two availability zones in realtime. However, there would need to be some way to join the logs of the two servers, deduplicating all the messages delivered to both. This could be done by adding a unique id on the sending side to each message and then write some manual deduplication runs on the logfiles. I haven't found an easy solution to the duplication problem. Logstash to Logstash to ElasticSearch: I could install Logstash on the servers and have them deliver to a central server via AMQP, with the durability options turned on. However, for this to work I would need to use some of the clustering capable AMQP implementations, or fan out the deliver just as in the Flume case. AMQP seems to be a yet another moving part with several implementations and no real guidance on what works best this sort of setup. And I'm not entirely convinced that I could get actual end-to-end durability from logstash to elasticsearch, assuming crashing servers in between. The fan-out solutions run in to the deduplication problem again. The best solution that would seem to handle all the cases, would be Beetle, which seems to provide high availability and deduplication via a redis store. However, I haven't seen any guidance on how to set this up with Logstash and Redis is one more moving part again for something that shouldn't be terribly difficult. Logstash to ElasticSearch: I could run Logstash on all the servers, have all the filtering and processing rules in the servers themselves and just have them log directly to a removet ElasticSearch server. I think this should bring me reliable logging and I can use the ElasticSearch clustering features to share the database transparently. However, I am not sure if the setup actually survives Logstash restarts and intermittent network problems without duplicating messages in a failover case or similar. But this approach sounds pretty promising. rsync: I could just rsync all the relevant log files to two different servers. The reliability aspect should be perfect here, as the files should be identical to the source files after a sync is done. However, doing an rsync several times per second doesn't sound fun. Also, I need the logs to be untamperable after they have been sent, so the rsyncs would need to be in append-only mode. And log rotations mess things up unless I'm careful. rsyslog with RELP: I could set up rsyslog to send messages to two remote hosts via RELP and have a local queue to store the messages. There is the deduplication problem again, and RELP itself might also duplicate some messages. However, this would only handle the things that log via syslog. None of these solutions seem terribly good, and they have many unknowns still, so I am asking for more information here from people who have set up centralized reliable logging as to what are the best tools to achieve that goal.

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Converting Encrypted Values

- by Johnm

Your database has been protecting sensitive data at rest using the cell-level encryption features of SQL Server for quite sometime. The employees in the auditing department have been inviting you to their after-work gatherings and buying you drinks. Thousands of customers implicitly include you in their prayers of thanks giving as their identities remain safe in your company's database. The cipher text resting snuggly in a column of the varbinary data type is great for security; but it can create some interesting challenges when interacting with other data types such as the XML data type. The XML data type is one that is often used as a message type for the Service Broker feature of SQL Server. It also can be an interesting data type to capture for auditing or integrating with external systems. The challenge that cipher text presents is that the need for decryption remains even after it has experienced its XML metamorphosis. Quite an interesting challenge nonetheless; but fear not. There is a solution. To simulate this scenario, we first will want to create a plain text value for us to encrypt. We will do this by creating a variable to store our plain text value: -- set plain text value DECLARE @PlainText NVARCHAR(255); SET @PlainText = 'This is plain text to encrypt'; The next step will be to create a variable that will store the cipher text that is generated from the encryption process. We will populate this variable by using a pre-defined symmetric key and certificate combination: -- encrypt plain text value DECLARE @CipherText VARBINARY(MAX); OPEN SYMMETRIC KEY SymKey DECRYPTION BY CERTIFICATE SymCert WITH PASSWORD='mypassword2010'; SET @CipherText = EncryptByKey ( Key_GUID('SymKey'), @PlainText ); CLOSE ALL SYMMETRIC KEYS; The value of our newly generated cipher text is 0x006E12933CBFB0469F79ABCC79A583--. This will be important as we reference our cipher text later in this post. Our final step in preparing our scenario is to create a table variable to simulate the existence of a table that contains a column used to hold encrypted values. Once this table variable has been created, populate the table variable with the newly generated cipher text: -- capture value in table variable DECLARE @tbl TABLE (EncVal varbinary(MAX)); INSERT INTO @tbl (EncVal) VALUES (@CipherText); We are now ready to experience the challenge of capturing our encrypted column in an XML data type using the FOR XML clause: -- capture set in xml DECLARE @xml XML; SET @xml = (SELECT EncVal FROM @tbl AS MYTABLE FOR XML AUTO, BINARY BASE64, ROOT('root')); If you add the SELECT @XML statement at the end of this portion of the code you will see the contents of the XML data in its raw format: <root> <MYTABLE EncVal="AG4Skzy/sEafeavMeaWDBwEAAACE--" /> </root> Strangely, the value that is captured appears nothing like the value that was created through the encryption process. The result being that when this XML is converted into a readable data set the encrypted value will not be able to be decrypted, even with access to the symmetric key and certificate used to perform the decryption. An immediate thought might be to convert the varbinary data type to either a varchar or nvarchar before creating the XML data. This approach makes good sense. The code for this might look something like the following: -- capture set in xml DECLARE @xml XML; SET @xml = (SELECT CONVERT(NVARCHAR(MAX),EncVal) AS EncVal FROM @tbl AS MYTABLE FOR XML AUTO, BINARY BASE64, ROOT('root')); However, this results in the following error: Msg 9420, Level 16, State 1, Line 26 XML parsing: line 1, character 37, illegal xml character A quick query that returns CONVERT(NVARCHAR(MAX),EncVal) reveals that the value that is causing the error looks like something off of a genuine Chinese menu. While this situation does present us with one of those spine-tingling, expletive-generating challenges, rest assured that this approach is on the right track. With the addition of the "style" argument to the CONVERT method, our solution is at hand. When dealing with converting varbinary data types we have three styles available to us: - The first is to not include the style parameter, or use the value of "0". As we see, this style will not work for us. - The second option is to use the value of "1" will keep our varbinary value including the "0x" prefix. In our case, the value will be 0x006E12933CBFB0469F79ABCC79A583-- - The third option is to use the value of "2" which will chop the "0x" prefix off of our varbinary value. In our case, the value will be 006E12933CBFB0469F79ABCC79A583-- Since we will want to convert this back to varbinary when reading this value from the XML data we will want the "0x" prefix, so we will want to change our code as follows: -- capture set in xml DECLARE @xml XML; SET @xml = (SELECT CONVERT(NVARCHAR(MAX),EncVal,1) AS EncVal FROM @tbl AS MYTABLE FOR XML AUTO, BINARY BASE64, ROOT('root')); Once again, with the inclusion of the SELECT @XML statement at the end of this portion of the code you will see the contents of the XML data in its raw format: <root> <MYTABLE EncVal="0x006E12933CBFB0469F79ABCC79A583--" /> </root> Nice! We are now cooking with gas. To continue our scenario, we will want to parse the XML data into a data set so that we can glean our freshly captured cipher text. Once we have our cipher text snagged we will capture it into a variable so that it can be used during decryption: -- read back xml DECLARE @hdoc INT; DECLARE @EncVal NVARCHAR(MAX); EXEC sp_xml_preparedocument @hDoc OUTPUT, @xml; SELECT @EncVal = EncVal FROM OPENXML (@hdoc, '/root/MYTABLE') WITH ([EncVal] VARBINARY(MAX) '@EncVal'); EXEC sp_xml_removedocument @hDoc; Finally, the decryption of our cipher text using the DECRYPTBYKEYAUTOCERT method and the certificate utilized to perform the encryption earlier in our exercise: SELECT CONVERT(NVARCHAR(MAX), DecryptByKeyAutoCert ( CERT_ID('AuditLogCert'), N'mypassword2010', @EncVal ) ) EncVal; Ah yes, another hurdle presents itself! The decryption produced the value of NULL which in cryptography means that either you don't have permissions to decrypt the cipher text or something went wrong during the decryption process (ok, sometimes the value is actually NULL; but not in this case). As we see, the @EncVal variable is an nvarchar data type. The third parameter of the DECRYPTBYKEYAUTOCERT method requires a varbinary value. Therefore we will need to utilize our handy-dandy CONVERT method: SELECT CONVERT(NVARCHAR(MAX), DecryptByKeyAutoCert ( CERT_ID('AuditLogCert'), N'mypassword2010', CONVERT(VARBINARY(MAX),@EncVal) ) ) EncVal; Oh, almost. The result remains NULL despite our conversion to the varbinary data type. This is due to the creation of an varbinary value that does not reflect the actual value of our @EncVal variable; but rather a varbinary conversion of the variable itself. In this case, something like 0x3000780030003000360045003--. Considering the "style" parameter got us past XML challenge, we will want to consider its power for this challenge as well. Knowing that the value of "1" will provide us with the actual value including the "0x", we will opt to utilize that value in this case: SELECT CONVERT(NVARCHAR(MAX), DecryptByKeyAutoCert ( CERT_ID('SymCert'), N'mypassword2010', CONVERT(VARBINARY(MAX),@EncVal,1) ) ) EncVal; Bingo, we have success! We have discovered what happens with varbinary data when captured as XML data. We have figured out how to make this data useful post-XML-ification. Best of all we now have a choice in after-work parties now that our very happy client who depends on our XML based interface invites us for dinner in celebration. All thanks to the effective use of the style parameter.

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Thoughts on home NAS server

- by user826955

I currently have a NAS with a 2x2TB HDD 1x16GB SSD layout on a mini-itx atom board. The NAS is in a Lian Li PC-Q07 case. On this system I was running freebsd 8 with a gmirror raid 1 setup, which was enough for my needs. So far I was using the NAS for: Fileserver with AFP protocol (only mac clients used) SVN server hosting all my source trees of my projects JIRA (performance was okay-ish) Timemachine backup for the macs The power consumption was about 38W, although I did not put HDDs asleep when unused (I think this is not possible in a raid setup). I liked the NAS because: the performance was good through gigabit LAN (enough for my needs) power consumption was good its a pretty small case and fits in one of my cupboards I disliked the NAS a bit because: it was a bit noisy, the Q07 case vibrated a good amount because of the HDDs. I switched the NAS off every evening I do not have a real backup of the data on the NAS, only the internal raid 1 as safety. I really dont want to loose my source trees under no circumstances, so I would really be sleeping better if I knew I had regular backups somewhere. Recently, the board seemed to have died, I can't boot anymore. Thus, I was thinking about a redesign of my NAS (I still have to find out what parts are broken, I probably need to replace the mainboard and SSD. HDDs seem to be okay). First of all, I was wondering what other users have as backup for their NAS? Are you actually using a second NAS, and regularly copying over the data to have it safe? Or is there any better solution to this? I was thinking about getting a cheap NAS like the synology DS112j with only one disk, and use rsync or something similar to regularly copy data over to the second NAS (wake the second NAS upon start, shut it down after copy). Although this approach seems somewhat weird, It would have the benefit (?) that I could use a single disk instead of raid in the main NAS, and put the disk asleep when idle, and have the NAS running 24/7 with low energy consumption (I found no way to do this with a gmirror setup). Is there any recommended backup solution for a small NAS? Then I was thinking about a different raid setup. Since I have to buy a new mainboard as well as SSD, I might as well switch over to a i3 board with more ram, and also switch to ZFS. I am not familar with ZFS, I've never used it, but I read and hear much about it. Would it be viable to set up a ZFS storage with only 2 disks? Can I easily extend this storage with more disks, once I choose to add some? I could maybe get a new case like the Fractal Design Array R2 which has more 3,5" slots. I could as well get another 2 disks, but I would prefer sticking with the existing 2 for enegery/heat/noise reasons. Should I go for a ZFS storage or stick to my gmirror setup? I would also like to keep freebsd as operating system, and also I dont need any web gui or something (that is, I dont need/want to use FreeNAS or Openfiler etc). Does anyone maybe have a sample setup in use so I can compare energy consumption/noise/software setup? Any guidance towards the NAS of my dreams (silent, low energy, safe w/ backups) much appreciated.

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Asus P8P67 Rev. 3.1 Motherboard issues powering on and saving settings

- by Scott

Edit: New Information Have some updated information from the old question below: So basically my issue right now is somewhat similar, but I've been able to rule out a couple of things. I don't think this has anything to do with light on the motherboard. No matter what lights are on/off on the motherboard when the computer is off, they don't affect this issue. The main power LED on the Mobo is always lit when the power supply is turned on, and that's what matters anyway. Even when the main power LED is on, the PC will NOT boot up the first time I hit the power switch. I have to go reset the power supply (make all lights turn off on the Mobo and back on), and THEN hit the power switch. Then everything boots up. Also, the BIOS settings are reset every time this happens. Asus Tech Support told me to try jumping the power with something metal to try and rule out that it's a problem with the connectors getting power, or if it's a problem with the case power switch pins - haven't done that yet though. Any ideas? This is a lot simpler than it was before when I thought it had to do with certain LED indicators for RAM, EPU, etc. Original Question So I built my new desktop just about 3 weeks ago. I've been having a few issues which I think are all related to my motherboard, an Asus P8P67 Revision 3.1, but I'm not 100% sure as this is really the first from-scratch build I've ever done. I've posted these questions on the Asus forums, Asus Tech Support, and the Corsair forums as well as I thought it might have something to do with my power supply at one point. None of these avenues have solved my issue until now completely, so I thought I'd come here to see what you guys think. Here's what's happening: My computer is off, and I go to power it on. I press the power switch on the case (Antec Nine Hundred), and nothing seems to happen. Upon further inspection, I see that what this actually does is simply turn on the EPU LED on my motherboard, but doesn't actually boot anything up. I then have to go and flip the main power switch on the power supply off and back on. What this does is turn off all lights on the Motherboard after a few seconds, and turn them all back on (including the EPU LED that was off before I hit the power switch the first time). Now, hitting the power switch works. The machine boots up fine, and starts going through the boot up process. As a side note: My Motherboard is set to "Force BIOS", and every single time I change this to do the opposite, the next time my computer boots up that change reverts itself. I think this may be due to the fact that I am doing the hard reset on the power supply each time, but I'm not sure. I had thought that the Motherboard would keep its BIOS settings unless you did something to the Mobo itself - so this may be a related issue, or something else completely. That's basically it. Once it's on, it's on. It works fine, recognizes all of my hardware, and runs great. All fans/lights in the case work great, and I'm getting standard readings. The next time I go to shut the computer down however, I can expect the same exact process getting it up and running, including being forced to go into BIOS and exit again before I can load Windows. Another side note: If I power on my computer using the power switch DIRECTLY after shutting it down, it powers right back on (I think this is because the EPU LED light doesn't have time to turn off). It looks as if as long as the EPU LED is lit up on the motherboard before I hit the power switch on the case, the thing will boot up fine (although this doesn't explain the "Force BIOS" issue, at least it's something). Any ideas? Thanks guys. P.S. - System Specs Asus P8P67 Rev. 3.1 Motherboard Intel Core i7 2600K Processor 16GB (4x4GB) G-Skill 1600 RAM NVIDIA EVGA GTX 570 Video Card Crucial 128GB SSD HD Corsair 850W Power Supply Seagate 2TB HDD

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How do I set an event off when player is on certain tile?

- by Tom Burman

Here is the code I use to create and print my map to the canvas: var board = []; function loadMap(map) { if (map == 1) { return [ [2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,3,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,3,0,0,2], [2,0,0,0,0,0,0,3,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,3,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,3,3,0,0,0,0,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,3,3,0,0,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,3,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,3,0,3,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,3,3,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,3,3,3,3,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,3,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,3,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,3,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,0,0,3,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,3,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,0,0,0,0,0,0,0,0,3,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,3,3,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,3,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,3,3,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,3,3,3,3,3,3,3,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2], [2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2] ]; } } board = loadMap(1); enterfor (y = 0; y <= viewHeight; y++) { for (x = 0; x <= viewWidth; x++) { var theX = x * 32; var theY = y * 32; context.drawImage(mapTiles[board[y+viewY][x+viewX]], theX, theY, 32, 32); } } And here is the code I use for player movement: canvas.addEventListener('keydown', function(e) { console.log(e); var key = null; switch (e.which) { case 37: // Left if (playerX > 0) playerX--; break; case 38: // Up if (playerY > 0) playerY--; break; case 39: // Right if (playerX < worldWidth) playerX++; break; case 40: // Down if (playerY < worldHeight) playerY++; break; } viewX = playerX - Math.floor(0.5 * viewWidth); if (viewX < 0) viewX = 0; if (viewX+viewWidth > worldWidth) viewX = worldWidth - viewWidth; viewY = playerY - Math.floor(0.5 * viewHeight); if (viewY < 0) viewY = 0; if (viewY+viewHeight > worldHeight) viewY = worldHeight - viewHeight; }, false); What I am looking for is a method for when the player lands on tile 3 he loses health. I have tried to use this in the player movement but it doesnt seem to work e.g the left movement: case 37: // Left if (playerX > 0) playerX--; if(board[x2 - 1] == 3) { health--; playerX--; }

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SQL Server 2008 Unique Problem for bring DB Online...

- by Nai

This is my error I am facing TITLE: Microsoft.SqlServer.Smo Set offline failed for Database 'Go3D_Retailer ------------------------------ ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) Unable to open the physical file "E:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\ftrow_Go3D_catalog.ndf". Operating system error 2: "2(failed to retrieve text for this error. Reason: 15105)". Database 'Go3D_Retailer' cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server errorlog for details. ALTER DATABASE statement failed. (Microsoft SQL Server, Error: 5120) Background to this error I've been trying to move my destination logshipping database to another physical server for analysis purposes. Because I do not have active directory set up, I had to hack my process by using the same username/password for both the source and destination servers to get the process to work. Following that, I used this guy's solution to move the destination database to another server. However, this error occurs when I try to bring the database back online. I don't have an E drive on my server and I have no idea why it's trying to open a file from E drive. I have over a 100gb left on my hard disk so it's definitely not a space issue. This sounds like a bug... Any ideas? I'm running SQL Server 2008 Enterprise edition on Windows Server 2008 R2 64bit

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Ubuntu 12.04 cloud edition on Amazon - Apache2 - /etc

- by jdog

I have setup a web server on Amazon with 3 Virtual hosts. For some reason I can't get any of the sites going on it, they all show a 404 error. /var/log/apache2/error.log shows "File does not exist: /etc/apache2/htdocs" I have checked: a2ensite all my virtual hosts actually checked softlinks in sites-enabled access rights in /var/www to 777, in case user is not www-data grep -r htdocs /etc/apache2 (returns nothing) ports.conf has NameVirtualHost directive exactly matching Virtual Hosts What else could this be? ports.conf # If you just change the port or add more ports here, you will likely also # have to change the VirtualHost statement in # /etc/apache2/sites-enabled/000-default # This is also true if you have upgraded from before 2.2.9-3 (i.e. from # Debian etch). See /usr/share/doc/apache2.2-common/NEWS.Debian.gz and # README.Debian.gz NameVirtualHost 107.20.169.163:80 Listen 80 <IfModule mod_ssl.c> # If you add NameVirtualHost *:443 here, you will also have to change # the VirtualHost statement in /etc/apache2/sites-available/default-ssl # to <VirtualHost *:443> # Server Name Indication for SSL named virtual hosts is currently not # supported by MSIE on Windows XP. Listen 443 </IfModule> <IfModule mod_gnutls.c> Listen 443 </IfModule> sites-available/www.seleconlight.com <VirtualHost 107.20.169.163:80> ServerName www.seleconlight.com DocumentRoot /var/www/www.seleconlight.com CustomLog /var/log/apache2/www.seleconlight.com-access.log combined ErrorLog /var/log/apache2/www.seleconlight.com-error.log </VirtualHost>

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SQL Server 2008 Bring Database Online trying to open a file from a drive that doesn't exist

- by Nai

This is my error I am facing TITLE: Microsoft.SqlServer.Smo Set offline failed for Database 'Go3D_Retailer ------------------------------ ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) Unable to open the physical file "E:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\ftrow_Go3D_catalog.ndf". Operating system error 2: "2(failed to retrieve text for this error. Reason: 15105)". Database 'Go3D_Retailer' cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server errorlog for details. ALTER DATABASE statement failed. (Microsoft SQL Server, Error: 5120) Background to this error I've been trying to move my destination logshipping database to another physical server for analysis purposes. Because I do not have domain keys and active directory set up, I had to hack my process by using the same username/password for both the source and destination servers to get the process to work. Following that, I used this guy's solution to move the destination database to another server. However, this error occurs when I try to bring the database back online. I don't have an E drive on my server and I have no idea why it's trying to open a file from E drive. I have over a 100gb left on my hard disk so it's definitely not a space issue. This sounds like a bug... Any ideas?

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android geting data from sql

- by sagar

Hello i m new to android. i wont to connect to sql server for store and get data so so me one can help me sending code of android for do it.. i had tried to do tht with java nd it was workink but now i wont to create a aplication for android my java code is :: import java.sql.*; public class MysqlTest { public static void main (String[] args) { Connection conn = null; try { String userName = "pietro"; //change it to your username String password = "pietro"; //change it to your password String url = "jdbc:mysql://192.168.0.67:3306/registro"; Class.forName("com.mysql.jdbc.Driver").newInstance(); conn = DriverManager.getConnection(url, userName, password); Statement s = (Statement) conn.createStatement(); // code for create a tabel in server s.execute("create table School2 (rolno integer,sub text)"); // code for create a tabel in server s.execute("insert into School2(rolno,sub)values(10,'java')"); //code for add value in tabel s.execute("select rolno,sub from School2");//code for add value in tabel s.close(); System.out.println("Database connection established"); } catch (Exception e) { System.err.println("Cannot connect to database server"); } finally { if (conn != null) { try { conn.close (); System.out.println("Database connection terminated"); } catch (Exception e) { /* ignore close errors */ } } } } }

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Finding custom printer-specific options on *nix

- by enbuyukfener

Hey all, I have a printer set up using CUPS (FujiXerox Document Center 1100), it is named DC1100. There are capabilities of the printer that are not shows as options of the printer as listed by: lpoptions -l -d DC1100 The output is below: PrintoutMode/Printout Mode: Draft *Normal High Photo InputSlot/Media Source: Upper Lower MultiPurpose LargeCapacity Manual *Standard PageSize/Page Size: *Letter A4 C5 C6 COM10 DL Executive Legal Monarch Statement PageRegion/PageRegion: Letter A4 C5 C6 COM10 DL Executive Legal Monarch Statement STP_Brightness/Brightness: 0.00 0.02 0.04 [snip] 2.00 STP_Contrast/Contrast: 0.00 0.05 0.10 0.15 [snip] 4.00 STP_ColorCorrection/Color Correction: Accurate Bright Density [snip] Uncorrected STP_DitherAlgorithm/Dither Algorithm: Adaptive EvenTone Fast [snip] VeryFast STP_EnableDensity/Density Enable: *Disabled Enabled STP_Density/Density Value: 0.1 0.2 0.3 0.4 [snip] 8.0 STP_EnableGamma/Composite Gamma Enable: *Disabled Enabled STP_Gamma/Composite Gamma Value: 0.10 0.15 0.20 0.25 [snip] 4.00 STP_LinearContrast/Linear Contrast Adjustment: *False True STP_Duplex/Double-Sided Printing: DuplexNoTumble DuplexTumble *None Resolution/Rendering Resolution: *FromPrintoutMode 150x150dpi 300x300dpi 600x600dpi OutputType/Output Type: *FromPrintoutMode BlackAndWhite Grayscale STP_ImageType/Image Type: *FromPrintoutMode Photo Graphics LineArt None Text TextGraphics STP_Resolution/Resolution: *FromPrintoutMode 150dpi 300dpi 600dpi I am particularly looking for options for: "secure print" (possibly by setting a mode and setting a username) stapling hole punching Perhaps I need a vendor specific driver/PPD file? If so, any pointers as I have no idea where to look for one. I haven't been able to find one on the official site or on sites such as http://www.openprinting.org

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What file transfer protocols can be used for PXE booting besides TFTP?

- by Stefan Lasiewski

According to ISC's dhcpd manpage: The filename statement filename "filename"; The filename statement can be used to specify the name of the initial boot file which is to be loaded by a client. The filename should be a filename recognizable to whatever file transfer protocol the client can be expected to use to load the file. My questions are: What file transfer protocols, besides tftp, are available to load the file (e.g. What protocols "can be expected to" load the file)? How can I tell? Can I see a list of these protocols? Does my choice of DHCP server influence which file transfer protocols are in use? Pretend I want to use dnsmasq instead of ISC's dhcpd Are these features dependent on the PXE which is in use (e.g. My Intel NICs use an Intel ROM)? I know that some PXE-variants, such as iPXE/gPXE/Etherboot, can also load files over HTTP. However, the PXE rom needs to be replaced with the iPXE image, either by chainloading or by burning the PXE rom onto the NIC. For example, the iPXE Howto "Using ISC dhcpd" says: ISC dhcpd is configured using the file /etc/dhcpd.conf. You can instruct iPXE to boot using the filename directive: filename "pxelinux.0"; or filename "http://boot.ipxe.org/demo/boot.php";

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What does this example bash startup script do?

- by Dimitri

I am trying to set up GNU Octave on my computer (Mac OS X 10.7.4). I am newbie in using Terminal and I need help to understand what the following script actually does: if [ -f ~/.bashrc ];then        . ~/.bashrc fi PATH=$PATH:/usr/local/bin BASH_ENV=~/.bashrc export BASH_ENV PATH export GNUTERM=aqua alias octave="/Applications/Octave.app/Contents/Resources/bin/octave" alias gnuplot="/Applications/Gnuplot.app/Contents/Resources/bin/gnuplot" (taken from here: http://wikibox.stanford.edu/me112/index.php/Main/OctaveMatlabNotes) So this script begins with the simple conditional if statement. I don't understand the conditional expression - what is -f and .bashrc? What the statement . ~/.bashrc actually does? Then 2 variables are defined PATH and BASH_ENV. Why are they exported? Why GNUTERM=aqua is exported even if it's not defined anywhere? All I need is a script that would allow me to run Octave by simply typing octave in the terminal. I don't need an alias for the gnu plot. Thanks

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Can I use @import to import Kod's default style sheet into my own?

- by Thomas Upton

I understand that Kod is being actively developed and is prone to drastic changes in any area. I would like to modify some small things (like font face and size or certain colors) while still being able to benefit from any changes or updates to the default Kod stylesheet. I thought that I would be able to @import the default stylesheet into my own to achieve this. This is what ~/.kod/custom.css would look like, @import url("file:///Applications/Kod.app/Contents/Resources/style/default.css"); /* Change the default font face and color. */ body { font-family: Menlo, monospace; color: #efefef; } This stylesheet was set with the following defaults command, per the comments at the top of Kod's default CSS file: defaults write se.hunch.kod style/url ~/.kod/custom.css Unfortunately, this didn't work. When I first tried to reload the style, Kod crashed. It opened fine again, but the @import statement wasn't working, and Kod crashed every time I saved the custom.css file. Am I doing something wrong? Did I write my @import statement wrong? Is that not how @import is supposed to work? Did I miss some sort of documentation or Kod Google Groups post that mentions that Kod explicitly disallows this?

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Why is the `remove rows` button not always present in MySQL Workbench?

- by Shawn

I'm using MySQL Workbench to remove rows from a table in my database. Most of the time, I will simply write a select statement, then select the rows I want to erase and use the remove rows button (circled in the screenshot below). But sometimes (quite often actually), the remove rows button does not appear. Instead, I get something like the screenshot below: The remove rows button is not there and the remove rows option is grayed out in the context menu, so basically, I can't remove rows... The only way I've found of solving this issue is to run the select query many times until the button appears (it usually does after 3 of 4 times). Does anyone know why this is happening? UPDATE Today, I've been running a select query dozens of times and the button never appears. It seems my incomprehensible workaround no longer works... Help! btw: Using a delete statement does work, though I would rather not have to write one for each row I want to remove as this happens quite frequently during development...

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Do I need a helper column, or can I do this with a formula?

- by dwwilson66

I am using this formula =IF((LEFT($B26,2)="<p"),0,IF($B26="",0,IF($F26<>"",0,(FIND("""../",$B26))))) To parse data similar to the following.     contractor information       <a href="../City_Electrical_Inspectors.htm"> City Electrical Inspectors</a>     <a href="../City_Electrical_Inspectors.htm">inspection</a> My problem comes in cases such as the first line, in which the line is not a new paragraph nor a link, and my FIND returns an error of #VALUE! Id like to create an IF test to scan the line for the existence of the pattern in my FIND statement before processing that statement. I figured that looking for an error condition may be the way to go. However, the only way I can envision this is as a self-referential formula, similart to the following pseudocode. IF(ISERROR($L26)=TRUE,$L26=0,L$26=the-result-of-the-formula-above) Can this be done with a formula or do I need to use a new helper column? Thanks.

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how to remove location block from $uri in nginx configuration?

- by Jason

I have a rewrite in my ngix conf file that works properly except it seems to include the location block as part of the $uri variable. I only want the path after the location block. My current config code is: location /cargo { try_files $uri $uri/ /cargo/index.php?_REWRITE_COMMAND=$uri&args; } Using an example url of http://localhost/cargo/testpage the redirect works, however the value of the "_REWRITE_COMMAND" parameter received by my php file is "/cargo/testpage". I need to strip off the location block and just have "testpage" as the $uri I am pretty sure there is a regex syntax to split the $uri and assign it to a new variable using $1 $2 etc, but I can't find any example to do just a variable assignment using a regex that is not part of a rewrite statement. I've been looking and trying for hours and I just can't seem to get past this last step. I also know I could just strip this out on the application code, but the reason I want to try to fix it in the nginx conf is for compatibility reasons as it also runs on Apache. I also should say that I have figured out a really hacky way to do it, but it involves an "if" statement to check for file existance and the documentation specifically says not to do it that way. -- UPDATE: ANSWERED BY theuni: The regex goes in the location block definition. one note of caution is that php handler location needs to be ABOVE this location, otherwise you will get a server error because it goes into an infinite redirect loop location ~ ^/cargo/(.*) { try_files $1 /cargo/$1/ /cargo/index.php?_REWRITE_COMMAND=$1&args; }

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Very high Magento/Apache memory usage even without visitors (are we fooled by our hosting company?)

- by MrDobalina

I am no server guy and we have issues with our speed so I come here asking for advise. We have a VPS with 2 cores and 2gb of RAM at a Magento specialized hosting company. Over the course of the last weeks our site speed has gotten worse, even though our store is new, has less than 1000 SKUs and not even 100 visitos a day. At magespeedtest.com we only get 1.87 trans/sec @ 2.11 secs each with a mere 5 concurrent users. Our magento log files are clean, we have no huge database tables or anything like that. When we take a look at our server real time stats, we see that the memory usage jumped up from about 34% to 71% and now 82% in just a few days in idle, with no visitors on the site. Our hosting company said that we do not need to worry about that as it`s maybe related to mysql which creates buffers (which are maybe not even actually being used) and what is important is CPU and swap - stats are ok here. They also said that the low benchmark scores are caused by bad extensions or template modifications on our side. We are not sure if we can trust that statement as we only have 4 plugins installed (all from aheadworks and amasty which are known to be one of the best magento extension developers). Our template modifications are purely html and css, no modifications to the php code. Our pagespeed is ranked with 93/100 in firebug and Magento is properly configured, so the problem really just gets obvious when there are a handful of users on the site at the same time. Can anyone confirm our hosting`s statement about memory usage and where can I start looking for a solution?

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Random movement of wandering monsters in x & y axis in LibGDX

- by Vishal Kumar

I am making a simple top down RPG game in LibGDX. What I want is ... the enemies should wander here and there in x and y directions in certain interval so that it looks natural that they are guarding something. I spend several hours doing this but could not achieve what I want. After a long time of coding, I came with this code. But what I observed is when enemies come to an end of x or start of x or start of y or end of y of the map. It starts flickering for random intervals. Sometimes they remain nice, sometimes, they start flickering for long time. public class Enemy extends Sprite { public float MAX_VELOCITY = 0.05f; public static final int MOVING_LEFT = 0; public static final int MOVING_RIGHT = 1; public static final int MOVING_UP = 2; public static final int MOVING_DOWN = 3; public static final int HORIZONTAL_GUARD = 0; public static final int VERTICAL_GUARD = 1; public static final int RANDOM_GUARD = 2; private float startTime = System.nanoTime(); private static float SECONDS_TIME = 0; private boolean randomDecider; public int enemyType; public static final float width = 30 * World.WORLD_UNIT; public static final float height = 32 * World.WORLD_UNIT; public int state; public float stateTime; public boolean visible; public boolean dead; public Enemy(float x, float y, int enemyType) { super(x, y); state = MOVING_LEFT; this.enemyType = enemyType; stateTime = 0; visible = true; dead = false; boolean random = Math.random()>=0.5f ? true :false; if(enemyType == HORIZONTAL_GUARD){ if(random) velocity.x = -MAX_VELOCITY; else velocity.x = MAX_VELOCITY; } if(enemyType == VERTICAL_GUARD){ if(random) velocity.y = -MAX_VELOCITY; else velocity.y = MAX_VELOCITY; } if(enemyType == RANDOM_GUARD){ //if(random) //velocity.x = -MAX_VELOCITY; //else //velocity.y = MAX_VELOCITY; } } public void update(Enemy e, float deltaTime) { super.update(deltaTime); e.stateTime+= deltaTime; e.position.add(velocity); // This is for updating the Animation for Enemy Movement Direction. VERY IMPORTANT FOR REAL EFFECTS updateDirections(); //Here the various movement methods are called depending upon the type of the Enemy if(e.enemyType == HORIZONTAL_GUARD) guardHorizontally(); if(e.enemyType == VERTICAL_GUARD) guardVertically(); if(e.enemyType == RANDOM_GUARD) guardRandomly(); //quadrantMovement(e, deltaTime); } private void guardHorizontally(){ if(position.x <= 0){ velocity.x= MAX_VELOCITY; velocity.y= 0; } else if(position.x>= World.mapWidth-width){ velocity.x= -MAX_VELOCITY; velocity.y= 0; } } private void guardVertically(){ if(position.y<= 0){ velocity.y= MAX_VELOCITY; velocity.x= 0; } else if(position.y>= World.mapHeight- height){ velocity.y= -MAX_VELOCITY; velocity.x= 0; } } private void guardRandomly(){ if (System.nanoTime() - startTime >= 1000000000) { SECONDS_TIME++; if(SECONDS_TIME % 5==0) randomDecider = Math.random()>=0.5f ? true :false; if(SECONDS_TIME>=30) SECONDS_TIME =0; startTime = System.nanoTime(); } if(SECONDS_TIME <=30){ if(randomDecider && position.x >= 0) velocity.x= -MAX_VELOCITY; else{ if(position.x < World.mapWidth-width) velocity.x= MAX_VELOCITY; else velocity.x= -MAX_VELOCITY; } velocity.y =0; } else{ if(randomDecider && position.y >0) velocity.y= -MAX_VELOCITY; else velocity.y= MAX_VELOCITY; velocity.x =0; } /* //This is essential so as to keep the enemies inside the boundary of the Map if(position.x <= 0){ velocity.x= MAX_VELOCITY; //velocity.y= 0; } else if(position.x>= World.mapWidth-width){ velocity.x= -MAX_VELOCITY; //velocity.y= 0; } else if(position.y<= 0){ velocity.y= MAX_VELOCITY; //velocity.x= 0; } else if(position.y>= World.mapHeight- height){ velocity.y= -MAX_VELOCITY; //velocity.x= 0; } */ } private void updateDirections() { if(velocity.x > 0) state = MOVING_RIGHT; else if(velocity.x<0) state = MOVING_LEFT; else if(velocity.y>0) state = MOVING_UP; else if(velocity.y<0) state = MOVING_DOWN; } public Rectangle getBounds() { return new Rectangle(position.x, position.y, width, height); } private void quadrantMovement(Enemy e, float deltaTime) { int temp = e.getEnemyQuadrant(e.position.x, e.position.y); boolean random = Math.random()>=0.5f ? true :false; switch(temp){ case 1: velocity.x = MAX_VELOCITY; break; case 2: velocity.x = MAX_VELOCITY; break; case 3: velocity.x = -MAX_VELOCITY; break; case 4: velocity.x = -MAX_VELOCITY; break; default: if(random) velocity.x = MAX_VELOCITY; else velocity.y =-MAX_VELOCITY; } } public float getDistanceFromPoint(float p1,float p2){ Vector2 v1 = new Vector2(p1,p2); return position.dst(v1); } private int getEnemyQuadrant(float x, float y){ Rectangle enemyQuad = new Rectangle(x, y, 30, 32); if(ScreenQuadrants.getQuad1().contains(enemyQuad)) return 1; if(ScreenQuadrants.getQuad2().contains(enemyQuad)) return 2; if(ScreenQuadrants.getQuad3().contains(enemyQuad)) return 3; if(ScreenQuadrants.getQuad4().contains(enemyQuad)) return 4; return 0; } } Is there a better way of doing this. I am new to game development. I shall be very grateful to any help or reference.

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HDMI video connection cuts top and bottom borders of screen

- by Luis Alvarado

Ok this is an extension of another problem I had with a VGA connection and an Nvidia Geforce GT 440 card. Here is goes the explanation of this particular problem: I have a Soneview 32' TV. This TV has many connections including VGA (First reason I bought it), HDMI (Second reason but did not have a HDMI cable at that time) and DVI. I have had this TV for little over a month now, actually I had it to celebrate the release of Ubuntu 11.10 and started using it exactly on that date (I know too much fan there but hey, I like geek stuff). I started using it with the VGA cable. After 2 weeks I bought an Nvidia GT440 card. The previous 9500GT was working correctly with no problems whatsoever. I installed the GT440 and the first problem that I encountered using this latest card is mentioned here: Nvidia GT 440 black screen problem when loading lightdm greeter. The solution to this problem was to actually disconnect then connect again the VGA cable. This would result in the screen showing me the lightdm screen for my login. If I did not disconnect then connect the cable I could be there forever thinking that there is no video signal. I got tired of looking for answers that did not work and for solutions that made me literally have to install Ubuntu again. I just went and bought a HDMI cable and changed the VGA one for that one. It worked and I did not have to disconnect/connect the cable but now I have this problem when using any resolution. My normal resolution is 1920x1080 (This TV is 1080HD) so in VGA I could use this resolution with no problem, but on HDMI am getting the borders cut out. Here is a pic: As you can see from the PIC, the Launcher icons only show less than 50% of their witdh. Forget about the top and bottom parts, I can access them with the mouse but I can not visualize them in the screen. It is like it's outside of the TVs view. Basically there is like 20 to 30 pixels gone from all sides. I searched around and came to running xrand --verbose to see what it could detect from the TV. I got this: cyrex@cyrex:~$ xrandr --verbose xrandr: Failed to get size of gamma for output default Screen 0: minimum 320 x 175, current 1920 x 1080, maximum 1920 x 1080 default connected 1920x1080+0+0 (0x164) normal (normal) 0mm x 0mm Identifier: 0x163 Timestamp: 465485 Subpixel: unknown Clones: CRTC: 0 CRTCs: 0 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: 1920x1080 (0x164) 103.7MHz *current h: width 1920 start 0 end 0 total 1920 skew 0 clock 54.0KHz v: height 1080 start 0 end 0 total 1080 clock 50.0Hz 1920x1080 (0x165) 105.8MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 55.1KHz v: height 1080 start 0 end 0 total 1080 clock 51.0Hz 1920x1080 (0x166) 107.8MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 56.2KHz v: height 1080 start 0 end 0 total 1080 clock 52.0Hz 1920x1080 (0x167) 109.9MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 57.2KHz v: height 1080 start 0 end 0 total 1080 clock 53.0Hz 1920x1080 (0x168) 112.0MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 58.3KHz v: height 1080 start 0 end 0 total 1080 clock 54.0Hz 1920x1080 (0x169) 114.0MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 59.4KHz v: height 1080 start 0 end 0 total 1080 clock 55.0Hz 1680x1050 (0x16a) 98.8MHz h: width 1680 start 0 end 0 total 1680 skew 0 clock 58.8KHz v: height 1050 start 0 end 0 total 1050 clock 56.0Hz 1680x1050 (0x16b) 100.5MHz h: width 1680 start 0 end 0 total 1680 skew 0 clock 59.9KHz v: height 1050 start 0 end 0 total 1050 clock 57.0Hz 1600x1024 (0x16c) 95.0MHz h: width 1600 start 0 end 0 total 1600 skew 0 clock 59.4KHz v: height 1024 start 0 end 0 total 1024 clock 58.0Hz 1440x900 (0x16d) 76.5MHz h: width 1440 start 0 end 0 total 1440 skew 0 clock 53.1KHz v: height 900 start 0 end 0 total 900 clock 59.0Hz 1360x768 (0x171) 65.8MHz h: width 1360 start 0 end 0 total 1360 skew 0 clock 48.4KHz v: height 768 start 0 end 0 total 768 clock 63.0Hz 1360x768 (0x172) 66.8MHz h: width 1360 start 0 end 0 total 1360 skew 0 clock 49.2KHz v: height 768 start 0 end 0 total 768 clock 64.0Hz 1280x1024 (0x173) 85.2MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 66.6KHz v: height 1024 start 0 end 0 total 1024 clock 65.0Hz 1280x960 (0x176) 83.6MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 65.3KHz v: height 960 start 0 end 0 total 960 clock 68.0Hz 1280x960 (0x177) 84.8MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 66.2KHz v: height 960 start 0 end 0 total 960 clock 69.0Hz 1280x720 (0x178) 64.5MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 50.4KHz v: height 720 start 0 end 0 total 720 clock 70.0Hz 1280x720 (0x179) 65.4MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 51.1KHz v: height 720 start 0 end 0 total 720 clock 71.0Hz 1280x720 (0x17a) 66.4MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 51.8KHz v: height 720 start 0 end 0 total 720 clock 72.0Hz 1152x864 (0x17b) 72.7MHz h: width 1152 start 0 end 0 total 1152 skew 0 clock 63.1KHz v: height 864 start 0 end 0 total 864 clock 73.0Hz 1152x864 (0x17c) 73.7MHz h: width 1152 start 0 end 0 total 1152 skew 0 clock 63.9KHz v: height 864 start 0 end 0 total 864 clock 74.0Hz ....Many Resolutions later... 320x200 (0x1d1) 10.2MHz h: width 320 start 0 end 0 total 320 skew 0 clock 31.8KHz v: height 200 start 0 end 0 total 200 clock 159.0Hz 320x175 (0x1d2) 9.0MHz h: width 320 start 0 end 0 total 320 skew 0 clock 28.0KHz v: height 175 start 0 end 0 total 175 clock 160.0Hz 1920x1080 (0x1dd) 333.8MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 173.9KHz v: height 1080 start 0 end 0 total 1080 clock 161.0Hz If it helps, the Refresh Rate at 1920x1080 is 60. There is a flickering effect at this resolution using HDMI but not VGA which I imagine is related to the borders cut off issue am asking here. I have also done the following but this will only solve the problem on lower resolutions than 1920x1080 or on others TV (My father has a Sony TV where this problem is also solved): NVIDIA WAY Go to Nvidia-Settings and there will be an option that will have more features if a HDMI cable is connected. In the next pic the option is DFP-1 (CNDLCD) but this name changes depending on what device the PC is connected to: Uncheck Force Full GPU Scaling What this will do for resolutions LOWER than 1920x1080 (At least in my case) is solve the flickering problem and fix the borders cut by the monitor. Save to Xorg.conf file the changes made after changing to a resolution acceptable to your eyes. TV WAY If you TV has OSD Menu and this menu has options for scanning the screen resolution or auto adjusting to it, disable them. Specifically the option about SCAN. If you have an option for AV Mode disable it. Basically disable any option that needs to scan and scale the resolution. Test one by one. In the case of my father's TV this did it. In my case, the Nvidia solved it for lower resolutions. NOTE: In the case this is not solved in the next couple of weeks I will add this as the answer but take into consideration that the issue is still active with 1920x1080 resolutions.

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Accessing a Service from within an XNA Content Pipeline Extension

- by David Wallace

I need to allow my content pipeline extension to use a pattern similar to a factory. I start with a dictionary type: public delegate T Mapper<T>(MapFactory<T> mf, XElement d); public class MapFactory<T> { Dictionary<string, Mapper<T>> map = new Dictionary<string, Mapper<T>>(); public void Add(string s, Mapper<T> m) { map.Add(s, m); } public T Get(XElement xe) { if (xe == null) throw new ArgumentNullException( "Invalid document"); var key = xe.Name.ToString(); if (!map.ContainsKey(key)) throw new ArgumentException( key + " is not a valid key."); return map[key](this, xe); } public IEnumerable<T> GetAll(XElement xe) { if (xe == null) throw new ArgumentNullException( "Invalid document"); foreach (var e in xe.Elements()) { var val = e.Name.ToString(); if (map.ContainsKey(val)) yield return map[val](this, e); } } } Here is one type of object I want to store: public partial class TestContent { // Test type public string title; // Once test if true public bool once; // Parameters public Dictionary<string, object> args; public TestContent() { title = string.Empty; args = new Dictionary<string, object>(); } public TestContent(XElement xe) { title = xe.Name.ToString(); args = new Dictionary<string, object>(); xe.ParseAttribute("once", once); } } XElement.ParseAttribute is an extension method that works as one might expect. It returns a boolean that is true if successful. The issue is that I have many different types of tests, each of which populates the object in a way unique to the specific test. The element name is the key to MapFactory's dictionary. This type of test, while atypical, illustrates my problem. public class LogicTest : TestBase { string opkey; List<TestBase> items; public override bool Test(BehaviorArgs args) { if (items == null) return false; if (items.Count == 0) return false; bool result = items[0].Test(args); for (int i = 1; i < items.Count; i++) { bool other = items[i].Test(args); switch (opkey) { case "And": result &= other; if (!result) return false; break; case "Or": result |= other; if (result) return true; break; case "Xor": result ^= other; break; case "Nand": result = !(result & other); break; case "Nor": result = !(result | other); break; default: result = false; break; } } return result; } public static TestContent Build(MapFactory<TestContent> mf, XElement xe) { var result = new TestContent(xe); string key = "Or"; xe.GetAttribute("op", key); result.args.Add("key", key); var names = mf.GetAll(xe).ToList(); if (names.Count() < 2) throw new ArgumentException( "LogicTest requires at least two entries."); result.args.Add("items", names); return result; } } My actual code is more involved as the factory has two dictionaries, one that turns an XElement into a content type to write and another used by the reader to create the actual game objects. I need to build these factories in code because they map strings to delegates. I have a service that contains several of these factories. The mission is to make these factory classes available to a content processor. Neither the processor itself nor the context it uses as a parameter have any known hooks to attach an IServiceProvider or equivalent. Any ideas?

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