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  • Quantifying the Performance of Garbage Collection vs. Explicit Memory Management

    - by EmbeddedProg
    I found this article here: Quantifying the Performance of Garbage Collection vs. Explicit Memory Management http://www.cs.umass.edu/~emery/pubs/gcvsmalloc.pdf In the conclusion section, it reads: Comparing runtime, space consumption, and virtual memory footprints over a range of benchmarks, we show that the runtime performance of the best-performing garbage collector is competitive with explicit memory management when given enough memory. In particular, when garbage collection has five times as much memory as required, its runtime performance matches or slightly exceeds that of explicit memory management. However, garbage collection’s performance degrades substantially when it must use smaller heaps. With three times as much memory, it runs 17% slower on average, and with twice as much memory, it runs 70% slower. Garbage collection also is more susceptible to paging when physical memory is scarce. In such conditions, all of the garbage collectors we examine here suffer order-of-magnitude performance penalties relative to explicit memory management. So, if my understanding is correct: if I have an app written in native C++ requiring 100 MB of memory, to achieve the same performance with a "managed" (i.e. garbage collector based) language (e.g. Java, C#), the app should require 5*100 MB = 500 MB? (And with 2*100 MB = 200 MB, the managed app would run 70% slower than the native app?) Do you know if current (i.e. latest Java VM's and .NET 4.0's) garbage collectors suffer the same problems described in the aforementioned article? Has the performance of modern garbage collectors improved? Thanks.

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  • groovy compile error

    - by Bunny Rabbit
    class x{ public static void main(String[] args){ String x="<html><head></head></html>"; String arr[]=x.split("<head>"); String script="hi"; x=arr[0]+"<head>"+script+arr[1]; System.out.println(x); } } the above code when compiled as a java file compiles fine but when used a s a groovy file spits the error : org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed: D:\Garage\groovy-binary-1.7.1\groovy-1.7.1\bin\x.groovy: 4: Apparent variable 'a rr' was found in a static scope but doesn't refer to a local variable, static fi eld or class. Possible causes: You attempted to reference a variable in the binding or an instance variable fro m a static context. You misspelled a classname or statically imported field. Please check the spelli ng. You attempted to use a method 'arr' but left out brackets in a place not allowed by the grammar. @ line 4, column 10. String arr[]=x.split(""); ^ D:\Garage\groovy-binary-1.7.1\groovy-1.7.1\bin\x.groovy: 6: Apparent variable 'a rr' was found in a static scope but doesn't refer to a local variable, static fi eld or class. Possible causes: You attempted to reference a variable in the binding or an instance variable fro m a static context. You misspelled a classname or statically imported field. Please check the spelli ng. You attempted to use a method 'arr' but left out brackets in a place not allowed by the grammar. @ line 6, column 5. x=arr[0]+""+script+arr[1]; ^ D:\Garage\groovy-binary-1.7.1\groovy-1.7.1\bin\x.groovy: 6: Apparent variable 'a rr' was found in a static scope but doesn't refer to a local variable, static fi eld or class. Possible causes: You attempted to reference a variable in the binding or an instance variable fro m a static context. You misspelled a classname or statically imported field. Please check the spelli ng. You attempted to use a method 'arr' but left out brackets in a place not allowed by the grammar. @ line 6, column 28. x=arr[0]+""+script+arr[1]; ^ 3 errors D:\Garage\groovy-binary-1.7.1\groovy-1.7.1\bin

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  • How do I avoid the loader lock?

    - by Mark0978
    We have a managed app, that uses an assembly. That assembly uses some unmanaged C++ code. The Managed C++ code is in a dll, that depends on several other dlls. All of those Dlls are loaded by this code. (We load all the dll's that ImageCore.dll depends on first, so we can tell which ones are missing, otherwise it would just show up as ImageCore.dll failed to load, and the log file would give no clues as to why). class Interop { private const int DONT_RESOLVE_DLL_REFERENCES = 1; private static log4net.ILog log = log4net.LogManager.GetLogger("Imagecore.NET"); [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr LoadLibraryEx(string fileName, IntPtr dummy, int flags); [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr FreeLibrary(IntPtr hModule); static private String[] libs = { "log4cplus.dll", "yaz.dll", "zlib1.dll", "libxml2.dll" }; public static void PreloadAssemblies() { for (int i=0; i < libs.Length; ++i) { String libname = libs[i]; IntPtr hModule = LoadLibraryEx(libname, IntPtr.Zero, DONT_RESOLVE_DLL_REFERENCES); if(hModule == IntPtr.Zero) { log.Error("Unable to pre-load '" + libname + "'"); throw new DllNotFoundException("Unable to pre-load '" + libname + "'"); } else { FreeLibrary(hModule); } } IntPtr h = LoadLibraryEx("ImageCore.dll", IntPtr.Zero, 0); if (h == IntPtr.Zero) { throw new DllNotFoundException("Unable to pre-load ImageCore.dll"); } } } And this code is called by public class ImageDoc : IDisposable { static ImageDoc() { ImageHawk.ImageCore.Utility.Interop.PreloadAssemblies(); } ... } Which is static constructor. As near as I can understand it, as soon as we attempt to use an ImageDoc object, the dll that contains that assembly is loaded and as part of that load, the static constructor is called which in turn causes several other DLLs to be loaded as well. What I'm trying to figure out, is how do we defer loading of those DLLs so that we don't run smack dab into this loader lock that is being kicked out because of the static constructor. I've pieced this much together by looking at: http://social.msdn.microsoft.com/Forums/en-US/vsto/thread/dd192d7e-ce92-49ce-beef-3816c88e5a86 http://msdn.microsoft.com/en-us/library/aa290048%28VS.71%29.aspx http://forums.devx.com/showthread.php?t=53529 http://www.yoda.arachsys.com/csharp/beforefieldinit.html But I just can't seem to find a way to get these external DLLs to load without it happening at the point the class is loading. I think I need to get these LoadLibrary calls out of the static constructor, but don't know how to get them called before they are needed (except for how it is done here). I would prefer to not have to put this kind of knowledge of the dlls into every app that uses this assembly. (And I'm not sure that would even fix the problem.... The strange thing is that the exception only appears to be happening while running within the debugger, not while running outside the debugger.

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  • Java: why is declaration not sufficient in interface?

    - by HH
    Big class contains Format-interfcase and Format-class. The Format-class contains the methods and the interface has the values of the fields. I could have the fields in the class Format but the goal is with Interface. So do I just create dummy-vars to get the errors away, design issue or something ELSE? KEY: Declaration VS Initialisation Explain by the terms, why you have to init in interface. What is the logic behind it? To which kind of problems it leads the use of interface? Sample Code having the init-interface-problem import java.util.*; import java.io.*; public class FormatBig { private static class Format implements Format { private static long getSize(File f){return f.length();} private static long getTime(File f){return f.lastModified();} private static boolean isFile(File f){if(f.isFile()){return true;}} private static boolean isBinary(File f){return Match.isBinary(f);} private static char getType(File f){return Match.getTypes(f);} private static String getPath(File f){return getNoErrPath(f);} //Java API: isHidden, --- SYSTEM DEPENDED: toURI, toURL Format(File f) { // PUZZLE 0: would Stack<Object> be easier? size=getSize(f); time=getTime(f); isfile=isFile(f); isBinary=isBinary(f); type=getType(f); path=getPath(f); //PUZZLE 1: how can simplify the assignment? values.push(size); values.push(time); values.push(isfile); values.push(isBinary); values.push(type); values.push(path); } } public static String getNoErrPath(File f) { try{return f.getCanonicalPath(); }catch(Exception e){e.printStackTrace();} } public static final interface Format { //ERR: IT REQUIRES "=" public long size; public long time; public boolean isFile=true; //ERROR goes away if I initialise wit DUMMY public boolean isBinary; public char type; public String path; Stack<Object> values=new Stack<Object>(); } public static void main(String[] args) { Format fm=new Format(new File(".")); for(Object o:values){System.out.println(o);} } }

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  • C# Reading and Writing a Char[] to and from a Byte[]

    - by Simon G
    Hi, I have a byte array of around 10,000 bytes which is basically a blob from delphi that contains char, string, double and arrays of various types. This need to be read in and updated via C#. I've created a very basic reader that gets the byte array from the db and converts the bytes to the relevant object type when accessing the property which works fine. My problem is when I try to write to a specific char[] item, it doesn't seem to update the byte array. I've created the following extensions for reading and writing: public static class CharExtension { public static byte ToByte( this char c ) { return Convert.ToByte( c ); } public static byte ToByte( this char c, int position, byte[] blob ) { byte b = c.ToByte(); blob[position] = b; return b; } } public static class CharArrayExtension { public static byte[] ToByteArray( this char[] c ) { byte[] b = new byte[c.Length]; for ( int i = 1; i < c.Length; i++ ) { b[i] = c[i].ToByte(); } return b; } public static byte[] ToByteArray( this char[] c, int positon, int length, byte[] blob ) { byte[] b = c.ToByteArray(); Array.Copy( b, 0, blob, positon, length ); return b; } } public static class ByteExtension { public static char ToChar( this byte[] b, int position ) { return Convert.ToChar( b[position] ); } } public static class ByteArrayExtension { public static char[] ToCharArray( this byte[] b, int position, int length ) { char[] c = new char[length]; for ( int i = 0; i < length; i++ ) { c[i] = b.ToChar( position ); position += 1; } return c; } } to read and write chars and char arrays my code looks like: Byte[] _Blob; // set from a db field public char ubin { get { return _tariffBlob.ToChar( 14 ); } set { value.ToByte( 14, _Blob ); } } public char[] usercaplas { get { return _tariffBlob.ToCharArray( 2035, 10 ); } set { value.ToByteArray( 2035, 10, _Blob ); } } So to write to the objects I can do: ubin = 'C'; // this will update the byte[] usercaplas = new char[10] { 'A', 'B', etc. }; // this will update the byte[] usercaplas[3] = 'C'; // this does not update the byte[] I know the reason is that the setter property is not being called but I want to know is there a way around this using code similar to what I already have? I know a possible solution is to use a private variable called _usercaplas that I set and update as needed however as the byte array is nearly 10,000 bytes in length the class is already long and I would like a simpler approach as to reduce the overall code length and complexity. Thank

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  • jQuery: Can't get tooltip plugin to work

    - by Rosarch
    I'm trying to use this tooltip plugin: http://bassistance.de/jquery-plugins/jquery-plugin-tooltip/. I can't seem to get it to work. <head> <script type="text/javascript" src="/static/JQuery.js"></script> <script type="text/javascript" src="/static/jquery-ui-1.8.1.custom.min.js"></script> <script type="text/javascript" src="/static/jquery.json-2.2.min.js"></script> <script type="text/javascript" src="/static/jquery.form.js"></script> <script type="text/javascript" src="/static/js-lib/jquery.bgiframe.js"></script> <script type="text/javascript" src="/static/js-lib/jquery.delegate.js"></script> <script type="text/javascript" src="/static/js-lib/jquery.dimensions.js"></script> <script type="text/javascript" src="/static/jquery.tooltip.js"></script> <script type="text/javascript" src="/static/sprintf.js"></script> <script type="text/javascript" src="/static/clientside.js"></script> </head> I try it out in a simple example: clientside.js: $(document).ready(function () { $("#set1 *").tooltip(); }); The target html: <div id="set1"> <p id="welcome">Welcome. What is your email?</p> <form id="form-username-form" action="api/user_of_email" method="get"> <p> <label for="form-username">Email:</label> <input type="text" name="email" id="form-username" /> <input type="submit" value="Submit" id="form-submit" /> </p> </form> <p id="msg-user-accepted"></p> </div> Unfortunately, nothing happens. What am I doing wrong?

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  • Grails many to many using a third 'join' class

    - by andy mccullough
    I read that a m:m relationship often means there is a third class that isn't yet required. So I have m:m on User and Project, and I created a third domain class, ProjectMembership The three domains are as follows (minimized for illustration purposes): User class User { String name static hasMany = [projectMemberships : ProjectMembership] } Project Membership class ProjectMembership { static constraints = { } static belongsTo = [user:User, project:Project] } Project: class Project { String name static hasMany = [projectMemberships : ProjectMembership] static constraints = { } } If I have the ID of the user, how can I get a list of Project objects that they are assigned to?

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  • Rails3 nomethod error #<ActiveRecord::Relation>

    - by Dodi
    Hi! I'm writing a static page controller. I get the menuname in the routes.rb and it's call the static controller show method. match '/:menuname' = 'static#show' And static_controller.rb: @static=Staticpage.where("menuname = ?", params[:menuname]) But if I want print @static.title in the view, I get this error: undefined method `title' for # Whats wrong? the SQL query looks good: SELECT staticpages.* FROM staticpages WHERE (menuname = 'asd')

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  • Guidance: A Branching strategy for Scrum Teams

    - by Martin Hinshelwood
    Having a good branching strategy will save your bacon, or at least your code. Be careful when deviating from your branching strategy because if you do, you may be worse off than when you started! This is one possible branching strategy for Scrum teams and I will not be going in depth with Scrum but you can find out more about Scrum by reading the Scrum Guide and you can even assess your Scrum knowledge by having a go at the Scrum Open Assessment. You can also read SSW’s Rules to Better Scrum using TFS which have been developed during our own Scrum implementations. Acknowledgements Bill Heys – Bill offered some good feedback on this post and helped soften the language. Note: Bill is a VS ALM Ranger and co-wrote the Branching Guidance for TFS 2010 Willy-Peter Schaub – Willy-Peter is an ex Visual Studio ALM MVP turned blue badge and has been involved in most of the guidance including the Branching Guidance for TFS 2010 Chris Birmele – Chris wrote some of the early TFS Branching and Merging Guidance. Dr Paul Neumeyer, Ph.D Parallel Processes, ScrumMaster and SSW Solution Architect – Paul wanted to have feature branches coming from the release branch as well. We agreed that this is really a spin-off that needs own project, backlog, budget and Team. Scenario: A product is developed RTM 1.0 is released and gets great sales.  Extra features are demanded but the new version will have double to price to pay to recover costs, work is approved by the guys with budget and a few sprints later RTM 2.0 is released.  Sales a very low due to the pricing strategy. There are lots of clients on RTM 1.0 calling out for patches. As I keep getting Reverse Integration and Forward Integration mixed up and Bill keeps slapping my wrists I thought I should have a reminder: You still seemed to use reverse and/or forward integration in the wrong context. I would recommend reviewing your document at the end to ensure that it agrees with the common understanding of these terms merge (forward integration) from parent to child (same direction as the branch), and merge  (reverse integration) from child to parent (the reverse direction of the branch). - one of my many slaps on the wrist from Bill Heys.   As I mentioned previously we are using a single feature branching strategy in our current project. The single biggest mistake developers make is developing against the “Main” or “Trunk” line. This ultimately leads to messy code as things are added and never finished. Your only alternative is to NEVER check in unless your code is 100%, but this does not work in practice, even with a single developer. Your ADD will kick in and your half-finished code will be finished enough to pass the build and the tests. You do use builds don’t you? Sadly, this is a very common scenario and I have had people argue that branching merely adds complexity. Then again I have seen the other side of the universe ... branching  structures from he... We should somehow convince everyone that there is a happy between no-branching and too-much-branching. - Willy-Peter Schaub, VS ALM Ranger, Microsoft   A key benefit of branching for development is to isolate changes from the stable Main branch. Branching adds sanity more than it adds complexity. We do try to stress in our guidance that it is important to justify a branch, by doing a cost benefit analysis. The primary cost is the effort to do merges and resolve conflicts. A key benefit is that you have a stable code base in Main and accept changes into Main only after they pass quality gates, etc. - Bill Heys, VS ALM Ranger & TFS Branching Lead, Microsoft The second biggest mistake developers make is branching anything other than the WHOLE “Main” line. If you branch parts of your code and not others it gets out of sync and can make integration a nightmare. You should have your Source, Assets, Build scripts deployment scripts and dependencies inside the “Main” folder and branch the whole thing. Some departments within MSFT even go as far as to add the environments used to develop the product in there as well; although I would not recommend that unless you have a massive SQL cluster to house your source code. We tried the “add environment” back in South-Africa and while it was “phenomenal”, especially when having to switch between environments, the disk storage and processing requirements killed us. We opted for virtualization to skin this cat of keeping a ready-to-go environment handy. - Willy-Peter Schaub, VS ALM Ranger, Microsoft   I think people often think that you should have separate branches for separate environments (e.g. Dev, Test, Integration Test, QA, etc.). I prefer to think of deploying to environments (such as from Main to QA) rather than branching for QA). - Bill Heys, VS ALM Ranger & TFS Branching Lead, Microsoft   You can read about SSW’s Rules to better Source Control for some additional information on what Source Control to use and how to use it. There are also a number of branching Anti-Patterns that should be avoided at all costs: You know you are on the wrong track if you experience one or more of the following symptoms in your development environment: Merge Paranoia—avoiding merging at all cost, usually because of a fear of the consequences. Merge Mania—spending too much time merging software assets instead of developing them. Big Bang Merge—deferring branch merging to the end of the development effort and attempting to merge all branches simultaneously. Never-Ending Merge—continuous merging activity because there is always more to merge. Wrong-Way Merge—merging a software asset version with an earlier version. Branch Mania—creating many branches for no apparent reason. Cascading Branches—branching but never merging back to the main line. Mysterious Branches—branching for no apparent reason. Temporary Branches—branching for changing reasons, so the branch becomes a permanent temporary workspace. Volatile Branches—branching with unstable software assets shared by other branches or merged into another branch. Note   Branches are volatile most of the time while they exist as independent branches. That is the point of having them. The difference is that you should not share or merge branches while they are in an unstable state. Development Freeze—stopping all development activities while branching, merging, and building new base lines. Berlin Wall—using branches to divide the development team members, instead of dividing the work they are performing. -Branching and Merging Primer by Chris Birmele - Developer Tools Technical Specialist at Microsoft Pty Ltd in Australia   In fact, this can result in a merge exercise no-one wants to be involved in, merging hundreds of thousands of change sets and trying to get a consolidated build. Again, we need to find a happy medium. - Willy-Peter Schaub on Merge Paranoia Merge conflicts are generally the result of making changes to the same file in both the target and source branch. If you create merge conflicts, you will eventually need to resolve them. Often the resolution is manual. Merging more frequently allows you to resolve these conflicts close to when they happen, making the resolution clearer. Waiting weeks or months to resolve them, the Big Bang approach, means you are more likely to resolve conflicts incorrectly. - Bill Heys, VS ALM Ranger & TFS Branching Lead, Microsoft   Figure: Main line, this is where your stable code lives and where any build has known entities, always passes and has a happy test that passes as well? Many development projects consist of, a single “Main” line of source and artifacts. This is good; at least there is source control . There are however a couple of issues that need to be considered. What happens if: you and your team are working on a new set of features and the customer wants a change to his current version? you are working on two features and the customer decides to abandon one of them? you have two teams working on different feature sets and their changes start interfering with each other? I just use labels instead of branches? That's a lot of “what if’s”, but there is a simple way of preventing this. Branching… In TFS, labels are not immutable. This does not mean they are not useful. But labels do not provide a very good development isolation mechanism. Branching allows separate code sets to evolve separately (e.g. Current with hotfixes, and vNext with new development). I don’t see how labels work here. - Bill Heys, VS ALM Ranger & TFS Branching Lead, Microsoft   Figure: Creating a single feature branch means you can isolate the development work on that branch.   Its standard practice for large projects with lots of developers to use Feature branching and you can check the Branching Guidance for the latest recommendations from the Visual Studio ALM Rangers for other methods. In the diagram above you can see my recommendation for branching when using Scrum development with TFS 2010. It consists of a single Sprint branch to contain all the changes for the current sprint. The main branch has the permissions changes so contributors to the project can only Branch and Merge with “Main”. This will prevent accidental check-ins or checkouts of the “Main” line that would contaminate the code. The developers continue to develop on sprint one until the completion of the sprint. Note: In the real world, starting a new Greenfield project, this process starts at Sprint 2 as at the start of Sprint 1 you would have artifacts in version control and no need for isolation.   Figure: Once the sprint is complete the Sprint 1 code can then be merged back into the Main line. There are always good practices to follow, and one is to always do a Forward Integration from Main into Sprint 1 before you do a Reverse Integration from Sprint 1 back into Main. In this case it may seem superfluous, but this builds good muscle memory into your developer’s work ethic and means that no bad habits are learned that would interfere with additional Scrum Teams being added to the Product. The process of completing your sprint development: The Team completes their work according to their definition of done. Merge from “Main” into “Sprint1” (Forward Integration) Stabilize your code with any changes coming from other Scrum Teams working on the same product. If you have one Scrum Team this should be quick, but there may have been bug fixes in the Release branches. (we will talk about release branches later) Merge from “Sprint1” into “Main” to commit your changes. (Reverse Integration) Check-in Delete the Sprint1 branch Note: The Sprint 1 branch is no longer required as its useful life has been concluded. Check-in Done But you are not yet done with the Sprint. The goal in Scrum is to have a “potentially shippable product” at the end of every Sprint, and we do not have that yet, we only have finished code.   Figure: With Sprint 1 merged you can create a Release branch and run your final packaging and testing In 99% of all projects I have been involved in or watched, a “shippable product” only happens towards the end of the overall lifecycle, especially when sprints are short. The in-between releases are great demonstration releases, but not shippable. Perhaps it comes from my 80’s brain washing that we only ship when we reach the agreed quality and business feature bar. - Willy-Peter Schaub, VS ALM Ranger, Microsoft Although you should have been testing and packaging your code all the way through your Sprint 1 development, preferably using an automated process, you still need to test and package with stable unchanging code. This is where you do what at SSW we call a “Test Please”. This is first an internal test of the product to make sure it meets the needs of the customer and you generally use a resource external to your Team. Then a “Test Please” is conducted with the Product Owner to make sure he is happy with the output. You can read about how to conduct a Test Please on our Rules to Successful Projects: Do you conduct an internal "test please" prior to releasing a version to a client?   Figure: If you find a deviation from the expected result you fix it on the Release branch. If during your final testing or your “Test Please” you find there are issues or bugs then you should fix them on the release branch. If you can’t fix them within the time box of your Sprint, then you will need to create a Bug and put it onto the backlog for prioritization by the Product owner. Make sure you leave plenty of time between your merge from the development branch to find and fix any problems that are uncovered. This process is commonly called Stabilization and should always be conducted once you have completed all of your User Stories and integrated all of your branches. Even once you have stabilized and released, you should not delete the release branch as you would with the Sprint branch. It has a usefulness for servicing that may extend well beyond the limited life you expect of it. Note: Don't get forced by the business into adding features into a Release branch instead that indicates the unspoken requirement is that they are asking for a product spin-off. In this case you can create a new Team Project and branch from the required Release branch to create a new Main branch for that product. And you create a whole new backlog to work from.   Figure: When the Team decides it is happy with the product you can create a RTM branch. Once you have fixed all the bugs you can, and added any you can’t to the Product Backlog, and you Team is happy with the result you can create a Release. This would consist of doing the final Build and Packaging it up ready for your Sprint Review meeting. You would then create a read-only branch that represents the code you “shipped”. This is really an Audit trail branch that is optional, but is good practice. You could use a Label, but Labels are not Auditable and if a dispute was raised by the customer you can produce a verifiable version of the source code for an independent party to check. Rare I know, but you do not want to be at the wrong end of a legal battle. Like the Release branch the RTM branch should never be deleted, or only deleted according to your companies legal policy, which in the UK is usually 7 years.   Figure: If you have made any changes in the Release you will need to merge back up to Main in order to finalise the changes. Nothing is really ever done until it is in Main. The same rules apply when merging any fixes in the Release branch back into Main and you should do a reverse merge before a forward merge, again for the muscle memory more than necessity at this stage. Your Sprint is now nearly complete, and you can have a Sprint Review meeting knowing that you have made every effort and taken every precaution to protect your customer’s investment. Note: In order to really achieve protection for both you and your client you would add Automated Builds, Automated Tests, Automated Acceptance tests, Acceptance test tracking, Unit Tests, Load tests, Web test and all the other good engineering practices that help produce reliable software.     Figure: After the Sprint Planning meeting the process begins again. Where the Sprint Review and Retrospective meetings mark the end of the Sprint, the Sprint Planning meeting marks the beginning. After you have completed your Sprint Planning and you know what you are trying to achieve in Sprint 2 you can create your new Branch to develop in. How do we handle a bug(s) in production that can’t wait? Although in Scrum the only work done should be on the backlog there should be a little buffer added to the Sprint Planning for contingencies. One of these contingencies is a bug in the current release that can’t wait for the Sprint to finish. But how do you handle that? Willy-Peter Schaub asked an excellent question on the release activities: In reality Sprint 2 starts when sprint 1 ends + weekend. Should we not cater for a possible parallelism between Sprint 2 and the release activities of sprint 1? It would introduce FI’s from main to sprint 2, I guess. Your “Figure: Merging print 2 back into Main.” covers, what I tend to believe to be reality in most cases. - Willy-Peter Schaub, VS ALM Ranger, Microsoft I agree, and if you have a single Scrum team then your resources are limited. The Scrum Team is responsible for packaging and release, so at least one run at stabilization, package and release should be included in the Sprint time box. If more are needed on the current production release during the Sprint 2 time box then resource needs to be pulled from Sprint 2. The Product Owner and the Team have four choices (in order of disruption/cost): Backlog: Add the bug to the backlog and fix it in the next Sprint Buffer Time: Use any buffer time included in the current Sprint to fix the bug quickly Make time: Remove a Story from the current Sprint that is of equal value to the time lost fixing the bug(s) and releasing. Note: The Team must agree that it can still meet the Sprint Goal. Cancel Sprint: Cancel the sprint and concentrate all resource on fixing the bug(s) Note: This can be a very costly if the current sprint has already had a lot of work completed as it will be lost. The choice will depend on the complexity and severity of the bug(s) and both the Product Owner and the Team need to agree. In this case we will go with option #2 or #3 as they are uncomplicated but severe bugs. Figure: Real world issue where a bug needs fixed in the current release. If the bug(s) is urgent enough then then your only option is to fix it in place. You can edit the release branch to find and fix the bug, hopefully creating a test so it can’t happen again. Follow the prior process and conduct an internal and customer “Test Please” before releasing. You can read about how to conduct a Test Please on our Rules to Successful Projects: Do you conduct an internal "test please" prior to releasing a version to a client?   Figure: After you have fixed the bug you need to ship again. You then need to again create an RTM branch to hold the version of the code you released in escrow.   Figure: Main is now out of sync with your Release. We now need to get these new changes back up into the Main branch. Do a reverse and then forward merge again to get the new code into Main. But what about the branch, are developers not working on Sprint 2? Does Sprint 2 now have changes that are not in Main and Main now have changes that are not in Sprint 2? Well, yes… and this is part of the hit you take doing branching. But would this scenario even have been possible without branching?   Figure: Getting the changes in Main into Sprint 2 is very important. The Team now needs to do a Forward Integration merge into their Sprint and resolve any conflicts that occur. Maybe the bug has already been fixed in Sprint 2, maybe the bug no longer exists! This needs to be identified and resolved by the developers before they continue to get further out of Sync with Main. Note: Avoid the “Big bang merge” at all costs.   Figure: Merging Sprint 2 back into Main, the Forward Integration, and R0 terminates. Sprint 2 now merges (Reverse Integration) back into Main following the procedures we have already established.   Figure: The logical conclusion. This then allows the creation of the next release. By now you should be getting the big picture and hopefully you learned something useful from this post. I know I have enjoyed writing it as I find these exploratory posts coupled with real world experience really help harden my understanding.  Branching is a tool; it is not a silver bullet. Don’t over use it, and avoid “Anti-Patterns” where possible. Although the diagram above looks complicated I hope showing you how it is formed simplifies it as much as possible.   Technorati Tags: Branching,Scrum,VS ALM,TFS 2010,VS2010

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  • Does HTML 5 &ldquo;Rich vs. Reach&rdquo; a False Choice?

    - by andrewbrust
    The competition between the Web and proprietary rich platforms, including Windows, Mac OS, iPhone/iPad, Adobe’s Flash/AIR and Microsoft’s Silverlight, is not new. But with the emergence of HTML 5 and imminent support for it in the next release of the major Web browsers, the battle is heating up. And with the announcements made Wednesday at Google's I/O conference, it's getting kicked up yet another notch. The impact of this platform battle on companies in the media and advertising world, and the developers who serve them, is significant. The most prominent question is whether video and rich media online will shift towards pure HTML and away from plug-ins like Flash and Silverlight. In fact, certain features in HTML 5 make it suitable for development for line of business applications as well, further threatening those plug-in technologies. So what's the deal? Is this real or hype? To answer that question, I've done my own research into HTML 5's features and talked to several media-focused, New York area developers to get their opinions. I present my findings to you in this post. Before bearing down into HTML 5 specifics and practitioners’ quotes, let's set the context. To understand what HTML 5 can do, take a look at this video of Sports Illustrated’s HTML 5 prototype. This should start to get you bought into the idea that HTML 5 could be a game-changer. Next, if you happen to have installed the beta version of Google's Chrome 5 browser, take a look at the page linked to below, and in that page, click on any of the game thumbnails to see what's possible, without a plug-in, in this brave new world. (Note, although the instructions for each game tell you to press the A key to start, press the Z key instead.). Here's the link: http://www.kesiev.com/akihabara As an adjunct to what's enabled by HTML 5, consider the various transforms that are part of CSS 3. If you're running Safari as your browser, the following link will showcase this live; if not, you'll see a bitmap that will give you an idea of what's possible: http://webkit.org/blog/386/3d-transforms Are you starting to get the picture (literally)? What has up until now required browser plug-ins and other patches to HTML, most typically Flash, will soon be renderable, natively, in all major browsers. Moreover, it's looking likely that developers will be able to deliver such content and experiences in these browsers using one base of markup and script code (using straight JavaScript and/or jQuery), without resorting to browser-specific code and workarounds. If you're skeptical of this, I wouldn't blame you, especially with respect to Microsoft's Internet Explorer. However, i can tell you with confidence that even Microsoft is dedicated to full-on HTML 5 support in version 9 of that browser, which is currently under development. So what’s new in HTML 5, specifically, that makes sites like this possible?  The specification documents go into deep detail, and there’s no sense in rehashing them here, but a summary is probably in order.   Here is a non-authoritative, but useful, list of the major new feature areas in HTML 5: 2D drawing capabilities and 3D transforms. 2D drawing instructions can be embedded statically into a Web page; application interactivity and animation can be achieved through script.  As mentioned above, 3D transforms are technically part of version 3 of the CSS (Cascading Style Sheets) spec, rather than HTML 5, but they can nonetheless be thought of as part of the bundle.  They allow for rendering of 3D images and animations that, together with 2D drawing, make HTML-based games much more feasible than they are presently, as the links above demonstrate. Embedded audio and video. A media player can appear directly in a rendered Web page, using HTML markup and no plug-ins. Alternately, player controls can be hidden and the content can play automatically. Major enhancements to form-based input. This includes such things as specification of required fields, embedding of text “hints” into a control, limiting valid input on a field to dates, email addresses or a list of values.  There’s more to this, but the gist is that line-of-business applications, with complicated input and data validation, are supported directly Offline caching, local storage and client-side SQL database. These facilities allow Web applications to function more like native apps, even if no internet connection is available. User-defined data. Data (or metadata – data about data) can easily be embedded statically and/or retrieved and updated with Javascript code. This avoids having to embed that data in a separate file, or within script code. Taken together, these features position HTML to compete with, and perhaps overtake, Adobe’s Flash/AIR (and Microsoft’s Silverlight) as a viable Web platform for media, RIAs (rich internet applications – apps that function more like desktop software than Web sites) and interactive Web content, including games. What do players in the media world think about this?  From the embedded video above, we know what Sports Illustrated (and, therefore, Time Warner) think.  Hulu, the major Internet site for broadcast TV content, is on record as saying HTML5 video does not pass muster with them, at least not yet.  YouTube, on the other hand, already has an experimental HTML 5-based version of their site.  TechCrunch has reported that NetFlix is flirting with HTML 5 too, especially as it pertains to embedded browsers in TV-based devices.  And the New York Times’ Web site now embeds some video clips without resorting to Flash.  They have to – otherwise iPhone, iPod Touch and iPad users couldn’t see them in the Mobile Safari browser. What do media-focused developers think about all this?  I talked to several to get their opinions. Michael Pinto is CEO and Founder of Very Memorable Design whose primary focus has been to help marketing directors get traction online.  The firm’s client roster includes the likes Time, Inc., Scholastic and PBS.  Pinto predicts that “More and more microsites that were done entirely in Flash will be done more and more using jQuery. I can also see slideshows and video now being done without Flash. However if you needed to create a game or highly interactive activity Flash would still be the way to go for the web.” A dissenting view comes from Jesse Erlbaum, CEO of The Erlbaum Group, LLC, which serves numerous clients in the magazine publishing sector.  When I asked Erlbaum whether he thought HTML 5 and jQuery/JavaScript would steal significant market share from Flash, he responded “Not at all!  In particular, not for media and advertising customers!  These sectors are not generally in the business of making highly functional applications, which is the one place where HTML5/jQuery/etc really shines.” Ironically, Pinto’s firm is a heavy user of Flash for its projects and Erlbaum’s develops atop the “LAMP” (Linux, Apache, MySQL and PHP/Perl) stack.  For whatever reason, each firm seems to see the other’s toolset as a more viable choice.  But both agree that the developer tool story around HTML 5 is deficient.  Pinto explains “What’s lost with [HTML 5 and Javascript] techniques is that there isn’t a single widely favored easy-to-use tool of choice for authoring. So with Flash you can get up and running right away and not worry about what is different from one browser to the next.“  Erlbaum agrees, saying: “HTML5/Javascript lacks a sophisticated integrated development environment (IDE) which is an essential part of Flash.  If what someone is trying to make is primarily animation, it's a waste of time…to do this in Javascript.  It can be done much more easily in Flash, and with greater cross-browser compatibility and consistency due to the ubiquity of Flash.” Adobe (maker of Flash since its 2005 acquisition of Macromedia) likely agrees.  And for better or worse, they’ve decided to address this shortcoming of HTML 5, even at risk of diminishing their Flash platfrom. Yesterday Adobe announced that their hugely popular Deamweaver Web design authoring tool would directly support HTML 5 and CSS 3 development.  In fact, the Adobe Dreamweaver CS5 HTML5 Pack is downloadable now from Adobe Labs. Maybe Adobe is bowing to pressure from ardent Web professionals like Scott Kellum, Lead Designer at Channel V Media,  a digital and offline branding firm, serving the media and marketing sectors, among others.  Kellum told me that HTML 5 “…will definitely move people away from Flash. It has many of the same functionalities with faster load times and better accessibility. HTML5 will help Flash as well: with the new caching methods you can now even run Flash apps offline.” Although all three Web developers I interviewed would agree that Flash is still required for more sophisticated applications, Kellum seems to have put his finger on why HTML 5 may nonetheless dominate.  In his view, much of the Web development out there has little need for high-end capabilities: “Most people want to add a little punch to a navigation bar or some video and now you can get the biggest bang for your buck with HTML5, CSS3 and Javascript.” I’ve already mentioned that Google’s ongoing I/O conference, at the Moscone West center in San Francisco, is driving the HTML 5 news cycle, big time.  And Google made many announcements of their own, including the open sourcing of their VP8 video codec, new enterprise-oriented capabilities for its App Engine cloud offering, and the creation of the Chrome Web Store, which the company says will make it easier to find and “install” Web applications, in a fashion similar to  the way users procure native apps on various mobile platforms. HTML 5 looks to be disruptive, especially to the media world.  And even if the technology ends up disappointing, the chatter around it alone is causing big changes in the technology world.  If the richness it promises delivers, then magazine publishers and non-text digital advertisers may indeed have a platform for creating compelling content that loads quickly, is standards-based and will render identically in (the newest versions of) all major Web browsers.  Can this development in the digital arena save the titans of the print world?  I can’t predict, but it’s going to be fun to watch, and the competitive innovation from all players in both industries will likely be immense.

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  • Loading class instance from XML with Texture2D

    - by Thegluestickman
    I'm having trouble with XML and XNA. I want to be able to load weapon settings through XML to make my weapons easier to make and to have less code in the actual project file. So I started out making a basic XML document, something to just assign variables with. But no matter what I changed it gave me a new error every time. The code below gives me a "XML element 'Tag' not found", I added and it started to say the variables weren't found. What I wanted to do in the XML file as well, was load a texture for the file too. So I created a static class to hold my texture values, then in the Texture tag of my XML document I would set it to that instance too. I think that's were the problems are occuring because that's where the "XML element 'Tag' not found" error is pointing me too. My XML document: <XnaContent> <Asset Type="ConversationEngine.Weapon"> <weaponStrength>0</weaponStrength> <damageModifiers>0</damageModifiers> <speed>0</speed> <magicDefense>0</magicDefense> <description>0</description> <identifier>0</identifier> <weaponTexture>LoadWeaponTextures.ironSword</weaponTexture> </Asset> </XnaContent> My Class to load the weapon XML: public class Weapon { public int weaponStrength; public int damageModifiers; public int speed; public int magicDefense; public string description; public string identifier; public Texture2D weaponTexture; } public static class LoadWeaponXML { static Weapon Weapons; public static Weapon WeaponLoad(ContentManager content, int id) { Weapons = content.Load<Weapon>(@"Weapons/" + id); return Weapons; } } public static class LoadWeaponTextures { public static Texture2D ironSword; public static void TextureLoad(ContentManager content) { ironSword = content.Load<Texture2D>("Sword"); } } I'm not entirely sure if you can load textures through XML, but any help would be greatly appreciated.

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  • Useful Extensions for SecurityToken Handling - Convert a SecurityToken to Claims

    - by Your DisplayName here!
    That’s a very common one: public static IClaimsPrincipal ToClaimsPrincipal( this SecurityToken token, X509Certificate2 signingCertificate) {     var configuration = CreateStandardConfiguration(signingCertificate);     return token.ToClaimsPrincipal(configuration.CreateDefaultHandlerCollection()); }   public static IClaimsPrincipal ToClaimsPrincipal(this SecurityToken token, X509Certificate2 signingCertificate, string audienceUri) {     var configuration = CreateStandardConfiguration(signingCertificate);     configuration.AudienceRestriction.AudienceMode = AudienceUriMode.Always;     configuration.AudienceRestriction.AllowedAudienceUris.Add(new Uri(audienceUri));     return token.ToClaimsPrincipal(configuration.CreateDefaultHandlerCollection()); }   public static IClaimsPrincipal ToClaimsPrincipal( this SecurityToken token, SecurityTokenHandlerCollection handler) {     var ids = handler.ValidateToken(token);     return ClaimsPrincipal.CreateFromIdentities(ids); }   private static SecurityTokenHandlerConfiguration CreateStandardConfiguration( X509Certificate2 signingCertificate) {     var configuration = new SecurityTokenHandlerConfiguration();     configuration.AudienceRestriction.AudienceMode = AudienceUriMode.Never;     configuration.IssuerNameRegistry = signingCertificate.CreateIssuerNameRegistry();     configuration.IssuerTokenResolver = signingCertificate.CreateSecurityTokenResolver();     configuration.SaveBootstrapTokens = true;     return configuration; }  private static IssuerNameRegistry CreateIssuerNameRegistry(this X509Certificate2 certificate) {     var registry = new ConfigurationBasedIssuerNameRegistry();     registry.AddTrustedIssuer(certificate.Thumbprint, certificate.Subject);     return registry; }   private static SecurityTokenResolver CreateSecurityTokenResolver( this X509Certificate2 certificate) {     var tokens = new List<SecurityToken>     {         new X509SecurityToken(certificate)     };     return SecurityTokenResolver.CreateDefaultSecurityTokenResolver(tokens.AsReadOnly(), true); }   private static SecurityTokenHandlerCollection CreateDefaultHandlerCollection( this SecurityTokenHandlerConfiguration configuration) {     return  SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection(configuration); }  

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  • Writing file from HttpWebRequest periodically vs. after download finishes?

    - by WB3000
    Right now I am using this code to download files (with a Range header). Most of the files are large, and it is running 99% of CPU currently as the file downloads. Is there any way that the file can be written periodically so that it does not remain in RAM constantly? private byte[] GetWebPageContent(string url, long start, long finish) { byte[] result = new byte[finish]; HttpWebRequest request; request = WebRequest.Create(url) as HttpWebRequest; //request.Headers.Add("Range", "bytes=" + start + "-" + finish); request.AddRange((int)start, (int)finish); using (WebResponse response = request.GetResponse()) { return ReadFully(response.GetResponseStream()); } } public static byte[] ReadFully(Stream stream) { byte[] buffer = new byte[32768]; using (MemoryStream ms = new MemoryStream()) { while (true) { int read = stream.Read(buffer, 0, buffer.Length); if (read <= 0) return ms.ToArray(); ms.Write(buffer, 0, read); } } }

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  • Address of array vs. address of array[0] - C language

    - by user324994
    My question is why does the address of an array differ from the address of its first position? I'm trying to write my own malloc, but to start out I'm just allocating a chunk of memory and playing around with the addresses. My code looks roughly like this: #define BUFF_SIZE 1024 static char *mallocbuff; int main(){ mallocbuff = malloc(BUFF_SIZE); printf("The address of mallocbuff is %d\n", &mallocbuff); printf("The address of mallocbuff[0] is %d\n", &mallocbuff[0]); } &mallocbuff is the same address every time I run it. &mallocbuff[0] is some random address every time. I was expecting the addresses to match each other. Can anyone explain why this isn't the case?

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  • ERROR: Can't find the archive-keyring

    - by 23tux
    I'm trying to upgrade my Debian Lenny to Squeeze. I've replaced the word lenny to squeeze in sources.list and ran apt-get clean apt-get update apt-get dist-upgrade But after a while, I get this error Preconfiguring packages ... Setting up debian-archive-keyring (2010.08.28) ... ERROR: Can't find the archive-keyring Is the ubuntu-keyring package installed? dpkg: error processing debian-archive-keyring (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: debian-archive-keyring E: Sub-process /usr/bin/dpkg returned an error code (1) So I tried to install apt-get -f install debian-archive-keyring and I got the same error. Then I tried to install apt-get -f install ubuntu-keyring and I got this error: Reading package lists... Done Building dependency tree Reading state information... Done Package ubuntu-keyring is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package ubuntu-keyring has no installation candidate Maybe I have the wrong sources in my sources.list: deb ftp://mirror.hetzner.de/debian/packages squeeze main contrib non-free deb ftp://mirror.hetzner.de/debian/security squeeze/updates main contrib non-free deb http://ftp.de.debian.org/debian/ squeeze main non-free contrib deb-src http://ftp.de.debian.org/debian/ squeeze main non-free contrib deb http://security.debian.org/ squeeze/updates main contrib non-free deb-src http://security.debian.org/ squeeze/updates main contrib non-free Hope anyone can help me, thx, tux

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  • BOINC error code -1200 when opening...

    - by Erik Vold
    I installed boinc 6.10.21 on my macosx 10.5 in order to upgrade from a 6.6 version that I was running today, and I am the admin user, and I was logged in as the admin user. As I was installing 6.10.21 I was asked if non admin users should be allowed to use boinc, and I said 'yes' to this. Then when I tried to open boinc I got a message like the following: "You currently are not authorized to manage the client. Either re-install and allow non-admin users or contact your administrator to add you to the 'boinc_master' user group." So I tried to reinstall first, and I was not asked if non admin users should be allowed to use boinc.. so I retried a few times and got no different result.. So I downloaded 6.10.43 and installed that, and again I was not asked if non admin users should be allowed to use boinc.. and when I tried to run boinc I got the same message like: "You currently are not authorized to manage the client. Either re-install and allow non-admin users or contact your administrator to add you to the 'boinc_master' user group." So I did a google search trying to figure out how to add my admin user to the bonic_master user group and found this which suggested I run the following in terminal: "sudo dscl . -append /Groups/boinc_master GroupMembership <your user's short name> CR" So I did this and now I get the following error: BOINC ownership or permissions are not set properly; please reinstall BOINC (Error code -1200) So I reinstall and I am ever asked the question about allowing non admin users again, and I still get this error message every after every reinstall attempt.. What should I do?..

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  • Firefox and Chrome keeps forcing HTTPS on Rails app using nginx/Passenger

    - by Steve
    I've got a really weird problem here where every time I try to browse my Rails app in non-SSL mode Chrome (v16) and Firefox (v7) keeps forcing my website to be served in HTTPS. My Rails application is deployed on a Ubuntu VPS using Capistrano, nginx, Passenger and a wildcard SSL certificate. I have set these parameters for port 80 in the nginx.conf: passenger_set_cgi_param HTTP_X_FORWARDED_PROTO http; passenger_set_cgi_param HTTPS off; The long version of my nginx.conf can be found here: https://gist.github.com/2eab42666c609b015bff The ssl-redirect.include file contains: rewrite ^/sign_up https://$host$request_uri? permanent ; rewrite ^/login https://$host$request_uri? permanent ; rewrite ^/settings/password https://$host$request_uri? permanent ; It is to make sure those three pages use HTTPS when coming from non-SSL request. My production.rb file contains this line: # Enable HTTP and HTTPS in parallel config.middleware.insert_before Rack::Lock, Rack::SSL, :exclude => proc { |env| env['HTTPS'] != 'on' } I have tried redirecting to HTTP via nginx rewrites, Ruby on Rails redirects and also used Rails view url using HTTP protocol. My application.rb file contains this methods used in a before_filter hook: def force_http if Rails.env.production? if request.ssl? redirect_to :protocol => 'http', :status => :moved_permanently end end end Every time I try to redirect to HTTP non-SSL the browser attempts to redirect it back to HTTPS causing an infinite redirect loop. Safari, however, works just fine. Even when I've disabled serving SSL in nginx the browsers still try to connect to the site using HTTPS. I should also mention that when I pushed my app on to Heroku, the Rails redirect work just fine for all browsers. The reason why I want to use non-SSL is that my homepage contains non-secure dynamic embedded objects and a non-secure CDN and I want to prevent security warnings. I don't know what is causing the browser to keep forcing HTTPS requests.

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  • Boinc permissions problem on OS X

    - by Erik Vold
    I installed boinc 6.10.21 on my OS X 10.5 in order to upgrade from a 6.6 version that I was running today, and I am the admin user, and I was logged in as the admin user. As I was installing 6.10.21 I was asked if non admin users should be allowed to use Boinc, and I said 'yes' to this. Then when I tried to open Boinc I got a message like the following: "You currently are not authorized to manage the client. Either re-install and allow non-admin users or contact your administrator to add you to the 'boinc_master' user group." So I tried to reinstall first, and I was not asked if non admin users should be allowed to use Boinc.. so I retried a few times and got no different result.. So I downloaded 6.10.43 and installed that, and again I was not asked if non admin users should be allowed to use boinc.. and when I tried to run Boinc I got the same message like: "You currently are not authorized to manage the client. Either re-install and allow non-admin users or contact your administrator to add you to the 'boinc_master' user group." So I did a Google search trying to figure out how to add my admin user to the bonic_master user group and found this which suggested I run the following in terminal: "sudo dscl . -append /Groups/boinc_master GroupMembership <your user's short name> CR" So I did this and now I get the following error: BOINC ownership or permissions are not set properly; please reinstall BOINC (Error code -1200) So I reinstall and I am ever asked the question about allowing non admin users again, and I still get this error message every after every reinstall attempt.. What should I do?..

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  • update from debian lenny to squeeze

    - by Daniel
    I'm trying to update from debian lenny to squeeze on my 64bit root server and did the following so far: modifying sources.list apt-get update apt-get upgrade apt-get install linux-image-2.6-amd64 The last step leads to the following error-output: Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: linux-image-2.6-amd64: Depends: linux-image-2.6.32-5-amd64 but it is not going to be installed E: Broken packages UPDATE: here's my sources.list deb ftp://mirror.hetzner.de/debian/packages squeeze main contrib non-free deb ftp://mirror.hetzner.de/debian/security squeeze/updates main contrib non-free deb http://ftp.de.debian.org/debian squeeze main non-free contrib deb-src http://ftp.de.debian.org/debian squeeze main non-free contrib deb http://security.debian.org/ squeeze/updates main contrib non-free deb-src http://security.debian.org/ squeeze/updates main contrib non-free How can I fix that safely? thx

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  • NHibernate Session Load vs Get when using Table per Hierarchy. Always use ISession.Get&lt;T&gt; for TPH to work.

    - by Rohit Gupta
    Originally posted on: http://geekswithblogs.net/rgupta/archive/2014/06/01/nhibernate-session-load-vs-get-when-using-table-per-hierarchy.aspxNHibernate ISession has two methods on it : Load and Get. Load allows the entity to be loaded lazily, meaning the actual call to the database is made only when properties on the entity being loaded is first accessed. Additionally, if the entity has already been loaded into NHibernate Cache, then the entity is loaded directly from the cache instead of querying the underlying database. ISession.Get<T> instead makes the call to the database, every time it is invoked. With this background, it is obvious that we would prefer ISession.Load<T> over ISession.Get<T> most of the times for performance reasons to avoid making the expensive call to the database. let us consider the impact of using ISession.Load<T> when we are using the Table per Hierarchy implementation of NHibernate. Thus we have base class/ table Animal, there is a derived class named Snake with the Discriminator column being Type which in this case is “Snake”. If we load This Snake entity using the Repository for Animal, we would have a entity loaded, as shown below: public T GetByKey(object key, bool lazy = false) { if (lazy) return CurrentSession.Load<T>(key); return CurrentSession.Get<T>(key); } var tRepo = new NHibernateReadWriteRepository<TPHAnimal>(); var animal = tRepo.GetByKey(new Guid("602DAB56-D1BD-4ECC-B4BB-1C14BF87F47B"), true); var snake = animal as Snake; snake is null As you can see that the animal entity retrieved from the database cannot be cast to Snake even though the entity is actually a snake. The reason being ISession.Load prevents the entity to be cast to Snake and will throw the following exception: System.InvalidCastException :  Message=Unable to cast object of type 'TPHAnimalProxy' to type 'NHibernateChecker.Model.Snake'. Thus we can see that if we lazy load the entity using ISession.Load<TPHAnimal> then we get a TPHAnimalProxy and not a snake. =============================================================== However if do not lazy load the same cast works perfectly fine, this is since we are loading the entity from database and the entity being loaded is not a proxy. Thus the following code does not throw any exceptions, infact the snake variable is not null: var tRepo = new NHibernateReadWriteRepository<TPHAnimal>(); var animal = tRepo.GetByKey(new Guid("602DAB56-D1BD-4ECC-B4BB-1C14BF87F47B"), false); var snake = animal as Snake; if (snake == null) { var snake22 = (Snake) animal; }

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  • Maintaining a Python web application: heavier vs lighter framework?

    - by Tiberiu Ana
    Five+ years from now, you are hired to support and extend a data-centric web application written in Python that hasn't been kept up to date. Would you rather prefer it was written in the current version of Django/Pylons at the time, using the available standard components, or kept minimal with something like CherryPy/web.py and a few library dependencies? Heavy framework Advantages: standard approach to application design and structure, as encouraged by framework; less application code to worry about. Disadvantages: requires learning the framework to understand how things work; broken things in old version of framework difficult to fix; upgrading to new version potentially difficult due to changing APIs; finding relevant documentation/help potentially difficult due to changing APIs. Light framework Advantages: most application code is directly "visible"; only needed features are implemented; architecture should be simpler to understand; less need to upgrade external dependencies; easier to upgrade external dependencies. Disadvantages: some reinventing the wheel; non-standard design and structure (with the associated unique issues and bugs). I will update the list with any helpful answers.

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  • "Work stealing" vs. "Work shrugging (tm)"?

    - by John
    Why is it that I can find lots of information on "work stealing" and nothing on a "work shrugging(tm)" as a load-balancing strategy? I am surprised because work-stealing seems to me to have an inherent weakness when implementating efficient fine-grained load-balancing. Vis:- Relying on consumer processors to implement distribution (by actively stealing) begs the question of what these processors do when they find no work? None of the work-stealing references and implementations I have come across so far address this issue satisfactorarily for me. They either:- 1) Manage not to disclose what they do with idle processors! [Cilk] (?anyone know?) 2) Have all idle processors sleep and wake periodically and scatter messages to the four winds to see if any work has arrived [e.g. JAWS] (= way too latent & inefficient for me). 3) Assume that it is acceptable to have processors "spinning" looking for work ( = non-starter for me!) Unless anyone thinks there is a solution for this I will move on to consider a "Work Shrugging(tm)" strategy. Having the task-producing processor distribute excess load seems to me inherently capable of a much more efficient implementation. However a quick google didn't show up anything under the heading of "Work Shrugging" so any pointers to prior-art would be welcome. tx Tags I would have added if I was allowed to [work-stealing]

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  • Visual C++ 2008 runtime error-- debug vs release exe problem?

    - by larryq
    Hi everyone, I have a Windows executable (native, not .Net) project that I'm trying to pass along to a new team member. It's a graphics modeling tool that uses the Qt widget library and OpenGL. The project runs fine on my box but when we buld and link it on this new member's machine and he tries deubugging it, here's what he sees (not all entries included, for brevity): ModelingTool.exe': Loaded 'C:\ModelingTool\ModelingTool\ModelingTool\Debug\ModelingTool.exe', Symbols loaded. 'ModelingTool.exe': Loaded 'C:\Windows\System32\ntdll.dll', Cannot find or open the PDB file 'ModelingTool.exe': Loaded 'C:\Windows\System32\kernel32.dll', Cannot find or open the PDB file 'ModelingTool.exe': Loaded 'C:\Windows\System32\opengl32.dll', Cannot find or open the PDB file 'ModelingTool.exe': Loaded 'C:\Windows\System32\msvcrt.dll', Cannot find or open the PDB file 'ModelingTool.exe': Loaded 'C:\Windows\System32\dwmapi.dll', Cannot find or open the PDB file 'ModelingTool.exe': Loaded 'C:\Qt\4.2.2\bin\Qt3Supportd4.dll', Symbols loaded. 'ModelingTool.exe': Loaded 'C:\Program Files\Spyware Doctor\smum32.dll', Binary was not built with debug information. Debugger:: An unhandled non-continuable exception was thrown during process load The program '[5936] ModelingTool.exe: Native' has exited with code -1072365566 (0xc0150002). Would anyone care to guess what's wrong here? Some sort of debug-release mismatch perhaps?

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  • HTTP Negotiate windows vs. Unix server implementation using python-kerberos

    - by ondra
    I tried to implement a simple single-sign-on in my python web server. I have used the python-kerberos package which works nicely. I have tested it from my Linux box (authenticating against active directory) and it was without problem. However, when I tried to authenticate using Firefox from Windows machine (no special setup, just having the user logged into the domain + added my server into negotiate-auth.trusted-uris), it doesn't work. I have looked at what is sent and it doesn't even resemble the things the Linux machine sends. This Microsoft description of the process pretty much resembles the way my interaction from Linux works, but the Windows machine generally sends a very short string, which doesn't even resemble the things microsoft documentation states, and when base64 decoded, it is something like 12 zero bytes followed by 3 or 4 non-zero bytes (GSS functions then return that it doesn't support such scheme) Either there is something wrong with the client Firefox settings, or there is some protocol which I am supposed to follow for the Negotiate protocol, but which I cannot find any reference anywhere. Any ideas what's wrong? Do you have any idea what protocol I should by trying to find, as it doesn' look like SPNEGO, at least from MS documentation.

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  • Retrieving an element by array index in jQuery vs the each() function.

    - by Alex Ciminian
    I was writing a "pluginable" function when I noticed the following behavior (tested in FF 3.5.9 with Firebug 1.5.3). $.fn.computerMove = function () { var board = $(this); var emptySquares = board.find('div.clickable'); var randPosition = Math.floor(Math.random() * emptySquares.length); emptySquares.each(function (index) { if (index === randPosition) { // logs a jQuery object console.log($(this)); } }); target = emptySquares[randPosition]; // logs a non-jQuery object console.log(target); // throws error: attr() not a function for target board.placeMark({'position' : target.attr('id')}); } I noticed the problem when the script threw an error at target.attr('id') (attr not a function). When I checked the log, I noticed that the output (in Firebug) for target was: <div style="width: 97px; height: 97px;" class="square clickable" id="8"></div> If I output $(target), or $(this) from the each() function, I get a nice jQuery object: [ div#8.square ] Now here comes my question: why does this happen, considering that find() seems to return an array of jQuery objects? Why do I have to do $() to target all over again? [div#0.square, div#1.square, div#2.square, div#3.square, div#4.square, div#5.square, div#6.square, div#7.square, div#8.square] Just a curiosity :).

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