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  • Thread management advice - Is TPL a good idea?

    - by Ian
    I'm hoping to get some advice on the use of thread managment and hopefully the task parallel library, because I'm not sure I've been going down the correct route. Probably best is that I give an outline of what I'm trying to do. Given a Problem I need to generate a Solution using a heuristic based algorithm. I start of by calculating a base solution, this operation I don't think can be parallelised so we don't need to worry about. Once the inital solution has been generated, I want to trigger n threads, which attempt to find a better solution. These threads need to do a couple of things: They need to be initalized with a different 'optimization metric'. In other words they are attempting to optimize different things, with a precedence level set within code. This means they all run slightly different calculation engines. I'm not sure if I can do this with the TPL.. If one of the threads finds a better solution that the currently best known solution (which needs to be shared across all threads) then it needs to update the best solution, and force a number of other threads to restart (again this depends on precedence levels of the optimization metrics). I may also wish to combine certain calculations across threads (e.g. keep a union of probabilities for a certain approach to the problem). This is probably more optional though. The whole system needs to be thread safe obviously and I want it to be running as fast as possible. I tried quite an implementation that involved managing my own threads and shutting them down etc, but it started getting quite complicated, and I'm now wondering if the TPL might be better. I'm wondering if anyone can offer any general guidance? Thanks...

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  • Most "thorough" distribution of points around a circle

    - by hippietrail
    This question is intended to both abstract and focus one approach to my problem expressed at "Find the most colourful image in a collection of images". Imagine we have a set of circles, each has a number of points around its circumference. We want to find a metric that gives a higher rating to a circle with points distributed evenly around the circle. Circles with some points scattered through the full 360° are better but circles with far greater numbers of points in one area compared to a smaller number in another area are less good. The number of points is not limited. Two or more points may coincide. Coincidental points are still relevant. A circle with one point at 0° and one point at 180° is better than a circle with 100 points at 0° and 1000 points at 180°. A circle with one point every degree around the circle is very good. A circle with a point every half degree around the circle is better. In my other (colour based question) it was suggested that standard deviation would be useful but with caveat. Is this a good suggestion and does it cope with the closeness of 359° to 1°?

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  • Should uni provide "correct answer" after programming assignment is due?

    - by Michael Mao
    Hi all: This is my very first subjective question. And I think it is programming related - the assignment is to be written in a programming language. I am not for "getting the full marks out of a subject". I am actually not for a "correct answer", but for a "better solution", so that I can compare, and can improve. I reckon it is good that I practice programming first and check the solution later to pick up the things I've done wrong/bad. Without a "benchmark" to against, this would be much harder. Unfortunately as far as I know, not all programming subjects taught in uni would kindly provide the students with a "correct answer" in the end, after the assignment is due. One bad metaphor for this is like someone asks you a question which they don't have a clear answer themselves and hope to take advantage of your answer as the basis for their answer. Personally, I feel having a assignment solution provided by the academic staff is essential to students. I do appreciate this, and I feel I might not be the only one. I am a very proactive student in uni. I learn more, I practice more, an assignment for me is more like a challenge to achieve "the best solution I can come up with", not something "I have to pass"... The cause of this question is that for the past few days I have crafted 500+ lines of Perl code, for a tiny assignment. I feel pain when I look at my solution(not finished yet) and I feel like I am an idiot doing some crap code. I know there must be a much better solution. And I reckon it is better for the lecturer in this subject to get me one, rather than asking for an answer here, even I would shamelessly add the link to my solution apart from the assignment requirements. I know in SO, there are a lot of tutors/lecturers for programming subjects/courses. I'd like to hear your words on this question.

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  • Java Executor: Small tasks or big ones?

    - by Arash Shahkar
    Consider one big task which could be broken into hundreds of small, independently-runnable tasks. To be more specific, each small task is to send a light network request and decide upon the answer received from the server. These small tasks are not expected to take longer than a second, and involve a few servers in total. I have in mind two approaches to implement this using the Executor framework, and I want to know which one's better and why. Create a few, say 5 to 10 tasks each involving doing a bunch of send and receives. Create a single task (Callable or Runnable) for each send & receive and schedule all of them (hundreds) to be run by the executor. I'm sorry if my question shows that I'm lazy to test these and see for myself what's better (at least performance-wise). My question, while looking after an answer to this specific case, has a more general aspect. In situations like these when you want to use an executor to do all the scheduling and other stuff, is it better to create lots of small tasks or to group those into a less number of bigger tasks?

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  • Threshold of blurry image - part 2

    - by 1''
    How can I threshold this blurry image to make the digits as clear as possible? In a previous post, I tried adaptively thresholding a blurry image (left), which resulted in distorted and disconnected digits (right): Since then, I've tried using a morphological closing operation as described in this post to make the brightness of the image uniform: If I adaptively threshold this image, I don't get significantly better results. However, because the brightness is approximately uniform, I can now use an ordinary threshold: This is a lot better than before, but I have two problems: I had to manually choose the threshold value. Although the closing operation results in uniform brightness, the level of brightness might be different for other images. Different parts of the image would do better with slight variations in the threshold level. For instance, the 9 and 7 in the top left come out partially faded and should have a lower threshold, while some of the 6s have fused into 8s and should have a higher threshold. I thought that going back to an adaptive threshold, but with a very large block size (1/9th of the image) would solve both problems. Instead, I end up with a weird "halo effect" where the centre of the image is a lot brighter, but the edges are about the same as the normally-thresholded image: Edit: remi suggested morphologically opening the thresholded image at the top right of this post. This doesn't work too well. Using elliptical kernels, only a 3x3 is small enough to avoid obliterating the image entirely, and even then there are significant breakages in the digits:

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  • C++ Namespaces & templates question

    - by Kotti
    Hi! I have some functions that can be grouped together, but don't belong to some object / entity and therefore can't be treated as methods. So, basically in this situation I would create a new namespace and put the definitions in a header file, the implementation in cpp file. Also (if needed) I would create an anonymous namespace in that cpp file and put all additional functions that don't have to be exposed / included to my namespace's interface there. See the code below (probably not the best example and could be done better with another program architecture, but I just can't think of a better sample...) Sample code (header) namespace algorithm { void HandleCollision(Object* object1, Object* object2); } Sample code (cpp) #include "header" // Anonymous namespace that wraps // routines that are used inside 'algorithm' methods // but don't have to be exposed namespace { void RefractObject(Object* object1) { // Do something with that object // (...) } } namespace algorithm { void HandleCollision(Object* object1, Object* object2) { if (...) RefractObject(object1); } } So far so good. I guess this is a good way to manage my code, but I don't know what should I do if I have some template-based functions and want to do basically the same. If I'm using templates, I have to put all my code in the header file. Ok, but how should I conceal some implementation details then? Like, I want to hide RefractObject function from my interface, but I can't simply remove it's declaration (just because I have all my code in a header file)... The only approach I came up with was something like: Sample code (header) namespace algorithm { // Is still exposed as a part of interface! namespace impl { template <typename T> void RefractObject(T* object1) { // Do something with that object // (...) } } template <typename T, typename Y> void HandleCollision(T* object1, Y* object2) { impl::RefractObject(object1); // Another stuff } } Any ideas how to make this better in terms of code designing?

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  • Suggestions on error handling of Win32 C++ code: AtlThrow vs. STL exceptions

    - by EmbeddedProg
    In writing Win32 C++ code, I'd appreciate some hints on how to handle errors of Win32 APIs. In particular, in case of a failure of a Win32 function call (e.g. MapViewOfFile), is it better to: use AtlThrowLastWin32 define a Win32Exception class derived from std::exception, with an added HRESULT data member to store the HRESULT corresponding to value returned by GetLastError? In this latter case, I could use the what() method to return a detailed error string (e.g. "MapViewOfFile call failed in MyClass::DoSomething() method."). What are the pros and cons of 1 vs. 2? Is there any other better option that I am missing? As a side note, if I'd like to localize the component I'm developing, how could I localize the exception what() string? I was thinking of building a table mapping the original English string returned by what() into a Unicode localized error string. Could anyone suggest a better approach? Thanks much for your insights and suggestions.

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  • Indirect property notification

    - by Carlo
    Hello, this question might look a little trivial, but it might not be. I'm just wondering which of the following two cases is better for indirect property notification, or perhaps there is an even better way. The scenario: I have two properties, the first one is an object called HoldingObject, the second one is a boolean called IsHoldingObject, which is false if HoldingObject == null, otherwise it's true. I'm just wondering what is the best notification mechanism for IsHoldingObject: Case (A) - Notify IsHoldingObject changed from the HoldingObject proeperty: public class NotifyingClass1 : INotifyPropertyChanged { private object _holdingObject; public object HoldingObject { get { return _holdingObject; } set { if (_holdingObject != value) { _holdingObject = value; NotifyPropertyChanged("HoldingObject"); // Notify from the property that is being checked NotifyPropertyChanged("IsHoldingObject"); } } } public bool IsHoldingObject { get { return this.HoldingObject == null; } } #region INotifyPropertyChanged Members public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } #endregion } Case (B) - Notify IsHoldingObject changed from the IsHoldingObject directly, by setting it to false or true from HoldingObject property: public class NotifyingClass2 : INotifyPropertyChanged { private object _holdingObject; public object HoldingObject { get { return _holdingObject; } set { if (_holdingObject != value) { _holdingObject = value; NotifyPropertyChanged("HoldingObject"); // 1) Set the property here this.IsHoldingObject = _holdingObject != null; } } } private bool _isHoldingObject; public bool IsHoldingObject { get { return _isHoldingObject; } set { if (_isHoldingObject != value) { _isHoldingObject = value; // 2) Notify directly from the property NotifyPropertyChanged("IsHoldingObject"); } } } #region INotifyPropertyChanged Members public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } #endregion } I personally lean to the first one because it requires less code, but I'm not sure how recommendable it is to do that. Let me know if there is another (better) way. Thanks!

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  • what's the performance difference between int and varchar for primary keys

    - by user568576
    I need to create a primary key scheme for a system that will need peer to peer replication. So I'm planning to combine a unique system ID and a sequential number in some way to come up with unique ID's. I want to make sure I'll never run out of ID's, so I'm thinking about using a varchar field, since I could always add another character if I start running out. But I've read that integers are better optimized for this. So I have some questions... 1) Are integers really better optimized? And if they are, how much of a performance difference is there between varchars and integers? I'm going to use firebird for now. But I may switch later. Or possibly support multiple db's. So I'm looking for generalizations, if that's possible. 2) If integers are significantly better optimized, why is that? And is it likely that varchars will catch up in the future, so eventually it won't matter anyway? My varchar keys won't have any meaning, except for the unique system ID part. But I may want to obscure that somehow. Also, I plan to efficiently use all the bits of each character. I don't, for example, plan to code the integer 123 as the character string "123". So I don't think varchars will require more space than integers.

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  • Excel VBA creating a new column with formula

    - by Amatya
    I have an excel file with a column which has date data. I want the user to input a date of their choosing and then I want to create a new column that lists the difference in days between the two dates. The Macro that I have is working but I have a few questions and I would like to make it better. Link to MWE small data file is here. The user input date was 9/30/2013, which I stored in H20 Macro: Sub Date_play() Dim x As Date Dim x2 As Date Dim y As Variant x = InputBox(Prompt:="Please enter the Folder Report Date. The following formats are acceptable: 4 1 2013 or April 1 2013 or 4/1/2013") x2 = Range("E2") y = DateDiff("D", x2, x) MsgBox y 'Used DateDiff above and it works but I don't know how to use it to fill a column or indeed a cell. Range("H20").FormulaR1C1 = x Range("H1").FormulaR1C1 = "Diff" Range("H2").Formula = "=DATEDIF(E2,$H$20,""D"")" Range("H2").AutoFill Destination:=Range("H2:H17") Range("H2:H17").Select End Sub Now, could I have done this without storing the user input date in a particular cell? I would've preferred to use the variable "x" in the formula but it wasn't working for me. I had to store the user input in H20 and then use $H$20. What's the difference between the function Datedif and the procedure DateDiff? I am able to use the procedure DateDiff in my macro but I don't know how to use it to fill out my column. Is one method better than the other? Is there a better way to add columns to the existing sheet, where the columns include some calculations involving existing data on the sheet and some user inputs? There are tons of more complicated calculations I want to do next. Thanks

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  • How to join multiple tables using LINQ-to-SQL?

    - by user603245
    Hi! I'm quite new to linq, so please bear with me. I'm working on a asp.net webpage and I want to add a "search function" (textbox where user inputs name or surname or both or just parts of it and gets back all related information). I have two tables ("Person" and "Application") and I want to display some columns from Person (name and surname) and some from Application (score, position,...). I know how I could do it using sql, but I want to learn more about linq and thus I want to do it using linq. For now I got two main ideas: 1.) var person = dataContext.GetTable<Person>(); var application = dataContext.GetTable<Application>(); var p1 = from p in Person where(p.Name.Contains(tokens[0]) || p.Surname.Contains(tokens[1])) select new {Id = p.Id, Name = p.Name, Surname = p.Surname}; //or maybe without this line //I don't know how to do the following properly var result = from a in Application where a.FK_Application.Equals(index) //just to get the "right" type of application //this is not right, but I don't know how to do it better join p1 on p1.Id == a.FK_Person 2.) The other idea is just to go through "Application" and instead of "join p1 ..." to use var result = from a in Application where a.FK_Application.Equals(index) //just to get the "right" type of application join p from Person on p.Id == a.FK_Person where p.Name.Contains(tokens[0]) || p.Surname.Contains(tokens[1]) I think that first idea is better for queries without the first "where" condition, which I also intended to use. Regardless of what is better (faster), I still don't know how to do it using linq. Also in the end I wanted to display / select just some parts (columns) of the result (joined tables + filtering conditions). I really want to know how to do such things using linq as I'll be dealing also with some similar problems with local data, where I can use only linq. Could somebody please explain me how to do it, I spent days trying to figure it out and searching on the internet for answers. Thank you for your time.

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  • Rapid Opening and Closing System.IO.StreamWriter in C#

    - by ccomet
    Suppose you have a file that you are programmatically logging information into with regards to a process. Kinda like your typical debug Console.WriteLine, but due to the nature of the code you're testing, you don't have a console to write onto so you have to write it somewhere like a file. My current program uses System.IO.StreamWriter for this task. My question is about the approach to using the StreamWriter. Is it better to open just one StreamWriter instance, do all of the writes, and close it when the entire process is done? Or is it a better idea to open a new StreamWriter instance to write a line into the file, then immediately close it, and do this for every time something needs to be written in? In the latter approach, this would probably be facilitated by a method that would do just that for a given message, rather than bloating the main process code with excessive amounts of lines. But having a method to aid in that implementation doesn't necessarily make it the better choice. Are there significant advantages to picking one approach or the other? Or are they functionally equivalent, leaving the choice on the shoulders of the programmer?

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  • Is programming overrated?

    - by aengine
    [Subjective and intended to be a community wiki] I am sorry for such an offensive question: But here are my arguments Most of the progress in "computing" has came from non-programming sources. i.e. People invented faster microprocessors and better routers and novel memory devices. I dont think on average people are writting more efficient programs than those written 10 years ago. And the newer and popular languages are infact slower than C. though speed is one of the lesser criterias. Most of the progress came from novel paradigms. Web, Internet, Cloud computing and Social networking are novel paradigms and did not involve progress in programming as such. Heck even facebook was written in PHP and not some extreme language. Though it did face scalability issues (same with twitter) but i believe money and better programmers (who came in much later) took care of that. Thus ideating capability trumped programming capability/ Even things like Map-Reduce, Column oriented database and Probablistic algorithms (E.g. bloom filters) came from hardcore Algorithms research, rather than some programming convention. Thus my final point is why programming skill is so overstressed? To point a recent example about how only 10% of programmers can "write code" (binary search) without debugging. Isnt it a bit hypocritical, considering your real successs lies in coming up with better algorithm or a novel feature rather than getting right first time???

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  • Preview of code-only WPF controls in VS2010 - how?

    - by Christian
    Hi, I hope I am able to illustrate the problem using a lot of images. First of all, I was no real fan of XAML (Silverlight issues, crashes in Preview, and so on...) Now, with VS2010 the situation has become better. There are still a lot of things I like better in code, but I also want a preview in my VS. So, take a look at the following control: It is really simple, a todo details list. The first screenshot shows the code of the control, pretty straighforward: There is no XAML, so obviously no preview. Of course, I could encapsulate it in another control, like shown in the next screenshot: But, in that case I have an additional file I do not want or need. So I had the idea to move the init stuff inside the contructor of a XAML control. For simplicity, I used simple elements. But they do not show up in the preview... Finally, I know I could use the controls in other parts of my app when creating UIs. But I am using layout manager, PRISM and a lot of other stuff, so I just want an easy preview of some specific control I created (without having to have a XAML wrapper file for each control) Thanks for help, and sorry for the post structure, but I though with images it is better to understand... Chris

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  • Prototype or jQuery for DOM manipulation (client-side dynamic content)

    - by luiggitama
    I need to know which of these two JavaScript frameworks is better for client-side dynamic content modification for known DOM elements (by id), in terms of performance, memory usage, etc.: Prototype's $('id').update(content) jQuery's jQuery('#id').html(content) BTW, both libraries coexist with no conflict in my app, because I'm using RichFaces for JSF development, that's why I can use "jQuery" instead of "$". I have at least 20 updatable areas in my page, and for each one I prepare content (tables, option lists, etc.), based on some user-defined client-side criteria filtering or some AJAX event, etc., like this: var html = []; int idx = 0; ... html[idx++] = '<tr><td class="cell"><span class="link" title="View" onclick="myFunction('; html[idx++] = param; html[idx++] = ')"></span>'; html[idx++] = someText; html[idx++] = '</td></tr>'; ... So here comes the question, which is better to use: // Prototype's $('myId').update(html.join('')); // or jQuery's jQuery('#myId').html(html.join('')); Other needed functions are hide() and show(), which are present in both frameworks. Which is better? Also I'm needing to enable/disable form controls, and to read/set their values. Note that I know my updatable area's id (I don't need CSS selectors at this point). And I must tell that I'm saving these queried objects in some data structure for later use, so they are requested just once when the page is rendered, like this: MyData = {div1:jQuery('#id1'), div2:$('id2'), ...}; ... div1.update('content 1'); div2.html('content 2'); So, which is the best practice?

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  • Which Java debugger do *you* use.

    - by mikevdg
    I spend a lot of time debugging applications in Eclipse using JPDA. There are a few issues with the Eclipse debugger which really annoy me. Can anybody recommend plug-ins, better debuggers or perhaps tricks that I don't know of yet? In the "Variables" tab, you can type in and execute bits of Java code. However, you first need to click on something (I usually click on "this") to give it some context. Then, after you've typed in a lengthy Java expression to debug something and "execute" it, your expression gets replaced with the result, so you need to type it in all over again. Is there some better way, such as a console or something that I'm missing? When you're poking through data structures, the presentation in the debugger leaves much to be desired. You see the internal representation of Lists, Maps, StringBuilders etc. What I want to see is what these objects conceptually contain. Is there a way of doing this, perhaps using some other debugger, or an extension or something? When an Exception is thrown, is there some way of inspecting the state of the application where the Exception was thrown? Currently I need to set breakpoints just before the Exception occurs and then try to reproduce it. When I'm stepping over a line with many statements on it, I can't actually see which of those statements is being executed, except by "stepping in" to each one to see where it takes me. If no source code is found, Eclipse just stares blankly at you. You get a helpful screen saying "Class File Editor / Source code not found" which is completely useless. I'd much prefer to be able to step through the bytecodes so I can at least see what is going on. Does anybody know of a Java debugger that does this better than Eclipse?

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  • ASP.NET Frameworks and Raw Throughput Performance

    - by Rick Strahl
    A few days ago I had a curious thought: With all these different technologies that the ASP.NET stack has to offer, what's the most efficient technology overall to return data for a server request? When I started this it was mere curiosity rather than a real practical need or result. Different tools are used for different problems and so performance differences are to be expected. But still I was curious to see how the various technologies performed relative to each just for raw throughput of the request getting to the endpoint and back out to the client with as little processing in the actual endpoint logic as possible (aka Hello World!). I want to clarify that this is merely an informal test for my own curiosity and I'm sharing the results and process here because I thought it was interesting. It's been a long while since I've done any sort of perf testing on ASP.NET, mainly because I've not had extremely heavy load requirements and because overall ASP.NET performs very well even for fairly high loads so that often it's not that critical to test load performance. This post is not meant to make a point  or even come to a conclusion which tech is better, but just to act as a reference to help understand some of the differences in perf and give a starting point to play around with this yourself. I've included the code for this simple project, so you can play with it and maybe add a few additional tests for different things if you like. Source Code on GitHub I looked at this data for these technologies: ASP.NET Web API ASP.NET MVC WebForms ASP.NET WebPages ASMX AJAX Services  (couldn't get AJAX/JSON to run on IIS8 ) WCF Rest Raw ASP.NET HttpHandlers It's quite a mixed bag, of course and the technologies target different types of development. What started out as mere curiosity turned into a bit of a head scratcher as the results were sometimes surprising. What I describe here is more to satisfy my curiosity more than anything and I thought it interesting enough to discuss on the blog :-) First test: Raw Throughput The first thing I did is test raw throughput for the various technologies. This is the least practical test of course since you're unlikely to ever create the equivalent of a 'Hello World' request in a real life application. The idea here is to measure how much time a 'NOP' request takes to return data to the client. So for this request I create the simplest Hello World request that I could come up for each tech. Http Handler The first is the lowest level approach which is an HTTP handler. public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public bool IsReusable { get { return true; } } } WebForms Next I added a couple of ASPX pages - one using CodeBehind and one using only a markup page. The CodeBehind page simple does this in CodeBehind without any markup in the ASPX page: public partial class HelloWorld_CodeBehind : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Response.Write("Hello World. Time is: " + DateTime.Now.ToString() ); Response.End(); } } while the Markup page only contains some static output via an expression:<%@ Page Language="C#" AutoEventWireup="false" CodeBehind="HelloWorld_Markup.aspx.cs" Inherits="AspNetFrameworksPerformance.HelloWorld_Markup" %> Hello World. Time is <%= DateTime.Now %> ASP.NET WebPages WebPages is the freestanding Razor implementation of ASP.NET. Here's the simple HelloWorld.cshtml page:Hello World @DateTime.Now WCF REST WCF REST was the token REST implementation for ASP.NET before WebAPI and the inbetween step from ASP.NET AJAX. I'd like to forget that this technology was ever considered for production use, but I'll include it here. Here's an OperationContract class: [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World" + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } } WCF REST can return arbitrary results by returning a Stream object and a content type. The code above turns the string result into a stream and returns that back to the client. ASP.NET AJAX (ASMX Services) I also wanted to test ASP.NET AJAX services because prior to WebAPI this is probably still the most widely used AJAX technology for the ASP.NET stack today. Unfortunately I was completely unable to get this running on my Windows 8 machine. Visual Studio 2012  removed adding of ASP.NET AJAX services, and when I tried to manually add the service and configure the script handler references it simply did not work - I always got a SOAP response for GET and POST operations. No matter what I tried I always ended up getting XML results even when explicitly adding the ScriptHandler. So, I didn't test this (but the code is there - you might be able to test this on a Windows 7 box). ASP.NET MVC Next up is probably the most popular ASP.NET technology at the moment: MVC. Here's the small controller: public class MvcPerformanceController : Controller { public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } } ASP.NET WebAPI Next up is WebAPI which looks kind of similar to MVC. Except here I have to use a StringContent result to return the response: public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } } Testing Take a minute to think about each of the technologies… and take a guess which you think is most efficient in raw throughput. The fastest should be pretty obvious, but the others - maybe not so much. The testing I did is pretty informal since it was mainly to satisfy my curiosity - here's how I did this: I used Apache Bench (ab.exe) from a full Apache HTTP installation to run and log the test results of hitting the server. ab.exe is a small executable that lets you hit a URL repeatedly and provides counter information about the number of requests, requests per second etc. ab.exe and the batch file are located in the \LoadTests folder of the project. An ab.exe command line  looks like this: ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld which hits the specified URL 100,000 times with a load factor of 20 concurrent requests. This results in output like this:   It's a great way to get a quick and dirty performance summary. Run it a few times to make sure there's not a large amount of varience. You might also want to do an IISRESET to clear the Web Server. Just make sure you do a short test run to warm up the server first - otherwise your first run is likely to be skewed downwards. ab.exe also allows you to specify headers and provide POST data and many other things if you want to get a little more fancy. Here all tests are GET requests to keep it simple. I ran each test: 100,000 iterations Load factor of 20 concurrent connections IISReset before starting A short warm up run for API and MVC to make sure startup cost is mitigated Here is the batch file I used for the test: IISRESET REM make sure you add REM C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin REM to your path so ab.exe can be found REM Warm up ab.exe -n100 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJsonab.exe -n100 -c20 http://localhost/aspnetperf/api/HelloWorldJson ab.exe -n100 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld ab.exe -n100000 -c20 http://localhost/aspnetperf/handler.ashx > handler.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_CodeBehind.aspx > AspxCodeBehind.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_Markup.aspx > AspxMarkup.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld > Wcf.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldCode > Mvc.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld > WebApi.txt I ran each of these tests 3 times and took the average score for Requests/second, with the machine otherwise idle. I did see a bit of variance when running many tests but the values used here are the medians. Part of this has to do with the fact I ran the tests on my local machine - result would probably more consistent running the load test on a separate machine hitting across the network. I ran these tests locally on my laptop which is a Dell XPS with quad core Sandibridge I7-2720QM @ 2.20ghz and a fast SSD drive on Windows 8. CPU load during tests ran to about 70% max across all 4 cores (IOW, it wasn't overloading the machine). Ideally you can try running these tests on a separate machine hitting the local machine. If I remember correctly IIS 7 and 8 on client OSs don't throttle so the performance here should be Results Ok, let's cut straight to the chase. Below are the results from the tests… It's not surprising that the handler was fastest. But it was a bit surprising to me that the next fastest was WebForms and especially Web Forms with markup over a CodeBehind page. WebPages also fared fairly well. MVC and WebAPI are a little slower and the slowest by far is WCF REST (which again I find surprising). As mentioned at the start the raw throughput tests are not overly practical as they don't test scripting performance for the HTML generation engines or serialization performances of the data engines. All it really does is give you an idea of the raw throughput for the technology from time of request to reaching the endpoint and returning minimal text data back to the client which indicates full round trip performance. But it's still interesting to see that Web Forms performs better in throughput than either MVC, WebAPI or WebPages. It'd be interesting to try this with a few pages that actually have some parsing logic on it, but that's beyond the scope of this throughput test. But what's also amazing about this test is the sheer amount of traffic that a laptop computer is handling. Even the slowest tech managed 5700 requests a second, which is one hell of a lot of requests if you extrapolate that out over a 24 hour period. Remember these are not static pages, but dynamic requests that are being served. Another test - JSON Data Service Results The second test I used a JSON result from several of the technologies. I didn't bother running WebForms and WebPages through this test since that doesn't make a ton of sense to return data from the them (OTOH, returning text from the APIs didn't make a ton of sense either :-) In these tests I have a small Person class that gets serialized and then returned to the client. The Person class looks like this: public class Person { public Person() { Id = 10; Name = "Rick"; Entered = DateTime.Now; } public int Id { get; set; } public string Name { get; set; } public DateTime Entered { get; set; } } Here are the updated handler classes that use Person: Handler public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { var action = context.Request.QueryString["action"]; if (action == "json") JsonRequest(context); else TextRequest(context); } public void TextRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public void JsonRequest(HttpContext context) { var json = JsonConvert.SerializeObject(new Person(), Formatting.None); context.Response.ContentType = "application/json"; context.Response.Write(json); } public bool IsReusable { get { return true; } } } This code adds a little logic to check for a action query string and route the request to an optional JSON result method. To generate JSON, I'm using the same JSON.NET serializer (JsonConvert.SerializeObject) used in Web API to create the JSON response. WCF REST   [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World " + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } [OperationContract] [WebGet(ResponseFormat=WebMessageFormat.Json,BodyStyle=WebMessageBodyStyle.WrappedRequest)] public Person HelloWorldJson() { // Add your operation implementation here return new Person(); } } For WCF REST all I have to do is add a method with the Person result type.   ASP.NET MVC public class MvcPerformanceController : Controller { // // GET: /MvcPerformance/ public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } public JsonResult HelloWorldJson() { return Json(new Person(), JsonRequestBehavior.AllowGet); } } For MVC all I have to do for a JSON response is return a JSON result. ASP.NET internally uses JavaScriptSerializer. ASP.NET WebAPI public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } [HttpGet] public Person HelloWorldJson() { return new Person(); } [HttpGet] public HttpResponseMessage HelloWorldJson2() { var response = new HttpResponseMessage(HttpStatusCode.OK); response.Content = new ObjectContent<Person>(new Person(), GlobalConfiguration.Configuration.Formatters.JsonFormatter); return response; } } Testing and Results To run these data requests I used the following ab.exe commands:REM JSON RESPONSES ab.exe -n100000 -c20 http://localhost/aspnetperf/Handler.ashx?action=json > HandlerJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJson > MvcJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorldJson > WebApiJson.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorldJson > WcfJson.txt The results from this test run are a bit interesting in that the WebAPI test improved performance significantly over returning plain string content. Here are the results:   The performance for each technology drops a little bit except for WebAPI which is up quite a bit! From this test it appears that WebAPI is actually significantly better performing returning a JSON response, rather than a plain string response. Snag with Apache Benchmark and 'Length Failures' I ran into a little snag with Apache Benchmark, which was reporting failures for my Web API requests when serializing. As the graph shows performance improved significantly from with JSON results from 5580 to 6530 or so which is a 15% improvement (while all others slowed down by 3-8%). However, I was skeptical at first because the WebAPI test reports showed a bunch of errors on about 10% of the requests. Check out this report: Notice the Failed Request count. What the hey? Is WebAPI failing on roughly 10% of requests when sending JSON? Turns out: No it's not! But it took some sleuthing to figure out why it reports these failures. At first I thought that Web API was failing, and so to make sure I re-ran the test with Fiddler attached and runiisning the ab.exe test by using the -X switch: ab.exe -n100 -c10 -X localhost:8888 http://localhost/aspnetperf/api/HelloWorldJson which showed that indeed all requests where returning proper HTTP 200 results with full content. However ab.exe was reporting the errors. After some closer inspection it turned out that the dates varying in size altered the response length in dynamic output. For example: these two results: {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.841926-10:00"} {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.8519262-10:00"} are different in length for the number which results in 68 and 69 bytes respectively. The same URL produces different result lengths which is what ab.exe reports. I didn't notice at first bit the same is happening when running the ASHX handler with JSON.NET result since it uses the same serializer that varies the milliseconds. Moral: You can typically ignore Length failures in Apache Benchmark and when in doubt check the actual output with Fiddler. Note that the other failure values are accurate though. Another interesting Side Note: Perf drops over Time As I was running these tests repeatedly I was finding that performance steadily dropped from a startup peak to a 10-15% lower stable level. IOW, with Web API I'd start out with around 6500 req/sec and in subsequent runs it keeps dropping until it would stabalize somewhere around 5900 req/sec occasionally jumping lower. For these tests this is why I did the IIS RESET and warm up for individual tests. This is a little puzzling. Looking at Process Monitor while the test are running memory very quickly levels out as do handles and threads, on the first test run. Subsequent runs everything stays stable, but the performance starts going downwards. This applies to all the technologies - Handlers, Web Forms, MVC, Web API - curious to see if others test this and see similar results. Doing an IISRESET then resets everything and performance starts off at peak again… Summary As I stated at the outset, these were informal to satiate my curiosity not to prove that any technology is better or even faster than another. While there clearly are differences in performance the differences (other than WCF REST which was by far the slowest and the raw handler which was by far the highest) are relatively minor, so there is no need to feel that any one technology is a runaway standout in raw performance. Choosing a technology is about more than pure performance but also about the adequateness for the job and the easy of implementation. The strengths of each technology will make for any minor performance difference we see in these tests. However, to me it's important to get an occasional reality check and compare where new technologies are heading. Often times old stuff that's been optimized and designed for a time of less horse power can utterly blow the doors off newer tech and simple checks like this let you compare. Luckily we're seeing that much of the new stuff performs well even in V1.0 which is great. To me it was very interesting to see Web API perform relatively badly with plain string content, which originally led me to think that Web API might not be properly optimized just yet. For those that caught my Tweets late last week regarding WebAPI's slow responses was with String content which is in fact considerably slower. Luckily where it counts with serialized JSON and XML WebAPI actually performs better. But I do wonder what would make generic string content slower than serialized code? This stresses another point: Don't take a single test as the final gospel and don't extrapolate out from a single set of tests. Certainly Twitter can make you feel like a fool when you post something immediate that hasn't been fleshed out a little more <blush>. Egg on my face. As a result I ended up screwing around with this for a few hours today to compare different scenarios. Well worth the time… I hope you found this useful, if not for the results, maybe for the process of quickly testing a few requests for performance and charting out a comparison. Now onwards with more serious stuff… Resources Source Code on GitHub Apache HTTP Server Project (ab.exe is part of the binary distribution)© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • C# development with Mono and MonoDevelop

    - by developerit
    In the past two years, I have been developing .NET from my MacBook by running Windows XP into VM Ware and more recently into Virtual Box from OS X. This way, I could install Visual Studio and be able to work seamlessly. But, this way of working has a major down side: it kills the battery of my laptop… I can easiely last for 3 hours if I stay in OS X, but can only last 45 min when XP is running. Recently, I gave MonoDevelop a try for developing Developer IT‘s tools and web site. While being way less complete then Visual Studio, it provides essentials tools when it comes to developping software. It works well with solutions and projects files created from Visual Studio, it has Intellisence (word completion), it can compile your code and can even target your .NET app to linux or unix. This tools can save me a lot of time and batteries! Although I could not only work with MonoDevelop, I find it way better than a simple text editor like Smultron. Thanks to Novell, we can now bring Microsoft technology to OS X.

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  • Password Security: Short and Complex versus ‘Short or Lengthy’ and Less Complex

    - by Akemi Iwaya
    Creating secure passwords for our online accounts is a necessary evil due to the huge increase in database and account hacking that occurs these days. The problem though is that no two companies have a similar policy for complex and secure password creation, then factor in the continued creation of insecure passwords or multi-site use of the same password and trouble is just waiting to happen. Ars Technica decided to take a look at multiple password types, how users fared with them, and how well those password types held up to cracking attempts in their latest study. The password types that Ars Technica looked at were comprehensive8, basic8, and basic16. The comprehensive type required a variety of upper-case, lower-case, digits, and symbols with no dictionary words allowed. The only restriction on the two basic types was the number of characters used. Which type do you think was easier for users to adopt and did better in the two password cracking tests? You can learn more about how well users did with the three password types and the results of the tests by visiting the article linked below. What are your thoughts on the matter? Are shorter, more complex passwords better or worse than using short or long, but less complex passwords? What methods do you feel work best since most passwords are limited to approximately 16 characters in length? Perhaps you use a service like LastPass or keep a dedicated list/notebook to manage your passwords. Let us know in the comments!    

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  • LED Monitor brightness

    - by Yuval
    I am in the market for a new monitor. I've been looking around and it seems that the general brightness for monitors is between 250-320 cd/m2. After hours of searching, I narrowed it down to the LG W2453V-PF vs. the LG E2350V-SN The W2453V-PF is not LED backlit yet it has a brightness level of 310 cd/m2 and a response time of 2ms. The E2350V-SN, on the other hand, has a brightness level of 250 cd/m2 and a response time of 5ms but it is LED backlit. My questions are, looking at these overall specs: Which monitor is better? What makes LED backlight better? Is the LED backlight worth the decreased brightness level? Thanks! p.s. if you have any other comparable monitor suggestions (that are not samsung - I read their customer service is absolutely terrible), feel free to share. thanks!

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  • Microsoft launches IE9 preview – No support for XP

    - by samsudeen
    Microsoft launched the developer preview version of Internet Explorer 9 (IE9) at MIX 10 web conference yesterday.This release is aimed getting the feedback from website designers , developers and other community to make IE9 development better from its previous versions. Microsoft will update the developer preview every eight weeks and the next update is expected on mid of march.So what is new and interesting  about IE9 Chakra Chakra (The new scripting engine of IE9) renders the Java script much faster compared to IE8 and other browsers thus improving the performance significantly.According to Microsoft Chakra renders the java script in background with a separate thread parallel to the main engine which is complete new way of rendering from the current browser technologies Standards Microsoft is desperate to make ( surprisingly!!!) IE9 compliance to  web standards by supporting the open standards such as Accelerated support for HTML5 video support for new web technologies such as CSS3 and SVG2. ACID3 Test IE9 scores (55/100) in its latest ACID3 test which is much better compared to the IE8 score (22/100) but not even  nearer to their rivals Chrome, Opera, and Safari which scores 100/100 in ACID3 testing I am little disappointed over not able to download the  developer preview on my XP machine. The early comments looks much positive for IE9.If you want to explore IE9,check the Microsoft Test drive site  at Microsoft IE9 Test-drive You can also download the IE9 developer preview at Download Preview Join us on Facebook to read all our stories right inside your Facebook news feed.

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  • How can I install a 32bit python on 64 bit Ubuntu

    - by moose
    I am using Ubuntu 10.10 (Linux pc07 2.6.35-27-generic #48-Ubuntu SMP Tue Feb 22 20:25:46 UTC 2011 x86_64 GNU/Linux) and the default python package (Python 2.6.6). I would like to install python-psyco to improve the performance of one of my scripts, but only python-psyco-doc is available for 64 bit. I tried a virtual machine, but the the performance boost is much less on the virtual machine than on a "real" installed 32-bit Ubuntu. So my question is: How can I install a 32Bit Python with psyco on my 64Bit Ubuntu machine? edit: I've found this article and made this: Download "Python 2.7.1 bzipped source tarball" from http://python.org/download/ Go in the directory where you decompressed "Python 2.7.1" $ OPT=-m32 LDFLAGS=-m32 ./configure --prefix=/opt/pym32 $ make But I got this error: gcc -pthread -m32 -Xlinker -export-dynamic -o python \ Modules/python.o \ libpython2.7.a -lpthread -ldl -lutil -lm libpython2.7.a(posixmodule.o): In function `posix_tmpnam': /home/moose/Downloads/Python-2.7.1/./Modules/posixmodule.c:7346: warning: the use of `tmpnam_r' is dangerous, better use `mkstemp' libpython2.7.a(posixmodule.o): In function `posix_tempnam': /home/moose/Downloads/Python-2.7.1/./Modules/posixmodule.c:7301: warning: the use of `tempnam' is dangerous, better use `mkstemp' Segmentation fault make: *** [sharedmods] Fehler 139 edit2: Now I've found http://indefinitestudies.org/2010/02/08/how-to-build-32-bit-python-on-ubuntu-9-10-x86_64/ and it seems like this worked: $ cd Python-2.7.1 $ CC="gcc -m32" LDFLAGS="-L/lib32 -L/usr/lib32 \ -Lpwd/lib32 -Wl,-rpath,/lib32 -Wl,-rpath,/usr/lib32" \ ./configure --prefix=/opt/pym32 $ make $ sudo make install But installing psyco didn't work: Download the lastest snapshot: http://psyco.sourceforge.net/download.html Extract it and go into the folder $ python setup.py install This error appeared: PROCESSOR = 'ivm' running install running build running build_py running build_ext building 'psyco._psyco' extension gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -DALL_STATIC=1 -Ic/ivm -I/usr/include/python2.6 -c c/psyco.c -o build/temp.linux-x86_64-2.6/c/psyco.o In file included from c/psyco.c:1: c/psyco.h:9: fatal error: Python.h: Datei oder Verzeichnis nicht gefunden compilation terminated. error: command 'gcc' failed with exit status 1

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  • Sending emails from PHP - email providers vs GAE

    - by nrph
    I need to send emails from my social service (this is continuation of Experiences in mailing to registered users). I got strong feeling that it's better to avoid problems with email server configuration and maintance and to choose email provider which will take care of all painful problems. So several offers were compared: http://imgur.com/JkK2X.jpg Three of them look very attractive: Postageapp / Sendgrid / CritSend As alternative i'm considering setup GAE app. Email provider is quite easy to start work with, but have no idea how much effort require GAE to integrate with PHP. So my question is: which option is better to choose: email provider GAE ? Two factors are important here: business background (therefore prices are mentioned), work required to setup and maintain desired solution. Preferably i would love to avoid all email-related problems (like black lists and so on).

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  • DevDays ‘00 The Netherlands day #1

    - by erwin21
    First day of DevDays 2010, I was looking forward to DevDays to see all the new things like VS2010, .NET4.0, MVC2. The lineup for this year is again better than the year before, there are 100+ session of all kind of topics like Cloud, Database, Mobile, SharePoint, User experience, Visual Studio, Web. The first session of the day was a keynote by Anders Hejlsberg he talked about the history and future of programming languages. He gave his view about trends and influences in programming languages today and in the future. The second talk that i followed was from the famous Scott Hanselman, he talked about the basics of ASP.NET MVC 2, although it was a 300 level session, it was more like a level 100 session, but it was mentioned by Scott at the beginning. Although it was interesting to see all the basic things about MVC like the controllers, actions, routes, views, models etc. After the lunch the third talk for me was about moving ASP.NET webform applications to MVC from Fritz Onion. In this session he changed an example webform application part by part to a MVC application. He gave some interesting tips and tricks and showed how to solve some issues that occur while converting. Next and the fourth talk was about the difference between LINQ to SQL and  the ADO.NET  Entity Framework from Kurt Claeys. He gave a good understanding about this two options, the demos where in LINQ to SQL and the Entity Framework, the goal was to get a good understanding when and where to use both options. The last talk about this day was also from Scott Hanselman, he goes deeper into the features of ASP.NET MVC 2 and gave some interesting tips, the ninja black belt tips. He gave some tips about the tooling, the new MVC 2 html helper methods, other view engines (like NHaml, spark),T4 templating. With this tips we can be more productive and create web applications better and faster. It was a long and interesting day, I am looking forward to day #2.

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  • Mobile Java, shiny and new: Nokia Asha and Nokia SDK 2.0

    - by terrencebarr
    Nokia has announced a series of new S40 phones called “Asha” – mass-market devices with smart-phone features: Good-sized touch screens, 1 GHz processors, WiFi connectivity, social networking integration, and more. Prices starting around €60 retail. In case you don’t know, the S40 series is built on Java ME and has a huge deployed base in many parts of the world where price/performance is critical. Along with the new phones, Nokia is also making available the new Nokia SDK 2.0 for Java (beta), which enables developers to build rich Java applications with multi-touch, sensor support, an improved Maps API, and the Lightweight UI Toolkit (LWUIT) (more API & tools details). Furthermore, there is a host of developer information, the remote device access service, and even a porting guide to help you port your Android app to the new Asha platform. Last, but not least: More and better options to monetize your applications. Nokia has enabled in-app advertising and in-app purchasing, and improved the way applications can be discovered by customers. Nokia has seen downloads from the Nokia app store rise by 63%, now totaling billions. From what I’m hearing, the revenue opportunities on S40 for developers are often way better than what is typical for other smart-phone platforms (where competition is huge and consumers are fickle). Cheers, – Terrence Filed under: Mobile & Embedded Tagged: Asha Series, Java ME, Java ME SDK, Mobile Java, monetization, Nokia, S40

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