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• GNU Smalltalk package

  - by Peter

  I've installed the GNU Smalltalk package and can get to the SmallTalk command line with the command 'gst'. However, I can't start the visual gst browser using the command: $ gst-browser When I try, this is what I get: peter@peredur:~$ gst-browser Object: CFunctionDescriptor new: 1 "<0x40488720>" error: Invalid C call-out gdk_colormap_get_type SystemExceptions.CInterfaceError(Smalltalk.Exception)>>signal (ExcHandling.st:254) SystemExceptions.CInterfaceError class(Smalltalk.Exception class)>>signal: (ExcHandling.st:161) Smalltalk.CFunctionDescriptor(Smalltalk.CCallable)>>callInto: (CCallable.st:165) GdkColormap class>>getType (GTK.star#VFS.ZipFile/Funcs.st:1) optimized [] in GLib class>>registerAllTypes (GTK.star#VFS.ZipFile/GtkDecl.st:78) Smalltalk.OrderedCollection>>do: (OrderColl.st:68) GLib class>>registerAllTypes (GTK.star#VFS.ZipFile/GtkDecl.st:78) Smalltalk.UndefinedObject>>executeStatements (GTK.star#VFS.ZipFile/GtkImpl.st:1078) Object: CFunctionDescriptor new: 1 "<0x404a7c28>" error: Invalid C call-out gtk_window_new SystemExceptions.CInterfaceError(Exception)>>signal (ExcHandling.st:254) SystemExceptions.CInterfaceError class(Exception class)>>signal: (ExcHandling.st:161) CFunctionDescriptor(CCallable)>>callInto: (CCallable.st:165) GTK.GtkWindow class>>new: (GTK.star#VFS.ZipFile/Funcs.st:1) VisualGST.GtkDebugger(VisualGST.GtkMainWindow)>>initialize (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:131) VisualGST.GtkDebugger class(VisualGST.GtkMainWindow class)>>openSized: (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:19) [] in VisualGST.GtkDebugger class>>open: (VisualGST.star#VFS.ZipFile/Debugger/GtkDebugger.st:16) [] in BlockClosure>>forkDebugger (DebugTools.star#VFS.ZipFile/DebugTools.st:380) [] in Process>>onBlock:at:suspend: (Process.st:392) BlockClosure>>on:do: (BlkClosure.st:193) [] in Process>>onBlock:at:suspend: (Process.st:393) BlockClosure>>ensure: (BlkClosure.st:269) [] in Process>>onBlock:at:suspend: (Process.st:370) [] in BlockClosure>>asContext: (BlkClosure.st:179) BlockContext class>>fromClosure:parent: (BlkContext.st:68) Everything hangs at this point until I hit ^C, after which, I get: Object: CFunctionDescriptor new: 1 "<0x404a7c28>" error: Invalid C call-out gtk_window_new SystemExceptions.CInterfaceError(Exception)>>signal (ExcHandling.st:254) SystemExceptions.CInterfaceError class(Exception class)>>signal: (ExcHandling.st:161) CFunctionDescriptor(CCallable)>>callInto: (CCallable.st:165) GTK.GtkWindow class>>new: (GTK.star#VFS.ZipFile/Funcs.st:1) VisualGST.GtkDebugger(VisualGST.GtkMainWindow)>>initialize (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:131) VisualGST.GtkDebugger class(VisualGST.GtkMainWindow class)>>openSized: (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:19) [] in VisualGST.GtkDebugger class>>open: (VisualGST.star#VFS.ZipFile/Debugger/GtkDebugger.st:16) [] in BlockClosure>>forkDebugger (DebugTools.star#VFS.ZipFile/DebugTools.st:380) [] in Process>>onBlock:at:suspend: (Process.st:392) BlockClosure>>on:do: (BlkClosure.st:193) [] in Process>>onBlock:at:suspend: (Process.st:393) BlockClosure>>ensure: (BlkClosure.st:269) [] in Process>>onBlock:at:suspend: (Process.st:370) [] in BlockClosure>>asContext: (BlkClosure.st:179) BlockContext class>>fromClosure:parent: (BlkContext.st:68) peter@peredur:~$ Is there a problem with this package?

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• Part 5, Moving Forum threads from CommunityServer to DotNetNuke

  - by Chris Hammond

  This is the fifth post in a series of blog posts about converting from CommunityServer to DotNetNuke. A brief background: I had a number of websites running on CommunityServer 2.1, I decided it was finally time to ditch CommunityServer due to the change in their licensing model and pricing that made it not good for the small guy. This series of blog posts is about how to convert your CommunityServer based sites to DotNetNuke . Previous Posts: Part 1: An Introduction Part 2: DotNetNuke Installation...(read more)

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• How to name a bug?

  - by Pieter

  Bugs usually receive a descriptive name: "That X-Y synchronization issue", "That crash after actions A, B and D but not C", "Yesterday's update problem". Even the JIRA issue tracker has a field "Summary" instead of "Name". In discussing "big" bugs, I actually use JIRA id's to prevent confusion. There's a few restrictions to take into account: When reporting a bug, only the consequence of a bug is known. The root cause might never even be found. Several reported bugs might be found out to be duplicates, or might be completely different consequences of the same bug. In large projects, bugs will come at you by the dozens every month. Now, how would you name a bug? Name them like hurricanes perhaps?

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• F# in ASP.NET, mathematics and testing

  - by DigiMortal

  Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#. F# and ASP.NET As I am ASP/ASP.NET MVP I am – of course – interested in how people use different languages and technologies with ASP.NET. C# MVP Tomáš Petrícek writes about developing ASP.NET MVC applications using F#. He also shows how to use LINQ To SQL in F# (using F# PowerPack) and provides sample solution and Visual Studio 2010 template for F# MVC web applications. You may also find interesting how you can create controllers in F#. Excellent work, Tomáš! Vladimir Matveev has interesting example about how to use F# and ApplicationHost class to process ASP.NET requests ouside of IIS. This is simple and very straight-forward example and I strongly suggest you to take a look at it. Very cool example is project Strom in Codeplex. Storm is web services testing tool that is fully written on F#. Take a look at this site because Codeplex offers also source code besides binaries. Math Functional languages are strong in fields like mathematics and physics. When I wrote my C# example about BigInteger class I found out that recursive version of Fibonacci algorithm in C# is not performing well. In same time I made same experiment on F# and in F# there were no performance problems with recursive version. You can find F# version of Fibonacci algorithm from Bob Palmer’s blog posting Fibonacci numbers in F#. Although golden spiral is useful for solving many problems I looked for some practical code example and found one. Kean Walmsley published in his Through the Interface blog very interesting posting Creating Fibonacci spirals in AutoCAD using F#. There are also other cool examples you may be interested in. Using numerical components by Extreme Optimization  it is possible to make some numerical integration (quadrature method) using F# (also C# example is available). fsharp.it introduces factorials calculation on F#. Robert Pickering has made very good work on programming The Game of Life in Silverlight and F# – I definitely suggest you to try out this example as it is very illustrative too. Who wants something more complex may take a look at Newton basin fractal example in F# by Jonathan Birge. Testing After some searching and surfing I found out that there is almost everything available for F# to write tests and test your F# code. FsCheck - FsCheck is a port of Haskell's QuickCheck. Important parts of the manual for using FsCheck is almost literally "adapted" from the QuickCheck manual and paper. Any errors and omissions are entirely my responsibility. FsTest - This project is designed to Language Oriented Programming constructs around unit testing and behavior testing in F#. The goal of this project is to create a Domain Specific Language for testing F# code in a way that makes sense for functional programming. FsUnit - FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework. xUnit.NET - xUnit.net is a developer testing framework, built to support Test Driven Development, with a design goal of extreme simplicity and alignment with framework features. It is compatible with .NET Framework 2.0 and later, and offers several runners: console, GUI, MSBuild, and Visual Studio integration via TestDriven.net, CodeRush Test Runner and Resharper. It also offers test project integration for ASP.NET MVC. Getting started Well, as a first thing you need Visual Studio 2010. Then take a look at these resources: F# samples @ MSDN Microsoft F# Developer Center @ MSDN F# Language Reference @ MSDN F# blog F# forums Real World Functional Programming: With Examples in F# and C# (Amazon) Happy F#-ing! :)

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• Expected sprint completion rate and load in scrum?

  - by bjarkef

  Recently at work there have been increased focus on completion rate and load on the developers in our sprints. With completion rate I mean, if we plan 20 user stories for a sprint, what percentage of these user stories are closed at the end of the sprint. And with load I mean, if we have a sprint with 3 developers of 60 hours each, i.e. 180 hours for the sprint, how many hours worth of user stories do we schedule for the sprint. So I am really interested in others experience with this, I guess this is something everybody working with scrum deals with. My question is, what completion rate and load are expected/usual, and how are your team doing with respect to these parameters?

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• Change default language settings in Visual Studio 2012

  - by sreejukg

  The first thing you need to do after the installation of Visual Studio 2012 is to choose the IDE preferences. Once you select your preferred collection of settings, the IDE will always choose dialogs and other options according to your selection. Nowadays developer’s needs to work with different programming environments and due to this, developers might need to reset the default settings. In this article, I am going to demonstrate how you can change the default settings in Visual Studio 2012. For the purpose of this demonstration, I have installed Visual Studio 2012 and selected C++ as my default environment settings. So now when I go to file -> new project, it will give me C++ templates by default as follows. If you want to select another language, you need to expand Other Languages section and select C# or VB. Now I am going to change these default settings. I am going to change the default language preference to C#. In Visual Studio 2012, go to tools menu and select Import and Export Settings. Here you have 3 options; one is to export the current settings so that the settings are saved for future use. Also you can import previously saved settings. The last option available is to reset it to default. It is a good Idea to export your settings and import it as you need in later stages. To reset the settings to default select the Reset option and click next. Now Visual Studio will ask you to whether you would like to save the settings, which can be used in future to restore. Select any one option and click next. For the purpose of this demo, I have selected not to save the settings. Click Next button to continue. Now Visual Studio will bring you the similar dialog that appears just after installation to select your IDE settings. Select the required settings from the available list and click Finish button. Click Finish once you are done. If everything OK, you will see the success message as below. Now go to file -> new Project, you will see the selected language appear by default. I selected C# in the previous step and the new project dialog appears as follows. Changing IDE settings in Visual Studio 2012 is very easy and straight forward.

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• Working with Legacy code #4 : Remove the hard dependencies

  - by andrewstopford

  During your refactoring cycle you should be seeking out the hard dependencies that the code may have, examples of these can include. File System Database Network (HTTP) Application Server (Crystal) Classes that service these kind (or code that can be abstracted to a class) of these kind of dependencies should be wrapped in an interface for easier mocking. If you team starts refering to the interface version of these classes the hard dependency will over time work it's self free.

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• Lessons from rewriting POP Forums for MVC, open source-like

  - by Jeff

  It has been a ton of work, interrupted over the last two years by unemployment, moving, a baby, failing to sell houses and other life events, but it's really exciting to see POP Forums v9 coming together. I'm not even sure when I decided to really commit to it as an open source project, but working on the same team as the CodePlex folks probably had something to do with it. Moving along the roadmap I set for myself, the app is now running on a quasi-production site... we launched MouseZoom last weekend. (That's a post-beta 1 build of the forum. There's also some nifty Silverlight DeepZoom goodness on that site.)I have to make a point to illustrate just how important starting over was for me. I started this forum thing for my sites in old ASP more than ten years ago. What a mess that stuff was, including SQL injection vulnerabilities and all kinds of crap. It went to ASP.NET in 2002, but even then, it felt a little too much like script. More than a year later, in 2003, I did an honest to goodness rewrite. If you've been in this business of writing code for any amount of time, you know how much you hate what you wrote a month ago, so just imagine that with seven years in between. The subsequent versions still carried a fair amount of crap, and that's why I had to start over, to make a clean break. Mind you, much of that crap is still running on some of my production sites in a stable manner, but it's a pain in the ass to maintain.So with that clean break, there is much that I have learned. These are a few of those lessons, in no particular order...Avoid shiny object syndromeOver the years, I've embraced new things without bothering to ask myself why. I remember spending the better part of a year trying to adapt this app to use the membership and profile API's in ASP.NET, just because they were there. They didn't solve any known problem. Early on in this version, I dabbled in exotic ORM's, even though I already had the fundamental SQL that I knew worked. I bloated up the client side code with all kinds of jQuery UI and plugins just because, and it got in the way. All the new shiny can be distracting, and I've come to realize that I've allowed it to be a distraction most of my professional life.Just query what you needI've spent a lot of time over-thinking how to query data. In the SQL world, this means exotic joins, special caches, the read-update-commit loop of ORM's, etc. There are times when you have to remind yourself that you aren't Facebook, you'll never be Facebook, and that databases are in fact intended to serve data. In a lot of projects, back in the day, I used to have these big, rich data objects and pass them all over the place, through various application tiers, when in reality, all I needed was some ID from the entity. I try to be mindful of how many queries hit the database on a given request, but I don't obsess over it. I just get what I need.Don't spend too much time worrying about your unit testsIf you've looked at any of the tests for POP Forums, you might offer an audible WTF. That's OK. There's a whole lot of mocking going on. In some cases, it points out where you're doing too much, and that's good for improving your design. In other cases it shows where your design sucks. But the biggest trap of unit testing is that you worry it should be prettier. That's a waste of time. When you write a test, in many cases before the production code, the important part is that you're testing the right thing. If you have to mock up a bunch of stuff to test the outcome, so be it, but it's not wasted time. You're still doing up the typical arrange-action-assert deal, and you'll be able to read that later if you need to.Get back to your HTTP rootsASP.NET Webforms did a reasonably decent job at abstracting us away from the stateless nature of the Web. A lot of people criticize it, but I think it all worked pretty well. These days, with MVC, jQuery, REST services, and what not, we've gone back to thinking about the wire. The nuts and bolts passing between our Web browser and server matters. This doesn't make things harder, in my opinion, it makes them easier. There is something incredibly freeing about how we approach development of Web apps now. HTTP is a really simple protocol, and the stuff we push through it, in particular HTML and JSON, are pretty simple too. The debugging points are really easy to trap and trace.Premature optimization is prematureI'll go back to the data thing for a moment. I've been known to look at a particular action or use case and stress about the number of calls that are made to the database. I'm not suggesting that it's a bad thing to keep these in mind, but if you worry about it outside of the context of the actual impact, you're wasting time. For example, I query the database for last read times in a forum separately of the user and the list of forums. The impact on performance barely exists. If I put it under load, exceeding the kind of load I expect, it still barely has an impact. Then consider it only counts for logged in users. The context of this "inefficient" action is that it doesn't matter. Did I mention I won't be Facebook?Solve your own problems firstThis is another trap I've fallen into. I've often thought about what other people might need for some feature or aspect of the app. In other words, I was willing to make design decisions based on non-existent data. How stupid is that? When I decided to truly open source this thing, building for myself first was a stated design goal. This app has to server the audiences of CoasterBuzz, MouseZoom and other sites first. In this development scenario, you don't have access to mountains of usability studies or user focus groups. You have to start with what you know.I'm sure there are other points I could make too. It has been a lot of fun to work on, and I look forward to evolving the UI as time goes on. That's where I hope to see more magic in the future.

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• 4th Annual Hartford Code Camp - The Code Camp Manifesto lives on!

  - by SB Chatterjee

  It is amazing that Thom Robbins' blog posting back in December 2004 laid the foundation of the Code Camps that have grown world-wide - there is at least one every week-end in some country (unscientific tweets stats sampling). This week end, we at the Connecticut .NET Developers Group had the 4th Annual Hartford Code Camp and it was well attended with 120+ attendees with ~30 sessions. Our thanks to the Speakers from near and far who made our event a success.

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• Logkeys fragile?

  - by Ahmed Nematallah

  The program logkeys (which seems to be the only keylogger for linux out there which I can run) has some problems, it stops logging after some time, never returns again, I don't know how to trigger that bug, if the file is edited while logging, it just stops, if the file exists before logging it doesn't try to append to it or delete it or anything, the first issue is the most important but the rest are quite annoying can anyone help me because I'm not a linux programmer (I don't really know anything about the linux API but I am a beginner C++ programmer) and I won't be able to make my own keylogger thanks for the interest BTW I'm sure I got the right input device because it starts logging then stops and I use the command "logkeys -s -u -d /dev/input/event3 -o '/home/ahmed/Documents/log.txt'"

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• Third-Grade Math Class

  - by andyleonard

  An Odd Thing Happened... ... when I was in third grade math class: I was handed a sheet of arithmetic problems to solve. There were maybe 20 problems on the page and we were given the remainder of the class to complete them. I don't remember how much time remained in the class, I remember I finished working on the problems before my classmates. That wasn't the odd part. The odd part was that I started working on the first problem, concentrating pretty hard. I worked the sum and moved to the next...(read more)

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• Secret Agent Man

  - by Bil Simser

  Just a quick one this morning as we all get started in the week. Something that comes into play (sometimes in a big way) is the user agent string your browser gives off. So for example using the User-Agent field in the request header, you can determine what browser the user is running and act accordingly.Internet Explorer 9 modified the UA string slightly so just in case you're looking for it here are the user agent strings for IE9 (in various modes):Internet Explorer 9 Mode: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)Internet Explorer 8 Mode: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; MS-RTC LM 8; InfoPath.3; .NET4.0C; .NET4.0E; Zune 4.7)Internet Explorer 7 Mode: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; MS-RTC LM 8; InfoPath.3; .NET4.0C; .NET4.0E; Zune 4.7)Internet Explorer 9 (Compatibility Mode): Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; MS-RTC LM 8; InfoPath.3; .NET4.0C; .NET4.0E; Zune 4.7)A couple of things to note here:This was from a 64-bit Windows 7 client so that might account for the WOW64 in the agent string (I don't have a 32-bit client to test from)Various applications and platforms add to the UA string just like they do in previous IE releases. So for example you can see I have various .NET versions installed as well as Zune. You can take advantage of this by querying the UA string for compatibilities and present options accordingly to the end user.As applications will continue to add and modify this string you'll want to query the string for parts not the entire string. For example if you want to detect if you're coming from IE running  on a Windows Phone 7 just look for "iemobile" in the user agent stringHappy hacking!

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• Part 4, Getting the conversion tables ready for CS to DNN

  - by Chris Hammond

  This is the fourth post in a series of blog posts about converting from CommunityServer to DotNetNuke. A brief background: I had a number of websites running on CommunityServer 2.1, I decided it was finally time to ditch CommunityServer due to the change in their licensing model and pricing that made it not good for the small guy. This series of blog posts is about how to convert your CommunityServer based sites to DotNetNuke . Previous Posts: Part 1: An Introduction Part 2: DotNetNuke Installation...(read more)

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• SQL Server Express and VS2010 Web Application .MDF file errors

  - by nannette

  I installed SQL Server 2008 as well as SQL Server Express 2008 on my new Windows 7 development environment, along with Visual Studio 2010. I could get SQL Server 2008 to work fine, but I could not use Express .MDF databases within sample web application projects without receiving the below error: Failed to generate a user instance of SQL Server due to a failure in starting the process for the user instance. The connection will be closed. For instance, I was creating an ASP.NET Web Application. When...(read more)

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• C# with keyword equivalent

  - by oazabir

  There’s no with keyword in C#, like Visual Basic. So you end up writing code like this: this.StatusProgressBar.IsIndeterminate = false; this.StatusProgressBar.Visibility = Visibility.Visible; this.StatusProgressBar.Minimum = 0; this.StatusProgressBar.Maximum = 100; this.StatusProgressBar.Value = percentage; Here’s a work around to this: With.A<ProgressBar>(this.StatusProgressBar, (p) => { p.IsIndeterminate = false; p.Visibility = Visibility.Visible; p.Minimum = 0; p.Maximum = 100; p.Value = percentage; }); Saves you repeatedly typing the same class instance or control name over and over again. It also makes code more readable since it clearly says that you are working with a progress bar control within the block. It you are setting properties of several controls one after another, it’s easier to read such code this way since you will have dedicated block for each control. It’s a very simple one line function that does it: public static class With { public static void A<T>(T item, Action<T> work) { work(item); } } You could argue that you can just do this: var p = this.StatusProgressBar; p.IsIndeterminate = false; p.Visibility = Visibility.Visible; p.Minimum = 0; p.Maximum = 100; p.Value = percentage; But it’s not elegant. You are introducing a variable “p” in the local scope of the whole function. This goes against naming conventions. Morever, you can’t limit the scope of “p” within a certain place in the function.

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• Keep website and webservices warm with zero coding

  - by oazabir

  If you want to keep your websites or webservices warm and save user from seeing the long warm up time after an application pool recycle, or IIS restart or new code deployment or even windows restart, you can use the tinyget command line tool, that comes with IIS Resource Kit, to hit the site and services and keep them warm. Here’s how: First get tinyget from here. Download and install the IIS 6.0 Resource Kit on some PC. Then copy the tinyget.exe from “c:\program files…\IIS 6.0 ResourceKit\Tools'\tinyget” to the server where your IIS 6.0 or IIS 7 is running. Then create a batch file that will hit the pages and webservices. Something like this: SET TINYGET=C:\Program Files (x86)\IIS Resources\TinyGet\tinyget.exe"%TINYGET%" -srv:dropthings.omaralzabir.com -uri:http://dropthings.omaralzabir.com/ -status:200"%TINYGET%" -srv:dropthings.omaralzabir.com -uri:http://dropthings.omaralzabir.com/WidgetService.asmx?WSDL - status:200 First I am hitting the homepage to keep the webpage warm. Then I am hitting the webservice URL with ?WSDL parameter, which allows ASP.NET to compile the service if not already compiled and walk through all the operations and reflect on them and thus loading all related DLLs into memory and reducing the warmup time when hit. Tinyget gets the servers name or IP in the –srv parameter and then the actual URI in the –uri. I have specified what’s the HTTP response code to expect in –status parameter. It ensures the site is alive and is returning http 200 code. Besides just warming up a site, you can do some load test on the site. Tinyget can run in multiple threads and run loops to hit some URL. You can literally blow up a site with commands like this: "%TINYGET%" -threads:30 -loop:100 -srv:google.com -uri:http://www.google.com/ -status:200 Tinyget is also pretty useful to run automated tests. You can record http posts in a text file and then use it to make http posts to some page. Then you can put matching clause to check for certain string in the output to ensure the correct response is given. Thus with some simple command line commands, you can warm up, do some transactions, validate the site is giving off correct response as well as run a load test to ensure the server performing well. Very cheap way to get a lot done.

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• Using TPL and PLINQ to raise performance of feed aggregator

  - by DigiMortal

  In this posting I will show you how to use Task Parallel Library (TPL) and PLINQ features to boost performance of simple RSS-feed aggregator. I will use here only very basic .NET classes that almost every developer starts from when learning parallel programming. Of course, we will also measure how every optimization affects performance of feed aggregator. Feed aggregator Our feed aggregator works as follows: Load list of blogs Download RSS-feed Parse feed XML Add new posts to database Our feed aggregator is run by task scheduler after every 15 minutes by example. We will start our journey with serial implementation of feed aggregator. Second step is to use task parallelism and parallelize feeds downloading and parsing. And our last step is to use data parallelism to parallelize database operations. We will use Stopwatch class to measure how much time it takes for aggregator to download and insert all posts from all registered blogs. After every run we empty posts table in database. Serial aggregation Before doing parallel stuff let’s take a look at serial implementation of feed aggregator. All tasks happen one after other. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();           for (var index = 0; index <blogs.Count; index++)         {              ImportFeed(blogs[index]);         }     }       private void ImportFeed(BlogDto blog)     {         if(blog == null)             return;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                 }       private void ImportRssFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = RssFeed.Create(uri);           foreach (var item in feed.Channel.Items)         {             SaveRssFeedItem(item, blog.Id, blog.CreatedById);         }     }       private void ImportAtomFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           foreach (var item in feed.Entries)         {             SaveAtomFeedEntry(item, blog.Id, blog.CreatedById);         }     } } Serial implementation of feed aggregator downloads and inserts all posts with 25.46 seconds. Task parallelism Task parallelism means that separate tasks are run in parallel. You can find out more about task parallelism from MSDN page Task Parallelism (Task Parallel Library) and Wikipedia page Task parallelism. Although finding parts of code that can run safely in parallel without synchronization issues is not easy task we are lucky this time. Feeds import and parsing is perfect candidate for parallel tasks. We can safely parallelize feeds import because importing tasks doesn’t share any resources and therefore they don’t also need any synchronization. After getting the list of blogs we iterate through the collection and start new TPL task for each blog feed aggregation. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();                var tasks = new Task[blogs.Count];           for (var index = 0; index <blogs.Count; index++)         {             tasks[index] = new Task(ImportFeed, blogs[index]);             tasks[index].Start();         }           Task.WaitAll(tasks);     }       private void ImportFeed(object blogObject)     {         if(blogObject == null)             return;         var blog = (BlogDto)blogObject;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                }       private void ImportRssFeed(BlogDto blog)     {          var uri = new Uri(blog.RssUrl);          var feed = RssFeed.Create(uri);           foreach (var item in feed.Channel.Items)          {              SaveRssFeedItem(item, blog.Id, blog.CreatedById);          }     }     private void ImportAtomFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           foreach (var item in feed.Entries)         {             SaveAtomFeedEntry(item, blog.Id, blog.CreatedById);         }     } } You should notice first signs of the power of TPL. We made only minor changes to our code to parallelize blog feeds aggregating. On my machine this modification gives some performance boost – time is now 17.57 seconds. Data parallelism There is one more way how to parallelize activities. Previous section introduced task or operation based parallelism, this section introduces data based parallelism. By MSDN page Data Parallelism (Task Parallel Library) data parallelism refers to scenario in which the same operation is performed concurrently on elements in a source collection or array. In our code we have independent collections we can process in parallel – imported feed entries. As checking for feed entry existence and inserting it if it is missing from database doesn’t affect other entries the imported feed entries collection is ideal candidate for parallelization. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();                var tasks = new Task[blogs.Count];           for (var index = 0; index <blogs.Count; index++)         {             tasks[index] = new Task(ImportFeed, blogs[index]);             tasks[index].Start();         }           Task.WaitAll(tasks);     }       private void ImportFeed(object blogObject)     {         if(blogObject == null)             return;         var blog = (BlogDto)blogObject;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                }       private void ImportRssFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = RssFeed.Create(uri);           feed.Channel.Items.AsParallel().ForAll(a =>         {             SaveRssFeedItem(a, blog.Id, blog.CreatedById);         });      }        private void ImportAtomFeed(BlogDto blog)      {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           feed.Entries.AsParallel().ForAll(a =>         {              SaveAtomFeedEntry(a, blog.Id, blog.CreatedById);         });      } } We did small change again and as the result we parallelized checking and saving of feed items. This change was data centric as we applied same operation to all elements in collection. On my machine I got better performance again. Time is now 11.22 seconds. Results Let’s visualize our measurement results (numbers are given in seconds). As we can see then with task parallelism feed aggregation takes about 25% less time than in original case. When adding data parallelism to task parallelism our aggregation takes about 2.3 times less time than in original case. More about TPL and PLINQ Adding parallelism to your application can be very challenging task. You have to carefully find out parts of your code where you can safely go to parallel processing and even then you have to measure the effects of parallel processing to find out if parallel code performs better. If you are not careful then troubles you will face later are worse than ones you have seen before (imagine error that occurs by average only once per 10000 code runs). Parallel programming is something that is hard to ignore. Effective programs are able to use multiple cores of processors. Using TPL you can also set degree of parallelism so your application doesn’t use all computing cores and leaves one or more of them free for host system and other processes. And there are many more things in TPL that make it easier for you to start and go on with parallel programming. In next major version all .NET languages will have built-in support for parallel programming. There will be also new language constructs that support parallel programming. Currently you can download Visual Studio Async to get some idea about what is coming. Conclusion Parallel programming is very challenging but good tools offered by Visual Studio and .NET Framework make it way easier for us. In this posting we started with feed aggregator that imports feed items on serial mode. With two steps we parallelized feed importing and entries inserting gaining 2.3 times raise in performance. Although this number is specific to my test environment it shows clearly that parallel programming may raise the performance of your application significantly.

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• How to evaluate the quality of Rails code?

  - by Fortuity

  In a code review, what do you look for to assess a developer's expertise? Given an opportunity to look at a developer's work on a real-world project, what tell-tale signs are a tip-off to carelessness or lack of experience? Conversely, where do you look in the code to find evidence of a developer's skill or knowledge of best practices? For example, if I'm looking at a typical Rails app, I would be happy to see the developer is using RSpec (showing a commitment to using test-driven development and knowledge that RSpec is currently more popular than the default TestUnit). But in examining the specs for a Rails model, I see that the developer is testing associations, which might indicate a lack of real understanding of Rails testing requirements (since such tests are redundant given that they only test what's already implemented and tested in ActiveRecord). More generally, I might look to see if developers are writing their own implementations versus using widely available gems or if they are cleaning up code versus leaving lots of commented-out "leftovers." What helps you determine the skill of a Rails developer? What's your code quality checklist?

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• Simple Netduino Go Tutorial Flashing RGB LEDs with a potentiometer

  - by Chris Hammond

  In case you missed the announcement on 4/4, the guys and Secret Labs, along with other members of the Netduino Community have come out with a new platform called Netduino Go . Head on over www.netduino.com for the introduction forum post . This post is how to quickly get up and running with your Netduino Go, based on Chris Walker’s getting started forum post , with some enhancements that I think will make it easier to get up and running, as Chris’ post unfortunately leaves a few things out. Hardware...(read more)

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• Why Ubuntu Softwares are not packaged in a single file?

  - by Anwar Shah

  We see Most of the Windows Softwares are packaged in a Single executable file. When I double-click Setup file, it sets up all the files, binaries and libraries with it. I understand the dependency of Ubuntu or more generally linux packages. But I wonder, Why these exists. Isn't it possible to build a single file with all dependencies. What is the problems with this method? Please try to give the reason in details.

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• Apple Mac App Store?

  - by Riddler

  The Mac App store seems like an ideal distribution channel for apps made specifically for OSX. However, due to the high quantity of apps, I wasn't sure if there was an actual chance of my app making money. What would be a reasonable amount of sales from the Mac App Store for an app made by a small developer? I am wondering if the profit would be worth the effort and money required to get the app in the store.

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• How to use the Netduino Go Piezo Buzzer Module

  - by Chris Hammond

  Originally posted on ChrisHammond.com Over the next couple of days people should be receiving their Netduino Go Piezo Buzzer Modules , at least if they have ordered them from Amazon. I was lucky enough to get mine very quickly from Amazon and put together a sample project the other night. This is by no means a complex project, and most of it is code from the public domain for projects based on the original Netduino. Project Overview So what does the project do? Essentially it plays 3 “tunes” that...(read more)

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• How can I save my university's Computer Science & Engineering department? [closed]

  - by Blake

  I'm currently pursuing a B.S. in Computer Engineering at the University of Florida, and we're having a bit of a problem right now... The state recently passed a budget plan that cuts funding for higher education in Florida. The dean of UF's College of Engineering decided that the best way for us to absorb the blow is by executing the following plan: All of the Computer Engineering Degree programs, BS, MS and PhD, would be moved from the Computer & Information Science and Engineering Dept. to the Electrical and Computer Engineering Dept. along with most of the advising staff. Roughly half of the faculty would be offered the opportunity to move to Electrical/Computer Eng., Biomedical Eng., or Industrial/Systems Eng. Staff positions in CISE which are currently supporting research and graduate programs would be eliminated. The activities currently covered by TAs would be reassigned to faculty and the TA budget for CISE would be eliminated. Any faculty member who wishes to stay in CISE may do so, but with a revised assignment focused on teaching and advising. In short: our department (at least as we know it) is being decimated. Computer & Information Sciences & Engineering (one of 9 departments in the College of Engineering) is taking more than 50% of the cuts. If you're interested in reading the full proposal, you can access it here. A vast, VAST majority of the students and faculty in the department are vehemently opposed to this plan, however the dean is already taking measures to implement it. This is the only proposal on the table right now, and she has not entertained our requests for alternatives. She sees it as an obvious (albeit drastic) solution to our budget problem, citing that many other universities have combined Computer and Electrical Engineering departments. I'll bet those universities didn't have to eliminate an established department to get there, though. The budget goes into effect July 1, 2012 (this is non-negotiable), and the dean's proposal is currently set to be finalized some time next week. We don't have much time! My question to everyone here is this: Are we overreacting to this plan, or are we justified? And could you explain why or why not? It's obvious that CISE students will resist any cuts to our department, but I'm curious to see what other people in the field have to say. Any feedback is greatly appreciated. I will select the answer that saves our department. Just kidding, I'll pick the one that best explains why this is a good or bad decision for the dean to make. Please note that anything you say can and will be used to further our cause (and we might track you down if you provide a compelling argument against us).

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• Assign programs permanently to different sound-outputs – PulseAudio.

  - by Mood

  I want to assign Skype input and output to my USB-headset while the rest of my laptop uses the internal sound-card. This is an easy task with PulseAudio Volume control (pavucontrol). The only problem I have is every time a call is made I manually have to set the output and input for Skype to my USB-device . When I hang up, Skype disappears from Volume Control. It reappears again with the next call only this time the default sound-card is selected again. It shouldn’t be hard to let PulseAudio look or the USB-headset is connected when Skype audio comes is before selecting the default. The way to do it is obvious not through Volume Control.

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• Toad Just Keeps Getting Better

  - by KKline

  Toad for SQL Server just keeps getting better. And with its win as Best of TechEd in the Database Development category, there's even more to love....(read more)

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