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• Minimal Lunix distribution with sshd and apt

  - by Sergey Mikhanov

  When I signed up for my Debian Linux VPS hosting and first logged on and invoked ps aux, there was the only user process running: sshd. As I can see, this was minimal Linux with only two things installed and configured: sshd and apt (plus all dependencies, of course). I want to build (or use existing) similar Linux distro, any advice on how to build (or pick) one? Googling "minimum linux", or "linux with sshd only" usually brings up Debian's netinstall, which is not what I want. Thanks in advance.

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• Compressing large text data before storing into db?

  - by Steel Plume

  Hello, I have application which retrieves many large log files from a system LAN. Currently I put all log files on Postgresql, the table has a column type TEXT and I don't plan any search on this text column because I use another external process which nightly retrieves all files and scans for sensitive pattern. So the column value could be also a BLOB or a CLOB, but now my question is the following, the database has already its compression system, but could I improve this compression manually like with common compressor utilities? And above all WHAT IF I manually pre-compress the large file and then I put as binary into the data table, is it unuseful as database system provides its internal compression?

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• Speech recognition with Flash or Silverlight

  - by Sebastián Grignoli

  I'm developing a web user interface to enter some information that is not very complex but needs to be loaded in real time. I think that the application could make use of speech recognition to facilitate the task. Te core of the interface is being built with Javascript and jQuery, but can easily include a flash or silverlight component. I believe that´s probably the way to go... I don't need to recognize everything that the user says, but only a few prerecorded commands. Also, I don't want the user to click on a button to specify the begining and the end of the spoken command. It should be detected live. Is there anything that does this? I would be grateful if anyone tells me about a complete solution, free or commercial, as well as any advice on capturing a sound stream from the mic and process it with flash or sliverlight. Sebastian.-

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• 2-Version software: Best VCS approach?

  - by Tom R

  I suppose I'd better explain my situation: I'm in the process of developing some software, and I'm at the stage where I'd like to split my project into two branches which differ in features. It so happens that this application is an Android application which I will be deploying on the Market, which has the constraint that every app must have a unique package identifier (sensible, no?). My current approach has been to clone the git repo of my original project, but this causes issues with package names. I want the system to be robust enough so that a bugfix/new feature on one branch will merge into another branch, but only when I want it to. Does anyone have any suggestions?

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• OpenGL extensions available on different Android devices

  - by MH114

  I'm in the process of writing an OpenGL ES powered framework for my next Android game(s). Currently I'm supporting three different techniques of drawing sprites: the basic way: using vertex arrays (slow) using vertex-buffer-objects (VBOs) (faster) using the draw_texture extension (fastest, but only for basic sprites, i.e. no transforming) Vertex arrays are supported in OpenGL ES 1.0 and thus in every Android-device. I'm guessing most (if not all) of the current devices also support VBOs and draw_texture. Instead of guessing, I'd like to know the extensions supported by different devices. If majority of devices support VBOs, I could simplify my code and focus only on VBOs + draw_texture. It'd be helpful to know what different devices support, so if you have an Android-device, do report the extensions list please. :) String extensions = gl.glGetString(GL10.GL_EXTENSIONS); I've got a HTC Hero, so I can share those extensions next.

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• Does MATLAB perform tail call optimization?

  - by Shea Levy

  I've recently learned Haskell, and am trying to carry the pure functional style over to my other code when possible. An important aspect of this is treating all variables as immutable, i.e. constants. In order to do so, many computations that would be implemented using loops in an imperative style have to be performed using recursion, which typically incurs a memory penalty due to the allocation a new stack frame for each function call. In the special case of a tail call (where the return value of a called function is immediately returned to the callee's caller), however, this penalty can be bypassed by a process called tail call optimization (in one method, this can be done by essentially replacing a call with a jmp after setting up the stack properly). Does MATLAB perform TCO by default, or is there a way to tell it to?

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• Paypal IPN Confirmation Screen immediately after redirect without reload

  - by Email

  Hi I made a script for IPN which works great but how can i immediately notify the user? I mean paypal redirects the customer to a custom-page i can define, simultanously my ipn.php checked the status, BUT how can i immediately tell the customer on this custom-page that it was successful or not. this custom-page does somehow has to know that this is the customer-xyz which made the ipn-verified!!! payment xyz, but how? i think also this custom-page redirect should wait the 5 seconds because php does only process files/request on-loads... so after 5 seconds the ipnscript surely did complete. Sorry if this question is too newby but i dont know how to notify the customer about the (ipn-verified!!!) payment-status immediately. How do you do this? Thanks so much

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• Compiling flex file into dll.

  - by Szpilona

  Hi, I've got a lexer created with flex (cygwin). Normally I compile it to an .exe file. For the newest project I need a lexer to use in a bigger C# program running on Windows XP. Of course I can execute a file using System.Diagnostics.Process. But it is not the best solution for me as I want that program to run on several machines. How can I create a dll under cygwin having the source code of the lexer? Thanks in advance... Szpilona

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• Does Amazon S3's HTTP Uploads feature support web-hook style callbacks?

  - by Gabe Hollombe

  When uploading files to Amazon S3 using the browser http upload feature, I know I can specify a success_action_redirect field/value that will tell my browser where to go when the upload is done. I'm wondering: is it possible to ask Amazon to make a web hook style POST request to my web server whenever a file gets uploaded? Basically, I want a way of being notified whenever a client uploads a new file, so that my server can process the upload. I'd like to do this without relying on the client to make the request to my server to tell me the file has been uploaded (never trust the client, right?).

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• malloc()/free() behavior differs between Debian and Redhat

  - by StasM

  I have a Linux app (written in C) that allocates large amount of memory (~60M) in small chunks through malloc() and then frees it (the app continues to run then). This memory is not returned to the OS but stays allocated to the process. Now, the interesting thing here is that this behavior happens only on RedHat Linux and clones (Fedora, Centos, etc.) while on Debian systems the memory is returned back to the OS after all freeing is done. Any ideas why there could be the difference between the two or which setting may control it, etc.?

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• What is the best possible technology for pulling huge data from 4 remote servers

  - by Habib Ullah Bahar

  Hello, For one of our project, we need to pull huge real time stock data from 4 remote servers across two countries. The trivial process here, check the sources for a regular interval and save the update to database. But as these are real time stock data of more than 1000 companies, I have to pull every second, which isn't good in case of memory, bandwidth I think. Please give me suggestion on which technology/platform [We are flexible here. PHP, Python, Java, PERL - anyone of them will be OK for us] we should choose, it can be achieved easily and with better performance.

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• Core dump utility for .NET

  - by Dave

  In my past life as a COBOL mainframe developer I made extensive use of a tool called Abendaid which, in the event of an exception, would give me a complete memory dump including a formatted list of every variable in memory as well as a complete stack trace of the program with the offending statement highlighted. This made pinpointing the cause of an error much simpler and saved a lot of step-through debugging and/or trace statements. Now I've made the transition to C# and .NET web development I find that the information provided by ASP.NET only tells half the story, giving me a stack trace, but not any of the variable or class information. This makes debugging more difficult as you then have to run the process again with the debugger to try and reproduce the error, not easy with intermittent errors or with assemblies that run under the likes of SQL Server or CRM. I've looked around quite a lot for something that does this but I can't find anything obvious. Does anyone have any idea if there is one, or if not, what I'd need to start with in order to write one?

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• Must .aspx files have a page directive?

  - by Keith Bloom

  Around 90% of the pages for our websites have no .Net code embedded in them yet are published as .aspx files. I want these to render as fast as possible so I'm removing as much as I can. Does the .Net page directive have an impact on performance? I am thinking about two factors; the page speed for each GET and what happens when the file changes. The CMS system re-creates each page daily and I'm wondering if this triggers the ASP.Net compilation process.

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• Python Imaging: YCbCr problems

  - by daver

  Hi, I'm doing some image processing in Python using PIL, I need to extract the luminance layer from a series of images, and do some processing on that using numpy, then put the edited luminance layer back into the image and save it. The problem is, I can't seem to get any meaningful representation of my Image in a YCbCr format, or at least I don't understand what PIL is giving me in YCbCr. PIL documentation claims YCbCr format gives three channels, but when I grab the data out of the image using np.asarray, I get 4 channels. Ok, so I figure one must be alpha. Here is some code I'm using to test this process: import Image as im import numpy as np pengIm = im.open("Data\\Test\\Penguins.bmp") yIm = pengIm.convert("YCbCr") testIm = np.asarray(yIm) grey = testIm[:,:,0] grey = grey.astype('uint8') greyIm = im.fromarray(grey, "L") greyIm.save("Data\\Test\\grey.bmp") I'm expecting a greyscale version of my image, but what I get is this jumbled up mess: http://i.imgur.com/zlhIh.png Can anybody explain to me where I'm going wrong? The same code in matlab works exactly as I expect.

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• Entity Framework with File-Based Database

  - by Dave Swersky

  I am in the process of developing a desktop application that needs a database. The application is currently targeted to SQL Express 2005 and works wonderfully. However, I'm not crazy about having this dependency on SQL Express and would prefer to use a small file-based database. My problem is that I am using Entity Framework. I have tried both SQL Compact and SQLite, and they both have bizarre problems with EF v1. I get errors creating the Model, invalid models when it does get created... it's a nightmare. I'm about ready to give up and write a data layer and repository in the good-old-school Connection/Command pattern. Not my favorite plan... Is there a lightweight, file-based database out there that plays well with EF? OR Is there a better ORM tool that I should use instead of EF with my lightweight DB?

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• a question on webpage data scraping using Java

  - by Gemma

  Hi there. I am now trying to implement a simple HTML webpage scraper using Java.Now I have a small problem. Suppose I have the following HTML fragment. <div id="sr-h-left" class="sr-comp"> <a class="link-gray-underline" id="compare_header" rel="nofollow" href="javascript:i18nCompareProd('/serv/main/buyer/ProductCompare.jsp?nxtg=41980a1c051f-0942A6ADCF43B802'); " Compare Showing 1 - 30 of 1,439 matches, The data I am interested is the integer 1.439 shown at the bottom.I am just wondering how can I get that integer out of the HTML. I am now considering using a regular expression,and then use the java.util.Pattern to help get the data out,but still not very clear about the process. I would be grateful if you guys could give me some hint or idea on this data scraping. Thanks a lot.

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• Socket ping-pong performance

  - by Kamil_H

  I have written two simple programs (tried it in C++ and C#). This is pseudo code: -------- Client --------------- for(int i = 0; i < 200.000; i++) { socket_send("ping") socket_receive(buff) } --------- Server ------------- while(1) { socket_receive(buff) socket_send("pong") } I tried it on Windows. Execution time of client is about 45 seconds. Can somebody explain me why this takes so long? I understand that if there were real network connection between client and server the time of one 'ping-pong' would be: generate_ping + send_via_network + generate_pong + send_via_network but here everything is done in 'local' mode. Is there any way to make this inter process ping-pong faster using network sockets (I'm not asking about shared memory for example :) )

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• Debugging ASP.NET on a built-in web server suddenly stops

  - by Anton Gogolev

  I have Windows Server 2008 (64-bit), VS 2008 with its built-in webserver and an ASP.NET MVC 1.0 webapp. All I'm trying to do is to debug said app. I have a bunch of breakpoints, but they behave in a very strange way. When I fist start a debugging session with F5 and hit a breakpoint, the debugger stops just fine. However, after serveral F10s/F11s debugging suddenly "stops" (no exceptions at that time), but neither VS detaches from browsers' process, nor webapp execution stops: Visual Studio stays attached, and web request continues executing as usual. I tried various browsers (Chrome, Firefox, IE), but to no avail. What do I do to solve this? It really drives me insane.

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• svn hangs when connecting to server but only for me!

  - by vgm64

  I've checked out two repositories with svn and they both have some odd behavior when using commands like svn -u status. That command in particular will hang, and top says the process is sleeping. I can check out and update those repos (usually), but this in particular will hang until I kill -9 it. It doesn't happen on anyone else's computer (I'm running Mac OSX 10.6) who uses these repos. I just checked out a fresh clean version of one of the repos, and did svn -u status and it froze. Anyone have any thoughts? Could some settings be corrupted?

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• php - feof error

  - by TwixxyKit

  The file that I'm trying to read is a pgp-encrypted file. This is part of the process to decrypt it and I'm actually attempting to read the contents into a string so that I can then decrypt it . I'm not sure if that's the core problem here or not, but I'm getting an error: Warning: feof(): supplied argument is not a valid stream resource Here's the file code: if($handle = opendir($dir)) { while( false !== ($file = readdir($handle))) { if($file != "." && $file != "..") { $fhandle = fopen($file, "r"); $encrypted = ''; $filename = explode('.',$file); while(!feof($fhandle)) { $encrypted .= fread($fhandle, filesize($file)); } fclose($fhandle); $decrypted = $filename[0].'.txt'; shell_exec("echo $passphrase | $gpg --passphrase-fd 0 -o $decrypted -d $encrypted"); } } }

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• how to pass url in mailto's body

  - by Simer

  i need to send a url of my site in body so that user can click on that to join my site. but it is coming like this in mail client: Link goes here http://www.example.com/foo.php?this=a url after & is not coming then whole process of joining failed. how can i pass url like these in mailto body http://www.example.com/foo.php?this=a&join=abc&user454 <a href="mailto:[email protected]?body=Link goes here http://www.example.com/foo.php?this=a&amp;really=long&amp;url=with&amp;lots=and&amp;lots=and&amp;lots=of&prameters=on_it ">Link text goes here</a> i have searched alot but did't got right answer thanks

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• CodePlex Daily Summary for Monday, October 21, 2013

  CodePlex Daily Summary for Monday, October 21, 2013Popular ReleasesVirtual Wifi Hotspot for Windows 7 & 8: Virtual Router Plus 2.6.0: Virtual Router Plus 2.6.0Fast YouTube Downloader: Fast YouTube Downloader 2.3.0: Fast YouTube DownloaderABCat: ABCat v.2.0a: ?????? ????? ??? ????????? ????????????. ???????? ???, ?? ?? ????? ???? :) ?? ??????? ??????????? ???????? ?? Windows 7 - ????? ??????? ????????? ?? ???? ??? ?????? ??????.Magick.NET: Magick.NET 6.8.7.101: Magick.NET linked with ImageMagick 6.8.7.1. Breaking changes: - Renamed Matrix classes: MatrixColor = ColorMatrix and MatrixConvolve = ConvolveMatrix. - Renamed Depth method with Channels parameter to BitDepth and changed the other method into a property.VidCoder: 1.5.9 Beta: Added Rip DVD and Rip Blu-ray AutoPlay actions for Windows: now you can have VidCoder start up and scan a disc when you insert it. Go to Start -> AutoPlay to set it up. Added error message for Windows XP users rather than letting it crash. Removed "quality" preset from list for QSV as it currently doesn't offer much improvement. Changed installer to ignore version number when copying files over. Should reduce the chances of a bug from me forgetting to increment a version number. Fixed ...MSBuild Extension Pack: October 2013: Release Blog Post The MSBuild Extension Pack October 2013 release provides a collection of over 480 MSBuild tasks. A high level summary of what the tasks currently cover includes the following: System Items: Active Directory, Certificates, COM+, Console, Date and Time, Drives, Environment Variables, Event Logs, Files and Folders, FTP, GAC, Network, Performance Counters, Registry, Services, Sound Code: Assemblies, AsyncExec, CAB Files, Code Signing, DynamicExecute, File Detokenisation, GUI...VG-Ripper & PG-Ripper: VG-Ripper 2.9.49: changes NEW: Added Support for "ImageTeam.org links NEW: Added Support for "ImgNext.com" links NEW: Added Support for "HostUrImage.com" links NEW: Added Support for "3XVintage.com" linksMedia Companion: Media Companion MC3.583b: As before release but fixed for no movie poster sourcesNew* Both - Added 'An' as option to ignore in title * Movie - Renaming - added %Z - Sorttitle to Legend * Movie - Renaming - added %O - Audio Channels to Legend * Movie - Remove a poster source from priority list. Reset List back to defaults. * Made Media Companion truly portable application. Fixed* Movie - browse for Poster Or Fanart, allows for jpg, tbn, png and bmp images * Movie - Alt Fanart Browser - Url or Browse window now fully...MoreTerra (Terraria World Viewer): MoreTerra 1.11.3.1: Release 1.11.3.1 ================ = New Features = ================ Added markers for Copper Cache, Silver Cache and the Enchanted Sword. ============= = Bug Fixes = ============= Use Official Colors now no longer tries to change the Draw Wires option instead. World reading was breaking for people with a stock 1.2 Terraria version. Changed world name reading so it does not crash the program if you load MoreTerra while Terraria is saving the world. =================== = Feature Removal = =...patterns & practices - Windows Azure Guidance: Cloud Design Patterns: 1st drop of Cloud Design Patterns project. It contains 14 patterns with 6 related guidance.Player Framework by Microsoft: Player Framework for Windows and WP (v1.3): Includes all changes in v1.3 beta 1 and v1.3 beta 2 Support for Windows 8.1 RTM and VS2013 RTM Xaml: New property: AutoLoadPluginTypes to help control which stock plugins are loaded by default (requires AutoLoadPlugins = true). Support for SystemMediaTransportControls on Windows 8.1 JS: Support for visual markers in the timeline. JS: Support for markers collection and markerreached event. JS: New ChaptersPlugin to automatically populate timeline with chapter tracks. JS: Audio an...Json.NET: Json.NET 5.0 Release 8: Fix - Fixed not writing string quotes when QuoteName is falsePowerShell Community Extensions: 3.1 Production: PowerShell Community Extensions 3.1 Release NotesOct 17, 2013 This version of PSCX supports Windows PowerShell 3.0 and 4.0 See the ReleaseNotes.txt download above for more information.SQL Power Doc: Version 1.0.2.1: Misc. bug fixes Added logic to resolve members of a Windows Group server login Added columns to Excel workbooks to show definitions for server permissions, server roles, database permissions, and database rolesSocial Network Importer for NodeXL: SocialNetImporter(v.1.9): This new version includes: - Download latest status update and use it as vertex tooltip - Limit the timelines to parse to me, my friends or both - Fixed some reported bugs about the fan page and group importer - Fixed the login bug reported latelyTerrariViewer: TerrariViewer v7.1 [Terraria Inventory Editor]: You can now backspace in number fields Items added in 1.2.0.3 no longer corrupt player files Buff durations capped at 9999999 Item stacks capped at 9999999 Version info added Prefix IDs corrected Shoe and Eye color box are now properly clickable Moved Bank and Safe into their own tab Users will now be notified of new updatesPython Tools for Visual Studio: 2.0: PTVS 2.0 We’re pleased to announce the release of Python Tools for Visual Studio 2.0 RTM. Python Tools for Visual Studio (PTVS) is an open-source plug-in for Visual Studio which supports programming with the Python language. PTVS supports a broad range of features including CPython/IronPython, Edit/Intellisense/Debug/Profile, Cloud, IPython, and cross platform and cross language debugging support. QUICK VIDEO OVERVIEW For a quick overview of the general IDE experience, please watch this v...LINQ to Twitter: LINQ to Twitter v2.1.09: Supports .NET 3.5, .NET 4.0, .NET 4.5, Silverlight 4.0, Windows Phone 7.1, Windows Phone 8, Client Profile, Windows 8, and Windows Azure. 100% Twitter API coverage. Also supports Twitter API v1.1! Also on NuGet.Sandcastle Help File Builder: SHFB v1.9.8.0 with Visual Studio Package: General InformationIMPORTANT: On some systems, the content of the ZIP file is blocked and the installer may fail to run. Before extracting it, right click on the ZIP file, select Properties, and click on the Unblock button if it is present in the lower right corner of the General tab in the properties dialog. This new release contains bug fixes and feature enhancements. There are some potential breaking changes in this release as some features of the Help File Builder have been moved into...C++ REST SDK (codename "Casablanca"): C++ REST SDK 1.3.0: This release fixes multiple customer reported issues as well as the following: Full support for Dev12 binaries and project files Full support for Windows XP New sample highlighting the Client and Server APIs : BlackJack Expose underlying native handle to set custom options on http_client Improvements to Listener Library Note: Dev10 binaries have been dropped as of this release, however the Dev10 project files are still available in the Source CodeNew Projects4Elements game project: Project for a game were players will be able to earn money by just playingBible: This project aims to deliver an awesome Bible application for as many platforms as possible.cIFrex: cIFrexConnecting SharePoint with Exchange Server 2010/2013 using remote sessions: The project focuses on connecting SharePoint 2013 with Exchange Server 2010/2013 via Remote PowerShell with C# API Crzy Cms: Crzy CMS is a content management system created in ASP.NET using MVC/Entity Framework.DownloadsArchiver: Kann automatisch das Downloads-Verzeichnis aufräumen.GatePass: Gatepass SystemGenerate PowerShell scripts for SharePoint 2010 Site Collection Administration: Winform tool to generate PowerShell scripts, to move, create, backup and restore site collections It needs to be run on SharePoint Server 2010Generate PowerShell scripts for SharePoint 2013 Site Collection Administration: Winform tool to generate PowerShell scripts, to move, create, backup and restore site collections It needs to be run on SharePoint Server 2013GTerm: GTerm is alternative Terminal for Windows Vista/XP/7 and 8.Ignitron Chess: A newly created software product for playing chess by Ignitron Development Team.Introduccion a C# con VS2012: El curso de Introducción a C# con Visual Studio 2012, tiene como objetivo principal enseñar al estudiante los conceptos básicos de programación utilizando C#Punch Clock: Punch Clock is a online tool for any employee to sign up and calculate their daily,weekly monthly hours and download the report in PDF/Excel format. PVMonitor: This project will provide a monitoring dashboard for PV systems.qttexteditor: qttexteditorRegister Interest app: Register Interest is an app template where you can use to record interest of attendees, useful in marketing distribution.SharePoint Simple Developer: Project allows to simply SharePoint 2010 and SharePoint 2013 daily developers tasks. Main goal is to implement validation of built solutions. Silverlight QB Rating Calculator: Silverlight QB Rating Calculator is a Silverlight 5 App that calculates a QB's NFL and NCAA passing efficiency ratings.SimpleAdditionPage: This projects consists of a simple ASP.NET in VB.NET page that allows users to enter 2 numbers, and display their sum.SP SIN Store: SP SIN Store is an extension to SP SIN that allows users to install solutions in SharePoint similar to the WordPress plugins. Project is in Alpha stage.

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• Modifications in default document (ASP.NET+IIS7) won't take effect

  - by Wilson

  We have a website developed by ASP.NET+IIS7 and its default document is default.aspx. It works fine. But when we tried to switch the default to index.html, weird things happened. We have modified web.config as follows: <defaultDocument> <files> <clear /> <add value="index.html" /> </files> </defaultDocument> and we have clear everything under C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files``, and restart the worker process. We even changed the name of Default.aspx to dddd.aspx. But everything stays the same when accessing with http://localhost/<MyAppName>/! And when we tried to access with http://localhost/<MyAppName>/index.html, it works fine. Any suggestions would be highly appreciated.

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• Passing Text for command line

  - by Kasun

  Hi, I need to pass some text which is in richtext box to command line. This is my Button click even which start the cmd. private void button1_Click(object sender, EventArgs e) { ProcessStartInfo psi = new ProcessStartInfo { FileName = "cmd", Arguments = @"/k ""C:\Program Files\Microsoft Visual Studio 9.0\VC\bin\vcvars32.bat""", }; Process.Start(psi); } In my rich text box contain following text. include iostream using namespace std; int main() { cout << "Welcome to the wonderful world of C++!!!\n"; return 0; } Can anyone provide me necessary codes.

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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