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  • Regulation of the software industry

    - by Flexo
    Every few years someone proposes tighter regulation for the software industry. This IEEE article has been getting some attention lately on the subject. If software engineers who write programs for systems that expose the public to physical or financial risk knew they would be tested on their competence, the thinking goes, it would reduce the flaws and failures in code—and maybe save a few lives in the bargain. I'm skeptical about the value and merit of this. To my mind it looks like a land grab by those that proposed it. The quote that clinches that for me is: The exam will test for basic knowledge, not mastery of subject matter because the big failures (e.g. THERAC-25) seem to be complex, subtle issues that "basic knowledge" would never be sufficient to prevent. Ignoring any local issues (such as existing protections of the title Engineer in some jurisdictions): The aims are noble - avoid the quacks/charlatans1 and make that distinction more obvious to those that buy their software. Can tighter regulation of the software industry ever achieve it's original goal? 1 Exactly as regulation of the medical profession was intended to do.

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  • Configuring SQL Server Management Studio to use Windows Integrated Authentication &hellip; from non-

    - by Enrique Lima
    Did you know you can pass your Windows credentials to SQL Server even when working from a workstation that is not joined to a domain? Here is how … From Start, then click All Programs, find Microsoft SQL Server (version 2005 or 2008). Once there, do a right-click on SQL Server Management Studio, then click on Properties Now, follow below to modify the entry for Target: Now the real task (we will be using the runas command) … Modify the shortcut’s target as follows, and remember to replace <domain\user> with the values that correspond to your environment : x64 SQL Server 2008 C:\Windows\System32\runas.exe /user:<domain\user> /netonly "C:\Program Files (x86)\Microsoft SQL Server\100\Tools\binn\VSShell\Common7\IDE\Ssms.exe -nosplash" SQL Server 2005 C:\Windows\System32\runas.exe /user:<domain\user> /netonly "C:\Program Files (x86)\Microsoft SQL Server\90\Tools\binn\VSShell\Common7\IDE\SqlWb.exe -nosplash" x86 SQL Server 2008 C:\Windows\System32\runas.exe /user:<domain\user> /netonly "C:\Program Files\Microsoft SQL Server\100\Tools\binn\VSShell\Common7\IDE\Ssms.exe -nosplash" SQL Server 2005 C:\Windows\System32\runas.exe /user:<domain\user> /netonly "C:\Program Files\Microsoft SQL Server\90\Tools\binn\VSShell\Common7\IDE\SqlWb.exe -nosplash" Since we modified the shortcut, we will need to fix the icon for SSMS.  We will fix it by pressing the Change Icon… button and pointing to the original “icon” providers. It is the executables for SSMS that hold the icon information, so we need to point to … x64 SQL Server 2008 %ProgramFiles% (x86)\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\Ssms.exe SQL Server 2005 C:\Program Files (x86)\Microsoft SQL Server\90\Tools\binn\VSShell\Common7\IDE\SqlWb.exe x86 SQL Server 2008 %ProgramFiles%\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\Ssms.exe SQL Server 2005 C:\Program Files\Microsoft SQL Server\90\Tools\binn\VSShell\Common7\IDE\SqlWb.exe When you start SSMS from a modified shortcut, you’ll be prompted for your domain password: SSMS will show up stating a different account in the username box, but the parameters from the configuration you are doing above do work and will pass on correctly.

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  • How can I make multiple displays work on my Asus UX32VD?

    - by oKtosiTe
    Original title: Why do I have two trash icons in the Unity Launcher? Whether I run Ubuntu as a live-USB or install it, I always have two trash bins on the Unity Launcher. Both work, and both open the same location. This seems a bit redundant; what could be done about it? Update: Turning auto-hide on made it obvious that I have multiple Launchers showing. With auto-hide off, they simply overlap, making it look like there's a double trash icon, but with auto-hide enabled, I can display one Launcher (and therefore one trash icon) at a time. Still, two are running simultaneously. Second update: This problem appears to be caused by the way Ubuntu handles multiple displays on my Asus UX32VD Ultrabook. Somehow, the laptop display cannot be used while my external display is connected. It is shown in the Displays list, but remains black no matter how I configure it. The external display runs at 1920x1200, the laptop monitor should run at 1920x1080. It therefore becomes obvious that the Launcher that's supposed to run on the laptop display, is actually displayed on the external monitor. Using nomodeset as a kernel parameter as indicated here makes the laptop display inaccessible altogether, detecting the external monitor as the laptop display and making resolutions other than 1920x1200 inaccessible. That is not an option.

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  • Software Licencing [closed]

    - by Craig
    A colleague of mine wanted a means to do something, so it was suggested that I write some software to do this. The software has turned into more than the original specification and is now something rather complex, however it is not fully functional still. My colleague has not paid me anything so far and I am unwilling to continue writing the software until some faith has been reciprocated in my direction, as I have put a lot of effort into writing the software. I am also unwilling to finish the software as I do not want to give away a huge chunk of my time and effort away as free, neither do I want to be under compensated for my efforts. Some concerns I have. If I finish the software, what if the client doesn't pay me anything or pays too little, or what if I write the software to a usable level, but not complete and the client pays me a too little. I have lost my motivation to finish the software, as more and more specifications have been added to the software and I have developed a substantially complex piece of software and been effectively paid nothing. To finish the software, I need motivation, money would do this, however the client doesn't want to pay for something that isn't complete, yet keeps adding more requirements. I seem to be in a catch 22 with this, as I have developed some software on faith and have had no faith reciprocated in my direction. I'm really not sure how to get some payment from the client or on how to develop a licencing model so that I get some money from the client and development resumes.

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  • Unit testing and Test Driven Development questions

    - by Theomax
    I'm working on an ASP.NET MVC website which performs relatively complex calculations as one of its functions. This functionality was developed some time ago (before I started working on the website) and defects have occurred whereby the calculations are not being calculated properly (basically these calculations are applied to each user which has certain flags on their record etc). Note; these defects have only been observed by users thus far, and not yet investigated in code while debugging. My questions are: Because the existing unit tests all pass and therefore do not indicate that the defects that have been reported exist; does this suggest the original code that was implemented is incorrect? i.e either the requirements were incorrect and were coded accordingly or just not coded as they were supposed to be coded? If I use the TDD approach, would I disgregard the existing unit tests as they don't show there are any problems with the calculations functionality - and I start by making some failing unit tests which test/prove there are these problems occuring, and then add code to make them pass? Note; if it's simply a bug that is occurring that can be found while debugging the code, do the unit tests need to be updated since they are already passing?

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  • Blurry printed raster images with Brother MFC-8840D

    - by Adam Monsen
    (NOTE: crossposted here: ubuntuforums.org/showthread.php?t=1621795) I've got a Brother MFC-8840D. Works great with Ubuntu server! Setting up a CUPS print server was pretty straightforward, and I also finally got network scanning working reliably with saned. Printing documents and Web pages works well: fonts are crisp/clear, etc. One issue has got me completely vexed: printing raster (ie: JPG) images. They are blurry. For example, I can scan a page of black and white text at 150 or 300 dpi. The grayscale image looks perfect on my monitor. But the printed version is much blurrier than the original, regardless of the "print resolution" dpi I choose. As a counterexample, if I use the "copy" function of the MFC-8840D, the copy looks excellent, and this function is much, much faster than if I scan then print a scan of same. I've googled around a bunch and tried different tricks (printing a PDF with the image from evince, printing with Gimp, EOG and other applications) but I just can't print anything that looks as good as a copy made with the MFC-8840D. Any ideas? I'm using Ubuntu 10.04.1 LTS server. I'm using the PPD file from solutions.brother.com. Thanks, -Adam

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  • "unresolvable problem" error when upgrading from 12.04 to 14.04

    - by flyingfisch
    So I have solved this issue, but now I have another problem: An unresolvable problem occurred while calculating the upgrade. This can be caused by: * Upgrading to a pre-release version of Ubuntu * Running the current pre-release version of Ubuntu * Unofficial software packages not provided by Ubuntu If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. I am not upgrading to a pre-release version of Ubuntu and I am not running a pre-release either. I have unchecked all my 3rd-party packages using Ubuntu Software Manager, EditSoftware Sources... What else might be wrong? UPDATE After doing sudo update-manager -d and sudo apt-get update;sudo apt-get dist-upgrade as per JimB's post, and then running sudo do-release-upgrade, here what I get: Err http://extras.ubuntu.com trusty/main Translation-en Err http://extras.ubuntu.com trusty/main Translation-en_US Err http://extras.ubuntu.com trusty/main Translation-en Ign http://extras.ubuntu.com trusty/main Translation-en_US Ign http://extras.ubuntu.com trusty/main Translation-en Fetched 0 B in 0s (0 B/s) Checking package manager Reading package lists... Done Building dependency tree Reading state information... Done Building data structures... Done Calculating the changes Calculating the changes Could not calculate the upgrade An unresolvable problem occurred while calculating the upgrade. This can be caused by: * Upgrading to a pre-release version of Ubuntu * Running the current pre-release version of Ubuntu * Unofficial software packages not provided by Ubuntu If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. Restoring original system state Aborting Reading package lists... Done Building dependency tree Reading state information... Done Building data structures... Done === Command detached from window (Mon Aug 18 23:53:10 2014) === === Command terminated with exit status 1 (Mon Aug 18 23:53:10 2014) ===

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  • Resolution changes when using switch

    - by Edward D
    So, the "real" resolution of my monitor is 1024x768. That's what I'd use on my docked Windows laptop, and what I'd use on my Xubuntu desktop connected directly. When I connect a switch, to switch between the two, however, the ubuntu machine's resolution changes. Everything's still proportional, and it still thinks it's doing 1024x768, but the icons and fonts appear larger. Not 800x600 larger, but still big. When I used Xubuntu Precise, I created an xorg.conf file to set a resolution of 1280x1024 which made it look the way it does without the switch ... as a workaround. When I upgraded to Trusty, I lost this. I tried to re-create it, but doesn't seem to load my file. Ideally, I'd like to correct the original problem, but I'd settle for being able to up the resolution. I searched for a while, and tried to do it, but I'm giving up ... please help me out. Controller: Intel Corporation 82915G/P/GV/GL/PL/910GL Memory Controller Hub (rev 04) Monitor: NEC MultiSync LCD 1850e http://www.necdisplay.com/documents/UserManuals/LCD1850E_manual.pdf OS: Xubuntu 14.04 Trusty /etc/X11/xorg.conf: # YOU CREATED THIS FILE # sudo leafpad /etc/X11/xorg.conf Section "Device" Identifier "Configured Video Device" EndSection Section "Monitor" Identifier "NEC LCD1850E" # I found Synchronization Range at: # http://www.necdisplay.com/documents/UserManuals/LCD1850E_manual.pdf HorizSync 31.0-82.0 VertRefresh 55.0-85.0 EndSection Section "Screen" Identifier "Default Screen" Monitor "NEC LCD1850E" Device "Configured Video Device" SubSection "Display" Depth 24 Modes "1280x1024" "1280x960" "1024x768" "800x600" "848x480" "640x480" EndSubSection EndSection

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  • Why create a Huffman tree per character instead of a Node?

    - by Omega
    For a school assignment we're supposed to make a Java implementation of a compressor/decompresser using Huffman's algorithm. I've been reading a bit about it, specially this C++ tutorial: http://www.cprogramming.com/tutorial/computersciencetheory/huffman.html In my program, I've been thinking about having Nodes that have the following properties: Total Frequency Character (if a leaf) Right child (if any) Left child (if any) Parent (if any) So when building the Huffman tree, it is just a matter of linking a node to others, etc. However, I'm a bit confused with the following quote (emphasis mine): First, every letter starts off as part of its own tree and the trees are ordered by the frequency of the letters in the original string. Then the two least-frequently used letters are combined into a single tree, and the frequency of that tree is set to be the combined frequency of the two trees that it links together. My question: why should I create a tree per letter, instead of just a node per letter and then do the linking later? I have not begun coding, I'm just studying the algorithm first, so I guess I'm missing an important detail. What is it?

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  • How to avoid throwing vexing exceptions?

    - by Mike
    Reading Eric Lippert's article on exceptions was definitely an eye opener on how I should approach exceptions, both as the producer and as the consumer. However, I'm still struggling to define a guideline regarding how to avoid throwing vexing exceptions. Specifically: Suppose you have a Save method that can fail because a) Somebody else modified the record before you, or b) The value you're trying to create already exists. These conditions are to be expected and not exceptional, so instead of throwing an exception you decide to create a Try version of your method, TrySave, which returns a boolean indicating if the save succeeded. But if it fails, how will the consumer know what was the problem? Or would it be best to return an enum indicating the result, kind of Ok/RecordAlreadyModified/ValueAlreadyExists? With integer.TryParse this problem doesn't exist, since there's only one reason the method can fail. Is the previous example really a vexing situation? Or would throwing an exception in this case be the preferred way? I know that's how it's done in most libraries and frameworks, including the Entity framework. How do you decide when to create a Try version of your method vs. providing some way to test beforehand if the method will work or not? I'm currently following these guidelines: If there is the chance of a race condition, then create a Try version. This prevents the need for the consumer to catch an exogenous exception. For example, in the Save method described before. If the method to test the condition pretty much would do all that the original method does, then create a Try version. For example, integer.TryParse(). In any other case, create a method to test the condition.

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  • It could be worse....

    - by Darryl Gove
    As "guest" pointed out, in my file I/O test I didn't open the file with O_SYNC, so in fact the time was spent in OS code rather than in disk I/O. It's a straightforward change to add O_SYNC to the open() call, but it's also useful to reduce the iteration count - since the cost per write is much higher: ... #define SIZE 1024 void test_write() { starttime(); int file = open("./test.dat",O_WRONLY|O_CREAT|O_SYNC,S_IWGRP|S_IWOTH|S_IWUSR); ... Running this gave the following results: Time per iteration 0.000065606310 MB/s Time per iteration 2.709711563906 MB/s Time per iteration 0.178590114758 MB/s Yup, disk I/O is way slower than the original I/O calls. However, it's not a very fair comparison since disks get written in large blocks of data and we're deliberately sending a single byte. A fairer result would be to look at the I/O operations per second; which is about 65 - pretty much what I'd expect for this system. It's also interesting to examine at the profiles for the two cases. When the write() was trapping into the OS the profile indicated that all the time was being spent in system. When the data was being written to disk, the time got attributed to sleep. This gives us an indication how to interpret profiles from apps doing I/O. It's the sleep time that indicates disk activity.

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  • Minimize Apps to the System Tray in Windows with MoveToTray

    - by Asian Angel
    Would you like an easy way to minimize apps to the System Tray in Windows and keep your Taskbar clear of clutter? Then all you need is the MoveToTray app to make it happen. MoveToTray does not require installation. Just double click on the exe file or create a shortcut to the app to activate it. When you see the icon for MoveToTray appear in the System Tray you are ready to minimize those apps. To minimize the active app window use the keyboard shortcut “Ctrl + Alt + M” and watch it instantly disappear to the System Tray. To maximize the window simply double click on the app’s icon in the System Tray. Sometimes an app’s regular icon will not display in the System Tray and a copy of MoveToTray’s icon will appear in its’ place (i.e. Paint.NET in our example). Note: There may occasionally be an app that will not minimize to the System Tray. Only one (CubicExplorer) would not minimize during our tests. Download MoveToTray at Softpedia View the Original Blog Post on MoveToTray HTG Explains: What’s the Difference Between the Windows 7 HomeGroups and XP-style Networking?Internet Explorer 9 Released: Here’s What You Need To KnowHTG Explains: How Does Email Work?

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  • How to diagnose Ubuntu CPU spikes / IO wait?

    - by Jeff Welling
    I'm using Ubuntu and every couple minutes it goes unresponsive for a half second to a full second, which isn't normally a problem but makes trying to code extremely frustrating when your trying to hit backspace or navigate the code and nothing is happening. The problem is, the freezes are so brief that top doesn't have time to show me what is spiking the CPU (assuming something is, but I don't know what else could cause this). Does anyone know how to troubleshoot this performance issue? Edit: I've tried login in with Gnome Classic (No Effects) instead of Unity but it still freezes up every once in awhile. Edit: The CPU graph doesn't seem to be showing any actual spikes so it seems you were right and my original diagnosis of CPU spikes being the problem was incorrect, I now suspect IO wait. I don't recall this happening for the brief few weeks I had Windows 7 Starter running on it though, which leads me to believe it isn't (just?) the hardware.. is there anything I can tweak to improve this? I'm using an Acer Aspire One D257, with Ubuntu 11.10. Edit: Output of dmesg is at http://paste.ubuntu.com/1060054/ and kern.log is at http://paste.ubuntu.com/1060055/

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  • How to monetize and protect a engine's and its framework's copyrights and patents?

    - by Arthur Wulf White
    I created a game engine that handles: Rendering levels with 2d textured curved surfaces Collisions with curved surfaces Animationn paths on and navigation in 2d-sapce I have also made a framework for: Procedural organic level generation with round surfaces Level editing Light weight sprite design The engine and framework are written in AS3 and I am in the process of translating the code into HaXe to better support other platforms. I am also interested in adding Animated curved platforms More advanced level editing features Currently, I have a part time job and any time I spend on this engine is either taken out of my limited free time (I'm a student working to support myself through school) or out my time working at my job. I really believe this engine can make life much easier for people designing Tower Defence games, Shooters and and Platformers while also possibly improving their results. It could also support RTS, RPGs and racing games very well. It continains original algorithms that could be used for procedural generation of organic round and smooth levels. The algorithms I used are new and are not available in any other level editor I've seen. In order to constantly improve the Engine and have it tested thoroughly I think the best route is releasing it to the public. What are the best ways to benefit myself and others with my new framework? I want to have some lisence, allowing me to share the framework and still benefit from it. Any advice would be appreciated. This issue has been on my mind a lot this year. I am hoping to find a solution that will bring me some relief. I am thinking of designing three sample games, releasing them and starting a kickstarter, any advice and thoughts on the matter would be valuable. My goal is like Markus von Broady suggested, to get people involved in developing the engine and let people use it for games for either a symbolic fee or for free and charge for support. That or use some form of croud sourcing. Do I need to hire a lawyer to get some sort of legal document to protect my work?

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  • Antenna Aligner Part 6: Little Robots

    - by Chris George
    A week ago I took temporary ownership of a HTC Desire S so that I could start testing my app under Android. Support for Android was not in my original plan, but when Nomad added support for it recently, I starting thinking why not! So with some trepidation, I clicked the Build for Android button on the Nomad toolbar... nothing. Hmm... that's not right, I was expecting something to build. After a bit of faffing around I finally realised that I hadn't read the text on the Android setup page properly (yes that's right, RTFM!), and I needed a two-part application identifier, separated by a dot. I did this (not sure what the two part thing is all about, that one my list to investigate!) After making the change, the Android build worked and created the apk file. I uploaded this to the device and nervously ran it... it worked!!!  Well, more or less! So, there was not splash screen, but this was no surprise because I only have the iOS icons and splash screen in my project at the moment. What was more concerning was the compass update didn't seem to be working. I suspect this is a result of using an iOS specific option in the Phonegap compass watcher. Another thing to investigate. I've also just noticed that the css gradient background hasn't worked either... These issues aside, it was actually more successful than I was expecting, so happy days! Right, lets get Googling...   Next time: Preparing for submission to the App Store! :-)

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  • Sponsored Giveaway: Free Copies of WinX DVD Copy Pro for All How-To Geek Readers

    - by The Geek
    Have you ever wanted to make a backup of a DVD, or even rip it to an ISO file to use on your computer without the original optical disc? You can use WinX DVD Copy Pro to make this happen, and we’ve got a giveaway for all HTG readers. To get your free copy, just click through the following link to download and get the license code, as long as you download it by December 20th. In addition, an iPhone / iPad Video Software Pack will be presented as the second round gift from December 21st to January 2nd, 2013. For Windows users: http://www.winxdvd.com/giveaway/ WinX DVD Copy Pro has many features, including this list, which we copied straight from their site: Supports latest released DVDs. Protect your DVD disc from damage. Copy DVD to DVD, ISO image, etc. 9 advanced DVD backup schemes. Support Disney’s Fake, scratched DVDs and Sony ARccOS bad sector. Secure Yourself by Using Two-Step Verification on These 16 Web Services How to Fix a Stuck Pixel on an LCD Monitor How to Factory Reset Your Android Phone or Tablet When It Won’t Boot

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  • Graph data structures and journal format for mini-IDE

    - by matec
    Background: I am writing a small/partial IDE. Code is internally converted/parsed into a graph data structure (for fast navigation, syntax-check etc). Functionality to undo/redo (also between sessions) and restoring from crash is implemented by writing to and reading from journal. The journal records modifications to the graph (not to the source). Question: I am hoping for advice on a decision on data-structures and journal format. For the graph I see two possible versions: g-a Graph edges are implemented in the way that one node stores references to other nodes via memory address g-b Every node has an ID. There is an ID-to-memory-address map. Graph uses IDs (instead of addresses) to connect nodes. Moving along an edge from one node to another each time requires lookup in ID-to-address map. And also for the journal: j-a There is a current node (like current working directory in a shell + file-system setting). The journal contains entries like "create new node and connect to current", "connect first child of current node" (relative IDs) j-b Journal uses absolute IDs, e.g. "delete edge 7 - 5", "delete node 5" I could e.g. combine g-a with j-a or combine g-b with j-b. In principle also g-b and j-a should be possible. [My first/original attempt was g-a and a version of j-b that uses addresses, but that turned out to cause severe restrictions: nodes cannot change their addresses (or journal would have to keep track of it), and using journal between two sessions is a mess (or even impossible)] I wonder if variant a or variant b or a combination would be a good idea, what advantages and disadvantages they would have and especially if some variant might be causing troubles later.

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  • How do I increase the open files limit for a non-root user?

    - by iCode
    This is happening on Ubuntu Release 12.04 (precise) 64-bit Kernel Linux 3.2.0-25-virtual I'm trying to increase the number of open files allowed for a user. This is for an my ecplise java application where the current limit of 1024 is not enough. According to the posts I've found so far, I should be able to put lines into /etc/security/limits.conf like this; soft nofile 4096 hard nofile 4096 to increase the number of open files allowed for all users. But, that's not working for me, and I think the problem is not related to that file. For all users, the default limit is 1024, regardless of what is in /etc/security/limits.conf (I have been rebooting after changing that file) $ ulimit -n 1024 Now, despite the entries in /etc/security/limits.conf I can't increase that; $ ulimit -n 2048 -bash: ulimit: open files: cannot modify limit: Operation not permitted The weird part is that I can change the limit downwards, but can't change it upwards - even to go back to a number which is below the original limit; $ ulimit -n 800 $ ulimit -n 800 $ ulimit -n 900 -bash: ulimit: open files: cannot modify limit: Operation not permitted As root, I can change that limit to whatever I want, up or down. It doesn't even seem to care about the supposedly system-wide limit in /proc/sys/fs/file-max # cat /proc/sys/fs/file-max 188897 # ulimit -n 188898 # ulimit -n 188898 So far, I haven't found any way to increase the open files limit for a non-root user, and I really don't want to be running my application as root. How should I properly do this? I have looked at all the posted and tried the given options but no luck!

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  • Update to SQL Server Configuration Scripting Utility

    - by Bill Graziano
    Last spring I released a utility to script SQL Server configuration information on CodePlex.  I’ve been making small changes in this application as my needs have changed.  The application is a .NET 2.0 console application.  This utility serves two needs for me.  First it helps with disaster recovery.  All server level objects (logins, jobs, linked servers, audits) are scripted to a single file per object type.  This enables the scripts to be easily run against a DR server.  If these are checked into source control you can view the history of the script and find out what changed and when. The second goal is to capture what changed inside a database.  Objects inside a database (tables, stored procedures, views, etc.) are each scripted to their own file.  This makes it easier to track the changes to an object over time.  This does include permissions and role membership so you can capture security changes.  My assumption is that a database backup is the primary method of disaster recovery for databases so this utility is designed to capture changes to objects.  You can find the full list of changes from the original on the Downloads page on CodePlex.

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  • How often is seq used in Haskell production code?

    - by Giorgio
    I have some experience writing small tools in Haskell and I find it very intuitive to use, especially for writing filters (using interact) that process their standard input and pipe it to standard output. Recently I tried to use one such filter on a file that was about 10 times larger than usual and I got a Stack space overflow error. After doing some reading (e.g. here and here) I have identified two guidelines to save stack space (experienced Haskellers, please correct me if I write something that is not correct): Avoid recursive function calls that are not tail-recursive (this is valid for all functional languages that support tail-call optimization). Introduce seq to force early evaluation of sub-expressions so that expressions do not grow to large before they are reduced (this is specific to Haskell, or at least to languages using lazy evaluation). After introducing five or six seq calls in my code my tool runs smoothly again (also on the larger data). However, I find the original code was a bit more readable. Since I am not an experienced Haskell programmer I wanted to ask if introducing seq in this way is a common practice, and how often one will normally see seq in Haskell production code. Or are there any techniques that allow to avoid using seq too often and still use little stack space?

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  • Getting the PC speaker to beep

    - by broiyan
    There has been much written on getting the beep sound from Ubuntu releases over the years. Example: fixing the beep My needs are slightly different in that I do not want to ensure sound card beeps are functioning. Instead, I want PC speaker beeps, the kind produced by the original built-in speaker because I believe they will produce less CPU load. I have confirmed that my computer has the PC speaker by unplugging the external speakers and shutting down Ubuntu. At some point in the shutdown and restart process a beep is heard even though the external speakers have no power. I have tried the following: In /etc/modprobe.d/blacklist.conf, turn these lines into comments: #blacklist snd_pcsp #blacklist pcspkr In .bashrc /usr/bin/xset b on /usr/bin/xset b 100 Enable in the gnome terminal: Edit Profile Prefs General Terminal Bell Ensure no "mute" selections in: System Prefs Sound various tabs (uncheck them all). Select "Enable window and button sounds" in: System Prefs Sound Sound Effects In gconf-editor desktop gnome sound, select the three sound check boxes. In gconf-editor apps metacity general select the audible bell check box. Still I get no PC speaker beeps when I send code 7 to the console via my Java program or use echo -e '\a' on the bash command line. What else should I try? Update Since my goal is to minimize load on the CPU, here is a comparison of elapsed times. Each test is for 100,000 iterations. Each variant was performed three times so three results are presented for each. printwriter.format("%c", 7); // 1.3 seconds, 1.5 seconds, 1.5 seconds Toolkit.getDefaultToolkit().beep(); // 0.8 seconds, 0.3 seconds, 0.5 seconds try { Runtime.getRuntime().exec("beep"); } catch (IOException e) { } // 10.3 seconds, 16.3 seconds, 11.4 seconds These runs were done inside Eclipse so multiply by some value less than 1 for standalone execution. Unfortunately, Toolkit's beep is silent on my computer and so is code 7. The beep utility works but has the most cost.

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  • 11.10 liveCD black screen

    - by Shaun Killingbeck
    Attempting to install/try ubuntu 11.10 on my new laptop, using a liveCD (and tried USB). I get the purple screen (with the man/keyboard at the bottom) and after that the screen flashes bright white before going black. Ubuntu continues to load in the background, with login sound etc but the screen is off. I have tried as many different solutions as I could find including: using nomodestep, xforcevesa, i915.modeset=0 in boot options (seperately): varying consequences, but either I end up at a blinking cursor with no prompt, a command line (startx fails: no screen found), or the original blank screen again Tried booting from VirtualBox - it crashes at the same place the screen would go blank when using a CD/USB tried 11.04: I don't have this problem BUT when trying to install, I get a ubi-partman error 141 (possibly down to the three partitions that came on my laptop... not sure why HP needed there own separate partition for HP Tools...) Model: HP Pavillion DV6 6B08SA Processor: AMD Quad-Core A6-3410MX APU with Radeon HD 6545G2 Dual Graphics (1.6 GHZ 4 MB L2 cache ) Chipset: AMD RS880M Any help would be greatly appreciated. I just want to be able to partition the drive and install Ubuntu. I'm assuming the issue is graphics card related, although I have no confirmation of that. I have caught a glimpse of some output to do with pulseaudio and [fail], but I can't imagine why that would cause a screen problem and the sound definitely works anyway.

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  • Need advice on framework design: how to make extending easy

    - by beginner_
    I'm creating a framework/library for a rather specific use-case (data type). It uses diverse spring components, including spring-data. The library has a set of entity classes properly set up and according service and dao layers. The main work or main benefit of the framework lies in the dao and service layer. Developers using the framework should be able to extend my entity classes to add additional fields they require. Therefore I made dao and service layer generic so it can be used by such extended entity classes. I now face an issue in the IO part of the framework. It must be able to import the according "special data type" into the database. In this part I need to create a new entity instance and hence need the actual class used. My current solution is to configure in spring a bean of the actual class used. The problem with this is that an application using the framework could only use 1 implementation of the entity (the original one from me or exactly 1 subclass but not 2 different classes of the same hierarchy. I'm looking for suggestions / desgins for solving this issue. Any ideas?

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  • Reconstruct a file from a TCP stream

    - by Abhishek Chanda
    I have a client and a server and a third box which sees all packets from the server to the client (but not the other way around). Now when the client requests a file from the server (over HTTP), the third box sees the response. I am trying to reconstruct the file there. I am using libpcap to capture TCP datagrams and trying to reconstruct the file there. Here is what I did Listen for packets on an interface Group all packets which have the same ACK number Sort the group based on SEQ number Extract data from each packet and combine them and write to the disk The problem is, the file thus generated is not exactly the same as the original file. Does everything sound correct here? Some more details: I am using C++ The packet data is being stored as std::vector<char> I did change the byte order while reading the ack number and seq number from the packet using ntohl I am not sure if I need to change the byte order for the data as well. I tried to reverse the data from each packet before combining them, even that did not work. Is there something I am missing?

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  • Newbie tips, please [closed]

    - by eXeP
    So, I just got a new computer and I want to put Ubuntu on my old laptop. I just need few tips before installing it. 1.Programs, where to download, how to download, what is the "ending" (windows has .exe) 2. How much is command line involved? And where to get the most usual commands? 3.Few programs you recommend (graphics editing, IDE, video player, web browser) 4. Do I have to download drivers when installing new OS? I plan on getting fully rid of Windows. I have no idea of the name of my graphics card, so how do I can get to know what it is if I have to download drivers? (I don't know the name because it's not on the original box, or anywhere on the internet, believe me) 5. When installing new OS does it destroy everything else on the hard drive? 6. Anti-virus, do I need one? I'm not super paranoid, and I don't visit "shady" sites. Please note that I have never used linux, or any other OS than Windows and sorry for my bad english. If this is the wrong place to post this, then please remove this. Thank you.

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