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  • What do you need to know to be a world-class master software developer? [closed]

    - by glitch
    I wanted to bring up this question to you folks and see what you think, hopefully advise me on the matter: let's say you had 30 years of learning and practicing software development in front of you, how would you dedicate your time so that you'd get the biggest bang for your buck. What would you both learn and work on to be a world-class software developer that would make a large impact on the industry and leave behind a legacy? I think that most great developers end up being both broad generalists and specialists in one-two areas of interest. I'm thinking Bill Joy, John Carmack, Linus Torvalds, K&R and so on. I'm thinking that perhaps one approach would be to break things down by categories and establish a base minimum of "software development" greatness. I'm thinking: Operating Systems: completely internalize the core concepts of OS, perhaps gain a lot of familiarity with an OSS one such as Linux. Anything from memory management to device drivers has to be complete second nature. Programming Languages: this is one of those topics that imho has to be fully grokked even if it might take many years. I don't think there's quite anything like going through the process of developing your own compiler, understanding language design trade-offs and so on. Programming Language Pragmatics is one of my favorite books actually, I think you want to have that internalized back to back, and that's just the start. You could go significantly deeper, but I think it's time well spent, because it's such a crucial building block. As a subset of that, you want to really understand the different programming paradigms out there. Imperative, declarative, logic, functional and so on. Anything from assembly to LISP should be at the very least comfortable to write in. Contexts: I believe one should have experience working in different contexts to truly be able to appreciate the trade-offs that are being made every day. Embedded, web development, mobile development, UX development, distributed, cloud computing and so on. Hardware: I'm somewhat conflicted about this one. I think you want some understanding of computer architecture at a low level, but I feel like the concepts that will truly matter will be slightly higher level, such as CPU caching / memory hierarchy, ILP, and so on. Networking: we live in a completely network-dependent era. Having a good understanding of the OSI model, knowing how the Web works, how HTTP works and so on is pretty much a pre-requisite these days. Distributed systems: once again, everything's distributed these days, it's getting progressively harder to ignore this reality. Slightly related, perhaps add solid understanding of how browsers work to that, since the world seems to be moving so much to interfacing with everything through a browser. Tools: Have a really broad toolset that you're familiar with, one that continuously expands throughout the years. Communication: I think being a great writer, effective communicator and a phenomenal team player is pretty much a prerequisite for a lot of a software developer's greatness. It can't be overstated. Software engineering: understanding the process of building software, team dynamics, the requirements of the business-side, all the pitfalls. You want to deeply understand where what you're writing fits from the market perspective. The better you understand all of this, the more of your work will actually see the daylight. This is really just a starting list, I'm confident that there's a ton of other material that you need to master. As I mentioned, you most likely end up specializing in a bunch of these areas as you go along, but I was trying to come up with a baseline. Any thoughts, suggestions and words of wisdom from the grizzled veterans out there who would like to share their thoughts and experiences with this? I'd really love to know what you think!

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  • No access to Samba shares

    - by koanhead
    I have three shared folders in my local home directory- that is to say, on my Ubuntu desktop's /home/me/. All were set up using "Sharing Options" in Nautilus' right-click menu. The standard "Music" and "Videos" folders are configured identically: the "Guest Access" box is checked, but the "Allow others to create and delete" is not. The third folder, called "shared", is configured to not allow Guest access but to allow others to modify files. I have not altered /etc/samba/smb.conf by hand, I have only used Sharing Options to create and modify these so-called "shares". My roommates have two Windows 7 computers and one Ubuntu Netbook Remix netbook. I have the aforementioned desktop machine and laptop running 10.04. None of these machines can access any of the shares. Attempts to access the Guest shares result in the message \\machine\directory is not accessible. The network name could not be found. This is the error message generated by a VM running Windows 2000. The other Windows machines generate a similar error. The Ubuntu laptop gives the error Unable to mount location: Failed to mount Windows share. Hurrah, once again, for informative error messages. That really helps a lot. When attempting to browse the folder called "shared" from the laptop, I'm confronted with a password dialog. This behavior is the same will all machines I've tried in the situation. On entering my username and password for the account to which the shares belong, the password dialog briefly disappears and is replaced with an identical dialog. No error message, useful or not, appears. When attempting to browse this folder with the VM, the outcome is the same except that the password dialog helpfully states "incorrect username or password". My assumption is that the username and password in question is that of the user which owns the shares. I have tried all other username and password combinations available in this context and the outcome is the same. I would like to be able to share files. Sharing them with Windows machines is a nice feature, or would be if it was available. Really I consider sharing files between two machines with the same version of the same operating system kind of a minimum condition for network usability. Samba last functioned reliably for me more than ten years ago. I have attempted to use it on and off since then with only intermittent success. Oh, and "Personal File Sharing" from the Preferences menu does not result in an entry in Places → Network → my-server. In fact, the old entry "MY-SERVER" goes away and is replaced by "koanhead's public files on my-server", which when I attempt to open it from the laptop gives a "DBus.Error.NoReply: Message did not receive a reply." I know I come here and gripe about Ubuntu a lot, but on the other hand I spend literally hours every day trying to fix things in Ubuntu. It's a good system which aspires to greatness, which is why things like this either Need to work; or Be adequately documented. Ideally both would be the case. Anyway, rant over. Hopefully someone will have some insight on this issue. Thanks all who bother to read this wall o'text for your time.

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  • Powershell Transcript is empty when running script from SQL Agent Job in 2005 SQL Server

    - by Greg Bray
    I have a complex Powershell script that gets run as part of a SQL 2005 Server Agent Job. The script works fine, but it uses the "Start-Transcript $strLogfile -Append" command to log all of it's actions to a transcript file. The problem is that the transcript is always empty. It adds the header and footer to indicate that the transcript is starting and stopping, but it doesn't actually log anything. Example: ********************** Windows PowerShell Transcript Start Start time: 20100304173001 Username : xxxxxxxxxxxx\SYSTEM Machine : xxxxx-xxx (Microsoft Windows NT 5.2.3790 Service Pack 2) ********************** ********************** Windows PowerShell Transcript End End time: 20100304173118 ********************** When I execute the script from a command prompt or start - run everything works just fine. Here is the command used to run the script (same command used in the Operating system CmdExec step of the SQL Agent Job) powershell.exe -File "c:\temp\Backup\backup script.ps1" I first thought it must have something to do with the script running under the System account (default SQL Agent account), but even when I tried changing the SQL Agent to run under my own personal account it still created a blank transcript. Is there any way to get PowerShell Transcripts to work when executing them as part of a 2005 SQL Server Agent Job?

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  • Restore DB - Error RESTORE HEADERONLY is terminating abnormally.

    - by Jordon
    I have taken backup of SQL Server 2008 DB on server, and download them to local environment. I am trying to restore that database and it is keep on giving me following error. An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) ------------------------------ ADDITIONAL INFORMATION: The media family on device 'C:\go4sharepoint_1384_8481.bak' is incorrectly formed. SQL Server cannot process this media family. RESTORE HEADERONLY is terminating abnormally. (Microsoft SQL Server, Error: 3241) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=09.00.4053&EvtSrc=MSSQLServer&EvtID=3241&LinkId=20476 I have tried to create a temp DB on server and tried to restore the same backup file and that works. I have also tried no. of times downloading file from server to local pc using different options on Filezila (Auto, Binary) But its not working. After that I tried to execute following command on server. BACKUP DATABASE go4sharepoint_1384_8481 TO DISK=' C:\HostingSpaces\dbname_jun14_2010_new.bak' with FORMAT And it is giving me following error. Msg 3201, Level 16, State 1, Line 1 Cannot open backup device 'c:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\Backup\ C:\HostingSpaces\dbname_jun14_2010_new.bak'. Operating system error 123(The filename, directory name, or volume label syntax is incorrect.). Msg 3013, Level 16, State 1, Line 1 BACKUP DATABASE is terminating abnormally. After researching I found following 2 useful links 1) http://support.microsoft.com/kb/290787 2) http://social.msdn.microsoft.com/Forums/en-US/sqlsetupandupgrade/thread/4d5836f6-be65-47a1-ad5d-c81caaf1044f But still I can't able to restore Database correctly. Any help would be much appreciated thanks.

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  • XNA Xbox 360 Content Manager Thread freezing Draw Thread

    - by Alikar
    I currently have a game that takes in large images, easily bigger than 1MB, to serve as backgrounds. I know exactly when this transition is supposed to take place, so I made a loader class to handle loading these large images in the background, but when I load the images it still freezes the main thread where the drawing takes place. Since this code runs on the 360 I move the thread to the 4th hardware thread, but that doesn't seem to help. Below is the class I am using. Any thoughts as to why my new content manager which should be in its own thread is interrupting the draw in my main thread would be appreciated. namespace FileSystem { /// <summary> /// This is used to reference how many objects reference this texture. /// Everytime someone references a texture we increase the iNumberOfReferences. /// When a class calls remove on a specific texture we check to see if anything /// else is referencing the class, if it is we don't remove it. If there isn't /// anything referencing the texture its safe to dispose of. /// </summary> class TextureContainer { public uint uiNumberOfReferences = 0; public Texture2D texture; } /// <summary> /// This class loads all the files from the Content. /// </summary> static class FileManager { static Microsoft.Xna.Framework.Content.ContentManager Content; static EventWaitHandle wh = new AutoResetEvent(false); static Dictionary<string, TextureContainer> Texture2DResourceDictionary; static List<Texture2D> TexturesToDispose; static List<String> TexturesToLoad; static int iProcessor = 4; private static object threadMutex = new object(); private static object Texture2DMutex = new object(); private static object loadingMutex = new object(); private static bool bLoadingTextures = false; /// <summary> /// Returns if we are loading textures or not. /// </summary> public static bool LoadingTexture { get { lock (loadingMutex) { return bLoadingTextures; } } } /// <summary> /// Since this is an static class. This is the constructor for the file loadeder. This is the version /// for the Xbox 360. /// </summary> /// <param name="_Content"></param> public static void Initalize(IServiceProvider serviceProvider, string rootDirectory, int _iProcessor ) { Content = new Microsoft.Xna.Framework.Content.ContentManager(serviceProvider, rootDirectory); Texture2DResourceDictionary = new Dictionary<string, TextureContainer>(); TexturesToDispose = new List<Texture2D>(); iProcessor = _iProcessor; CreateThread(); } /// <summary> /// Since this is an static class. This is the constructor for the file loadeder. /// </summary> /// <param name="_Content"></param> public static void Initalize(IServiceProvider serviceProvider, string rootDirectory) { Content = new Microsoft.Xna.Framework.Content.ContentManager(serviceProvider, rootDirectory); Texture2DResourceDictionary = new Dictionary<string, TextureContainer>(); TexturesToDispose = new List<Texture2D>(); CreateThread(); } /// <summary> /// Creates the thread incase we wanted to set up some parameters /// Outside of the constructor. /// </summary> static public void CreateThread() { Thread t = new Thread(new ThreadStart(StartThread)); t.Start(); } // This is the function that we thread. static public void StartThread() { //BBSThreadClass BBSTC = (BBSThreadClass)_oData; FileManager.Execute(); } /// <summary> /// This thread shouldn't be called by the outside world. /// It allows the File Manager to loop. /// </summary> static private void Execute() { // Make sure our thread is on the correct processor on the XBox 360. #if WINDOWS #else Thread.CurrentThread.SetProcessorAffinity(new int[] { iProcessor }); Thread.CurrentThread.IsBackground = true; #endif // This loop will load textures into ram for us away from the main thread. while (true) { wh.WaitOne(); // Locking down our data while we process it. lock (threadMutex) { lock (loadingMutex) { bLoadingTextures = true; } bool bContainsKey = false; for (int con = 0; con < TexturesToLoad.Count; con++) { // If we have already loaded the texture into memory reference // the one in the dictionary. lock (Texture2DMutex) { bContainsKey = Texture2DResourceDictionary.ContainsKey(TexturesToLoad[con]); } if (bContainsKey) { // Do nothing } // Otherwise load it into the dictionary and then reference the // copy in the dictionary else { TextureContainer TC = new TextureContainer(); TC.uiNumberOfReferences = 1; // We start out with 1 referece. // Loading the texture into memory. try { TC.texture = Content.Load<Texture2D>(TexturesToLoad[con]); // This is passed into the dictionary, thus there is only one copy of // the texture in memory. // There is an issue with Sprite Batch and disposing textures. // This will have to wait until its figured out. lock (Texture2DMutex) { bContainsKey = Texture2DResourceDictionary.ContainsKey(TexturesToLoad[con]); Texture2DResourceDictionary.Add(TexturesToLoad[con], TC); } // We don't have the find the reference to the container since we // already have it. } // Occasionally our texture will already by loaded by another thread while // this thread is operating. This mainly happens on the first level. catch (Exception e) { // If this happens we don't worry about it since this thread only loads // texture data and if its already there we don't need to load it. } } Thread.Sleep(100); } } lock (loadingMutex) { bLoadingTextures = false; } } } static public void LoadTextureList(List<string> _textureList) { // Ensuring that we can't creating threading problems. lock (threadMutex) { TexturesToLoad = _textureList; } wh.Set(); } /// <summary> /// This loads a 2D texture which represents a 2D grid of Texels. /// </summary> /// <param name="_textureName">The name of the picture you wish to load.</param> /// <returns>Holds the image data.</returns> public static Texture2D LoadTexture2D( string _textureName ) { TextureContainer temp; lock (Texture2DMutex) { bool bContainsKey = false; // If we have already loaded the texture into memory reference // the one in the dictionary. lock (Texture2DMutex) { bContainsKey = Texture2DResourceDictionary.ContainsKey(_textureName); if (bContainsKey) { temp = Texture2DResourceDictionary[_textureName]; temp.uiNumberOfReferences++; // Incrementing the number of references } // Otherwise load it into the dictionary and then reference the // copy in the dictionary else { TextureContainer TC = new TextureContainer(); TC.uiNumberOfReferences = 1; // We start out with 1 referece. // Loading the texture into memory. try { TC.texture = Content.Load<Texture2D>(_textureName); // This is passed into the dictionary, thus there is only one copy of // the texture in memory. } // Occasionally our texture will already by loaded by another thread while // this thread is operating. This mainly happens on the first level. catch(Exception e) { temp = Texture2DResourceDictionary[_textureName]; temp.uiNumberOfReferences++; // Incrementing the number of references } // There is an issue with Sprite Batch and disposing textures. // This will have to wait until its figured out. Texture2DResourceDictionary.Add(_textureName, TC); // We don't have the find the reference to the container since we // already have it. temp = TC; } } } // Return a reference to the texture return temp.texture; } /// <summary> /// Go through our dictionary and remove any references to the /// texture passed in. /// </summary> /// <param name="texture">Texture to remove from texture dictionary.</param> public static void RemoveTexture2D(Texture2D texture) { foreach (KeyValuePair<string, TextureContainer> pair in Texture2DResourceDictionary) { // Do our references match? if (pair.Value.texture == texture) { // Only one object or less holds a reference to the // texture. Logically it should be safe to remove. if (pair.Value.uiNumberOfReferences <= 1) { // Grabing referenc to texture TexturesToDispose.Add(pair.Value.texture); // We are about to release the memory of the texture, // thus we make sure no one else can call this member // in the dictionary. Texture2DResourceDictionary.Remove(pair.Key); // Once we have removed the texture we don't want to create an exception. // So we will stop looking in the list since it has changed. break; } // More than one Object has a reference to this texture. // So we will not be removing it from memory and instead // simply marking down the number of references by 1. else { pair.Value.uiNumberOfReferences--; } } } } /*public static void DisposeTextures() { int Count = TexturesToDispose.Count; // If there are any textures to dispose of. if (Count > 0) { for (int con = 0; con < TexturesToDispose.Count; con++) { // =!THIS REMOVES THE TEXTURE FROM MEMORY!= // This is not like a normal dispose. This will actually // remove the object from memory. Texture2D is inherited // from GraphicsResource which removes it self from // memory on dispose. Very nice for game efficency, // but "dangerous" in managed land. Texture2D Temp = TexturesToDispose[con]; Temp.Dispose(); } // Remove textures we've already disposed of. TexturesToDispose.Clear(); } }*/ /// <summary> /// This loads a 2D texture which represnets a font. /// </summary> /// <param name="_textureName">The name of the font you wish to load.</param> /// <returns>Holds the font data.</returns> public static SpriteFont LoadFont( string _fontName ) { SpriteFont temp = Content.Load<SpriteFont>( _fontName ); return temp; } /// <summary> /// This loads an XML document. /// </summary> /// <param name="_textureName">The name of the XML document you wish to load.</param> /// <returns>Holds the XML data.</returns> public static XmlDocument LoadXML( string _fileName ) { XmlDocument temp = Content.Load<XmlDocument>( _fileName ); return temp; } /// <summary> /// This loads a sound file. /// </summary> /// <param name="_fileName"></param> /// <returns></returns> public static SoundEffect LoadSound( string _fileName ) { SoundEffect temp = Content.Load<SoundEffect>(_fileName); return temp; } } }

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  • Restore DB - Error RESTORE HEADERONLY is terminating abnormally

    - by Jordon Willis
    I have taken backup of SQL Server 2008 DB on server, and download them to local environment. I am trying to restore that database and it is keep on giving me following error. An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) ------------------------------ ADDITIONAL INFORMATION: The media family on device 'C:\go4sharepoint_1384_8481.bak' is incorrectly formed. SQL Server cannot process this media family. RESTORE HEADERONLY is terminating abnormally. (Microsoft SQL Server, Error: 3241) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=09.00.4053&EvtSrc=MSSQLServer&EvtID=3241&LinkId=20476 I have tried to create a temp DB on server and tried to restore the same backup file and that works. I have also tried no. of times downloading file from server to local pc using different options on Filezila (Auto, Binary) But its not working. After that I tried to execute following command on server. BACKUP DATABASE go4sharepoint_1384_8481 TO DISK=' C:\HostingSpaces\dbname_jun14_2010_new.bak' with FORMAT It is giving me following error: Msg 3201, Level 16, State 1, Line 1 Cannot open backup device 'c:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\Backup\ C:\HostingSpaces\dbname_jun14_2010_new.bak'. Operating system error 123(The filename, directory name, or volume label syntax is incorrect.). Msg 3013, Level 16, State 1, Line 1 BACKUP DATABASE is terminating abnormally. After researching I found the following 2 useful links: http://support.microsoft.com/kb/290787 http://social.msdn.microsoft.com/Forums/en-US/sqlsetupandupgrade/thread/4d5836f6-be65-47a1-ad5d-c81caaf1044f But I am still not able to restore Database correctly. Any help would be much appreciated. Thanks.

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  • Client Certificate installed in IE8 on Windows 7 doesn't work - 403.7

    - by mlauter
    We have configured IIS 6 to accept client certificates and have installed the certificate services on our server. When we go to http://[our site]/CertSrv and request a Web Browser Certificate (client certificate) from IE7/8 on Windows XP and Vista and Windows 7, then issue the cert on the server certificate authority manager, all combinations of the client/OS seem to install the client certificate properly in the personal certificate store. When we visit our test application that requires client certificates, all IE versions installed in Windows XP propmt for the client certificate and then properly display the page. Uhfortunately, all IE versions installed on Vista and Windows 7 do not prompt for the cert, nor do they automatically send the cert. It's like IE on these operating systems is unaware of the client certificate and it doesn't prompt for it, nor does it send it to the site. Since everything works as expected, at least on the XP configurations, we assume that IIS6 is correctly configured. It's been 8 hours with two of us trying to figure this out and we're ready to throw a laptop through a window and "the google" has let us down. Thanks for anyone who can help. Mark

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  • alphanumeric and special character sorting

    - by Kaushik Gopal
    Hi ppl, I wanted to know the different standards of sorting. To be more specific take the sample set: (Please note there's capitals, small letters, special characters, null values and numbers here) A a 3F Zx - 1Ad NULL How would the Oracle Database sort this by default? How would LINQ sort this by default? How would db2 sort this by default? (the following may get even more vague) How does the Windows platform sort this? (I mean say you have a couple of filenames, by default how would this get treated in a name sort) How does the *nix platform sort this? Is there some sort of standard for alphanumeric/special character sorting? The Windows operating system orders with numbers first, then alphabets. The Oracle database however treats alphabets first. I'm not sure of the *nix platform. It would be nice to have one place to know all these rules for the most common platforms (listed in questions above). Would the gurus throw some light on this topic? Cheers, K

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  • MVC Multiple submit buttons on a array of objects

    - by Kieron
    Hi, I've got a list of objects in an MVC view, each with a set of submit buttons - Move up, Move down and Remove. Using the answer from this question, I can get the button clicked - but I need to know which item it would be operating on. The problem comes from the fact the input's value attribute is passed back, I need more information than that - i.e. an id. Below is a snippet of the contents of a for loop, rendering each item. <ul> <li><input type="submit" name="SubmitButton" value="Move-Up" class="linked-content-position-modifier" /></li> <li><input type="submit" name="SubmitButton" value="Move-Down" class="linked-content-position-modifier" /></li> <li><input type="submit" name="SubmitButton" value="Remove" class="linked-content-modifier" /></li> <li><%= Model.Contents[i] %></li> </ul> When the form is posted back, I can see that the SubmitButton has a value of either Move-Up, Move-Down or Remove - but no idea which item in the array it's referring too. Without changing the value to something really ugly, how would I tell which item it's referring to?

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  • Best Diff Tool?

    - by ila
    For all my present Diff / Merge needs I'm using Beyond Compare; when I decided to buy a license for it I tried other similar tools, both payware and freeware. Now BC is at version 3, and I think it's a great tool... but what are your experience in this field? Do you think there is something better? And what are the feature you like best on your favorite Diff tool? EDIT I'm recollecting here a list of the tools mentioned in the answers below, in order of preferences (more or less), separating pay- from free- ware and indicating supported operating system. Hope this helps. PAYWARE Beyond Compare (win + linux) - http://www.scootersoftware.com/ Araxis Merge (win + osX) - http://www.araxis.com/merge/index.html ExamDiff Pro (win) - http://www.prestosoft.com/edp_examdiffpro.asp ECMerge (win, osX, linux) - http://www.elliecomputing.com/Home/default.asp MergePlant (win) - http://www.mikado-ltd.com/ Changes (OSX) http://www.changesapp.com Deltopia DeltaWalker (win, osx, linux) http://www.deltopia.com/ FREEWARE FileMerge (OSX) - http://en.wikipedia.org/wiki/Apple_Developer_Tools#FileMerge Tortoise SVN (win) - http://tortoisesvn.net/ WinMerge (win) - http://winmerge.org/ ExamDiff (win) - http://www.prestosoft.com/ps.asp?page=edp_examdiff Diff Merge from SourceGear - http://www.sourcegear.com/diffmerge/index.html Perforce Merge (win + linux + OSX) - http://www.perforce.com/perforce/products/merge.html meld (linux) - sudo apt-get install meld http://meld.sourceforge.net/ Vimdiff - vim distribution KDiff3 - http://kdiff3.sf.net/ ediff - EMacs distribution Tiny Hexer Kompare (KDE, linux) - http://www.caffeinated.me.uk/kompare/ tkdiff (win, linux, osX) - http://tkdiff.sourceforge.net

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  • 8 bit enum, in C

    - by oxinabox.ucc.asn.au
    I have to store instuctions, commands that I will be receiving via serial. The commands will be 8 bits long. I'd like to use Enumerations to deal with them in my code. Only a enumeration corresponds to a ... on this platform I think a 16 bit integer. I need to preserve transparancy between command name, and its value. So as to avoid having to translate an 8-bit number received in serial into any type. BTW the platform is AVR ATmega169V microcontroller, on the Butterfly demo board. It may be being underclocked to preserve power (I'm opposed to this, I believe the ATmega169V uses no power, not next to a router. But that's getting offtopic.) So I need to keep things fast, and I don't have any luxuries like file I/O. Or operating systems. So any suggestions as to what type I should be using to store 8-bit commands? There has got to be something better than a massive header of #defines.

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  • Which Computer Organization & Architecture book is good for me?

    - by claws
    I'm always interested in learning the inner working of things. I started with C programming and then learnt Operating systems (from stallings) and then linkers & loaders and then assembly language after reading these now I want to go into little more depth. Computer Architecture. I feel that makes everything clear. As per SO archives these are the two good books: Computer Architecture: A Quantitative Approach, 4th Edition Computer Organization and Design, Fourth Edition, ~ David A. Patterson, John L. Hennessy But I've browsed through the contents of these books and found that they don't exactly meet my needs. I want to learn more about caches, Memory Management Unit , mapping b/w virtual memory & physical memory I'm no way interested in other ISAs like MIPS etc.. I'm IA32 and X86-64 fan and I want to stick to it. I'm not a hardware developer I don't want to details like circuit diagrams or How is L1, L2 & L3 caches are implemented? I want to know the parallel processing technologies like HyperThreading at the architecture level but again I don't want to design them. I liked the table of Contents of - Computer Architecture: A Quantitative Approach, 4th Edition but Quantitave Approach? Seriously?? I want to know the details of current technologies and I dont want to spend reading 200 pages of outdated old technologies ( I experienced this while learning ASM}

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  • Computer science textbooks

    - by Barrett Conrad
    I would like to try the book question a little bit differently. My goal is to know what the community thinks are the quintessential computer science textbooks. <beginsadstory>I lost all of my computer science and math books from college in Hurricane Katrina in 2005. I greatly miss having my familiar tomes to refer to when topics and problems come up, so I am looking to rebuild my library.<endsadstory> What are your recommendations for the best examples of academic caliber books for the field of computer science and its associated mathematics? I am looking for books on subjects like computational theory, programming languages, compilers, operating systems, algorithms and so on. Don't limit your suggestions to your textbooks only. If there is a book you have read that covers computer science or a related math in a formal way, but is not strictly a textbook, I would be love to hear about them as well. Finally, for the sake of creating a good reference for all of us, may I suggest posting one book per answer so they can be rated individually.

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  • Python libusb pyusb "mach-o, but wrong architecture"

    - by Jon
    I am having some trouble with the pyusb module. I have narrowed down the problem to a single line, and have created a small example script to replicate the error. #!/usr/bin/env python """ This module was created to isolate the problem in the pyusb package. Operating system: Mac OS 10.6.3 Python Version: 2.6.4 libusb 1.0.8 has been successfully installed using: sudo port install libusb I have also tried modifying /opt/local/etc/macports/macports.conf to force the i386 architecture instead of x86_64. """ from ctypes import * import ctypes.util libname = ctypes.util.find_library('usb-1.0') print 'libname: ', libname l = CDLL(libname, RTLD_GLOBAL) # RESULT: #libname: /usr/local/lib/libusb-1.0.dylib #Traceback (most recent call last): # File "./pyusb_problem.py", line 7, in <module> # l = CDLL(libname, RTLD_GLOBAL) # File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/ctypes/__init__.py", line 353, in __init__ # self._handle = _dlopen(self._name, mode) #OSError: dlopen(/usr/local/lib/libusb-1.0.dylib, 10): no suitable image found. Did find: # /usr/local/lib/libusb-1.0.dylib: mach-o, but wrong architecture # End of File This same script runs on Ubuntu 10.04 successfully. I have tried building the libusb module (directly from source AND through macports) for 32-bit (i386) instead of x86_64 (default for OS 10.6), but I receive the same error. Thank-you in advance for your help!

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  • UX question: is better to have "serious delete" or have "trash"

    - by ftrotter
    I am developing an application that allows for a user to manage some individual data points. One of the things that my users will want to do is "delete" but what should that mean? For a web application is it better to present a user with the option to have serious delete or to use a "trash" system? Under "serious delete" (would love to know if there is a better name for this...) you click "delete" and then the user is warned "this is final and tragic action. Once you do this you will not be able to get -insert data point name here- back, even if you are crying..." Then if they click delete... well it truly is gone forever. Under the "trash" model, you never trust that the user really wants to delete... instead you remove the data point from the "main display" and put into a bucket called "the trash". This gets it out of the users way, which is what they usually want, but they can get it back if they make a mistake. Obviously this is the way most operating systems have gone. The advantages of "serious delete" are: Easy to implement Easy to explain to users The disadvantages of "serious delete" are: it can be tragically final sometimes, cats walk on keyboards The advantages of the "trash" system are: user is safe from themselves bulk methods like "delete a bunch at once" make more sense saves support headaches The disadvantages of the "trash" system are": For sensitive data, you create an illusion of destruction users think something is gone, but it is not. Lots of subtle distinctions make implementation more difficult Do you "eventually" delete the contents of the trash? My question is which one is the right design pattern for modern web applications? With enough discussion to justify your answer... Would love to be pointed towards some relevant research. -FT

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  • Matlab crashes on library initialize when called from Java

    - by David Sauter
    Hello everyone. The setup I have is I'm using a Java application to call native C-code with JNI, which in turn starts up the MATLAB runtime and calls functions on it (I know there are other solutions to call MATLAB methods from Java). The problem is that the MATLAB engine crashes at some point during the initialization and I don't know what's causing it exactly. The crash causes my jvm to terminate, I assume it's some kind of memory corruption. The C++ code calling MATLAB functions that is actually crashing is JNIEXPORT void JNICALL some_jni_vodoo_initializeLibrary(JNIEnv* env, jclass thisClass) { try { if (!mclInitializeApplication(NULL, 0)) { THROW_EXCEPTION(env, "Could not initialize the application properly."); return; } if (!<library>Initialize()) { THROW_EXCEPTION(env, "Could not initialize the library."); return; } } ... The function <library>Initialize() crashes here, the Java error log reads Stack Trace: [0] jmi.dll:0x793f4175(0x7934cdca, 1, 0x7937e67c "à;.y`[email protected] in C:\BUILD_ARE..", 0x792d6a32) [1] jvm.dll:0x792df9a5(0xc0000005, 0x79356791, 0x4961b400 "Ð\8y", 0x6d8b29de) [2] jvm.dll:0x792e0431(0x8b515008, 0x70f0e8ce, 0x8b5ffffa, 0xc25d5ec6) ------------------------------------------------------------------------ Fatal Java Exception detected at Fri Apr 30 11:08:08 2010 ------------------------------------------------------------------------ Configuration: MATLAB Version: 7.8.0.347 (R2009a) MATLAB License: unknown Operating System: Microsoft Windows Vista Window System: Version 6.0 (Build 6002: Service Pack 2) Processor ID: x86 Family 6 Model 10 Stepping 5, GenuineIntel Virtual Machine: Java is not enabled Default Encoding: windows-1252 Java is not enabled I really have no idea what could be wrong. Is there not enough memory from the jvm? I guess the problem is somehow related to Java, since calling the JNI functions from a simple test C++ program works fine... Thanks

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  • FOR BOUNTY: "QFontEngine(Win) GetTextMetrics failed ()" error on 64-bit Windows

    - by David Murdoch
    I'll add a large bounty to this when Stack Overflow lets me. I'm using wkhtmltopdf to convert HTML web pages to PDFs. This works perfectly on my 32-bit dev server [unfortunately, I can't ship my machine :-p ]. However, when I deploy to the web application's 64-bit server the following errors are displayed: C:\>wkhtmltopdf http://www.google.com google.pdf Loading pages (1/5) QFontEngine::loadEngine: GetTextMetrics failed () ] 10% QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngine::loadEngine: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngine::loadEngine: GetTextMetrics failed () ] 36% QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () // ...etc.... and the PDF is created and saved... just WITHOUT text. All form-fields, images, borders, tables, divs, spans, ps, etc are rendered accurately...just void of any text at all. Server information: Windows edition: Windows Server Standard Service Pack 2 Processor: Intel Xeon E5410 @ 2.33GHz 2.33 GHz Memory: 8.00 GB System type: 64-bit Operating System Can anyone give me a clue as to what is happening and how I can fix this? Also, I wasn't sure what to tag/title this question with...so if you can think of better tags/title comment them or edit the question. :-)

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  • Debugging SQL Server Slowness: Same Database, Different Servers

    - by Craig Walker
    For a while now we've been having anecdotal slowness on our newly-minted (VMWare-based) SQL Server 2005 database servers. Recently the problem has come to a head and I've started looking for the root cause of the issue. Here's the weird part: on the stored procedure that I'm using as a performance test case, I get a 30x difference in the execution speed depending on which DB server I run it on. This is using the same database (mdf) and log (ldf) files, detached, copied, and reattached from the slow server to the fast one. This doesn't appear to be a (virtualized) hardware issue: he slow server has 4x the CPU capacity and 2x the memory as the fast one. As best as I can tell, the problem lies in the environment/configuration of the servers (either operating system or SQL Server installation). However, I've checked a bunch of variables (SQL Server config options, running services, disk fragmentation) and found nothing that has made a difference in testing. What things should I be looking at? What tools can I use to investigate why this is happening?

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  • What is the best way to send structs containing enum values via sockets in C.

    - by Axel
    I've lots of different structs containing enum members that I have to transmit via TCP/IP. While the communication endpoints are on different operating systems (Windows XP and Linux) meaning different compilers (gcc 4.x.x and MSVC 2008) both program parts share the same header files with type declarations. For performance reasons, the structures should be transmitted directly (see code sample below) without expensively serializing or streaming the members inside. So the question is how to ensure that both compilers use the same internal memory representation for the enumeration members (i.e. both use 32-bit unsigned integers). Or if there is a better way to solve this problem... //type and enum declaration typedef enum { A = 1, B = 2, C = 3 } eParameter; typedef enum { READY = 400, RUNNING = 401, BLOCKED = 402 FINISHED = 403 } eState; #pragma pack(push,1) typedef struct { eParameter mParameter; eState mState; int32_t miSomeValue; uint8_t miAnotherValue; ... } tStateMessage; #pragma pack(pop) //... send via socket tStateMessage msg; send(iSocketFD,(void*)(&msg),sizeof(tStateMessage)); //... receive message on the other side tStateMessage msg_received; recv(iSocketFD,(void*)(&msg_received),sizeof(tStateMessage)); Additionally... Since both endpoints are little endian maschines, endianess is not a problem here. And the pack #pragma solves alignment issues satisfactorily. Thx for your answers, Axel

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  • Text editor capable of viewing invisibles?

    - by Timo
    A recent problem* left me wondering whether there is a text editor out there that lets you see every single character of the file, even if they are invisible? Specifically, I'm not looking for hex editing capabilities, I am interested in a text editor that'll show me all of the invisible characters (not just the common whitespace / line break characters). The BOM marker is just one example, others are e.g. mathematical invisibles or possibly unsupported characters. I'm not looking for a text editor that simply supports a large variety of text encoding / translations between encodings. All text editors I've come across treat the invisible characters correctly i.e. leave them invisible (or simply get removed in the translation as in the case of the BOM marker). I'm asking this mostly out of academic interests, so I'm not particular about any specific OS. I can easily test Linux and OSX solutions, but if you recommend a Windows editor, I would appreciate if you include descriptions of how the editor handles invisibles other than whitespace / line breaks. *The incident that lead me to this question: I wrote a perl script using TextWrangler and managed to change the encoding to UTF8 BOM, which inserts te BOM marker at the start of the file. Perl (or rather the operating system) promptly misses the #! and mayhem ensues. It then took me the better part of an afternoon to figure this out since most text editors do not show the BOM marker even with various "show invisibles" options turned on. Now I've learned my lesson and will use less immediately :-).

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  • Why is Available Physical Memory (dwAvailPhys) > Available Virtual Memory (dwAvailVirtual) in call G

    - by Andrew
    I am playing with an MSDN sample to do memory stress testing (see: http://msdn.microsoft.com/en-us/magazine/cc163613.aspx) and an extension of that tool that specifically eats physical memory (see http://www.donationcoder.com/Forums/bb/index.php?topic=14895.0;prev_next=next). I am obviously confused though on the differences between Virtual and Physical Memory. I thought each process has 2 GB of virtual memory (although I also read 1.5 GB because of "overhead". My understanding was that some/all/none of this virtual memory could be physical memory, and the amount of physical memory used by a process could change over time (memory could be swapped out to disc, etc.)I further thought that, in general, when you allocate memory, the operating system could use physical memory or virtual memory. From this, I conclude that dwAvailVirtual should always be equal to or greater than dwAvailPhys in the call GlobalMemoryStatus. However, I often (always?) see the opposite. What am I missing. I apologize in advance if my question is not well formed. I'm still trying to get my head around the whole memory management system in Windows. Tutorials/Explanations/Book recs are most welcome! Andrew

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  • Reference for proper handling of PID file on Unix

    - by bignose
    Where can I find a well-respected reference that details the proper handling of PID files on Unix? On Unix operating systems, it is common practice to “lock” a program (often a daemon) by use of a special lock file: the PID file. This is a file in a predictable location, often ‘/var/run/foo.pid’. The program is supposed to check when it starts up whether the PID file exists and, if the file does exist, exit with an error. So it's a kind of advisory, collaborative locking mechanism. The file contains a single line of text, being the numeric process ID (hence the name “PID file”) of the process that currently holds the lock; this allows an easy way to automate sending a signal to the process that holds the lock. What I can't find is a good reference on expected or “best practice” behaviour for handling PID files. There are various nuances: how to actually lock the file (don't bother? use the kernel? what about platform incompatibilities?), handling stale locks (silently delete them? when to check?), when exactly to acquire and release the lock, and so forth. Where can I find a respected, most-authoritative reference (ideally on the level of W. Richard Stevens) for this small topic?

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  • maps, iterators, and complex structs - STL errors

    - by Austin Hyde
    So, I have two structs: struct coordinate { float x; float y; } struct person { int id; coordinate location; } and a function operating on coordinates: float distance(const coordinate& c1, const coordinate& c2); In my main method, I have the following code: map<int,person> people; // populate people map<int,map<float,int> > distance_map; map<int,person>::iterator it1,it2; for (it1=people.begin(); it1!=people.end(); ++it1) { for (it2=people.begin(); it2!=people.end(); ++it2) { float d = distance(it1->second.location,it2->second.location); distance_map[it1->first][d] = it2->first; } } However, I get the following error upon build: stl_iterator_base_types.h: In instantiation of ‘std::iterator_traits<coordinate>’: stl_iterator_base_types.h:129: error: no type named ‘iterator_category’ in ‘struct coordinate’ stl_iterator_base_types.h:130: error: no type named ‘value_type’ in ‘struct coordinate’ stl_iterator_base_types.h:131: error: no type named ‘difference_type’ in ‘struct coordinate’ stl_iterator_base_types.h:132: error: no type named ‘pointer’ in ‘struct coordinate’ stl_iterator_base_types.h:133: error: no type named ‘reference’ in ‘struct coordinate’ And it blames it on the line: float d = distance(it1->second.location,it2->second.location); Why does the STL complain about my code?

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  • Are web-safe colors still relevant?

    - by Gavin Miller
    Since the vast majority of monitors are 16-bit color or more, including mobile devices, does it make sense to even consider web-safe colors when choosing color schemes? Or is it something that ought to be relegated to history as a piece of trivia? For those of you that don't know what web-safe colors are: Another set of 216 color values is commonly considered to be the "web-safe" color palette, developed at a time when many computer displays were only capable of displaying 256 colors. A set of colors was needed that could be shown without dithering on 256-color displays; the number 216 was chosen partly because computer operating systems customarily reserved sixteen to twenty colors for their own use; it was also selected because it allows exactly six shades each of red, green, and blue (6 × 6 × 6 = 216). The list of colors is often presented as if it has special properties that render them immune to dithering. In fact, on 256-color displays applications can set a palette of any selection of colors that they choose, dithering the rest. These colors were chosen specifically because they matched the palettes selected by the then leading browser applications. [Wikipedia]

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  • "QFontEngine(Win) GetTextMetrics failed ()" error on 64-bit Windows

    - by David Murdoch
    I'll add 500 of my own rep as a bounty when SO lets me. I'm using wkhtmltopdf to convert HTML web pages to PDFs. This works perfectly on my 32-bit dev server [unfortunately, I can't ship my machine :-p ]. However, when I deploy to the web application's 64-bit server the following errors are displayed: C:\>wkhtmltopdf http://www.google.com google.pdf Loading pages (1/5) QFontEngine::loadEngine: GetTextMetrics failed () ] 10% QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngine::loadEngine: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () QFontEngine::loadEngine: GetTextMetrics failed () ] 36% QFontEngineWin: GetTextMetrics failed () QFontEngineWin: GetTextMetrics failed () // ...etc.... and the PDF is created and saved... just WITHOUT text. All form-fields, images, borders, tables, divs, spans, ps, etc are rendered accurately...just void of any text at all. Server information: Windows edition: Windows Server Standard Service Pack 2 Processor: Intel Xeon E5410 @ 2.33GHz 2.33 GHz Memory: 8.00 GB System type: 64-bit Operating System Can anyone give me a clue as to what is happening and how I can fix this? Also, I wasn't sure what to tag/title this question with...so if you can think of better tags/title comment them or edit the question. :-)

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