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• Is this distributed database server idea feasible?

  - by David

  I often use SQLite for creating simple programs in companies. The database is placed on a file server. This works fine as long as there are not more than about 50 users working towards the database concurrently (though depending on whether it is reads or writes). Once there are more than this, they will notice a slowdown if there are a lot of concurrent writing on the server as lots of time is spent on locks, and there is nothing like a cache as there is no database server. The advantage of not needing a database server is that the time to set up something like a company Wiki or similar can be reduced from several months to just days. It often takes several months because some IT-department needs to order the server and it needs to conform with the company policies and security rules and it needs to be placed on the outsourced server hosting facility, which screws up and places it in the wrong localtion etc. etc. Therefore, I thought of an idea to create a distributed database server. The process would be as follows: A user on a company computer edits something on a Wiki page (which uses this database as its backend), to do this he reads a file on the local harddisk stating the ip-address of the last desktop computer to be a database server. He then tries to contact this computer directly via TCP/IP. If it does not answer, then he will read a file on the file server stating the ip-address of the last desktop computer to be a database server. If this server does not answer either, his own desktop computer will become the database server and register its ip-address in the same file. The SQL update statement can then be executed, and other desktop computers can connect to his directly. The point with this architecture is that, the higher load, the better it will function, as each desktop computer will always know the ip-address of the database server. Also, using this setup, I believe that a database placed on a fileserver could serve hundreds of desktop computers instead of the current 50 or so. I also do not believe that the load on the single desktop computer, which has become database server will ever be noticable, as there will be no hard disk operations on this desktop, only on the file server. Is this idea feasible? Does it already exist? What kind of database could support such an architecture?

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• How do I organize a GUI application for passing around events and for setting up reads from a shared resource

  - by Savanni D'Gerinel

  My tools involved here are GTK and Haskell. My questions are probably pretty trivial for anyone who has done significant GUI work, but I've been off in the equivalent of CGI applications for my whole career. I'm building an application that displays tabular data, displays the same data in a graph form, and has an edit field for both entering new data and for editing existing data. After asking about sharing resources, I decided that all of the data involved will be stored in an MVar so that every component can just read the current state from the MVar. All of that works, but now it is time for me to rearrange the application so that it can be interactive. With that in mind, I have three widgets: a TextView (for editing), a TreeView (for displaying the data), and a DrawingArea (for displaying the data as a graph). I THINK I need to do two things, and the core of my question is, are these the right things, or is there a better way. Thing the first: All event handlers, those functions that will be called any time a redisplay is needed, need to be written at a high level and then passed into the function that actually constructs the widget to begin with. For instance: drawStatData :: DrawingArea -> MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO () createStatView :: (DrawingArea -> IO ()) -> IO VBox createUI :: MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO HBox createUI storeMVar field = do graphs <- createStatView (\area -> drawStatData area storeMVar field) hbox <- hBoxNew False 10 boxPackStart hbox graphs PackNatural 0 return hbox In this case, createStatView builds up a VBox that contains a DrawingArea to graph the data and potentially other widgets. It attaches drawStatData to the realize and exposeEvent events for the DrawingArea. I would do something similar for the TreeView, but I am not completely sure what since I have not yet done it and what I am thinking of would involve replacing the TreeModel every time the TreeView needs to be updated. My alternative to the above would be... drawStatData :: DrawingArea -> MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO () createStatView :: IO (VBox, DrawingArea) ... but in this case, I would arrange createUI like so: createUI :: MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO HBox createUI storeMVar field = do (graphbox, graph) <- createStatView (\area -> drawStatData area storeMVar field) hbox <- hBoxNew False 10 boxPackStart hbox graphs PackNatural 0 on graph realize (drawStatData graph storeMVar field) on graph exposeEvent (do liftIO $ drawStatData graph storeMVar field return ()) return hbox I'm not sure which is better, but that does lead me to... Thing the second: it will be necessary for me to rig up an event system so that various events can send signals all the way to my widgets. I'm going to need a mediator of some kind to pass events around and to translate application-semantic events to the actual events that my widgets respond to. Is it better for me to pass my addressable widgets up the call stack to the level where the mediator lives, or to pass the mediator down the call stack and have the widgets register directly with it? So, in summary, my two questions: 1) pass widgets up the call stack to a global mediator, or pass the global mediator down and have the widgets register themselves to it? 2) pass my redraw functions to the builders and have the builders attach the redraw functions to the constructed widgets, or pass the constructed widgets back and have a higher level attach the redraw functions (and potentially link some widgets together)? Okay, and... 3) Books or wikis about GUI application architecture, preferably coherent architectures where people aren't arguing about minute details? The application in its current form (displays data but does not write data or allow for much interaction) is available at https://bitbucket.org/savannidgerinel/fitness . You can run the application by going to the root directory and typing runhaskell -isrc src/Main.hs data/ or... cabal build dist/build/fitness/fitness data/ You may need to install libraries, but cabal should tell you which ones.

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• Computer freezes +/- 30 seconds, suspicion on SSD

  - by Robert vE

  My computer freezes for about 30 seconds, this happens occasionally. When it happens I can still move the mouse, sometimes even alternate between tabs in google chrome. If I try to open windows explorer nothing happens. Also chrome rapports "waiting for cache". It also happens in starcraft II, during which the sounds loops. I have made a Trace as this topic describes: How do I troubleshoot a Windows 7 freeze or slowness? Trace: https://docs.google.com/open?id=0B_VkKdh535p6NklhSDdBLURUMnc I have looked at it, but I couldn't figure it out. My system specs are: AMD Athlon X4 651 Asus Ati HD6670 ADATA SSD sp900 Asus f1a55 mainboard 4 GB crucial 1333 ram 500 watt atx ps I'm running Windows 7, fully updated. Any help is much appreciated. Update: I tried something before your reply that may have helped the problem. I don't know for sure if it has, it's too soon to tell. A bit of history first. I had problems installing win7 on my ssd from the start. In IDE mode it worked, but I had the same problems as above. AHCI was a total fail, with it on before install as well as turning it on after install (including tweaking register). I didn't bother installing the AMD chipset/AHCI as it was reported to have no TRIM function and thus make problems worse. Eventually I did install the AMD SMbus driver as the stability issues were driving me crazy. It worked, no more issues, until I installed some extra drivers and software. Audio/LAN/ASUS suite, I don’t see the relation, but somehow it screwed up my system again. As a last effort I posted here on this site. After which the thought occurred to me turn on AHCI again as by now I had all necessary drivers installed anyway. (plus all windows updates downloaded/installed in the meantime) I did and stability didn’t seem great the first few reboots, but eventually everything seemed to work great. I tried to play starcraft II – an almost guaranteed freeze before – and I had no problems. I’m basically crossing my fingers and hope the problem is gone for good. I still think it has something to do with my SSD. In my research into the problem I noticed a lot of these issues with sandforce 2281 firmware, the exact same firmware I have. People reported the same problem that I had, freezes. Additionally they reported that during a freeze the hdd light stayed on, I noticed after I read this that this happened with my computer as well. None of this is conclusive evidence that my SSD is really to fault, but it is suspicious. And why turning on AHCI would fix it I don’t know. Thank you Tom for taking a look, if the problem returns I will certainly do what you advised.

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• Pirates, Treasure Chests and Architectural Mapping

  Pirate 1: Why do pirates create treasure maps? Pirate 2: I do not know.Pirate 1: So they can find their gold. Yes, that was a bad joke, but it does illustrate a point. Pirates are known for drawing treasure maps to their most prized possession. These documents detail the decisions pirates made in order to hide and find their chests of gold. The map allows them to trace the steps they took originally to hide their treasure so that they may return. As software engineers, programmers, and architects we need to treat software implementations much like our treasure chest. Why is software like a treasure chest? It cost money, time,  and resources to develop (Usually) It can make or save money, time, and resources (Hopefully) If we operate under the assumption that software is like a treasure chest then wouldn’t make sense to document the steps, rationale, concerns, and decisions about how it was designed? Pirates are notorious for documenting where they hide their treasure.  Shouldn’t we as creators of software do the same? By documenting our design decisions and rationale behind them will help others be able to understand and maintain implemented systems. This can only be done if the design decisions are correctly mapped to its corresponding implementation. This allows for architectural decisions to be traced from the conceptual model, architectural design and finally to the implementation. Mapping gives software professional a method to trace the reason why specific areas of code were developed verses other options. Just like the pirates we need to able to trace our steps from the start of a project to its implementation,  so that we will understand why specific choices were chosen. The traceability of a software implementation that actually maps back to its originating design decisions is invaluable for ensuring that architectural drifting and erosion does not take place. The drifting and erosion is prevented by allowing others to understand the rational of why an implementation was created in a specific manor or methodology The process of mapping distinct design concerns/decisions to the location of its implemented is called traceability. In this context traceability is defined as method for connecting distinctive software artifacts. This process allows architectural design models and decisions to be directly connected with its physical implementation. The process of mapping architectural design concerns to a software implementation can be very complex. However, most design decision can be placed in  a few generalized categories. Commonly Mapped Design Decisions Design Rationale Components and Connectors Interfaces Behaviors/Properties Design rational is one of the hardest categories to map directly to an implementation. Typically this rational is mapped or document in code via comments. These comments consist of general design decisions and reasoning because they do not directly refer to a specific part of an application. They typically focus more on the higher level concerns. Components and connectors can directly be mapped to architectural concerns. Typically concerns subdivide an application in to distinct functional areas. These functional areas then can map directly back to their originating concerns.Interfaces can be mapped back to design concerns in one of two ways. Interfaces that pertain to specific function definitions can be directly mapped back to its originating concern(s). However, more complicated interfaces require additional analysis to ensure that the proper mappings are created. Depending on the complexity some Behaviors\Properties can be translated directly into a generic implementation structure that is ready for business logic. In addition, some behaviors can be translated directly in to an actual implementation depending on the complexity and architectural tools used. Mapping design concerns to an implementation is a lot of work to maintain, but is doable. In order to ensure that concerns are mapped correctly and that an implementation correctly reflects its design concerns then one of two standard approaches are usually used. All Changes Come From ArchitectureBy forcing all application changes to come through the architectural model prior to implementation then the existing mappings will be used to locate where in the implementation changes need to occur. Allow Changes From Implementation Or Architecture By allowing changes to come from the implementation and/or the architecture then the other area must be kept in sync. This methodology is more complex compared to the previous approach.  One reason to justify the added complexity for an application is due to the fact that this approach tends to detect and prevent architectural drift and erosion. Additionally, this approach is usually maintained via software because of the complexity. Reference:Taylor, R. N., Medvidovic, N., & Dashofy, E. M. (2009). Software architecture: Foundations, theory, and practice Hoboken, NJ: John Wiley & Sons  

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• Indexed Drawing in OpenGL not working

  - by user2050846

  I am trying to render 2 types of primitives- - points ( a Point Cloud ) - triangles ( a Mesh ) I am rendering points simply without any index arrays and they are getting rendered fine. To render the meshes I am using indexed drawing with the face list array having the indices of the vertices to be rendered as Triangles. Vertices and their corresponding vertex colors are stored in their corresponding buffers. But the indexed drawing command do not draw anything. The code is as follows- Main Display Function: void display() { simple->enable(); simple->bindUniform("MV",modelview); simple->bindUniform("P", projection); // rendering Point Cloud glBindVertexArray(vao); // Vertex buffer Point Cloud glBindBuffer(GL_ARRAY_BUFFER,vertexbuffer); glEnableVertexAttribArray(0); glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,0); // Color Buffer point Cloud glBindBuffer(GL_ARRAY_BUFFER,colorbuffer); glEnableVertexAttribArray(1); glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,0,0); // Render Colored Point Cloud //glDrawArrays(GL_POINTS,0,model->vertexCount); glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); // ---------------- END---------------------// //// Floor Rendering glBindBuffer(GL_ARRAY_BUFFER,fl); glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,0); glVertexAttribPointer(1,4,GL_FLOAT,GL_FALSE,0,(void *)48); glDrawArrays(GL_QUADS,0,4); glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); // -----------------END---------------------// //Rendering the Meshes //////////// PART OF CODE THAT IS NOT DRAWING ANYTHING //////////////////// glBindVertexArray(vid); for(int i=0;i<NUM_MESHES;i++) { glBindBuffer(GL_ARRAY_BUFFER,mVertex[i]); glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,0); glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,0,(void *)(meshes[i]->vertexCount*sizeof(glm::vec3))); //glDrawArrays(GL_TRIANGLES,0,meshes[i]->vertexCount); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,mFace[i]); //cout<<gluErrorString(glGetError()); glDrawElements(GL_TRIANGLES,meshes[i]->faceCount*3,GL_FLOAT,(void *)0); glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); } glUseProgram(0); glutSwapBuffers(); glutPostRedisplay(); } Point Cloud Buffer Allocation Initialization: void initGLPointCloud() { glGenBuffers(1,&vertexbuffer); glGenBuffers(1,&colorbuffer); glGenBuffers(1,&fl); //Populates the position buffer glBindBuffer(GL_ARRAY_BUFFER,vertexbuffer); glBufferData(GL_ARRAY_BUFFER, model->vertexCount * sizeof (glm::vec3), &model->positions[0], GL_STATIC_DRAW); //Populates the color buffer glBindBuffer(GL_ARRAY_BUFFER, colorbuffer); glBufferData(GL_ARRAY_BUFFER, model->vertexCount * sizeof (glm::vec3), &model->colors[0], GL_STATIC_DRAW); model->FreeMemory(); // To free the not needed memory, as the data has been already // copied on graphic card, and wont be used again. glBindBuffer(GL_ARRAY_BUFFER,0); } Meshes Buffer Initialization: void initGLMeshes(int i) { glBindBuffer(GL_ARRAY_BUFFER,mVertex[i]); glBufferData(GL_ARRAY_BUFFER,meshes[i]->vertexCount*sizeof(glm::vec3)*2,NULL,GL_STATIC_DRAW); glBufferSubData(GL_ARRAY_BUFFER,0,meshes[i]->vertexCount*sizeof(glm::vec3),&meshes[i]->positions[0]); glBufferSubData(GL_ARRAY_BUFFER,meshes[i]->vertexCount*sizeof(glm::vec3),meshes[i]->vertexCount*sizeof(glm::vec3),&meshes[i]->colors[0]); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,mFace[i]); glBufferData(GL_ELEMENT_ARRAY_BUFFER,meshes[i]->faceCount*sizeof(glm::vec3), &meshes[i]->faces[0],GL_STATIC_DRAW); meshes[i]->FreeMemory(); //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,0); } Initialize the Rendering, load and create shader and calls the mesh and PCD initializers. void initRender() { simple= new GLSLShader("shaders/simple.vert","shaders/simple.frag"); //Point Cloud //Sets up VAO glGenVertexArrays(1, &vao); glBindVertexArray(vao); initGLPointCloud(); //floorData glBindBuffer(GL_ARRAY_BUFFER, fl); glBufferData(GL_ARRAY_BUFFER, sizeof(floorData), &floorData[0], GL_STATIC_DRAW); glBindBuffer(GL_ARRAY_BUFFER,0); glBindVertexArray(0); //Meshes for(int i=0;i<NUM_MESHES;i++) { if(i==0) // SET up the new vertex array state for indexed Drawing { glGenVertexArrays(1, &vid); glBindVertexArray(vid); glGenBuffers(NUM_MESHES,mVertex); glGenBuffers(NUM_MESHES,mColor); glGenBuffers(NUM_MESHES,mFace); } initGLMeshes(i); } glEnable(GL_DEPTH_TEST); } Any help would be much appreciated, I have been breaking my head on this problem since 3 days, and still it is unsolved.

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• how to setup kismet.conf on Ubuntu

  - by Registered User

  I installed Kismet on my Ubuntu 10.04 machine as apt-get install kismet every thing seems to work fine. but when I launch it I see following error kismet Launching kismet_server: //usr/bin/kismet_server Suid priv-dropping disabled. This may not be secure. No specific sources given to be enabled, all will be enabled. Non-RFMon VAPs will be destroyed on multi-vap interfaces (ie, madwifi-ng) Enabling channel hopping. Enabling channel splitting. NOTICE: Disabling channel hopping, no enabled sources are able to change channel. Source 0 (addme): Opening none source interface none... FATAL: Please configure at least one packet source. Kismet will not function if no packet sources are defined in kismet.conf or on the command line. Please read the README for more information about configuring Kismet. Kismet exiting. Done. I followed this guide http://www.ubuntugeek.com/kismet-an-802-11-wireless-network-detector-sniffer-and-intrusion-detection-system.html#more-1776 how ever in kismet.conf I am not clear with following line source=none,none,addme as to what should I change this to. lspci -vnn shows 0c:00.0 Network controller [0280]: Broadcom Corporation BCM4312 802.11b/g [14e4:4315] (rev 01) Subsystem: Dell Device [1028:000c] Flags: bus master, fast devsel, latency 0, IRQ 17 Memory at f69fc000 (64-bit, non-prefetchable) [size=16K] Capabilities: [40] Power Management version 3 Capabilities: [58] Vendor Specific Information <?> Capabilities: [e8] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable- Capabilities: [d0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting <?> Capabilities: [13c] Virtual Channel <?> Capabilities: [160] Device Serial Number Capabilities: [16c] Power Budgeting <?> Kernel driver in use: wl Kernel modules: wl, ssb and iwconfig shows lo no wireless extensions. eth0 no wireless extensions. eth1 IEEE 802.11bg ESSID:"WIKUCD" Mode:Managed Frequency:2.462 GHz Access Point: <00:43:92:21:H5:09> Bit Rate=11 Mb/s Tx-Power:24 dBm Retry min limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Managementmode:All packets received Link Quality=1/5 Signal level=-81 dBm Noise level=-90 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:169 Invalid misc:0 Missed beacon:0 So what should I be putting in place of source=none,none,addme with output I mentioned above ?

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• UIView with IrrlichtScene - iOS

  - by user1459024

  i have a UIViewController in a Storyboard and want to draw a IrrlichtScene in this View Controller. My Code: WWSViewController.h #import <UIKit/UIKit.h> @interface WWSViewController : UIViewController { IBOutlet UILabel *errorLabel; } @end WWSViewController.mm #import "WWSViewController.h" #include "../../ressources/irrlicht/include/irrlicht.h" using namespace irr; using namespace core; using namespace scene; using namespace video; using namespace io; using namespace gui; @interface WWSViewController () @end @implementation WWSViewController -(void)awakeFromNib { errorLabel = [[UILabel alloc] init]; errorLabel.text = @""; IrrlichtDevice *device = createDevice( video::EDT_OGLES1, dimension2d<u32>(640, 480), 16, false, false, false, 0); /* Set the caption of the window to some nice text. Note that there is an 'L' in front of the string. The Irrlicht Engine uses wide character strings when displaying text. */ device->setWindowCaption(L"Hello World! - Irrlicht Engine Demo"); /* Get a pointer to the VideoDriver, the SceneManager and the graphical user interface environment, so that we do not always have to write device->getVideoDriver(), device->getSceneManager(), or device->getGUIEnvironment(). */ IVideoDriver* driver = device->getVideoDriver(); ISceneManager* smgr = device->getSceneManager(); IGUIEnvironment* guienv = device->getGUIEnvironment(); /* We add a hello world label to the window, using the GUI environment. The text is placed at the position (10,10) as top left corner and (260,22) as lower right corner. */ guienv->addStaticText(L"Hello World! This is the Irrlicht Software renderer!", rect<s32>(10,10,260,22), true); /* To show something interesting, we load a Quake 2 model and display it. We only have to get the Mesh from the Scene Manager with getMesh() and add a SceneNode to display the mesh with addAnimatedMeshSceneNode(). We check the return value of getMesh() to become aware of loading problems and other errors. Instead of writing the filename sydney.md2, it would also be possible to load a Maya object file (.obj), a complete Quake3 map (.bsp) or any other supported file format. By the way, that cool Quake 2 model called sydney was modelled by Brian Collins. */ IAnimatedMesh* mesh = smgr->getMesh("/Users/dbocksteger/Desktop/test/media/sydney.md2"); if (!mesh) { device->drop(); if (!errorLabel) { errorLabel = [[UILabel alloc] init]; } errorLabel.text = @"Konnte Mesh nicht laden."; return; } IAnimatedMeshSceneNode* node = smgr->addAnimatedMeshSceneNode( mesh ); /* To let the mesh look a little bit nicer, we change its material. We disable lighting because we do not have a dynamic light in here, and the mesh would be totally black otherwise. Then we set the frame loop, such that the predefined STAND animation is used. And last, we apply a texture to the mesh. Without it the mesh would be drawn using only a color. */ if (node) { node->setMaterialFlag(EMF_LIGHTING, false); node->setMD2Animation(scene::EMAT_STAND); node->setMaterialTexture( 0, driver->getTexture("/Users/dbocksteger/Desktop/test/media/sydney.bmp") ); } /* To look at the mesh, we place a camera into 3d space at the position (0, 30, -40). The camera looks from there to (0,5,0), which is approximately the place where our md2 model is. */ smgr->addCameraSceneNode(0, vector3df(0,30,-40), vector3df(0,5,0)); /* Ok, now we have set up the scene, lets draw everything: We run the device in a while() loop, until the device does not want to run any more. This would be when the user closes the window or presses ALT+F4 (or whatever keycode closes a window). */ while(device->run()) { /* Anything can be drawn between a beginScene() and an endScene() call. The beginScene() call clears the screen with a color and the depth buffer, if desired. Then we let the Scene Manager and the GUI Environment draw their content. With the endScene() call everything is presented on the screen. */ driver->beginScene(true, true, SColor(255,100,101,140)); smgr->drawAll(); guienv->drawAll(); driver->endScene(); } /* After we are done with the render loop, we have to delete the Irrlicht Device created before with createDevice(). In the Irrlicht Engine, you have to delete all objects you created with a method or function which starts with 'create'. The object is simply deleted by calling ->drop(). See the documentation at irr::IReferenceCounted::drop() for more information. */ device->drop(); } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. } - (void)viewDidUnload { [super viewDidUnload]; // Release any retained subviews of the main view. } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown); } @end Sadly the result is just a black View in the Simulator. :( Hope here is anyone who can explain me how i draw the scene in a UIView. Furthermore I'm getting this Error: Could not load sprite bank because the file does not exist: #DefaultFont How can i fix it ?

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• Managing text-maps in a 2D array on to be painted on HTML5 Canvas

  - by weka

  So, I'm making a HTML5 RPG just for fun. The map is a <canvas> (512px width, 352px height | 16 tiles across, 11 tiles top to bottom). I want to know if there's a more efficient way to paint the <canvas>. Here's how I have it right now. How tiles are loaded and painted on map The map is being painted by tiles (32x32) using the Image() piece. The image files are loaded through a simple for loop and put into an array called tiles[] to be PAINTED on using drawImage(). First, we load the tiles... and here's how it's being done: // SET UP THE & DRAW THE MAP TILES tiles = []; var loadedImagesCount = 0; for (x = 0; x <= NUM_OF_TILES; x++) { var imageObj = new Image(); // new instance for each image imageObj.src = "js/tiles/t" + x + ".png"; imageObj.onload = function () { console.log("Added tile ... " + loadedImagesCount); loadedImagesCount++; if (loadedImagesCount == NUM_OF_TILES) { // Onces all tiles are loaded ... // We paint the map for (y = 0; y <= 15; y++) { for (x = 0; x <= 10; x++) { theX = x * 32; theY = y * 32; context.drawImage(tiles[5], theY, theX, 32, 32); } } } }; tiles.push(imageObj); } Naturally, when a player starts a game it loads the map they last left off. But for here, it an all-grass map. Right now, the maps use 2D arrays. Here's an example map. [[4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 1, 1, 1, 1], [1, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 1, 1, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 1, 1, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 13, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 13, 11, 11, 11, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 1, 1, 1, 1, 1, 1, 1, 13, 13, 13, 13, 13, 1], [1, 1, 1, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 1, 1, 1]]; I get different maps using a simple if structure. Once the 2d array above is return, the corresponding number in each array will be painted according to Image() stored inside tile[]. Then drawImage() will occur and paint according to the x and y and times it by 32 to paint on the correct x-y coordinate. How multiple map switching occurs With my game, maps have five things to keep track of: currentID, leftID, rightID, upID, and bottomID. currentID: The current ID of the map you are on. leftID: What ID of currentID to load when you exit on the left of current map. rightID: What ID of currentID to load when you exit on the right of current map. downID: What ID of currentID to load when you exit on the bottom of current map. upID: What ID of currentID to load when you exit on the top of current map. Something to note: If either leftID, rightID, upID, or bottomID are NOT specific, that means they are a 0. That means they cannot leave that side of the map. It is merely an invisible blockade. So, once a person exits a side of the map, depending on where they exited... for example if they exited on the bottom, bottomID will the number of the map to load and thus be painted on the map. Here's a representational .GIF to help you better visualize: As you can see, sooner or later, with many maps I will be dealing with many IDs. And that can possibly get a little confusing and hectic. The obvious pros is that it load 176 tiles at a time, refresh a small 512x352 canvas, and handles one map at time. The con is that the MAP ids, when dealing with many maps, may get confusing at times. My question Is this an efficient way to store maps (given the usage of tiles), or is there a better way to handle maps? I was thinking along the lines of a giant map. The map-size is big and it's all one 2D array. The viewport, however, is still 512x352 pixels. Here's another .gif I made (for this question) to help visualize: Sorry if you cannot understand my English. Please ask anything you have trouble understanding. Hopefully, I made it clear. Thanks.

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• Speakers, Please Check Your Time

  - by AjarnMark

  Woodrow Wilson was once asked how long it would take him to prepare for a 10 minute speech. He replied "Two weeks". He was then asked how long it would take for a 1 hour speech. "One week", he replied. 2 hour speech? "I'm ready right now," he replied.  Whether that is a true story or an urban legend, I don’t really know, but either way, it is a poignant reminder for all speakers, and particularly apropos this week leading up to the PASS Community Summit. (Cross-posted to the PASS Professional Development Virtual Chapter blog #PASSProfDev.) What’s the point of that story?  Simply this…if you have plenty of time to do your presentation, you don’t need to prepare much because it is easy to throw in more and more material to stretch out to your allotted time.  But if you are on a tight time constraint, then it will take significant preparation to distill your talk down to only the essential points. I have attended seven of the last eight North American Summit events, and every one of them has been fantastic.  The speakers are great, the material is timely and relevant, and the networking opportunities are awesome.  And every year, there is one little thing that just bugs me…speakers going over their allotted time.  Why does it bother me so?  Well, if you look at a typical schedule for a Summit, you’ll see that there are six or more sessions going on at the same time, and only 15 minutes to move from one to another.  If you’re trying to maximize your training dollar by attending something during every session time slot, and you don’t want to be the last guy trying to squeeze into the middle of the row, then those 15 minutes can be critical.  All the more so if you need to stop and use the bathroom or if you have to hike to the opposite end of the convention center.  It is really a bad position to find yourself having to choose between learning the last key points of Speaker A who is going over time, and getting over to Speaker B on time so you don’t miss her key opening remarks. And frankly, I think it is just rude.  Yes, the speakers are the function, after all they are bringing the content that the rest of us are paying to learn.  But it is also an honor to be given the opportunity to speak at a conference like this, and no one speaker is so important that the conference would be a disaster without him.  Speakers know when they submit their abstract, long before the conference, how much time they will have.  It has been the same pattern at the Summit for at least the last eight years.  Program Sessions are 75 minutes long.  Some speakers who have a good track record, and meet other qualifying criteria, are extended an invitation to present a Spotlight Session which is 90 minutes (a 20% increase).  So there really is no excuse.  It’s not like you were promised a 2-hour segment and then discovered when you got here that it was only 75 minutes.  In fact, it’s not like PASS advertised 90-minute sessions for everyone and then a select few were cut back to only 75.  As a speaker, you know well before you get here which type of session you are doing and how long it is, so as a professional, you should plan accordingly. Now you might think that this only happens to rookies, but I’ll tell you that some of the worst offenders are big-name veterans who draw huge attendance numbers for their sessions.  Some attendees blow this off as, “Hey, it’s so-and-so, and I’d stay here for hours and listen to him/her talk.”  To which I would reply, “Then they should have submitted for a pre- or post-conference day-long seminar instead, but don’t try to squeeze your day-long talk into a 90-minute session.”  Now I don’t really believe that these speakers are being malicious or just selfishly trying to extend their time in the spotlight.  I think that most of them are merely being undisciplined and did not trim their presentation sufficiently, or allowed themselves to get off-track (often in a generous attempt to help someone in the audience with a question or problem that really should have been noted for further discussion after the session). So here is my recommendation…my plea, even.  TRIM THE FAT!  Now.  Before it’s too late.  Before you even get on the airplane, take a long, hard look at your presentation and eliminate some of the points that you originally thought you had to make, but in reality are not truly crucial to your main topic.  Delete a few slides.  Test your demos and have them already scripted rather than typing them during your talk.  It is better to cut out too much and end up with plenty of time at the end for Questions & Answers.  And you can always keep some notes on the stuff that you cut out so that you could fill it back in at the end as bonus material if you really do end up with a whole bunch of time on your hands.  But I don’t think you will.  And if you do, that will look even better to the audience as it will look like you’re giving them something extra that not every audience gets.  And they will thank you for that.

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• Microsoft Sql Server 2008 R2 System Databases

  For a majority of software developers little time is spent understanding the inner workings of the database management systems (DBMS) they use to store data for their applications.  I personally place myself in this grouping. In my case, I have used various versions of Microsoft’s SQL Server (2000, 2005, and 2008 R2) and just recently learned how valuable they really are when I was preparing to deliver a lecture on "SQL Server 2008 R2, System Databases". Microsoft Sql Server 2008 R2 System DatabasesSo what are system databases in MS SQL Server, and why should I know them? Microsoft uses system databases to support the SQL Server DBMS, much like a developer uses config files or database tables to support an application. These system databases individually provide specific functionality that allows MS SQL Server to function. Name Database File Log File Master master.mdf mastlog.ldf Resource mssqlsystemresource.mdf mssqlsystemresource.ldf Model model.mdf modellog.ldf MSDB msdbdata.mdf msdblog.ldf Distribution distmdl.mdf distmdl.ldf TempDB tempdb.mdf templog.ldf Master DatabaseIf you have used MS SQL Server then you should recognize the Master database especially if you used the SQL Server Management Studio (SSMS) to connect to a user created database. MS SQL Server requires the Master database in order for DBMS to start due to the information that it stores. Examples of data stored in the Master database User Logins Linked Servers Configuration information Information on User Databases Resource DatabaseHonestly, until recently I never knew this database even existed until I started to research SQL Server system databases. The reason for this is due largely to the fact that the resource database is hidden to users. In fact, the database files are stored within the Binn folder instead of the standard MS SQL Server database folder path. This database contains all system objects that can be accessed by all other databases.  In short, this database contains all system views and store procedures that appear in all other user databases regarding system information. One of the many benefits to storing system views and store procedures in a single hidden database is the fact it improves upgrading a SQL Server database; not to mention that maintenance is decreased since only one code base has to be mainlined for all of the system views and procedures. Model DatabaseThe Model database as the name implies is the model for all new databases created by users. This allows for predefining default database objects for all new databases within a MS SQL Server instance. For example, if every database created by a user needs to have an “Audit” table when it is  created then defining the “Audit” table in the model will guarantees that the table will be located in every new database create after the model is altered. MSDB DatabaseThe MSDBdatabase is used by SQL Server Agent, SQL Server Database Mail, SQL Server Service Broker, along with SQL Server. The SQL Server Agent uses this database to store job configurations and SQL job schedules along with SQL Alerts, and Operators. In addition, this database also stores all SQL job parameters along with each job’s execution history.  Finally, this database is also used to store database backup and maintenance plans as well as details pertaining to SQL Log shipping if it is being used. Distribution DatabaseThe Distribution database is only used during replication and stores meta data and history information pertaining to the act of replication data. Furthermore, when transactional replication is used this database also stores information regarding each transaction. It is important to note that replication is not turned on by default in MS SQL Server and that the distribution database is hidden from SSMS. Tempdb DatabaseThe Tempdb as the name implies is used to store temporary data and data objects. Examples of this include temp tables and temp store procedures. It is important to note that when using this database all data and data objects are cleared from this database when SQL Server restarts. This database is also used by SQL Server when it is performing some internal operations. Typically, SQL Server uses this database for the purpose of large sort and index operations. Finally, this database is used to store row versions if row versioning or snapsot isolation transactions are being used by SQL Server. Additionally, I would love to hear from others about their experiences using system databases, tables, and objects in a real world environments.

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• iOS Support with Windows Azure Mobile Services – now with Push Notifications

  - by ScottGu

  A few weeks ago I posted about a number of improvements to Windows Azure Mobile Services. One of these was the addition of an Objective-C client SDK that allows iOS developers to easily use Mobile Services for data and authentication.  Today I'm excited to announce a number of improvement to our iOS SDK and, most significantly, our new support for Push Notifications via APNS (Apple Push Notification Services).  This makes it incredibly easy to fire push notifications to your iOS users from Windows Azure Mobile Service scripts. Push Notifications via APNS We've provided two complete tutorials that take you step-by-step through the provisioning and setup process to enable your Windows Azure Mobile Service application with APNS (Apple Push Notification Services), including all of the steps required to configure your application for push in the Apple iOS provisioning portal: Getting started with Push Notifications - iOS Push notifications to users by using Mobile Services - iOS Once you've configured your application in the Apple iOS provisioning portal and uploaded the APNS push certificate to the Apple provisioning portal, it's just a matter of uploading your APNS push certificate to Mobile Services using the Windows Azure admin portal: Clicking the “upload” within the “Push” tab of your Mobile Service allows you to browse your local file-system and locate/upload your exported certificate.  As part of this you can also select whether you want to use the sandbox (dev) or production (prod) Apple service: Now, the code to send a push notification to your clients from within a Windows Azure Mobile Service is as easy as the code below: push.apns.send(deviceToken, {      alert: 'Toast: A new Mobile Services task.',      sound: 'default' }); This will cause Windows Azure Mobile Services to connect to APNS (Apple Push Notification Service) and send a notification to the iOS device you specified via the deviceToken: Check out our reference documentation for full details on how to use the new Windows Azure Mobile Services apns object to send your push notifications. Feedback Scripts An important part of working with any PNS (Push Notification Service) is handling feedback for expired device tokens and channels. This typically happens when your application is uninstalled from a particular device and can no longer receive your notifications. With Windows Notification Services you get an instant response from the HTTP server.  Apple’s Notification Services works in a slightly different way and provides an additional endpoint you can connect to poll for a list of expired tokens. As with all of the capabilities we integrate with Mobile Services, our goal is to allow developers to focus more on building their app and less on building infrastructure to support their ideas. Therefore we knew we had to provide a simple way for developers to integrate feedback from APNS on a regular basis.  This week’s update now includes a new screen in the portal that allows you to optionally provide a script to process your APNS feedback – and it will be executed by Mobile Services on an ongoing basis: This script is invoked periodically while your service is active. To poll the feedback endpoint you can simply call the apns object's getFeedback method from within this script: push.apns.getFeedback({       success: function(results) {           // results is an array of objects with a deviceToken and time properties      } }); This returns you a list of invalid tokens that can now be removed from your database. iOS Client SDK improvements Over the last month we've continued to work with a number of iOS advisors to make improvements to our Objective-C SDK. The SDK is being developed under an open source license (Apache 2.0) and is available on github. Many of the improvements are behind the scenes to improve performance and memory usage. However, one of the biggest improvements to our iOS Client API is the addition of an even easier login method.  Below is the Objective-C code you can now write to invoke it: [client loginWithProvider:@"twitter"                     onController:self                        animated:YES                      completion:^(MSUser *user, NSError *error) {      // if no error, you are now logged in via twitter }]; This code will automatically present and dismiss our login view controller as a modal dialog on the specified controller.  This does all the hard work for you and makes login via Twitter, Google, Facebook and Microsoft Account identities just a single line of code. My colleague Josh just posted a short video demonstrating these new features which I'd recommend checking out: Summary The above features are all now live in production and are available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using Mobile Services today. Visit the Windows Azure Mobile Developer Center to learn more about how to build apps with Mobile Services. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• freebsd-update from 8.3-RELEASE to 9.0-RELEASE: How to deal with dozens of diffs?

  - by Stefan Lasiewski

  I am upgrading a FreeBSD 8.3-RELEASE system to FreeBSD 9.0-RELEASE using freebsd-update. This is my first time performing a major version upgrade in FreeBSD. At one point in the process, freebsd-update performs a diff on files which are different then what is expected for the 9.0-RELEASE. It compares the current version on the system with the new changes added from 9.0-RELEASE. There are dozens of files in the list. Thus, I am presented with dozens and dozens of diffs which open in a vi window and look like this: The following file could not be merged automatically: /etc/ntp.conf Press Enter to edit this file in vi and resolve the conflicts manually... ### vi window opens <<<<<<< current version driftfile /etc/ntp/drift ======= # # $FreeBSD: release/9.0.0/etc/ntp.conf 195652 2009-07-13 05:51:33Z dwmalone $ # # Default NTP servers for the FreeBSD operating system. # # Don't forget to enable ntpd in /etc/rc.conf with: # ntpd_enable="YES" # # The driftfile is by default /var/db/ntpd.drift, check # /etc/defaults/rc.conf on how to change the location. # >>>>>>> 9.0-RELEASE restrict default notrust nomodify ignore And so on. This requires that I manually edit each file and remove the strings like <<<<<<< current version >>>>>>> 9.0-RELEASE and =======. As I discovered afterwards, if I don't remove these strings, they end up in the file afterwards. There are dozens of files which differ between 8.3 and 9.0, and I have a dozen local modifications myself. It appears that freebsd-update is using a diff, sdiff or mergemaster function of some sort, but I can't tell what it is doing exactly. Processing these files is tedious. Is there a way that I can just say "Accept new version" or "keep old version" or "Your merge is correct"? There has got to be an easier way to deal with these files. I must be missing something. This isn't a huge problem for one machine, but eventually I'll be doing this dozens of times and I want to find an easier way.

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• Microsoft Sql Server 2008 R2 System Databases

  For a majority of software developers little time is spent understanding the inner workings of the database management systems (DBMS) they use to store data for their applications.  I personally place myself in this grouping. In my case, I have used various versions of Microsoft’s SQL Server (2000, 2005, and 2008 R2) and just recently learned how valuable they really are when I was preparing to deliver a lecture on "SQL Server 2008 R2, System Databases". Microsoft Sql Server 2008 R2 System DatabasesSo what are system databases in MS SQL Server, and why should I know them? Microsoft uses system databases to support the SQL Server DBMS, much like a developer uses config files or database tables to support an application. These system databases individually provide specific functionality that allows MS SQL Server to function. Name Database File Log File Master master.mdf mastlog.ldf Resource mssqlsystemresource.mdf mssqlsystemresource.ldf Model model.mdf modellog.ldf MSDB msdbdata.mdf msdblog.ldf Distribution distmdl.mdf distmdl.ldf TempDB tempdb.mdf templog.ldf Master DatabaseIf you have used MS SQL Server then you should recognize the Master database especially if you used the SQL Server Management Studio (SSMS) to connect to a user created database. MS SQL Server requires the Master database in order for DBMS to start due to the information that it stores. Examples of data stored in the Master database User Logins Linked Servers Configuration information Information on User Databases Resource DatabaseHonestly, until recently I never knew this database even existed until I started to research SQL Server system databases. The reason for this is due largely to the fact that the resource database is hidden to users. In fact, the database files are stored within the Binn folder instead of the standard MS SQL Server database folder path. This database contains all system objects that can be accessed by all other databases.  In short, this database contains all system views and store procedures that appear in all other user databases regarding system information. One of the many benefits to storing system views and store procedures in a single hidden database is the fact it improves upgrading a SQL Server database; not to mention that maintenance is decreased since only one code base has to be mainlined for all of the system views and procedures. Model DatabaseThe Model database as the name implies is the model for all new databases created by users. This allows for predefining default database objects for all new databases within a MS SQL Server instance. For example, if every database created by a user needs to have an “Audit” table when it is  created then defining the “Audit” table in the model will guarantees that the table will be located in every new database create after the model is altered. MSDB DatabaseThe MSDBdatabase is used by SQL Server Agent, SQL Server Database Mail, SQL Server Service Broker, along with SQL Server. The SQL Server Agent uses this database to store job configurations and SQL job schedules along with SQL Alerts, and Operators. In addition, this database also stores all SQL job parameters along with each job’s execution history.  Finally, this database is also used to store database backup and maintenance plans as well as details pertaining to SQL Log shipping if it is being used. Distribution DatabaseThe Distribution database is only used during replication and stores meta data and history information pertaining to the act of replication data. Furthermore, when transactional replication is used this database also stores information regarding each transaction. It is important to note that replication is not turned on by default in MS SQL Server and that the distribution database is hidden from SSMS. Tempdb DatabaseThe Tempdb as the name implies is used to store temporary data and data objects. Examples of this include temp tables and temp store procedures. It is important to note that when using this database all data and data objects are cleared from this database when SQL Server restarts. This database is also used by SQL Server when it is performing some internal operations. Typically, SQL Server uses this database for the purpose of large sort and index operations. Finally, this database is used to store row versions if row versioning or snapsot isolation transactions are being used by SQL Server. Additionally, I would love to hear from others about their experiences using system databases, tables, and objects in a real world environments.

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• 10.6.4 Apple Wiki: New just created users can do nothing?

  - by beefon

  Hello, After update to 10.6.4 there's an issue: any new users that I create in Server Prefs/WGM can't post to their blogs, comment, create wiki pages... They can't do anything! There's log from Wiki errors (when user DURAK tries to create new blog entry): [HTTPChannel,5,127.0.0.1] Traceback (most recent call last): [HTTPChannel,5,127.0.0.1] File "/usr/share/caldavd/lib/python/twisted/web/server.py", line 126, in process self.render(resrc) [HTTPChannel,5,127.0.0.1] File "/usr/share/caldavd/lib/python/twisted/web/server.py", line 133, in render body = resrc.render(self) [HTTPChannel,5,127.0.0.1] File "/usr/share/wikid/lib/python/apple_xmlrpc_server/WebAppServer.py", line 90, in render d = defer.maybeDeferred(function, *args) [HTTPChannel,5,127.0.0.1] File "/usr/share/caldavd/lib/python/twisted/internet/defer.py", line 104, in maybeDeferred result = f(*args, **kw) [HTTPChannel,5,127.0.0.1] --- <exception caught here> --- [HTTPChannel,5,127.0.0.1] File "/usr/share/wikid/lib/python/apple_xmlrpc_server/ContentServiceBase.py", line 121, in xmlrpc_addEntry aPage = ContentEntry.newBundleBasedContentEntry (path = path, content = content, author = author, title = title, uid = uid, type = kind, versioned = self.versioned, templateName = template) [HTTPChannel,5,127.0.0.1] File "/usr/share/wikid/lib/python/apple_wlt/ContentEntry.py", line 794, in newBundleBasedContentEntry aPage.save('First created', 'created') [HTTPChannel,5,127.0.0.1] File "/usr/share/wikid/lib/python/apple_wlt/ContentEntry.py", line 445, in save revisions.addRevision(self.serializeEntry(revisionAttributes), inComment = comment, inAuthor = updateAuthor, inChangeType = editType) [HTTPChannel,5,127.0.0.1] File "/usr/share/wikid/lib/python/apple_utilities/sqlitersion.py", line 36, in _func result = f(self, *args, **kwargs) [HTTPChannel,5,127.0.0.1] File "/usr/share/wikid/lib/python/apple_utilities/sqlitersion.py", line 49, in addRevision contentPlistStr = plistlib.writePlistToString(inContentDict).decode("utf-8") [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 110, in writePlistToString [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 94, in writePlist [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 251, in writeValue [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 280, in writeDict [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 238, in writeValue [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 171, in simpleElement [HTTPChannel,5,127.0.0.1] File "/S-m/Lib-ry/Fr-ks/Python.fr-k/Ver-s/2.6/lib/pyth-2.6/plistlib.py", line 221, in _escapeAndEncode [HTTPChannel,5,127.0.0.1] exceptions.UnicodeDecodeError: 'ascii' codec can't decode byte 0xd0 in position 0: ordinal not in range(128) [HTTPChannel,5,127.0.0.1] 'Unparseable html in page, removing whatever was already written.' [HTTPChannel,5,127.0.0.1] Removing /Library/Collaboration/Users/durak/weblog/27133.page Any "old" user CAN create, modify, comment, etc. What can you recommend to fix this issue? Hope for your help...

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• Joining on NULLs

  - by Dave Ballantyne

  A problem I see on a fairly regular basis is that of dealing with NULL values.  Specifically here, where we are joining two tables on two columns, one of which is ‘optional’ ie is nullable.  So something like this: i.e. Lookup where all the columns are equal, even when NULL.   NULL’s are a tricky thing to initially wrap your mind around.  Statements like “NULL is not equal to NULL and neither is it not not equal to NULL, it’s NULL” can cause a serious brain freeze and leave you a gibbering wreck and needing your mummy. Before we plod on, time to setup some data to demo against. Create table #SourceTable ( Id integer not null, SubId integer null, AnotherCol char(255) not null ) go create unique clustered index idxSourceTable on #SourceTable(id,subID) go with cteNums as ( select top(1000) number from master..spt_values where type ='P' ) insert into #SourceTable select Num1.number,nullif(Num2.number,0),'SomeJunk' from cteNums num1 cross join cteNums num2 go Create table #LookupTable ( Id integer not null, SubID integer null ) go insert into #LookupTable Select top(100) id,subid from #SourceTable where subid is not null order by newid() go insert into #LookupTable Select top(3) id,subid from #SourceTable where subid is null order by newid() If that has run correctly, you will have 1 million rows in #SourceTable and 103 rows in #LookupTable.  We now want to join one to the other. First attempt – Lets just join select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and #LookupTable.SubID = #SourceTable.SubID OK, that’s a fail.  We had 100 rows back,  we didn’t correctly account for the 3 rows that have null values.  Remember NULL <> NULL and the join clause specifies SUBID=SUBID, which for those rows is not true. Second attempt – Lets deal with those pesky NULLS select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and isnull(#LookupTable.SubID,0) = isnull(#SourceTable.SubID,0) OK, that’s the right result, well done and 99.9% of the time that is where its left. It is a relatively trivial CPU overhead to wrap ISNULL around both columns and compare that result, so no problems.  But, although that’s true, this a relational database we are using here, not a procedural language.  SQL is a declarative language, we are making a request to the engine to get the results we want.  How we ask for them can make a ton of difference. Lets look at the plan for our second attempt, specifically the clustered index seek on the #SourceTable   There are 2 predicates. The ‘seek predicate’ and ‘predicate’.  The ‘seek predicate’ describes how SQLServer has been able to use an Index.  Here, it has been able to navigate the index to resolve where ID=ID.  So far so good, but what about the ‘predicate’ (aka residual probe) ? This is a row-by-row operation.  For each row found in the index matching the Seek Predicate, the leaf level nodes have been scanned and tested using this logical condition.  In this example [Expr1007] is the result of the IsNull operation on #LookupTable and that is tested for equality with the IsNull operation on #SourceTable.  This residual probe is quite a high overhead, if we can express our statement slightly differently to take full advantage of the index and make the test part of the ‘Seek Predicate’. Third attempt – X is null and Y is null So, lets state the query in a slightly manner: select * from #SourceTable join #LookupTable on #LookupTable.id = #SourceTable.id and ( #LookupTable.SubID = #SourceTable.SubID or (#LookupTable.SubID is null and #SourceTable.SubId is null) ) So its slightly wordier and may not be as clear in its intent to the human reader, that is what comments are for, but the key point is that it is now clearer to the query optimizer what our intention is. Let look at the plan for that query, again specifically the index seek operation on #SourceTable No ‘predicate’, just a ‘Seek Predicate’ against the index to resolve both ID and SubID.  A subtle difference that can be easily overlooked.  But has it made a difference to the performance ? Well, yes , a perhaps surprisingly high one. Clever query optimizer well done. If you are using a scalar function on a column, you a pretty much guaranteeing that a residual probe will be used.  By re-wording the query you may well be able to avoid this and use the index completely to resolve lookups. In-terms of performance and scalability your system will be in a much better position if you can.

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• Seeking past end of file causes Apache hang, and it never restarts.

  - by talkingnews

  I've actually solved my problem with a better script, but I'm still left wondering why Apache2 hung completely - this is an out-of-the-box ISPCONFIG 3.03 install, everything bang up to date, running perfectly. Until... The troublesome but innocent-looking script: $fp = fopen("/var/log/ispconfig/cron.log", "r"); fseek($fp, -5000, SEEK_END); $line_buffer = array(); while (!feof($fp)) { $line = fgets($fp, 1024); $line_buffer[] = $line; $line_buffer = array_slice($line_buffer, -10, 10); } foreach ($line_buffer as $line) { echo $line; } You get the idea, just a script I found on a forum somwehere. I did this for various logs, since it's a nice easy window on what's occurring (in a protect dir, of course!). One day, the logs having grown large an me having sorted all my cron, scripting and mail queue errors, I thought I was time to start afresh. updated, rebooted, archived and deleted the logs. When I ran my script a couple of hours later, it hung. And hung. 8 minutes I waited. Chrome timed the page out, of course, but the server never came back to life. htop showed /usr/sbin/apache2 -k restart using 100% CPU. Never came back until I did a service apache2 restart. Ran fine, as soon as I hit that logfile again...dead. So, I worked out it was the logfile script, and I worked out that seeking beyond the end of the file wasn't good, and I found a better script http://www.php.net/manual/en/function.fseek.php#90450 But what I'm left wondering is... why didn't something restart or kill the process? How was one hanging page able to bring down the whole server? It's running suphp. I say "out of the box", I've tweaked mysql and apache to fork and reserve sensible amounts of processes for the 512Mb RAM the VPS has, and it'll handle multiple refreshes of large pages, and hadn't hung before. Any ideas how I'd avoid this? Google isn't my friend in this instance beyond the reccs. above about number of processes vs RAM available.

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• Wordpress Theme

  - by HotPizzaBox

  I'm trying to create a basic wordpress theme. As far as I know the basic files I need are the style.css, header.php, index.php, footer.php, functions.php. Then it should show a blank site with some meta tags in the header. These are my files: functions.php <?php // load the language files load_theme_textdomain('brianroyfoundation', get_template_directory() . '/languages'); // add menu support add_theme_support('menus'); register_nav_menus(array('primary_navigation' => __('Primary Navigation', 'BrianRoyFoundation'))); // create widget areas: sidebar $sidebars = array('Sidebar'); foreach ($sidebars as $sidebar) { register_sidebar(array('name'=> $sidebar, 'before_widget' => '<div class="widget %2$s">', 'after_widget' => '</div>', 'before_title' => '<h6><strong>', 'after_title' => '</strong></h6>' )); } // Add Foundation 'active' class for the current menu item function active_nav_class($classes, $item) { if($item->current == 1) { $classes[] = 'active'; } return $classes; } add_filter( 'nav_menu_css_class', 'active_nav_class', 10, 2); ?> header.php <!DOCTYPE html> <html <?php language_attributes(); ?>> <head> <meta charset="<?php bloginfo('charset'); ?>" /> <meta name="description" content="<?php bloginfo('description'); ?>"> <meta name="google-site-verification" content=""> <meta name="author" content="Your Name Here"> <!-- No indexing if Search page is displayed --> <?php if(is_search()){ echo '<meta name="robots" content="noindex, nofollow" />' } ?> <title><?php wp_title('|', true, 'right'); bloginfo('name'); ?></title> <link rel="stylesheet" type="text/css" href="<?php bloginfo('stylesheet_url'); ?>" /> <?php wp_head(); ?> </head> <body> <div id="page"> <div id="page-header"> <div id="page-title"> <a href="<?php bloginfo('url'); ?>" title="<?php bloginfo('name'); ?>"><?php bloginfo('name'); ?></a> </div> <div id="page-navigation"> <?php wp_nav_menu( array( 'theme_location' => 'primary_navigation', 'container' =>false, 'menu_class' => '' ); ?> </div> </div> <div id="page-content"> index.php <?php get_header(); ?> <div class="page-blog"> <?php get_template_part('loop', 'index'); ?> </div> <div class="page-sidebar"> <?php get_sidebar(); ?> </div> <?php get_footer(); ?> footer.php </div> <div id="page-footer"> &copy; 2008 - <?php echo date('Y'); ?> All rights reserved. </div> </div> <?php wp_footer(); ?> </body> </html> I activated the theme in wordpress. But it just shows nothing. Not even if I view the page source. Can anyone help?

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• Cloud Computing Forces Better Design Practices

  - by Herve Roggero

  Is cloud computing simply different than on premise development, or is cloud computing actually forcing you to create better applications than you normally would? In other words, is cloud computing merely imposing different design principles, or forcing better design principles?  A little while back I got into a discussion with a developer in which I was arguing that cloud computing, and specifically Windows Azure in his case, was forcing developers to adopt better design principles. His opinion was that cloud computing was not yielding better systems; just different systems. In this blog, I will argue that cloud computing does force developers to use better design practices, and hence better applications. So the first thing to define, of course, is the word “better”, in the context of application development. Looking at a few definitions online, better means “superior quality”. As it relates to this discussion then, I stipulate that cloud computing can yield higher quality applications in terms of scalability, everything else being equal. Before going further I need to also outline the difference between performance and scalability. Performance and scalability are two related concepts, but they don’t mean the same thing. Scalability is the measure of system performance given various loads. So when developers design for performance, they usually give higher priority to a given load and tend to optimize for the given load. When developers design for scalability, the actual performance at a given load is not as important; the ability to ensure reasonable performance regardless of the load becomes the objective. This can lead to very different design choices. For example, if your objective is to obtains the fastest response time possible for a service you are building, you may choose the implement a TCP connection that never closes until the client chooses to close the connection (in other words, a tightly coupled service from a connectivity standpoint), and on which a connection session is established for faster processing on the next request (like SQL Server or other database systems for example). If you objective is to scale, you may implement a service that answers to requests without keeping session state, so that server resources are released as quickly as possible, like a REST service for example. This alternate design would likely have a slower response time than the TCP service for any given load, but would continue to function at very large loads because of its inherently loosely coupled design. An example of a REST service is the NO-SQL implementation in the Microsoft cloud called Azure Tables. Now, back to cloud computing… Cloud computing is designed to help you scale your applications, specifically when you use Platform as a Service (PaaS) offerings. However it’s not automatic. You can design a tightly-coupled TCP service as discussed above, and as you can imagine, it probably won’t scale even if you place the service in the cloud because it isn’t using a connection pattern that will allow it to scale [note: I am not implying that all TCP systems do not scale; I am just illustrating the scalability concepts with an imaginary TCP service that isn’t designed to scale for the purpose of this discussion]. The other service, using REST, will have a better chance to scale because, by design, it minimizes resource consumption for individual requests and doesn’t tie a client connection to a specific endpoint (which means you can easily deploy this service to hundreds of machines without much trouble, as long as your pockets are deep enough). The TCP and REST services discussed above are both valid designs; the TCP service is faster and the REST service scales better. So is it fair to say that one service is fundamentally better than the other? No; not unless you need to scale. And if you don’t need to scale, then you don’t need the cloud in the first place. However, it is interesting to note that if you do need to scale, then a loosely coupled system becomes a better design because it can almost always scale better than a tightly-coupled system. And because most applications grow overtime, with an increasing user base, new functional requirements, increased data and so forth, most applications eventually do need to scale. So in my humble opinion, I conclude that a loosely coupled system is not just different than a tightly coupled system; it is a better design, because it will stand the test of time. And in my book, if a system stands the test of time better than another, it is of superior quality. Because cloud computing demands loosely coupled systems so that its underlying service architecture can be leveraged, developers ultimately have no choice but to design loosely coupled systems for the cloud. And because loosely coupled systems are better… … the cloud forces better design practices. My 2 cents.

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• Defining scope for Record Count functoid:

  - by ArunManick

  Defining scope for Record Count functoid: Problem: One of the most common scenarios in BizTalk is calculating the record count of repeating structure. BizTalk has come up with an advanced functoid called Record Count functoid which will give the record count for the repeating structure however you cannot define the scope for a Record Count functoid. Because Record Count functoid accepts exactly one parameter which can be repeating record or field element.   If somebody don’t know what “scope” means I will explain with a simple example. Consider that we have a source schema having a structure Country -> State -> City. Country will have various states and each state will have different cities. Now you want to calculate no. of cities present in each state. Here scope is defined at the parent node “State”. Traditional Record Count functoid will give the total no. of cities present in the source message and not the State level city count.   Source Schema:   Destination Schema:   Soultion #1: As the title indicates we are not going to add one more parameter to the record count functoid. Instead of that, we are going to achieve the solution with the help of Scripting functoid with Inline XSLT script. XSLT is basically the transformation language used in the mapping.     “No.OfCities” indicates the destination field name to which we are going to send the value. In count(City), “count” refers to built in XPath function used in XSLT and “City” refers to source schema record name. Here you can find the list of built-in functions available in XSLT.   The mapping will look like as follows:   The 2 Record Count functoids used in this map will give the total number of states and total number of cities as that of input message.   Soultion #2:  If someone doesn’t like XSLT code and they wish to achieve the solution using functoids alone, then here is another solution.   Use logical Existence functoid to check whether “City” exist or not Connect the output of Logical Existence functoid to the Value Mapping functoid with second parameter as constant “1”. Hence if the first parameter is TRUE it will give the output as “1”. Connect the output of Value Mapping functoid to the Cumulative Sum functoid with scope as “1”   This will calculate the City count at the state level. The mapping will look like as follows:     Let us see the sample input and the map output.   Input: <?xml version="1.0" encoding="utf-8"?> <ns0:Country xmlns:ns0="http://RecordCount.Source">   <State>     <StateName>Tamilnadu</StateName>     <City>       <CityName>Pollachi</CityName>     </City>     <City>       <CityName>Coimbatore</CityName>     </City>     <City>       <CityName>Chennai</CityName>     </City>   </State>   <State>     <StateName>Kerala</StateName>     <City>       <CityName>Palakad</CityName>     </City>   </State>   <State>     <StateName>Karnataka</StateName>     <City>       <CityName>Bangalore</CityName>     </City>     <City>       <CityName>Mangalore</CityName>     </City>   </State> </ns0:Country>     Output: <ns0:Country xmlns:ns0="http://RecordCount.Destination">           <No.OfStates>3</No.OfStates>           <No.OfCities>6</No.OfCities>           <States>                    <No.OfCities>3</No.OfCities>           </States>           <States>                    <No.OfCities>1</No.OfCities>           </States>           <States>                    <No.OfCities>2</No.OfCities>           </States> </ns0:Country>   Conclusion: This is my first post and I hope you enjoyed it.   -Arun

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• PHP `virtual()` with Apache MultiViews not working after upgrade to Ubuntu 12.04

  - by Izzy

  I use PHP's virtual() directive quite a lot on one of my sites, including central elements. This worked fine for the last ~10 years -- but after upgrading (or rather moving, as it is on a new machine) to Ubuntu 12.04 it somehow got broken. Example setup (simplified) To make it easier to understand, I simplify some things (contents). So say I need a HTML fragment like <P>For further instructions, please look <A HREF='foobar'>here</P> in multiple pages. 10 years ago, I used SSI for that, so it is put into a file in a central place -- so if e.g. the targeted URL changes, I only need to update it in one place. To serve multiple languages, I have Apache's MultiViews enabled -- and at $DOCUMENT_ROOT/central/ there are the files: foobar.html (English variant, and the default) foobar.html.de (German variant). Now in the PHP code, I simply placed: <? virtual("/central/foobar"); ?> and let Apache take care to deliver the correct language variant. The problem As said, this worked fine for about 10 years: German visitors got the German variant, all others the English (depending on their preferred language). But after upgrading to Ubuntu 12.04, it no longer worked: Either nothing was delivered from the virtual() command, or (in connection with framesets) it even ended up in binary gibberish. Trying to figure out what happens, I played with a lot of things. I first thought MultiViews was (somehow) not available anymore -- but calling http://<server>/central/foobar showed the right variant, depending on the configured language preferences. This also proved there was nothing wrong with file permissions. The error.log gave no clues either (no error message thrown). Finally, just as a "last ressort", I changed the PHP command to <? virtual("central/foobar.html"); ?> -- and that very same file was in fact included. So PHP's virtual() function basically worked -- but the language dependend stuff obviously did no longer work together with it as it did before. Of course I tried to find some change (most likely in PHP's virtual() command), using Google a lot, and also searching the questions here -- unfortunately to no avail. Finally: The question Putting "design questions" aside (surely today I would design things differently -- but at least currently I miss the time to change that for a quite huge amount of pages): What can be done to make it work again? I surely missed something -- but I cannot figure out what...

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• Google analytics and multiple independent subdomains

  - by MTilsted

  I need some help trying to setup google analytics correct. Here is my setup: We host sites for multiple customers, and each customer have their own subdomain on our site. So we have customerA.oursite.com and customerB.oursite.com As we add more customers we get more subdomains. We do want to track all data for each customer independent, but I don't want to to create a new google tracking code for each new customer. So my plan is to track all visits with "oursite.com", and then I will create a filter in google Analytics to get data for each specific customer(All visits for a specific subdomain). Is this(One tracking code, and a subdomain filter) the right way to do it? To create a subdomain filter i add a new profile for each customer, and then add a custom filter saying include "Request URI" and fill in "CustomerDomain.oursite.com". Is this the correct way to do it? And a general question about filters: Is it really impossible to create a new filter by applying it to data in an existing profile? I would really like to just collect all the data in one "main" profile and then create subdomain filters as we need them. But it seems that google only apply filters to new incomming data, not existing data. Is this really true? The following is my tracking code. Is '_setDomainName','none' the right thing to do? <script type="text/javascript"> /* Tracking code for qrtown.com */ var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-11584298-10']); _gaq.push(['_setDomainName', 'none']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script>

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• "LNK2001: unresolved external symbol" when trying to build my program

  - by random

  I get the following error(s) on my program that captures the mouse and then draws a line. Errors: 1>------ Build started: Project: Capture_Mouse_Line, Configuration: Debug Win32 ------ 1> main.cpp 1>main.obj : error LNK2001: unresolved external symbol "public: static long * Line::yc2" (?yc2@Line@@2PAJA) 1>main.obj : error LNK2001: unresolved external symbol "public: static long * Line::xc2" (?xc2@Line@@2PAJA) 1>main.obj : error LNK2001: unresolved external symbol "public: static long * Line::yc1" (?yc1@Line@@2PAJA) 1>main.obj : error LNK2001: unresolved external symbol "public: static long * Line::xc1" (?xc1@Line@@2PAJA) 1>MSVCRTD.lib(crtexe.obj) : error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup 1>D:\Visual C++ Projects\Capture_Mouse_Line\Debug\Capture_Mouse_Line.exe : fatal error LNK1120: 5 unresolved externals ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Here is my code: #include<allegro5\allegro.h> #include<allegro5\allegro_native_dialog.h> #include<allegro5\allegro_primitives.h> #include<Windows.h> #include<allegro5\allegro_windows.h> #ifndef WIDTH #define WIDTH 1440 #endif #ifndef HEIGHT #define HEIGHT 900 #endif class Line { public: static void ErasePreviousLine(); static void DrawLine(long* x, long* y,long* x2,long* y2); static bool Erasable(); static long* xc1; static long* yc1; static long* xc2; static long* yc2; }; void Line::ErasePreviousLine() { delete xc1; xc1 = NULL; delete yc1; yc1 = NULL; delete xc2; xc2 = NULL; delete yc2; yc2 = NULL; } bool Line::Erasable() { if(xc1 && yc1 && xc2 && yc2 == NULL) { return false; } else { return true; } } void Line::DrawLine(long* x,long* y,long* x2,long* y2) { if(!al_init_primitives_addon()) { al_show_native_message_box(NULL,NULL,NULL,"failed to initialize allegro", NULL,NULL); } xc1 = x; yc1 = y; xc2 = x2; yc2 = y2; al_draw_line((float)*xc1, (float)*yc1, (float)*xc2, (float)*yc2,al_map_rgb(255,0,255), 1); delete x; delete y; delete x2; delete y2; } LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam); int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { MSG msg; ALLEGRO_DISPLAY* display = NULL; if(!al_init()) { al_show_native_message_box(NULL,NULL,NULL,"failed to initialize allegro", NULL,NULL); return -1; } display = al_create_display(WIDTH,HEIGHT); if(!display) { al_show_native_message_box(NULL,NULL,NULL,"failed to initialize display", NULL,NULL); return -1; } HWND hwnd = al_get_win_window_handle(display); if(hwnd == NULL) { MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK); return 0; } ShowWindow(hwnd, nCmdShow); UpdateWindow(hwnd); while(GetMessage(&msg, NULL, 0, 0) > 0) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) { static bool bIsCaptured; static POINTS ptsBegin; static POINTS ptsEnd; switch(msg) { case WM_LBUTTONDOWN: SetCapture(hwnd); bIsCaptured = true; ptsBegin = MAKEPOINTS(lParam); return 0; case WM_MOUSEMOVE: if(wParam & MK_LBUTTON) { if(!Line::Erasable()) { return 0; } Line::ErasePreviousLine(); ptsEnd = MAKEPOINTS(lParam); Line::DrawLine(new long(ptsBegin.x),new long(ptsBegin.y),new long(ptsEnd.x),new long(ptsEnd.y)); } break; case WM_LBUTTONUP: bIsCaptured = false; ReleaseCapture(); break; case WM_ACTIVATEAPP: { if(wParam == TRUE) { if(bIsCaptured){ SetCapture(hwnd);} } } break; } return 0; }

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• Alienware m15x (older model) BSOD investigation

  - by Crishu

  A frined of mine asked me to help him with an Alienware m15x laptop that had a little service history. It was bought in june 2008, serviced in january 2009 for a random fps drop problem, Alienware returned it saying nothing was wrong. The laptop still had hiccups, but after juggling a few drivers and settings, the fps drops weren't as noticeable. Eventually it died in Sept. 2009. It would not boot up locking itself on a white/gray screen. (i think it was overheating .. clocking in 100 degrees Celsius). So back to Alienware it went. They replaced the GPU and all was fine. Up until these blue screens started showing up. One other thing that was updated was the HDD and a Windows 7 reinstall, in August. From then on it seems to have started its BSOD. Could this be the culprit? Why? 0_o The original Windows was Vista but it was upgraded with a digital download/purchase of Windows 7 Home Premium and activated after installing windows. No errors on the old HDD, just on the latest installation. LE:Due note that now the old HDD is used to see if issues re-occur. So please, I am in need of someone who can interpret these windows dump files: Minidump I may have come to some conflicting conclusions. So if someone can clarify each dump/date and the probable cause/error it had; and a final conclusion or solution, we would be very grateful. Also please consult report for other system info I omitted: same link,code: XRWIVLWG If I missed something or if you have any other questions I'll be happy to answer them. Thank you. Good day. Processor: Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz Network Adapter Properties: Broadcom NetLink (TM) Gigabit Ethernet Intel(R) Wireless WiFi Link 4965AGN Video Adapter Properties: Driver Description NVIDIA GeForce 8800M GTX Driver Date 19.08.2009 Driver Version 8.16.11.8681 Driver Provider NVIDIA INF File oem19.inf Hardware ID PCI\VEN_10DE&DEV_060C&SUBSYS_0770152D&REV_A2 Location Information @system32\DRIVERS\pci.sys,#65536;PCI bus %1, device %2, function %3;(1,0,0) PCI Device NVIDIA GeForce 8800M GTX [NoDB] BIOS String Version 62.92.34.0.8 Installed Drivers nvd3dum (8.16.11.8681), nvwgf2um, nvwgf2um Hard Dik Drive: Model ID ST9120823ASG (**older one 120gb**) Model ID WD32000BEKT (new 320gb with fresh OS)

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• Why Photoshop CS5's photomerge's result immediately disappear?

  - by koiyu

  I have a bunch of JPG-files which I want to stitch together with Photoshop's Photomerge function. I choose File → Automate → Photomerge... and browse for the files. Photoshop opens the files and starts analyzing. I see the process bar filling and different phases are mentioned on the process bar. Nothing weird there. When the merging is done (and if I don't blink my eyes), I can see layers-palette is populated with the chosen files and, by quickly judging from the layer thumbnails, they're properly aligned. Sometimes the image window itself can be seen, but not always. Problem is that the layers and the image disappear in a flash. There is no error message. Everything is like prior starting the photomerge. No file has been changed. I could continue to use Photoshop normally. This is what I've tried so far: Loaded folder which has 38 JPG images, 4272 x 2848 and ˜ 5 megabytes per file Loaded the same files, but chose Use Files instead of Use Folder in the photomerge's window Loaded 19 JPG images, 4272 x 2848 and ˜ 5 megabytes per file Loaded 10 JPG images, ⇑ see above Loaded 5 JPG images, see above Loaded 3 JPG images, see above Scaled the images to 2256 x 1504 and ˜< 1 megabytes per file Loaded in a set of 38, 19, 10, 5, 3 Following steps are tested with these smaller files and with a set of 5 images Read Adobe's forums and reduced the amount of RAM Photoshop uses gradually from ˜ 80 % to 50 % (though I didn't understand the logic behind this) Would've reduced cache tile size to 128K, but it was set so already Disabled OpenGL Scaled the images to 800 x 533 and ˜ 100 kilobytes per file, loaded a set of 5 Read more unanswered threads around the internet In between each test I closed and reopened Photoshop. This is the first time I've even tried using photomerge. Am I doing something wrong? How can I locate what is the problem? How do I fix this? Photoshop is 64 bit Extended CS5 version. I'm on a mid-2010 quad-core (i5) iMac with up-to-date Mac OS X 10.6.6. Edit: Weird. First loading the images into one file via File → Scripts → Load Files into Stack… and then using Edit → Auto-Align Layers…, which, effectively, is the same as photomerge (even the dialog looks kind of the same), works! Even with the original JPGs without any issues. This doesn't fix photomerge, though.

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• Is it feasible and useful to auto-generate some code of unit tests?

  - by skiwi

  Earlier today I have come up with an idea, based upon a particular real use case, which I would want to have checked for feasability and usefulness. This question will feature a fair chunk of Java code, but can be applied to all languages running inside a VM, and maybe even outside. While there is real code, it uses nothing language-specific, so please read it mostly as pseudo code. The idea Make unit testing less cumbersome by adding in some ways to autogenerate code based on human interaction with the codebase. I understand this goes against the principle of TDD, but I don't think anyone ever proved that doing TDD is better over first creating code and then immediatly therafter the tests. This may even be adapted to be fit into TDD, but that is not my current goal. To show how it is intended to be used, I'll copy one of my classes here, for which I need to make unit tests. public class PutMonsterOnFieldAction implements PlayerAction { private final int handCardIndex; private final int fieldMonsterIndex; public PutMonsterOnFieldAction(final int handCardIndex, final int fieldMonsterIndex) { this.handCardIndex = Arguments.requirePositiveOrZero(handCardIndex, "handCardIndex"); this.fieldMonsterIndex = Arguments.requirePositiveOrZero(fieldMonsterIndex, "fieldCardIndex"); } @Override public boolean isActionAllowed(final Player player) { Objects.requireNonNull(player, "player"); Hand hand = player.getHand(); Field field = player.getField(); if (handCardIndex >= hand.getCapacity()) { return false; } if (fieldMonsterIndex >= field.getMonsterCapacity()) { return false; } if (field.hasMonster(fieldMonsterIndex)) { return false; } if (!(hand.get(handCardIndex) instanceof MonsterCard)) { return false; } return true; } @Override public void performAction(final Player player) { Objects.requireNonNull(player); if (!isActionAllowed(player)) { throw new PlayerActionNotAllowedException(); } Hand hand = player.getHand(); Field field = player.getField(); field.setMonster(fieldMonsterIndex, (MonsterCard)hand.play(handCardIndex)); } } We can observe the need for the following tests: Constructor test with valid input Constructor test with invalid inputs isActionAllowed test with valid input isActionAllowed test with invalid inputs performAction test with valid input performAction test with invalid inputs My idea mainly focuses on the isActionAllowed test with invalid inputs. Writing these tests is not fun, you need to ensure a number of conditions and you check whether it really returns false, this can be extended to performAction, where an exception needs to be thrown in that case. The goal of my idea is to generate those tests, by indicating (through GUI of IDE hopefully) that you want to generate tests based on a specific branch. The implementation by example User clicks on "Generate code for branch if (handCardIndex >= hand.getCapacity())". Now the tool needs to find a case where that holds. (I haven't added the relevant code as that may clutter the post ultimately) To invalidate the branch, the tool needs to find a handCardIndex and hand.getCapacity() such that the condition >= holds. It needs to construct a Player with a Hand that has a capacity of at least 1. It notices that the capacity private int of Hand needs to be at least 1. It searches for ways to set it to 1. Fortunately it finds a constructor that takes the capacity as an argument. It uses 1 for this. Some more work needs to be done to succesfully construct a Player instance, involving the creation of objects that have constraints that can be seen by inspecting the source code. It has found the hand with the least capacity possible and is able to construct it. Now to invalidate the test it will need to set handCardIndex = 1. It constructs the test and asserts it to be false (the returned value of the branch) What does the tool need to work? In order to function properly, it will need the ability to scan through all source code (including JDK code) to figure out all constraints. Optionally this could be done through the javadoc, but that is not always used to indicate all constraints. It could also do some trial and error, but it pretty much stops if you cannot attach source code to compiled classes. Then it needs some basic knowledge of what the primitive types are, including arrays. And it needs to be able to construct some form of "modification trees". The tool knows that it needs to change a certain variable to a different value in order to get the correct testcase. Hence it will need to list all possible ways to change it, without using reflection obviously. What this tool will not replace is the need to create tailored unit tests that tests all kinds of conditions when a certain method actually works. It is purely to be used to test methods when they invalidate constraints. My questions: Is creating such a tool feasible? Would it ever work, or are there some obvious problems? Would such a tool be useful? Is it even useful to automatically generate these testcases at all? Could it be extended to do even more useful things? Does, by chance, such a project already exist and would I be reinventing the wheel? If not proven useful, but still possible to make such thing, I will still consider it for fun. If it's considered useful, then I might make an open source project for it depending on the time. For people searching more background information about the used Player and Hand classes in my example, please refer to this repository. At the time of writing the PutMonsterOnFieldAction has not been uploaded to the repo yet, but this will be done once I'm done with the unit tests.

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