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• Too Clever for My Own Good

  - by AjarnMark

  Yesterday I caught myself being a little too clever for my own good with some ASP.NET code.  It seems that I have forgotten some of my good old classic HTML and JavaScript skills, and become too dependent on the .NET Framework and WebControls to do the work for me.  Here’s the scenario… In order to improve the User Interface and better communicate to the user when something is happening that they need to wait for, we have started to modify some of our larger (slower) pages to display messages like Processing… or Reloading… while they are cycling through a postback.  (Yes, I understand this could be improved by using AJAX / Callbacks and so on, but even then, you need to let your user know that they need to wait for that section to be re-rendered, so for the moment these pages will continue to use good ol’ Postbacks.)  It’s a very simple trick, really.  All I want to do is when some control triggers a postback, first run a little client-side JavaScript to hide the main contents of the page (such as a GridView) and display the appropriate message.  This lets the user know, “Hey, we’re doing something, don’t click another link or scroll and try to take action right now.” The first places I hooked this up were easy.  Most common cause of a postback:  Buttons.  And when you’re writing the markup or declarative code for an ASP:Button control, there is the handy OnClientClick property which is designed for just this purpose…to run client-side JavaScript before the postback occurs.  This is distinguished from the OnClick property which tells the control what Server-side code to run.  Great!  Done!  Easy! But then there are other controls like DropDownLists and CheckBoxes that we use on our pages with the AutoPostback=True setting which cause postbacks.  And these don’t have OnClientClick or OnClientSelectedIndexChanged events.  So I started getting creative, using an ASP:CustomValidator control in conjunction with setting the CausesValidation and ValidationGroup settings on these controls, which basically caused the action on the control to fire the Custom Validator, which was defined with a Client Side validation function which then did the hide content/show message code (and return a meaningless IsValid setting).  This also caused me to define a different ValidationGroup setting for my real data entry validator controls so that I could control them separately and only have them fire when I really wanted validation, and not just my show/hide trick. For a little while I was pretty proud of myself for coming up with this clever approach to get around what I considered to be a serious oversight on the DropDownList and CheckBox controls declarative syntax.  Then, in the midst of my smugness, just as I was about to commit my changes to the source code repository, it dawned on me that there is a much simpler and much more appropriate way to accomplish this.  All that I really needed to do was to put in my server-side code (I used the Page_Init section) a call to MyControl.Attributes.Add(“onClick”, “myJavaScriptFunctionName()”) for the checkboxes, and for the DropDownLists (which become select tags) use “onChange” instead of “onClick”.  This is exactly the type of thing that the Attributes collection is there for…so you can add attributes to be rendered with the control that you would have otherwise stuck right into the HTML markup if you had been doing this by hand in the first place. Ugh!  A few hours wasted on clever tricks that I ended up completely removing, but I did learn a lot more about custom validators and validation groups in the process.  And got a good reminder that all that stuff (HTML, JavaScript, and CSS) I learned back when I wrote classic ASP pages is still valuable today.  Oh, and one more thing…don’t get lulled into too much reliance on the the whiz-bang tool to do it for you.  After all, WebControls are just another layer of abstraction, and sometimes you need to dig down through the layers and get a little closer to the native language.

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• 5.1 surround sound on Acer Aspire 5738ZG with Ubuntu 11.10

  - by kbargais_LV

  I got a problem with sound. I tried everything but no results. :( I got 3 sound ports. my daemon: # This file is part of PulseAudio. # # PulseAudio is free software; you can redistribute it and/or modify # it under the terms of the GNU Lesser General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # PulseAudio is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU Lesser General Public License # along with PulseAudio; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 # USA. ## Configuration file for the PulseAudio daemon. See pulse-daemon.conf(5) for ## more information. Default values are commented out. Use either ; or # for ## commenting. ; daemonize = no ; fail = yes ; allow-module-loading = yes ; allow-exit = yes ; use-pid-file = yes ; system-instance = no ; local-server-type = user ; enable-shm = yes ; shm-size-bytes = 0 # setting this 0 will use the system-default, usually 64 MiB ; lock-memory = no ; cpu-limit = no ; high-priority = yes ; nice-level = -11 ; realtime-scheduling = yes ; realtime-priority = 5 ; exit-idle-time = 20 ; scache-idle-time = 20 ; dl-search-path = (depends on architecture) ; load-default-script-file = yes ; default-script-file = /etc/pulse/default.pa ; log-target = auto ; log-level = notice ; log-meta = no ; log-time = no ; log-backtrace = 0 resample-method = speex-float-1 ; enable-remixing = yes ; enable-lfe-remixing = no flat-volumes = no ; rlimit-fsize = -1 ; rlimit-data = -1 ; rlimit-stack = -1 ; rlimit-core = -1 ; rlimit-as = -1 ; rlimit-rss = -1 ; rlimit-nproc = -1 ; rlimit-nofile = 256 ; rlimit-memlock = -1 ; rlimit-locks = -1 ; rlimit-sigpending = -1 ; rlimit-msgqueue = -1 ; rlimit-nice = 31 ; rlimit-rtprio = 9 ; rlimit-rttime = 1000000 ; default-sample-format = s16le ; default-sample-rate = 44100 ; default-sample-channels = 6 ; default-channel-map = front-left,front-right default-fragments = 8 default-fragment-size-msec = 10 ; enable-deferred-volume = yes ; deferred-volume-safety-margin-usec = 8000 ; deferred-volume-extra-delay-usec = 0

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• Is there an IDE that can simplify the process of creating a game matchmaking website?

  - by Scott

  Yes, I'm an old guy. And I'm well versed in "C" and have written several games which I have been selling on the web for a number of years. And now, I would like to adapt one of my games to be "online". Sounds simple. I'm sure I can use the thousands of lines of "C" code that I've already written. Right? So my initial investigation begins. First, I think I'll need a server program that lives on a dedicated server (or a VPS probably) that talks to a bunch of client applications that live on individual devices around the world. I can certainly handle that! (I think to myself). I'll break up my existing game into two pieces, a client piece that is just the game displays and buttons, and a server piece that does everything else. Piece of cake, right? But that means that the "server piece" must be executed on a remote machine somewhere and run 24/7. Can I do that? [apparently, that question is so basic, so uneducated, and so lame, that nobody has ever posed it before. Because hours of Googling does not yield an answer. Fine. I'll assume I can do that and move on.] I'll need a "game room", which to me means a website where you log in and then go to a lobby of some kind where you can setup your preferences, see if any of your friends are connected, and create or join games. Should be easy, but it's not. No way. Can I do all this with my local website builder? (which happens to be 90 Second Website Builder, a nice product, btw). It turns out, I can not. I can start with that, but must modify each page, so I can interact with my sql database. So I begin making each page a "PHP" page and dynamically modifying the HTML code with PHP code. I'm already starting to get a headache. Because the resulting web pages looked terrible, I began looking at using JQuery. I want to user a JQuery dialog on my website to display a list of friends and allow the user to select one to invite to the game. [google search for "how to populate a JQuery dialog from a sql database" yields nothing but more confusion.] Javascript? Java? HTML? XML? HTML5? PHP? JQuery? Flash? Sockets? Forms? CSS? Learning about each one of these, and how they interact with each other and/or depend on each other is too much for my feeble old brain. Can anyone simplify this process for me? Is there an IDE that will help me do all this without having to go back to college for a few years? Thanks, Scott

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• Computing a normal matrix in conjunction with gluLookAt

  - by Chris Smith

  I have a hand-rolled camera class that converts yaw, pitch, and roll angles into a forward, side, and up vector suitable for calling gluLookAt. Using this camera class I can modify the model-view matrix to move about the 3D world just fine. However, I am having trouble when using this camera class (and associated model-view matrix) when trying to perform directional lighting in my vertex shader. The problem is that the light direction, (0, 1, 0) for example, is relative to where the 'camera is looking' and not the actual world coordinates. (Or is this eye coordinates vs. model coordinates?) I would like the light direction to be unaffected by the camera's viewing direction. For example, when the camera is looking down the Z axis the ground is lit correctly. However, if I point the camera straight at the ground, then it goes dark. This is (I think) because the light direction is parallel with the camera's 'up' vector which is perpendicular with the ground's normal vector. I tried computing the normal matrix without taking the camera's model view into account, but then none of my objects were rotated correctly. Sorry if this sounds vague. I suspect there is a straight forward answer, but I'm not 100% clear on how the normal matrix should be used for transforming vertex normals in my vertex shader. For reference, here is pseudo code for my rendering loop: pMatrix = new Matrix(); pMatrix = makePerspective(...) mvMatrix = new Matrix() camera.apply(mvMatrix); // Calls gluLookAt // Move the object into position. mvMatrix.translatev(position); mvMatrix.rotatef(rotation.x, 1, 0, 0); mvMatrix.rotatef(rotation.y, 0, 1, 0); mvMatrix.rotatef(rotation.z, 0, 0, 1); var nMatrix = new Matrix(); nMatrix.set(mvMatrix.get().getInverse().getTranspose()); // Set vertex shader uniforms. gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, new Float32Array(pMatrix.getFlattened())); gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, new Float32Array(mvMatrix.getFlattened())); gl.uniformMatrix4fv(shaderProgram.nMatrixUniform, false, new Float32Array(nMatrix.getFlattened())); // ... gl.drawElements(gl.TRIANGLES, this.vertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0); And the corresponding vertex shader: // Attributes attribute vec3 aVertexPosition; attribute vec4 aVertexColor; attribute vec3 aVertexNormal; // Uniforms uniform mat4 uMVMatrix; uniform mat4 uNMatrix; uniform mat4 uPMatrix; // Varyings varying vec4 vColor; // Constants const vec3 LIGHT_DIRECTION = vec3(0, 1, 0); // Opposite direction of photons. const vec4 AMBIENT_COLOR = vec4 (0.2, 0.2, 0.2, 1.0); float ComputeLighting() { vec4 transformedNormal = vec4(aVertexNormal.xyz, 1.0); transformedNormal = uNMatrix * transformedNormal; float base = dot(normalize(transformedNormal.xyz), normalize(LIGHT_DIRECTION)); return max(base, 0.0); } void main(void) { gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0); float lightWeight = ComputeLighting(); vColor = vec4(aVertexColor.xyz * lightWeight, 1.0) + AMBIENT_COLOR; } Note that I am using WebGL, so if the anser is use glFixThisProblem(...) any pointers on how to re-implement that on WebGL if missing would be appreciated.

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• Tuning Default WorkManager - Advantages and Disadvantages

  - by Murali Veligeti

  Before discussing on Tuning Default WorkManager, lets have a brief introduction on What is Default WorkManger Before Weblogic Server 9.0 release, we had the concept of Execute Queues. WebLogic Server (before WLS 9.0), processing was performed in multiple execute queues. Different classes of work were executed in different queues, based on priority and ordering requirements, and to avoid deadlocks. In addition to the default execute queue, weblogic.kernel.default, there were pre-configured queues dedicated to internal administrative traffic, such as weblogic.admin.HTTP and weblogic.admin.RMI.Users could control thread usage by altering the number of threads in the default queue, or configure custom execute queues to ensure that particular applications had access to a fixed number of execute threads, regardless of overall system load. From WLS 9.0 release onwards WebLogic Server uses is a single thread pool (single thread pool which is called Default WorkManager), in which all types of work are executed. WebLogic Server prioritizes work based on rules you define, and run-time metrics, including the actual time it takes to execute a request and the rate at which requests are entering and leaving the pool.The common thread pool changes its size automatically to maximize throughput. The queue monitors throughput over time and based on history, determines whether to adjust the thread count. For example, if historical throughput statistics indicate that a higher thread count increased throughput, WebLogic increases the thread count. Similarly, if statistics indicate that fewer threads did not reduce throughput, WebLogic decreases the thread count. This new strategy makes it easier for administrators to allocate processing resources and manage performance, avoiding the effort and complexity involved in configuring, monitoring, and tuning custom executes queues. The Default WorkManager is used to handle thread management and perform self-tuning.This Work Manager is used by an application when no other Work Managers are specified in the application’s deployment descriptors. In many situations, the default Work Manager may be sufficient for most application requirements. WebLogic Server’s thread-handling algorithms assign each application its own fair share by default. Applications are given equal priority for threads and are prevented from monopolizing them. The default work-manager, as its name tells, is the work-manager defined by default.Thus, all applications deployed on WLS will use it. But sometimes, when your application is already in production, it's obvious you can't take your EAR / WAR, update the deployment descriptor(s) and redeploy it.The default work-manager belongs to a thread-pool, as initial thread-pool comes with only five threads, that's not much. If your application has to face a large number of hits, you may want to start with more than that.Well, that's quite easy. You have  two option to do so.1) Modify the config.xmlJust add the following line(s) in your server definition : <server> <name>AdminServer</name> <self-tuning-thread-pool-size-min>100</self-tuning-thread-pool-size-min> <self-tuning-thread-pool-size-max>200</self-tuning-thread-pool-size-max> [...] </server> 2) Adding some JVM parameters Add the following system property in setDomainEnv.sh/setDomainEnv.cmd or startWebLogic.sh/startWebLogic.cmd : -Dweblogic.threadpool.MinPoolSize=100 -Dweblogic.threadpool.MaxPoolSize=100 Reboot WLS and see the option has been taken into account . Disadvantage: So far its fine. But here there is an disadvantage in tuning Default WorkManager. Internally Weblogic Server has many work managers configured for different types of work.  if we run out of threads in the self-tuning pool(because of system property -Dweblogic.threadpool.MaxPoolSize) due to being undersized, then important work that WLS might need to do could be starved.  So, while limiting the self-tuning would limit the default WorkManager and internally it also limits all other internal WorkManagers which WLS uses.So the best alternative is to override the default WorkManager that means creating a WorkManager for the Application and assign the WorkManager for the application instead of tuning the Default WorkManager.

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• Resolve SRs Faster Using RDA - Find the Right Profile

  - by Daniel Mortimer

  Introduction Remote Diagnostic Agent (RDA) is an excellent command-line data collection tool that can aid troubleshooting / problem solving. The tool covers the majority of Oracle's vast product range, and its data collection capability is comprehensive. RDA collects data about the operating system and environment, including environment variable, kernel settings network o/s performance o/s patches and much more the Oracle Products installed, including patches logs and debug metrics configuration and much more In effect, RDA can obtain a snapshot of an Oracle Product and its environment. Oracle Support encourages the use of RDA because it greatly reduces service request resolution time by minimizing the number of requests from Oracle Support for more information. RDA is designed to be as unobtrusive as possible; it does not modify systems in any way. It collects useful data for Oracle Support only and a security filter is provided if required. Find and Use the Right RDA Profile One problem of any tool / utility, which covers a large range of products, is knowing how to target it against only the products you wish to troubleshoot. RDA does not have a GUI. Nor does RDA have an intelligent mechanism for detecting and automatically collecting data only for those Oracle products installed. Instead, you have to tell RDA what to do. There is a mind boggling large number of RDA data collection modules which you can configure RDA to use. It is easier, however, to setup RDA to use a "Profile". A profile consists of a list of data collection modules and predefined settings. As such profiles can be used to diagnose a problem with a particular product or combination of products. How to run RDA with a profile? ( <rda> represents the command you selected to run RDA (for example, rda.pl, rda.cmd, rda.sh, and perl rda.pl).) 1. Use the embedded spreadsheet to find the RDA profile which is appropriate for your problem / chosen Oracle Fusion Middleware products. 2. Use the following command to perform the setup <rda> -S -p <profile_name>  3. Run the data collection <rda> Run the data collection. If you want to perform setup and run in one go, then use a command such as the following: <rda> -vnSCRP -p <profile name> For more information, refer to: Remote Diagnostic Agent (RDA) 4 - Profile Manual Pages [ID 391983.1] Additional Hints / Tips: 1. Be careful! Profile names are case sensitive.2. When profiles are not used, RDA considers all existing modules by default. For example, if you have downloaded RDA for the first time and run the command <rda> -S you will see prompts for every RDA collection module many of which will be of no interest to you. Also, you may, in your haste to work through all the questions, forget to say "Yes" to the collection of data that is pertinent to your particular problem or product. Profiles avoid such tedium and help ensure the right data is collected at the first time of asking.

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• New R Interface to Oracle Data Mining Available for Download

  - by charlie.berger

    The R Interface to Oracle Data Mining ( R-ODM) allows R users to access the power of Oracle Data Mining's in-database functions using the familiar R syntax. R-ODM provides a powerful environment for prototyping data analysis and data mining methodologies. R-ODM is especially useful for: Quick prototyping of vertical or domain-based applications where the Oracle Database supports the application Scripting of "production" data mining methodologies Customizing graphics of ODM data mining results (examples: classification, regression, anomaly detection) The R-ODM interface allows R users to mine data using Oracle Data Mining from the R programming environment. It consists of a set of function wrappers written in source R language that pass data and parameters from the R environment to the Oracle RDBMS enterprise edition as standard user PL/SQL queries via an ODBC interface. The R-ODM interface code is a thin layer of logic and SQL that calls through an ODBC interface. R-ODM does not use or expose any Oracle product code as it is completely an external interface and not part of any Oracle product. R-ODM is similar to the example scripts (e.g., the PL/SQL demo code) that illustrates the use of Oracle Data Mining, for example, how to create Data Mining models, pass arguments, retrieve results etc. R-ODM is packaged as a standard R source package and is distributed freely as part of the R environment's Comprehensive R Archive Network (CRAN). For information about the R environment, R packages and CRAN, see www.r-project.org. R-ODM is particularly intended for data analysts and statisticians familiar with R but not necessarily familiar with the Oracle database environment or PL/SQL. It is a convenient environment to rapidly experiment and prototype Data Mining models and applications. Data Mining models prototyped in the R environment can easily be deployed in their final form in the database environment, just like any other standard Oracle Data Mining model. What is R? R is a system for statistical computation and graphics. It consists of a language plus a run-time environment with graphics, a debugger, access to certain system functions, and the ability to run programs stored in script files. The design of R has been heavily influenced by two existing languages: Becker, Chambers & Wilks' S and Sussman's Scheme. Whereas the resulting language is very similar in appearance to S, the underlying implementation and semantics are derived from Scheme. R was initially written by Ross Ihaka and Robert Gentleman at the Department of Statistics of the University of Auckland in Auckland, New Zealand. Since mid-1997 there has been a core group (the "R Core Team") who can modify the R source code archive. Besides this core group many R users have contributed application code as represented in the near 1,500 publicly-available packages in the CRAN archive (which has shown exponential growth since 2001; R News Volume 8/2, October 2008). Today the R community is a vibrant and growing group of dozens of thousands of users worldwide. It is free software distributed under a GNU-style copyleft, and an official part of the GNU project ("GNU S"). Resources: R website / CRAN R-ODM

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• Silverlight ProgressBar issues with Binding

  - by Chris Skardon

  The ProgressBar pretty much does what it says on the tin, displays progress, in a bar form (well, by default anyhow). It’s pretty simple to use: <ProgressBar Minimum="0" Maximum="100" Value="50"/> Gives you a progress bar with 50% of it filled: Easy! But of course, we’re wanting to use binding to change the value, again, pretty easy, have a ViewModel with a ‘Value’ in it, and bind: <ProgressBar Minimum="0" Maximum="100" Value="{Binding Value}"/> Spiffy, and whilst we’re at it, why not bind the Maximum value as well – after all, we can’t be sure of the size of the progress, and it’s a pain to have to work out the percentage (when the progress bar can do it for us): <ProgressBar Minimum="0" Maximum="MaximumValue" Value="{Binding Value}"/> Right, this will work absolutely fine. Or will it??? On the face of it, it looks good, and testing it shows no issues, until at one point we go from: Maximum = 100; Value = 90; to Maximum=60; Value=50; On the face of it not unreasonable. The problem is more obvious if we look at the states of the properties after each set (initially Maximum is set at 1, Value = 0): Code Maximum Value Value < Maximum Maximum = 100; 100 0 True Value = 90; 100 90 True Maximum = 60; 60 90 False Value = 50; 60 50 True Everything is good until the Value is less than the Maximum, at this point the Progress Bar breaks. That’s right, it no longer updates itself, it will always look 100% full. The simple solution – always ensuring you set Value before Maximum is fine unless you’re using a ProgressBar in a less controlled environment – where for example you’re setting a ‘container’ with both values at the same time. The example I have is in a DataTemplate, I have a DataTemplate for a BusyIndicator, (specifically the BusyContentTemplate). The binding works this way: <BusyIndicator BusyContent="{Binding BusyContent}" BusyContentTemplate="{Binding ProgressTemplate}"/> With the template as the ProgressBar defined above… I was setting my BusyContent like this: BusyContent = content; aaaaaand finally, ‘content’ is a class: public class ContentClass : INotifyPropertyChanged { //Obviously this is properly implemented… public double Maximum { get;set;} public double Value { get;set;} } Soooo… As I was replacing the BusyContent wholesale, the order of the binding being set was outside of my control, so – how to go about it? Basically? Fudge it. Modify the ContentClass to include a method: public void Update(double value, double max) { Value = value; Maximum = max; } and change where the setting is to be: BusyContent.Update(content.Value, content.Maximum); Thereby getting the order correct.. Obvious really. Meh :|

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• Workflow versioning

  - by Nitra

  I believe I have a fundamental misunderstanding when it comes to workflow engines which I would appreciate if you could help me sort out. I'm not sure if my misunderstanding is specific to the workflow engine I'm using, or if it's a general misunderstanding. I happen to use Windows Workflow Foundation (WWF). TLDR-version WWF allows you to implement business processes in long-running workflows (think months or even years). When started, the workflows can't be changed. But what business process can't change at any time? And if a business process changes, wouldn't you want your software to reflect this change for already started 'instances' of the business process? What am I missing? Background In WWF you define a workflow by combining a set of activites. There are different types of activities - some of them are for flow control, such as the IfElseActivity and the WhileActivty while others allows you to perform actual tasks, such as the CodeActivity wich allows you to run .NET code and the InvokeWebServiceActivity which allows you to call web services. The activites are combined to a workflow using a visual designer. You pretty much drag-and-drop activities from a toolbox to a designer area and connect the activites to each other. The workflow and activities have input paramters, output parameters and variables. We have a single workflow which sometimes runs in a matter of a few days, but it may run for 5-6 months. WWF takes care of persisting the workflow state (what activity are we currently executing, what are the variable values and so on). So far I think WWF makes sense. Some people will prefer to implement a software representation of a business process using a visual designer over writing all of it in code. So what's the issue then? What I don't really get is the following: WWF is designed to take care of long-running workflows. But at the same time, WWF has no built-in functionality which allows you to modify the running workflows. So if you model a business process using a workflow and run that for 6 months, you better hope that the business process does not change. Because if it do, you'll have to have multiple versions of the workflow executing at the same time. This seems like a fundamental design mistake to me, but at the same time it seems more likely that I've misunderstood something. For us, this has had some real-world effects: We release new versions every month, but some workflows may run for a year. This means that we have several versions of the workflow running in parallell, in other words several versions of the business logics. This is the same as having many differnt versions of your code running in production in the same system at the same time, which becomes a bit hard to understand for users. (depending on on whether they clicked a 'Start' button 9 or 10 months ago, the software will behave differently) Our workflow refers to different types of entities and since WWF now has persisted and serialized these we can't really refactor the entities since then existing workflows can't be resumed (deserialization will fail We've received some suggestions on how to handle this When we create a new version of the workflow, cancel all running workflows and create new ones. But in our workflows there's a lot of manual work involved and if we start from scratch a lot of people has to re-do their work. Track what has been done in the workflow and when you create a new one skip activites which have already been executed. I feel that this alternative may work for simple workflows, but it becomes hairy to automatically figure out what activities to skip if there's major refactoring done to a workflow. When we create a new version of the workflow, upgrade old versions using the new WWF 4.5 functionality for upgrading workflows. But then we would have to skip using the visual designer and write code to inject activities in the right places in the workflow. According to MSDN, this upgrade functionality is only intended for minor bug fixes and not larger changes. What am I missing?

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• Types of semantic bugs, logic errors [closed]

  - by C-Otto

  I am a PhD student and currently focus on automatically finding instances of new types of bugs in (Java) programs that cannot be found by existing tools like FindBugs. The existing tool currently is used to prove/disprove termination of (Java) programs. I have some ideas (see below), but I could need more input from you (experienced programmers, potential users of my tool). What kind of bugs do you wish to find? What types of bugs exist and might be suitable for my analysis? One strength of the approach I use is detailled information about the heap. So in contrast to FindBugs, I can work with knowledge of the form "variable x and variable y are disjoint on the heap" or "variable z is not cyclic". It is also possible to see if a method might have side effects (and if so, which variables may/may not be affected by it). Example 1: Vacuous call: Graph graphOne = createGraph(); Graph graphTwo = createGraph(); Node source = graphTwo.getRootNode(); for (Node n : graphOne.getNodes()) { if (areConnected(source, n)) { graphTwo.addNode(n); } } Imagine createGraph() creates a fresh graph, so that graphOne and graphTwo are disjoint on the heap. Then, because source is taken from graphTwo instead of graphOne, the call to areConnected always returns false. In this situation I could find out that the call areConnected is useless (because it does not have any side effect and the return value always is false) which helps finding the real bug (taking source from the wrong graph). For this the information that x and y are disjoint (because graphOne and graphTwo are disjoint) is crucial. This bug is related to calling x.equals(y) where x and y are objects of different classes. In this scenario, most implementations of equals() always return false, which most likely is not the intended result. FindBugs already finds this bug (hardcoded to equals(), semantics of implementation is not checked). Example 2: Useless code: someCode(); while (something()) { yetMoreSomething(); } moreCode(); In the case that the loop (so the code in something() and yetMoreSomething()) does not modify anything visible outside the loop, it does not make sense to run this code - the program has the same behaviour as someCode(); moreCode() (i.e., without the loop). To find this out, one needs detailled information about the side effects of the (possibly useless) code. If I can prove that the code does not have any side effect that can be observed afterwards (in the example: in moreCode() or later), then the code indeed is useless. Of course, here Input/Output of any form must be seen as a side effect, so that a System.out.println(...) is not considered useless. Example 3: Ignored return value: Instead of x = foo(); and making use of x, the method is called without storing the result: foo();. If the method does not have any side effect, its invocation is useless and can be dropped. Most likely, the bug here is that the returned value should have been used. Here, too, detailled information about side effects are needed. Can you think of similar types of bugs that might be detected (only) with detailled information about the heap, side effects, semantics of called methods, ...? Did you encounter bugs related to the ones shown below in "real life"? By the way, the tool is AProVE and Java related publications can be found on my homepage. Thanks a lot, Carsten

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• AccelerometerInput XNA GameComponent

  - by Michael B. McLaughlin

  Bad accelerometer controls kill otherwise good games. I decided to try to do something about it. So I create an XNA GameComponent called AccelerometerInput. It’s still a beta project but you are welcome to try it, use it, modify it, etc. I’m releasing under the terms of the Microsoft Public License. Important info: First, it only supports tilt-style controls currently. I have not implemented motion-style controls yet (and make no promises as to when I might find time to do so). Second, I commented it heavily so that you can (hopefully) understand what it is doing. Please read the comments and examine the sample game for a usage overview. There are configurable parameters which I encourage you to make use of (both by modifying the default values where your testing shows it to be appropriate and also by implementing a calibration mechanism in your game that lets the user adjust those configurable values based on his or her own circumstances). Third, even with this code, accelerometer controls are still a fairly advanced topic area; you will likely find nothing but disappointment if you simply plunk this into some project without testing it on a device (or preferably on several devices). Fourth, if you do try this code and find that something doesn’t work as expected on your phone, please let me know as I want to improve it and can only do so with your help. Let me know what phone model it is, what you tried doing, what you expected, and what result you had instead. I may or may not be able to incorporate it into the code, but I can let others know at the very least so that they can make appropriate modifications to their games (I’m hopeful that all phones are reasonably similar in their workings and require, at most, a slight calibration change, but I simply don’t know). Fifth, although I’ll do my best to answer any questions you may have about it, I’m very busy with a number of things currently so it might take a little while. Please look through the code and examine the comments and sample game first before asking any questions. It’s likely that the answer is in there. If not, or if you just aren’t really sure, ask away. Sixth, there are differences between a portrait-mode game and a landscape mode game (specifically in the appropriate default tilt adjustment for toward the user/away from the user calculations). This is documented and the default is set for landscape. If you use this for a portrait game, make the appropriate change (look for the TODO: comment in AccelerometerInput.cs). Seventh, no provision whatsoever is made for disabling screen locking. It is up to you to implement that and to take appropriate measures to detect when the user has been idle for too long and timeout the game. That code is very game-specific. If you have questions about such matters, consult the relevant MSDN documentation and, if you still have questions, visit the App Hub forums and ask there. I answer questions there a lot and so I may even stumble across your question and answer it. But that’s a much better forum than the comments section here for questions of that sort so I would appreciate it if you asked idle detection-related questions there (or on some other suitable site that you may be more familiar and comfortable with). Eighth, this is an XNA GameComponent intended for XNA-based games on WP7. A sufficiently knowledgeable Silverlight developer should have no problem adapting it for use in a Silverlight game or app. I may create a Silverlight version at some point myself. Right now I do not have the time, unfortunately. Ok. Without further ado: http://www.bobtacoindustries.com/developers/utils/AccelerometerInput.zip Have a great St. Patrick’s Day!

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• Information on upgrading Kinect Applications to MS SDK Beta 2.

  - by mbcrump

  Introduction Microsoft recently released the Kinect for Windows SDK Beta 2. It contains many enhancements and fixes that can be found here. The only problem with it is that a lot of current demo applications no longer function properly. Today, I’m going to walk you through a typical scenario of upgrading a Kinect application built with Beta 1 to Beta 2. Note: This tutorial covers WPF, but you can use the same techniques for WinForms. 1) Fix the references Let’s start with a fairly popular Kinect demo called Kinect User Interface Demo. This project uses the beta 1 version of Microsoft.Research.Kinect.dll and version 1.0.0.0 of Coding4Fun’s Kinect library. After you download the source code and extract the zip you will see the following references in Visual Studio 2010: Pay attention to the following references as these are the .dlls that you will have to update: Coding4Fun.Kinect.Wpf Microsoft.Research.Kinect If you click on Coding4Fun.Kinect.Wpf file you will see the following version information (v1.0.0.0): This needs to be upgraded to the Coding4Fun Kinect library built against Beta 2. So head over to http://c4fkinect.codeplex.com/ and hit download and you will have the following files. Go ahead and hit the delete key on your keyboard to remove the Coding4Fun.Kinect.Wpf.dll file from your project. Select “Add Reference” and navigate out to the folder where you extracted the files and select Coding4Fun.Kinect.Wpf.dll. If you click on the Coding4Fun.Kinect.Wpf.dll file and check properties it should be listed at 1.1.0.0: Fix Microsoft.Research.Kinect.dll The official SDK Beta 2 released a new .dll that you will need to reference in your application. Go ahead and select Microsoft.Research.Kinect.dll in your application and hit the Delete key on your keyboard. Go ahead and select Add Reference again and select Microsoft.Research.Kinect.dll from the .NET tab. Double check and make sure the version number is 1.0.0.45 as shown below. References fixed – Runtime needs to be updated. So we have fixed the references in a typical Kinect application that uses Microsoft’s SDK and C4F Kinect libraries. Now, we will need to update the runtime. All Beta 1 Kinect applications will instantiate the Runtime with the following code: Can you see that it is now marked with [Depreciated]? That means we need to update it before Microsoft decides to remove it from future versions of the SDK. We can fix this very easily by replacing this code: readonly Runtime _runtime = new Runtime(); with Microsoft.Research.Kinect.Nui.Runtime _nui; and adding similar code to our Loaded event as shown below public MainWindow() { InitializeComponent(); Loaded += new RoutedEventHandler(MainWindow_Loaded); } void MainWindow_Loaded(object sender, RoutedEventArgs e) { if (Runtime.Kinects.Count == 0) { txtInfo.Text = "Missing Kinect"; } else { _nui = Runtime.Kinects[0]; _nui.Initialize(RuntimeOptions.UseColor); // Video Frame Ready Event can happen now!!! //_nui.VideoFrameReady += new EventHandler<ImageFrameReadyEventArgs>(_nui_VideoFrameReady); _nui.VideoStream.Open(ImageStreamType.Video, 2, ImageResolution.Resolution640x480, ImageType.Color); } } In this sample, I am testing to see if a Kinect is detected and if it is then I initialize the runtime with my first Kinect by using the Runtime.Kinects[0]. You can also specify other Kinect devices here. The rest of the code is standard code that you simply modify however you wish (ie Skeletal, Depth, etc) depending on what type of video feed you want. Conclusion As you can see it really wasn’t that painful to upgrade your project to Beta 2. I would recommend that you go ahead and upgrade to Beta 2 as future versions of the SDK will use these methods.  Thanks for reading. Subscribe to my feed

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• C++ property system interface for game editors (reflection system)

  - by Cristopher Ismael Sosa Abarca

  I have designed an reusable game engine for an project, and their functionality is like this: Is a completely scripted game engine instead of the usual scripting languages as Lua or Python, this uses Runtime-Compiled C++, and an modified version of Cistron (an component-based programming framework).to be compatible with Runtime-Compiled C++ and so on. Using the typical GameObject and Component classes of the Component-based design pattern, is serializable via JSON, BSON or Binary useful for selecting which objects will be loaded the next time. The main problem: We want to use our custom GameObjects and their components properties in our level editor, before used hardcoded functions to access GameObject base class virtual functions from the derived ones, if do you want to modify an property specifically from that class you need inside into the code, this situation happens too with the derived classes of Component class, in little projects there's no problem but for larger projects becomes tedious, lengthy and error-prone. I've researched a lot to find a solution without luck, i tried with the Ogitor's property system (since our engine is Ogre-based) but we find it inappropiate for the component-based design and it's limited only for the Ogre classes and can lead to performance overhead, and we tried some code we find in the Internet we tested it and worked a little but we considered the macro and lambda abuse too horrible take a look (some code omitted): IWE_IMPLEMENT_PROP_BEGIN(CBaseEntity) IWE_PROP_LEVEL_BEGIN("Editor"); IWE_PROP_INT_S("Id", "Internal id", m_nEntID, [](int n) {}, true); IWE_PROP_LEVEL_END(); IWE_PROP_LEVEL_BEGIN("Entity"); IWE_PROP_STRING_S("Mesh", "Mesh used for this entity", m_pModelName, [pInst](const std::string& sModelName) { pInst->m_stackMemUndoType.push(ENT_MEM_MESH); pInst->m_stackMemUndoStr.push(pInst->getModelName()); pInst->setModel(sModelName, false); pInst->saveState(); }, false); IWE_PROP_VECTOR3_S("Position", m_vecPosition, [pInst](float fX, float fY, float fZ) { pInst->m_stackMemUndoType.push(ENT_MEM_POSITION); pInst->m_stackMemUndoVec3.push(pInst->getPosition()); pInst->saveState(); pInst->m_vecPosition.Get()[0] = fX; pInst->m_vecPosition.Get()[1] = fY; pInst->m_vecPosition.Get()[2] = fZ; pInst->setPosition(pInst->m_vecPosition); }, false); IWE_PROP_QUATERNION_S("Orientation (Quat)", m_quatOrientation, [pInst](float fW, float fX, float fY, float fZ) { pInst->m_stackMemUndoType.push(ENT_MEM_ROTATE); pInst->m_stackMemUndoQuat.push(pInst->getOrientation()); pInst->saveState(); pInst->m_quatOrientation.Get()[0] = fW; pInst->m_quatOrientation.Get()[1] = fX; pInst->m_quatOrientation.Get()[2] = fY; pInst->m_quatOrientation.Get()[3] = fZ; pInst->setOrientation(pInst->m_quatOrientation); }, false); IWE_PROP_LEVEL_END(); IWE_IMPLEMENT_PROP_END() We are finding an simplified way to this, without leading confusing the programmers, (will be released to the public) i find ways to achieve this but they are only available for the common scripting as Lua or editors using C#. also too portable, we can write "wrappers" for different GUI toolkits as Qt or GTK, also i'm thinking to using Boost.Wave to get additional macro functionality without creating my own compiler. The properties designed to use in the editor they are removed in the game since the save file contains their data and loads it using an simple 'load' function to reduce unnecessary code bloat may will be useful if some GameObject property wants to be hidden instead. In summary, there's a way to implement an reflection(property) system for a level editor based in properties from derived classes? Also we can use C++11 and Boost (restricted only to Wave and PropertyTree)

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• Design pattern for logging changes in parent/child objects saved to database

  - by andrew

  I’ve got a 2 database tables in parent/child relationship as one-many. I’ve got three classes representing the data in these two tables: Parent Class { Public int ID {get; set;} .. other properties } Child Class { Public int ID {get;set;} Public int ParentID {get; set;} .. other properties } TogetherClass { Public Parent Parent; Public List<Child> ChildList; } Lastly I’ve got a client and server application – I’m in control of both ends so can make changes to both programs as I need to. Client makes a request for ParentID and receives a Together Class for the matching parent, and all of the child records. The client app may make changes to the children – add new children, remove or modify existing ones. Client app then sends the Together Class back to the server app. Server app needs to update the parent and child records in the database. In addition I would like to be able to log the changes – I’m doing this by having 2 separate tables one for Parent, one for child; each containing the same columns as the original plus date time modified, by whom and a list of the changes. I’m unsure as to the best approach to detect the changes in records – new records, records to be deleted, records with no fields changed, records with some fields changed. I figure I need to read the parent & children records and compare those to the ones in the Together Class. Strategy A: If Together class’s child record has an ID of say 0, that indicates a new record; insert. Any deleted child records are no longer in the Together Class; see if any of the comparison child records are not found in the Together class and delete if not found (Compare using ID). Check each child record for changes and if changed log. Strategy B: Make a new Updated TogetherClass UpdatedClass { Public Parent Parent {get; set} Public List<Child> ListNewChild {get;set;} Public List<Child> DeletedChild {get;set;} Public List<Child> ExistingChild {get;set;} // used for no changes and modified rows } And then process as per the list. The reason why I’m asking for ideas is that both of these solutions don’t seem optimal to me and I suspect this problem has been solved already – some kind of design pattern ? I am aware of one potential problem in this general approach – that where Client App A requests a record; App B requests same record; A then saves changes; B then saves changes which may overwrite changes A made. This is a separate locking issue which I’ll raise a separate question for if I’ve got trouble implementing. The actual implementation is c#, SQL Server and WCF between client and server - sharing a library containing the class implementations. Apologies if this is a duplicate post – I tried searching various terms without finding a match though.

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• Handling "related" work within a single agile work item

  - by Tesserex

  I'm on a project team of 4 devs, myself included. We've been having a long discussion on how to handle extra work that comes up in the course of a single work item. This extra work is usually things that are slightly related to the task, but not always necessary to accomplish the goal of the item (that may be an opinion). Examples include but are not limited to: refactoring of the code changed by the work item refactoring code neighboring the code changed by the item re-architecting the larger code area around the ticket. For example if an item has you changing a single function, you realize the entire class now could be redone to better accommodate this change. improving the UI on a form you just modified When this extra work is small we don't mind. The problem is when this extra work causes a substantial extension of the item beyond the original feature point estimation. Sometimes a 5 point item will actually take 13 points of time. In one case we had a 13 point item that in retrospect could have been 80 points or more. There are two options going around in our discussion for how to handle this. We can accept the extra work in the same work item, and write it off as a mis-estimation. Arguments for this have included: We plan for "padding" at the end of the sprint to account for this sort of thing. Always leave the code in better shape than you found it. Don't check in half-assed work. If we leave refactoring for later, it's hard to schedule and may never get done. You are in the best mental "context" to handle this work now, since you're waist deep in the code already. Better to get it out of the way now and be more efficient than to lose that context when you come back later. We draw a line for the current work item, and say that the extra work goes into a separate ticket. Arguments include: Having a separate ticket allows for a new estimation, so we aren't lying to ourselves about how many points things really are, or having to admit that all of our estimations are terrible. The sprint "padding" is meant for unexpected technical challenges that are direct barriers to completing the ticket requirements. It is not intended for side items that are just "nice-to-haves". If you want to schedule refactoring, just put it at the top of the backlog. There is no way for us to properly account for this stuff in an estimation, since it seems somewhat arbitrary when it comes up. A code reviewer might say "those UI controls (which you actually didn't modify in this work item) are a bit confusing, can you fix that too?" which is like an hour, but they might say "Well if this control now inherits from the same base class as the others, why don't you move all of this (hundreds of lines of) code into the base and rewire all this stuff, the cascading changes, etc.?" And that takes a week. It "contaminates the crime scene" by adding unrelated work into the ticket, making our original feature point estimates meaningless. In some cases, the extra work postpones a check-in, causing blocking between devs. Some of us are now saying that we should decide some cut off, like if the additional stuff is less than 2 FP, it goes in the same ticket, if it's more, make it a new ticket. Since we're only a few months into using Agile, what's the opinion of all the more seasoned Agile veterans around here on how to handle this?

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• SQL SERVER – How to Get SQL Server Restart Notification?

  - by Pinal Dave

  Few days back my friend called me to know if there is any tool which can be used to get restart notification about SQL in their environment. I told that SQL Server can do it by itself with some configurations. He was happy and surprised to know that he need not spend any extra money. In SQL Server, we can configure stored procedure(s) to run at start-up of SQL Server. This blog would give steps to achieve how to achieve it. There are many situations where this feature can be used. Below are few. Logging SQL Server startup timings Modify data in some table during startup (i.e. table in tempdb) Sending notification about SQL start. Step 1 – Enable ‘scan for startup procs’ This can be done either using T-SQL or User Interface of Management Studio. EXEC sys.sp_configure N'Show Advanced Options', N'1' GO RECONFIGURE WITH OVERRIDE GO EXEC sys.sp_configure N'scan for startup procs', N'1' GO RECONFIGURE WITH OVERRIDE GO Below is the interface to change the setting. We need to go to “Server” > “Properties” and use “Advanced” tab. “Scan for Startup Procs” is the parameter under “Miscellaneous” section as shown below. We need to make value as “True” and hit OK. Step 2 – Create stored procedure It’s important to note that the procedure is executed after recovery is finished for ALL databases. Here is a sample stored procedure. You can use your own logic in the procedure. CREATE PROCEDURE SQLStartupProc AS BEGIN CREATE TABLE ##ThisTableShouldAlwaysExists (AnyColumn INT) END Step 3 – Set Procedure to run at startup We need to use sp_procoption to mark the procedure to run at startup. Here is the code to let SQL know that this is startup proc. sp_procoption 'SQLStartupProc', 'startup', 'true' This can be used only for procedures in master database. Msg 15398, Level 11, State 1, Procedure sp_procoption, Line 89 Only objects in the master database owned by dbo can have the startup setting changed. We also need to remember that such procedure should not have any input/output parameter. Here is the error which would be raised. Msg 15399, Level 11, State 1, Procedure sp_procoption, Line 107 Could not change startup option because this option is restricted to objects that have no parameters. Verification Here is the query to find which procedures is marked as startup procedures. SELECT name FROM sys.objects WHERE OBJECTPROPERTY(OBJECT_ID, 'ExecIsStartup') = 1 Once this is done, I have restarted SQL instance and here is what we would see in SQL ERRORLOG Launched startup procedure 'SQLStartupProc'. This confirms that stored procedure is executed. You can also notice that this is done after all databases are recovered. Recovery is complete. This is an informational message only. No user action is required. After few days my friend again called me and asked – I want to turn this OFF? Use comments section and post the answer for him.  Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL

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• What is the best practice, point of view of well experienced developers

  - by Damien MIRAS

  My manager pushes me to use his self defined best practices. All of these practices are based on is own assumptions. I disagree with them and I would like to have some feedback of well experienced people about these practices. I would prefer answers from people involved in the maintenance of huge products and people whom have maintained the product for years. Developers with 15+ years of experience are preferred because my manager has that much experience himself. I have 7 years of experience. Here are the practices he wants me to use: never extends classes, use composition and interface instead because extending classes are unmaintainable and difficult to debug. What I think about that Extend when needed, respect "Liskov's Substitution Principle" and you'll never be stuck with a problem, but prefer composition and decoration. I don't know any serious project which has banned inheriting, sometimes it's impossible to not use that, i.e. in a UI framework. Design patterns are just unusable. In PHP, for simple use cases (for example a user needs a web interface to view a database table), his "best practice" is: copy some random php code wich we own, paste and modify it, put html and php code in same file, never use classes in PHP, it doesn't work well for small jobs, and in fact it doesn't work well at all, there is no good tool to work with. Copy & paste PHP code is good practice for maintenance because scripts are independent, if you have a bug somewhere you can fix it without side effects. What I think about that: NEVER EVER COPY code or do it because you have five minutes to deliver something, you will do some refactoring after that. Copy & paste code is a beginners error, if you have errors you'll have the error everywhere any time you have pasted it's a nightmare to maintain. If you repsect the "Open Close Principle" you'll rarely get edge effects, use unit test if you are afraid of that. For small jobs in PHP use at least something you get or write the HTML separately from the PHP code and reuse it any time you need it. Classes in PHP are mature, not as mature as other languages like python or java, but they are usable. There is tools to work with classes in PHP like Zend Studio that work very well. The use of classes or not depends not on the language you use but the programming paradigm you have choosen. I'm a OOP developer, I use PHP5, why do I have to shoot myself in the foot? When you find a simple bug in the code, and you can fix it simply, if you are not working on the code where you have found it, never fix it, even if it takes 5 seconds. He says to me his "best practices" are driven by the fact that he has a lot of experience in maintaining software in production (14 years) and he now knows what works and what doesn't work, what the community says is a fad, and the people advocating such principles as never copy & paste code, are not evolved in maintaining applications. What I think about that: If you find a bug fix it if you can do it quickly inform the people who've touched that code before, check if you have not introduced a new bug, ideally add a unit test for it. I currently work on a web commerce project, which serves 15k unique users per day. The code base has to be maintained and has been maintained this way since 2005. Ideally you include a short description of your position and experience in terms of years effectively maintaining an application which has been in production for real.

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• The Raspberry Pi JavaFX In-Car System (Part 3)

  - by speakjava

  Ras Pi car pt3 Having established communication between a laptop and the ELM327 it's now time to bring in the Raspberry Pi. One of the nice things about the Raspberry Pi is the simplicity of it's power supply.  All we need is 5V at about 700mA, which in a car is as simple as using a USB cigarette lighter adapter (which is handily rated at 1A).  My car has two cigarette lighter sockets (despite being specified with the non-smoking package and therefore no actual cigarette lighter): one in the centre console and one in the rear load area.  This was convenient as my idea is to mount the Raspberry Pi in the back to minimise the disruption to the very clean design of the Audi interior. The first task was to get the Raspberry Pi to communicate using Wi-Fi with the ELM 327.  Initially I tried a cheap Wi-Fi dongle from Amazon, but I could not get this working with my home Wi-Fi network since it just would not handle the WPA security no matter what I did.  I upgraded to a Wi Pi from Farnell and this works very well. The ELM327 uses Ad-Hoc networking, which is point to point communication.  Rather than using a wireless router each connecting device has its own assigned IP address (which needs to be on the same subnet) and uses the same ESSID.  The settings of the ELM327 are fixed to an IP address of 192.168.0.10 and useing the ESSID, "Wifi327".  To configure Raspbian Linux to use these settings we need to modify the /etc/network/interfaces file.  After some searching of the web and a few false starts here's the settings I came up with: auto lo eth0 wlan0 iface lo inet loopback iface eth0 inet static     address 10.0.0.13     gateway 10.0.0.254     netmask 255.255.255.0 iface wlan0 inet static     address 192.168.0.1     netmask 255.255.255.0     wireless-essid Wifi327     wireless-mode ad-ho0 After rebooting, iwconfig wlan0 reported that the Wi-Fi settings were correct.  However, ifconfig showed no assigned IP address.  If I configured the IP address manually using ifconfig wlan0 192.168.0.1 netmask 255.255.255.0 then everything was fine and I was able to happily ping the IP address of the ELM327.  I tried numerous variations on the interfaces file, but nothing I did would get me an IP address on wlan0 when the machine booted.  Eventually I decided that this was a pointless thing to spend more time on and so I put a script in /etc/init.d and registered it with update-rc.d.  All the script does (currently) is execute the ifconfig line and now, having installed the telnet package I am able to telnet to the ELM327 via the Raspberry Pi.  Not nice, but it works. Here's a picture of the Raspberry Pi in the car for testing In the next part we'll look at running the Java code on the Raspberry Pi to collect data from the car systems.

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• Reducing Deadlocks - not a DBA issue ?

  - by steveh99999

   As a DBA, I'm involved on an almost daily basis troubleshooting 'SQL Server' performance issues. Often, this troubleshooting soon veers away from a 'its a SQL Server issue' to instead become a wider application/database design/coding issue.One common perception with SQL Server is that deadlocking is an application design issue - and is fixed by recoding...  I see this reinforced by MCP-type questions/scenarios where the answer to prevent deadlocking is simply to change the order in code in which tables are accessed....Whilst this is correct, I do think this has led to a situation where many 'operational' or 'production support' DBAs, when faced with a deadlock, are happy to throw the issue over to developers without analysing the issue further....A couple of 'war stories' on deadlocks which I think are interesting :- Case One , I had an issue recently on a third-party application that I support on SQL 2008.  This particular third-party application has an unusual support agreement where the customer is allowed to change the index design on the third-party provided database.  However, we are not allowed to alter application code or modify table structure..This third-party application is also known to encounter occasional deadlocks – indeed, I have documentation from the vendor that up to 50 deadlocks per day is not unusual !So, as a DBA I have to support an application which in my opinion has too many deadlocks - but, I cannot influence the design of the tables or stored procedures for the application. This should be the classic - blame the third-party developers scenario, and hope this issue gets addressed in a future application release - ie we could wait years for this to be resolved and implemented in our production environment...But, as DBAs  can change the index layout, is there anything I could do still to reduce the deadlocks in the application ?I initially used SQL traceflag 1222 to write deadlock detection output to the SQL Errorlog – using this I was able to identify one table heavily involved in the deadlocks.When I examined the table definition, I was surprised to see it was a heap – ie no clustered index existed on the table.Using SQL profiler to see locking behaviour and plan for the query involved in the deadlock, I was able to confirm a table scan was being performed.By creating an appropriate clustered index - it was possible to produce a more efficient plan and locking behaviour.So, less locks, held for less time = less possibility of deadlocks. I'm still unhappy about the overall number of deadlocks on this system - but that's something to be discussed further with the vendor.Case Two,  a system which hadn't changed for months suddenly started seeing deadlocks on a regular basis. I love the 'nothing's changed' scenario, as it gives me the opportunity to appear wise and say 'nothings changed on this system, except the data'.. This particular deadlock occurred on a table which had been growing rapidly. By using DBCC SHOW_STATISTICS - the DBA team were able to see that the deadlocks seemed to be occurring shortly after auto-update stats had regenerated the table statistics using it's default sampling behaviour.As a quick fix, we were able to schedule a nightly UPDATE STATISTICS WITH FULLSCAN on the table involved in the deadlock - thus, greatly reducing the potential for stats to be updated via auto_update_stats, consequently reducing the potential for a bad plan to be generated based on an unrepresentative sample of the data. This reduced the possibility of a deadlock occurring.  Not a perfect solution by any means, but quick, easy to implement, and needed no application code changes. This fix gave us some 'breathing space'  to properly fix the code during the next scheduled application release.   The moral of this post - don't dismiss deadlocks as issues that can only be fixed by developers...

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• Efficiently separating Read/Compute/Write steps for concurrent processing of entities in Entity/Component systems

  - by TravisG

  Setup I have an entity-component architecture where Entities can have a set of attributes (which are pure data with no behavior) and there exist systems that run the entity logic which act on that data. Essentially, in somewhat pseudo-code: Entity { id; map<id_type, Attribute> attributes; } System { update(); vector<Entity> entities; } A system that just moves along all entities at a constant rate might be MovementSystem extends System { update() { for each entity in entities position = entity.attributes["position"]; position += vec3(1,1,1); } } Essentially, I'm trying to parallelise update() as efficiently as possible. This can be done by running entire systems in parallel, or by giving each update() of one system a couple of components so different threads can execute the update of the same system, but for a different subset of entities registered with that system. Problem In reality, these systems sometimes require that entities interact(/read/write data from/to) each other, sometimes within the same system (e.g. an AI system that reads state from other entities surrounding the current processed entity), but sometimes between different systems that depend on each other (i.e. a movement system that requires data from a system that processes user input). Now, when trying to parallelize the update phases of entity/component systems, the phases in which data (components/attributes) from Entities are read and used to compute something, and the phase where the modified data is written back to entities need to be separated in order to avoid data races. Otherwise the only way (not taking into account just "critical section"ing everything) to avoid them is to serialize parts of the update process that depend on other parts. This seems ugly. To me it would seem more elegant to be able to (ideally) have all processing running in parallel, where a system may read data from all entities as it wishes, but doesn't write modifications to that data back until some later point. The fact that this is even possible is based on the assumption that modification write-backs are usually very small in complexity, and don't require much performance, whereas computations are very expensive (relatively). So the overhead added by a delayed-write phase might be evened out by more efficient updating of entities (by having threads work more % of the time instead of waiting). A concrete example of this might be a system that updates physics. The system needs to both read and write a lot of data to and from entities. Optimally, there would be a system in place where all available threads update a subset of all entities registered with the physics system. In the case of the physics system this isn't trivially possible because of race conditions. So without a workaround, we would have to find other systems to run in parallel (which don't modify the same data as the physics system), other wise the remaining threads are waiting and wasting time. However, that has disadvantages Practically, the L3 cache is pretty much always better utilized when updating a large system with multiple threads, as opposed to multiple systems at once, which all act on different sets of data. Finding and assembling other systems to run in parallel can be extremely time consuming to design well enough to optimize performance. Sometimes, it might even not be possible at all because a system just depends on data that is touched by all other systems. Solution? In my thinking, a possible solution would be a system where reading/updating and writing of data is separated, so that in one expensive phase, systems only read data and compute what they need to compute, and then in a separate, performance-wise cheap, write phase, attributes of entities that needed to be modified are finally written back to the entities. The Question How might such a system be implemented to achieve optimal performance, as well as making programmer life easier? What are the implementation details of such a system and what might have to be changed in the existing EC-architecture to accommodate this solution?

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• PaaS, DBaaS and the Oracle Database Cloud Service

  - by yaldahhakim

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} As with many widely hyped areas, there is much more variation within the broad spectrum of products referred to as “Cloud” that is immediately apparent. This variation is evident in one of the key misunderstandings about the Oracle Database Cloud Service. People could be forgiven for thinking that the Database Cloud Service was a Database-as-a-Service (DBaaS), but this is actually not true. The Database Cloud Service is a Platform-as-a-Service, which presents a different user and developer interface and has a different set of qualities. A good way to think about the difference between these two varieties of Cloud offerings is that you, the customer, have to deal with things at the level of the offering, but not for anything below it. In practice, this means that you do not have to deal with hardware or system software, including installation and maintenance, for DBaaS. You also do not have much control over configuration of these options. For PaaS, you don’t have to deal with hardware, system software, or database software – and also do not have control over these levels in the stack. So you cannot modify configuration parameters for the database with the Database Cloud Service – your interface is through SQL and PL/SQL, with Application Express, included in the Database Cloud Service, or through JDBC for Java apps running in the Java Cloud Service, or through RESTful Web Services. You will notice what is not mentioned there – SQL*Net. You cannot access your Oracle Database Cloud Service by changing an entry in the TNSNames file and using SQL*Net. So the effort involved in migrating an existing Oracle Database in your data center to the Database Cloud Service may be prohibitive. The good news is that Application Express and the RESTful Web Services wizard in the Database Cloud Service allow you to develop new applications very quickly, and, of course, the provisioning of the entire Database Cloud Service takes only minutes.

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• How change LOD in geometry?

  - by ChaosDev

  Im looking for simple algorithm of LOD, for change geometry vertexes and decrease frame time. Im created octree, but now I want model or terrain vertex modify algorithm,not for increase(looking on tessellation later) but for decrease. I want something like this Questions: Is same algorithm can apply either to model and terrain correctly? Indexes need to be modified ? I must use octree or simple check distance between camera and object for desired effect ? New value of indexcount for DrawIndexed function needed ? Code: //m_LOD == 10 in the beginning //m_RawVerts - array of 3d Vector filled with values from vertex buffer. void DecreaseLOD() { m_LOD--; if(m_LOD<1)m_LOD=1; RebuildGeometry(); } void IncreaseLOD() { m_LOD++; if(m_LOD>10)m_LOD=10; RebuildGeometry(); } void RebuildGeometry() { void* vertexRawData = new byte[m_VertexBufferSize]; void* indexRawData = new DWORD[m_IndexCount]; auto context = mp_D3D->mp_Context; D3D11_MAPPED_SUBRESOURCE data; ZeroMemory(&data,sizeof(D3D11_MAPPED_SUBRESOURCE)); context->Map(mp_VertexBuffer->mp_buffer,0,D3D11_MAP_READ,0,&data); memcpy(vertexRawData,data.pData,m_VertexBufferSize); context->Unmap(mp_VertexBuffer->mp_buffer,0); context->Map(mp_IndexBuffer->mp_buffer,0,D3D11_MAP_READ,0,&data); memcpy(indexRawData,data.pData,m_IndexBufferSize); context->Unmap(mp_IndexBuffer->mp_buffer,0); DWORD* dwI = (DWORD*)indexRawData; int sz = (m_VertexStride/sizeof(float));//size of vertex element //algorithm must be here. std::vector<Vector3d> vertices; int i = 0; for(int j = 0; j < m_VertexCount; j++) { float x1 = (((float*)vertexRawData)[0+i]); float y1 = (((float*)vertexRawData)[1+i]); float z1 = (((float*)vertexRawData)[2+i]); Vector3d lv = Vector3d(x1,y1,z1); //my useless attempts if(j+m_LOD+1<m_RawVerts.size()) { float v1 = VECTORHELPER::Distance(m_RawVerts[dwI[j]],m_RawVerts[dwI[j+m_LOD]]); float v2 = VECTORHELPER::Distance(m_RawVerts[dwI[j]],m_RawVerts[dwI[j+m_LOD+1]]); if(v1>v2) lv = m_RawVerts[dwI[j+1]]; else if(v2<v1) lv = m_RawVerts[dwI[j+2]]; } (((float*)vertexRawData)[0+i]) = lv.x; (((float*)vertexRawData)[1+i]) = lv.y; (((float*)vertexRawData)[2+i]) = lv.z; i+=sz;//pass others vertex format values without change } for(int j = 0; j < m_IndexCount; j++) { //indices ? } //set vertexes to device UpdateVertexes(vertexRawData,mp_VertexBuffer->getSize()); delete[] vertexRawData; delete[] indexRawData; }

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• PowerShell Script To Find Where SharePoint 2007 Features Are Activated

  - by Brian T. Jackett

  Recently I posted a script to find where SharePoint 2010 Features Are Activated.  I built the original version to use SharePoint 2010 PowerShell commandlets as that saved me a number of steps for filtering and gathering features at each level.  If there was ever demand for a 2007 version I could modify the script to handle that by using the object model instead of commandlets.  Just the other week a fellow SharePoint PFE Jason Gallicchio had a customer asking about a version for SharePoint 2007.  With a little bit of work I was able to convert the script to work against SharePoint 2007.   Solution    Below is the converted script that works against a SharePoint 2007 farm.  Note: There appears to be a bug with the 2007 version that does not give accurate results against a SharePoint 2010 farm.  I ran the 2007 version against a 2010 farm and got fewer results than my 2010 version of the script.  Discussing with some fellow PFEs I think the discrepancy may be due to sandboxed features, a new concept in SharePoint 2010.  I have not had enough time to test or confirm.  For the time being only use the 2007 version script against SharePoint 2007 farms and the 2010 version against SharePoint 2010 farms.    Note: This script is not optimized for medium to large farms.  In my testing it took 1-3 minutes to recurse through my demo environment.  This script is provided as-is with no warranty.  Run this in a smaller dev / test environment first. 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 function Get-SPFeatureActivated { # see full script for help info, removed for formatting [CmdletBinding()] param(     [Parameter(position = 1, valueFromPipeline=$true)]     [string]     $Identity )#end param     Begin     {         # load SharePoint assembly to access object model         [void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint")             # declare empty array to hold results. Will add custom member for Url to show where activated at on objects returned from Get-SPFeature.         $results = @()                 $params = @{}     }     Process     {         if([string]::IsNullOrEmpty($Identity) -eq $false)         {             $params = @{Identity = $Identity}         }                 # create hashtable of farm features to lookup definition ids later         $farm = [Microsoft.SharePoint.Administration.SPFarm]::Local                         # check farm features         $results += ($farm.FeatureDefinitions | Where-Object {$_.Scope -eq "Farm"} | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                          % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value ([string]::Empty) -PassThru} |                          Select-Object -Property Scope, DisplayName, Id, Url)                 # check web application features         $contentWebAppServices = $farm.services | ? {$_.typename -like "Windows SharePoint Services Web Application"}                 foreach($webApp in $contentWebAppServices.WebApplications)         {             $results += ($webApp.Features | Select-Object -ExpandProperty Definition | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                          % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value $webApp.GetResponseUri(0).AbsoluteUri -PassThru} |                          Select-Object -Property Scope, DisplayName, Id, Url)                         # check site collection features in current web app             foreach($site in ($webApp.Sites))             {                 $results += ($site.Features | Select-Object -ExpandProperty Definition | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                                  % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value $site.Url -PassThru} |                                  Select-Object -Property Scope, DisplayName, Id, Url)                                 # check site features in current site collection                 foreach($web in ($site.AllWebs))                 {                     $results += ($web.Features | Select-Object -ExpandProperty Definition | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                                      % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value $web.Url -PassThru} |                                      Select-Object -Property Scope, DisplayName, Id, Url)                                                        $web.Dispose()                 }                 $site.Dispose()             }         }     }     End     {         $results     } } #end Get-SPFeatureActivated Get-SPFeatureActivated   Conclusion    I have posted this script to the TechNet Script Repository (click here).  As always I appreciate any feedback on scripts.  If anyone is motivated to run this 2007 version script against a SharePoint 2010 to see if they find any differences in number of features reported versus what they get with the 2010 version script I’d love to hear from you.         -Frog Out

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• Workarounds for supporting MVVM in the Silverlight ContextMenu service

  - by cibrax

  As I discussed in my last post, some of the Silverlight controls does not support MVVM quite well out of the box without specific customizations. The Context Menu is another control that requires customizations for enabling data binding on the menu options. There are a few things that you might want to expose as view model for a menu item, such as the Text, the associated icon or the command that needs to be executed. That view model should look like this, public class MenuItemModel { public string Name { get; set; } public ICommand Command { get; set; } public Image Icon { get; set; } public object CommandParameter { get; set; } } This is how you can modify the built-in control to support data binding on the model above, public class CustomContextMenu : ContextMenu { protected override DependencyObject GetContainerForItemOverride() { CustomMenuItem item = new CustomMenuItem(); Binding commandBinding = new Binding("Command"); item.SetBinding(CustomMenuItem.CommandProperty, commandBinding);   Binding commandParameter = new Binding("CommandParameter"); item.SetBinding(CustomMenuItem.CommandParameterProperty, commandParameter);   return item; } }   public class CustomMenuItem : MenuItem { protected override DependencyObject GetContainerForItemOverride() { CustomMenuItem item = new CustomMenuItem();   Binding commandBinding = new Binding("Command"); item.SetBinding(CustomMenuItem.CommandProperty, commandBinding);   return item; } } The change is very similar to the one I made in the TreeView for manually data binding some of the Menu item properties to the model. Once you applied that change in the control, you can define it in your XAML like this. <toolkit:ContextMenuService.ContextMenu> <e:CustomContextMenu ItemsSource="{Binding MenuItems}"> <e:CustomContextMenu.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal" > <ContentPresenter Margin="0 0 4 0" Content="{Binding Icon}" /> <TextBlock Margin="0" Text="{Binding Name, Mode=OneWay}" FontSize="12"/> </StackPanel> </DataTemplate> </e:CustomContextMenu.ItemTemplate> </e:CustomContextMenu> </toolkit:ContextMenuService.ContextMenu> The property MenuItems associated to the “ItemsSource” in the parent model just returns a list of supported options (menu items) in the context menu. this.menuItems = new MenuItemModel[] { new MenuItemModel { Name = "My Command", Command = new RelayCommand(OnCommandClick), Icon = ImageLoader.GetIcon("command.png") } }; The only problem I found so far with this approach is that the context menu service does not support a HierarchicalDataTemplate in case you want to have an hierarchy in the context menu (MenuItem –> Sub menu items), but I guess we can live without that.

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• XNA 2D Board game - trouble with the cursor

  - by Adorjan

  I just have started making a simple 2D board game using XNA, but I got stuck at the movement of the cursor. This is my problem: I have a 10x10 table on with I should use a cursor to navigate. I simply made that table with the spriteBatch.Draw() function because I couldn't do it on another way. So here is what I did with the cursor: public override void LoadContent() { ... mutato.Position = new Vector2(X, Y); //X=103, Y=107; mutato.Sebesseg = 45; ... mutato.Initialize(content.Load<Texture2D>("cursor"),mutato.Position,mutato.Sebesseg); ... } public override void HandleInput(InputState input) { if (input == null) throw new ArgumentNullException("input"); // Look up inputs for the active player profile. int playerIndex = (int)ControllingPlayer.Value; KeyboardState keyboardState = input.CurrentKeyboardStates[playerIndex]; if (input.IsPauseGame(ControllingPlayer) || gamePadDisconnected) { ScreenManager.AddScreen(new PauseMenuScreen(), ControllingPlayer); } else { // Otherwise move the player position. if (keyboardState.IsKeyDown(Keys.Down)) { Y = (int)mutato.Position.Y + mutato.Move; } if (keyboardState.IsKeyDown(Keys.Up)) { Y = (int)mutato.Position.Y - mutato.Move; } if (keyboardState.IsKeyDown(Keys.Left)) { X = (int)mutato.Position.X - mutato.Move; } if (keyboardState.IsKeyDown(Keys.Right)) { X = (int)mutato.Position.X + mutato.Move; } } } public override void Draw(GameTime gameTime) { mutato.Draw(spriteBatch); } Here's the cursor's (mutato) class: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; namespace Battleship.Components { class Cursor { public Texture2D Cursortexture; public Vector2 Position; public int Move; public void Initialize(Texture2D texture, Vector2 position,int move) { Cursortexture = texture; Position = position; Move = move; } public void Update() { } public void Draw(SpriteBatch spriteBatch) { spriteBatch.Draw(Cursortexture, Position, Color.White); } } } And here is a part of the InputState class where I think I should change something: public bool IsNewKeyPress(Keys key, PlayerIndex? controllingPlayer, out PlayerIndex playerIndex) { if (controllingPlayer.HasValue) { // Read input from the specified player. playerIndex = controllingPlayer.Value; int i = (int)playerIndex; return (CurrentKeyboardStates[i].IsKeyDown(key) && LastKeyboardStates[i].IsKeyUp(key)); } } If I leave the movement operation like this it doesn't have any sense: X = (int)mutato.Position.X - mutato.Move; However if I modify it to this: X = (int)mutato.Position.X--; it moves smoothly. Instead of this I need to move the cursor by fields (45 pixels), but I don't have any idea how to manage it.

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