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• how to keep display tick rate steady when using continuous collision detection?

  - by nas Ns

  (I've just found about this forum). I hope it is ok to repost my question again here. I posted this question at stackoverflow, but it looks like I might get better help here. Here is the question: I've implemented basic particles motion simulation with continuous collision detection. But there is small issue in display. Assume simple case of circles moving inside square. All elastic collisions. no firction. All motion is constant speed. No forces are involved, no gravity. So when a particle is moving, it is always moving at constant speed (in between collisions) What I do now is this: Let the simulation time step be 1 second (for example). This is the time step simulation is advanced before displaying the new state (unless there is a collision sooner than this). At start of each time step, time for the next collision between any particles or a particle with a wall is determined. Call this the TOC time; let’s say TOC was .5 seconds in this case. Since TOC is smaller than the standard time step, then the system is moved by TOC and the new system is displayed so that the new display shows any collisions as just taking place (say 2 circles just touched each other’s, or a circle just touched a wall) Next, the collision(s) are resolved (i.e. speeds updated, changed directions etc..). A new step is started. The same thing happens. Now assume there is no collision detected within the next 1 second (those 2 circles above will not be in collision any more, even though they are still touching, due to their speeds showing they are moving apart now), Hence, simulation time is advanced now by the full one second, the standard time step, and particles are moved on the screen using 1 second simulation time and new display is shown. You see what has just happened: One frame ran for .5 seconds, but the next frame runs for 1 second, may be the 3rd frame is displayed after 2 seconds, may be the 4th frame is displayed after 2.8 seconds (because TOC was .8 seconds then) and so on. What happens is that the motion of a particle on the screen appears to speed up or slow down, even though it is moving at constant speed and was not even involved in a collision. i.e. Looking at one particle on its own, I see it suddenly speeding up or slowing down, becuase another particle had hit a wall. This is because the display tick is not uniform. i.e. the frame rate update is changing, giving the false illusion that a particle is moving at non-constant speed while in fact it is moving at constant speed. The motion on the screen is not smooth, since the screen is not updating at constant rate. I am not able to figure how to fix this. If I want to show 2 particles at the moment of the collision, I must draw the screen at different times. Drawing the screen always at the same tick interval, results in seeing 2 particles before the collision, and then after the collision, and not just when they colliding, which looked bad when I tried it. So, how do real games handle this issue? How to display things in order to show collisions when it happen, yet keep the display tick constant? These 2 requirements seem to contradict each other’s.

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• Dynamically load and call delegates based on source data

  - by makerofthings7

  Assume I have a stream of records that need to have some computation. Records will have a combination of these functions run Sum, Aggregate, Sum over the last 90 seconds, or ignore. A data record looks like this: Date;Data;ID Question Assuming that ID is an int of some kind, and that int corresponds to a matrix of some delegates to run, how should I use C# to dynamically build that launch map? I'm sure this idea exists... it is used in Windows Forms which has many delegates/events, most of which will never actually be invoked in a real application. The sample below includes a few delegates I want to run (sum, count, and print) but I don't know how to make the quantity of delegates fire based on the source data. (say print the evens, and sum the odds in this sample) using System; using System.Threading; using System.Collections.Generic; internal static class TestThreadpool { delegate int TestDelegate(int parameter); private static void Main() { try { // this approach works is void is returned. //ThreadPool.QueueUserWorkItem(new WaitCallback(PrintOut), "Hello"); int c = 0; int w = 0; ThreadPool.GetMaxThreads(out w, out c); bool rrr =ThreadPool.SetMinThreads(w, c); Console.WriteLine(rrr); // perhaps the above needs time to set up6 Thread.Sleep(1000); DateTime ttt = DateTime.UtcNow; TestDelegate d = new TestDelegate(PrintOut); List<IAsyncResult> arDict = new List<IAsyncResult>(); int count = 1000000; for (int i = 0; i < count; i++) { IAsyncResult ar = d.BeginInvoke(i, new AsyncCallback(Callback), d); arDict.Add(ar); } for (int i = 0; i < count; i++) { int result = d.EndInvoke(arDict[i]); } // Give the callback time to execute - otherwise the app // may terminate before it is called //Thread.Sleep(1000); var res = DateTime.UtcNow - ttt; Console.WriteLine("Main program done----- Total time --> " + res.TotalMilliseconds); } catch (Exception e) { Console.WriteLine(e); } Console.ReadKey(true); } static int PrintOut(int parameter) { // Console.WriteLine(Thread.CurrentThread.ManagedThreadId + " Delegate PRINTOUT waited and printed this:"+parameter); var tmp = parameter * parameter; return tmp; } static int Sum(int parameter) { Thread.Sleep(5000); // Pretend to do some math... maybe save a summary to disk on a separate thread return parameter; } static int Count(int parameter) { Thread.Sleep(5000); // Pretend to do some math... maybe save a summary to disk on a separate thread return parameter; } static void Callback(IAsyncResult ar) { TestDelegate d = (TestDelegate)ar.AsyncState; //Console.WriteLine("Callback is delayed and returned") ;//d.EndInvoke(ar)); } }

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• MVC Communication Pattern

  - by Kedu

  This is kind of a follow up question to this http://stackoverflow.com/questions/23743285/model-view-controller-and-callbacks, but I wanted to post it separately, because its kind of a different topic. I'm working on a multiplayer cardgame for the Android platform. I split the project into MVC which fits the needs pretty good, but I'm currently stuck because I can't figure out a good way to communicate between the different parts. I have everything setup and working with the controller being a big state machine, which is called over and over from the gameloop, and calls getter methods from the GUI and the android/network part to get the input. The input itself in the GUI and network is set by inputlisteners that set a local variable which I read in the getter method. So far so good, this is working. But my problem is, the controller has to check every input separately,so if I want to add an input I have to check in which states its valid and call the getter method from all these states. This is not good, and lets the code look pretty ugly, makes additions uncomfortable and adds redundance. So what I've got from the question I mentioned above is that some kind of command or event pattern will fit my needs. What I want to do is to create a shared and threadsafe queue in the controller and instead of calling all these getter methods, I just check the queue for new input and proceed it. On the other side, the GUI and network don't have all these getters, but instead create an event or command and send it to the controller through, for example, observer/observable. Now my problem: I can't figure out a way, for these commands/events to fit a common interface (which the queue can store) and still transport different kind of data (button clicks, cards that are played, the player id the command comes from, synchronization data etc.). If I design the communication as command pattern, I have to stick all the information that is needed to execute the command into it when its created, that's impossible because the GUI or network has no knowledge of all the things the controller needs to execute stuff that needs to be done when for example a card is played. I thought about getting this stuff into the command when executing it. But over all the different commands I have, I would need all the information the controller has, and thus give the command a reference to the controller which would make everything in it public, which is real bad design I guess. So, I could try some kind of event pattern. I have to transport data in the event. So, like the command, I would have an interface, which all events have in common, and can be stored in the shared queue. I could create a big enum with all the different events that a are possible, save one of these enums in the actual event, and build a big switch case for the events, to proceed different stuff for different events. The problem here: I have different data for all the events. But I need a common interface, to store the events in a queue. How do I get the specific data, if I can only access the event through the interface? Even if that wouldn't be a problem, I'm creating another big switch case, which looks ugly, and when i want to add a new event, I have to create the event itself, the case, the enum, and the method that's called with the data. I could of course check the event with the enum and cast it to its type, so I can call event type specific methods that give me the data I need, but that looks like bad design too.

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• What Counts For a DBA – Depth

  - by Louis Davidson

  SQL Server offers very simple interfaces to many of its features. Most people could open up SSMS, connect to a server, write a simple query and see the results. Even several of the core DBA tasks are deceptively straightforward. It doesn’t take a rocket scientist to perform a basic database backup or run a trace (even using the newfangled Extended Events!). However, appearances can be deceptive, and often times it is really important that a DBA understands not just the basics of how to perform a task, but why we do a task, and how that task works. As an analogy, consider a child walking into a darkened room. Most would know that they need to turn on the light, and how to do it, so they flick the switch. But what happens if light fails to shine forth. Most would immediately tell you that you need to consider changing the light bulb. So you hop in the car and take them to the local home store and instruct them to buy a replacement. Confronted with a 40 foot display of light bulbs, how will they decide which of the hundreds of types of bulbs, of different types, fittings, shapes, colors, power and efficiency ratings, is the right choice? Obviously the main lesson the child is going to learn this day is how to use their cell phone as a flashlight so they don’t have to ask for help the next time. Likewise, when the metaphorical toddlers who use your database server have issues, they will instinctively know something is wrong, and may even have some idea what caused it, but will have no depth of knowledge to figure out the right solution. That is where the DBA comes in and attempts to save the day. However, when one looks beneath the shiny UI, SQL Server has its own “40 foot display of light bulbs”, in the form of the tremendous number of tools and the often-bewildering amount of information they can present to the DBA, to help us find issues. Unfortunately, resorting to guesswork, to trying different “bulbs” over and over, hoping to stumble on the answer. This is where the right depth of knowledge goes a long way. If we need to write a SELECT statement, then knowing the syntax and where to find the data is not enough. Knowledge of indexes and query plans is essential. Without it, we might hit on a query that “works”, but we are basically still a user, not a programmer, because we have no real control over our platform. Is that level of knowledge deep enough? Probably not, since knowledge of the underlying metadata and structures would be very useful in helping us make sense of any query plan. Understanding the structure of an index makes the “key lookup” operator not sound like what you do when someone tapes your car key to the ceiling. So is even this level of understanding deep enough? Do we need to understand the memory architecture used to process the query? It might be a comforting level of knowledge, and will doubtless come in handy at some point, but is not strictly necessary in most cases. Beyond that lies (more or less) full knowledge of SQL language and the intricacies of every step the SQL Server engine takes to process our query. My personal theory is that, as a professional, our knowledge of a given task should extend, at a minimum, one level deeper than is strictly necessary to perform the task. Anything deeper can be left to the ridiculously smart, or obsessive, or both. As an example. tasked with storing an integer value between 0 and 99999999, it’s essential that I know that choosing an Integer over Decimal(8,0) will likely offer performance benefits. It is then useful that I also understand the value of adding a CHECK constraint, to make sure the values are valid to the desired range; and comforting that I know a little about the underlying processors, registers and computer math. Anything further, I leave to the likes of Joe Chang, whose recent blog post on the topic offers depth by the bucketful!  

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• Dual monitor not working completely in 12.10 after upgrade

  - by Mark Baldridge

  At 12.04, dual monitors worked perfectly. After upgrading to 12.10, the primary monitor works, the second monitor only partly works. I am sure there is some difference between the releases that I have missed setting properly. System settings - Displays show both correctly as Acer 22" monitors at 1680x1050 (16:10). An icon on monitor 2 is present, but elongated; almost an artifact, since other icons on the primary screen are absent, but this one icon is there on th second monitor. Selecting the icons on both screens exist. Painting is weird on monitor 2. Launcher exists and works on both screens, but even with sticky edges off, the cursor stops at the left edge of monitor 2. Clicking on text editor on screen 2 launcer will launch gedit there. If I drag it, it leaves a trail of after images like repaint is failing. If I drive the cursor on the launcher, the help tags like "LibreOffice Writer" appear, but stay on screen unless I drag the active gedit window over them. Then part of the help bubbles are overwritten, leaving behind after images of the gedit window on screen. What is really fascinating is that the System settings - Displays is now ignoring monitor selection, after allowing it earlier. Just before this, the help popup which said "Select a monitor to change its properties; drag to rearrange its placement" actually let me do that. Maybe a trick of where I grab the edge of the monitor in the Displays setting. I just found a working handle. When I drag monitor 1 to the right of monitor 2, "Apply" and confirm, both monitors work normally (although the right monitor lets the cursor slide off the right edge onto the left edge of monitor 1 - which sounds correct). Painting of windows does not leave an after image. However, success is only temporary. The setting survives the reboot, but painting on the left monitor, now monitor 2, now replicates the issues from before. The after image of the gedit window and the small window for "Are you sure you want to close all programs and restart the computer?" are still on monitor 2 (on the left now), even though they are not real windows, nor do they have processes behind them. Curiously, in Displays, the "green" monitor on the left in the display window is matched by the right monitor color in the monitor upper left corner. Probably makes sense as the one on the right is now monitor 1. If I repeat the "drag the left monitor to the right of the right monitor on the "Displays" window, things are oriented properly, with no display artifacts as I drag windows around either screen. Also the description bubbles that pop up are overwritten on both screens, so none of those artifacts either. This goodness does not survive a reboot, however. Have not tried logging out and back in. All of this after positing that the motherboard VGA and HDMI ports could have been the issue. So, I installed an e-GeForce 7600 GT Dual DVI (I know the web thinks it is not DVI, but VGA, but the connectors are DVI). No change to the weird behavior. The good parts continue to work, the weirdness also works, and swapping monitor positions seems to cure the issue. So, is there a setting I have missed? Given "swapping" monitor 1 and 2 on the System Settings... - Displays makes it work, just not across boot, I suspect so.

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• How much am I worth hourly as a software/web developer? [closed]

  - by luckysmack

  I may be starting a new job very soon as a developer for both web and desktop software. The primary languages I will be using is ASP.NET with C# with some php for existing projects(I've already had one interview which went very well). The job deals primarily in advertising. But this is my first real job in the market, I have no degrees, but have some college time(~1yr). So I am primarily self taught. They are fully aware of my skill set and lack of degrees or certificates. I applied as an entry level developer. It will be a permanent and full time/hourly position, and not a per contract job. So since it my cherry job, im not really sure what to ask for. even though im self taught im pretty confident in my skills and know what im doing fairly well. I pick up on new concepts very well and find new things fairly easy to learn. Here is a very brief summary of my skills: PHP: ~2years C#/.NET: 2 months Python: Basics only. ~1 month OOP Familiarity: Great (1 year) MVC Familiarity: Great (1 year) PHP Frameworks used: CakePHP(6 months), Yii(3 months), Lithium(3 months) CMS Familiar with: Drupal(1.5 years), Wordpress(only basics) I also have ~2yrs experience in maintaining my own VPS server and the hassles all that entails (linux/debian) Pretty much all the above will be used at this job. Although I will be using C# a vast majority of the time. I only recently started learning it but am moving along fairly rapidly and its all going smooth as butter. So what have I built? I have one proprietary site built in drupal which is used an an order log for products, inventory, and their shipments. It is also able to process payments through paypal merchant services. I have worked on a handful of other small apps used here and there I'm not able to show but which worked fairly well (all in php using frameworks though). The business does fairly well and is far from a a typical corporate type environment. It is much closer to a small development studio. And it is based out of northern California. I don't know how/what more info I can give on them. I also want this to be able to be referenced by other people possibly so I am looking for general tips and ideas to get an answer as well. I had trouble finding a reasonable range on other websites which seemed to be either way to low, or showed what a veteran developer makes. I know this is a fairly subjective question, but it is difficult to get a reasonable answer or guesstimate anywhere else. Even if only a little bit help, its much appreciated. So as for the direct question, based on all this info (did I miss anything?), how much should I ask for hourly? How much am I worth as a software developer?

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• iOS 5 New Features vs Android

  - by kerry

  Browsing through the iOS 5 features list, I can’t help but notice a lot of it is catch up. Having owned both an iPhone and an Android for a considerable amount of time, I figured I would jot down my opinions. Notification Center – Completely ripped off from Android but looks good and is a much needed addition iMessage – This is very interesting as most people who would think it’s cool, probably really wouldn’t understand the significance.  Basically, Apple is adding an IM application to iOS.  Now iPhone / iPad users can sit around messaging each other how cool it is like Crackberry users circa 2003.  I guess the only real improvement over MMS is that you can easily setup groups, see when each other are typing, and don’t incur text messaging charges; at the expense of leaving your non-iOS buddies out (who wants to talk to those losers anyways?). Newstand – An app update and not an OS one (Apple typically doesn’t make distinctions).  It all seems like stuff my current Nook stuff will do.  Note: I did look to compare prices but it seems that information is not available without downloading iTunes.  lame. Reminders – TODO lists are ho hum, but the ability to have reminders when you arrive or leave a position is pretty cool. Twitter integration – The fact that the best Apple can come up with is ‘one at a timing’ online service integration is laughable at best. Camera – Can control it from the lock screen.  Now you’ll have tons of pocket lint photos in your iCloud to go along with the wicked shot of that cheetah that just unexpectedly ran by your apartment. Photos – Speaking of iCloud, all of your devices photos will be synced through it.  That’s cool I guess, not sure if Android will do the same. Safari – What?  You haven’t been reading rss feeds on your device this whole time?  Something tells me you aren’t about to start. PC Free – Finely Apple untethers the iPhone.  What took them so long? Game Center – This should be an interesting service.  Attention Apple fanboys immediately forget how they are blatantly copying Microsoft achievements (at least rename them). Wifi Sync – Just couldn’t cut the cord completely could they?  For what it’s worth, the Zune has been doing this for 5 years now. All in all a pretty big update.  Mostly iCloud.  Mostly keeping up the mobile status quo.  As an Android user, I can’t say there is anything I am envious of.

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• Oracle Executive Strategy Brief: Enterprise-Grade Cloud Applications

  - by B Shashikumar

  Cloud Computing has clearly evolved into one of the dominant secular trends in the industry. Organizations are looking to the cloud to change how they buy and consume IT. And its no longer about just lower up-front costs. The cloud promises to deliver greater agility and free up resources to focus on innovation versus running and maintaining systems. But are organizations actually realizing these benefits? The full promise of cloud is not being realized by customers who entrust their business to multiple niche cloud providers. While almost 9 out of 10 companies  expect more IT agility with cloud, only 47% are actually getting it (Source: 2011 State of Cloud Survey by Symantec). These niche cloud customers have also seen the promises of lower costs, efficiency gains, improved security, and compliance go unfulfilled. Having one cloud provider for customer relationship management (CRM) and another for human capital management (HCM), and then trying to glue these proprietary systems together while integrating to a back-office financial system can add to complexity and long-term costs. Completing a business process or generating an integrated report is cumbersome, and leverages incomplete data. Why can’t niche cloud providers deliver on the full promise of cloud? It’s simple: you still need to complete business processes. You still need reporting that enables you to take action using data from multiple systems. You still have to comply with SOX and other industry regulations. These requirements don’t go away just because you deploy in the cloud. Delivering lower up-front costs by enabling customers to buy software as a service (SaaS) is the easy part. To get real value that lasts longer than your quarterly report, it’s important to realize the benefits of cloud without compromising on functionality and while having the right level of control and flexibility. This is the true promise of cloud. Oracle’s cloud strategy centers around delivering the benefits of cloud—without compromise. We uniquely empower our customers with complete solutions and choice. From the richest functionality to integrated reporting and great user experience. It’s all available in the cloud. And it works not just with other Oracle cloud applications, but with your existing Oracle and third-party systems as well. This helps protect your current investments and extend their value as you journey to the cloud. We’ve made the necessary investments not only in our applications but also in the underlying technology that makes it all run—from the platform down to the hardware and operating system. We make it all. And we’ve engineered it to work together and be highly optimized for our customers, in the cloud. With Oracle enterprise-grade cloud applications, you get the benefits of cloud plus more power, more choice, and more confidence. Read more about how you can realize the true advantage of Cloud with Oracle Enterprise-grade Cloud applications in the Oracle Executive Strategy Brief here.  You can also attend an Oracle Cloud Conference event at a city near you. Register here. 

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• Consolidation in a Database Cloud

  - by B R Clouse

  Consolidation of multiple databases onto a shared infrastructure is the next step after Standardization.  The potential consolidation density is a function of the extent to which the infrastructure is shared.  The three models provide increasing degrees of sharing: Server: each database is deployed in a dedicated VM. Hardware is shared, but most of the software infrastructure is not. Standardization is often applied incompletely since operating environments can be moved as-is onto the shared platform. The potential for VM sprawl is an additional downside. Database: multiple database instances are deployed on a shared software / hardware infrastructure. This model is very efficient and easily implemented with the features in the Oracle Database and supporting products. Many customers have moved to this model and achieved significant, measurable benefits. Schema: multiple schemas are deployed within a single database instance. The most efficient model, it places constraints on the environment. Usually this model will be implemented only by customers deploying their own applications.  (Note that a single deployment can combine Database and Schema consolidations.) Customer value: lower costs, better system utilization In this phase of the maturity model, under-utilized hardware can be used to host more workloads, or retired and those workloads migrated to consolidation platforms. Customers benefit from higher utilization of the hardware resources, resulting in reduced data center floor space, and lower power and cooling costs. And, the OpEx savings from Standardization are multiplied, since there are fewer physical components (both hardware and software) to manage. Customer value: higher productivity The OpEx benefits from Standardization are compounded since not only are there fewer types of things to manage, now there are fewer entities to manage. In this phase, customers discover that their IT staff has time to move away from "day-to-day" tasks and start investing in higher value activities. Database users benefit from consolidating onto shared infrastructures by relieving themselves of the requirement to maintain their own dedicated servers. Also, if the shared infrastructure offers capabilities such as High Availability / Disaster Recovery, which are often beyond the budget and skillset of a standalone database environment, then moving to the consolidation platform can provide access to those capabilities, resulting in less downtime. Capabilities / Characteristics In this phase, customers will typically deploy fixed-size clusters and consolidate on a cluster until that cluster is deemed "full," at which point a new cluster is built. Customers will define one or a few cluster architectures that are used wherever possible; occasionally there may be deployments which must be handled as exceptions. The "full" policy may be based on number of databases deployed on the cluster, or observed peak workload, etc. IT will own the provisioning of new databases on a cluster, making the decision of when and where to place new workloads. Resources may be managed dynamically, e.g., as a priority workload increases, it may be given more CPU and memory to handle the spike. Users will be charged at a fixed, relatively coarse level; or in some cases, no charging will be applied. Activities / Tasks Oracle offers several tools to plan a successful consolidation. Real Application Testing (RAT) has a feature to help plan and validate database consolidations. Enterprise Manager 12c's Cloud Management Pack for Database includes a planning module. Looking ahead, customers should start planning for the Services phase by defining the Service Catalog that will be made available for database services.

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• Ask the Readers: How Many Monitors Do You Use with Your Computer?

  - by Asian Angel

  Most people have a single monitor for their computers, many have two, and some individuals enjoy “3 monitor plus” goodness. This week we would like to know how many monitors you use with your computer. Photo by DamnedNice. A good majority of people have a single monitor that they use with their computers and that single monitor serves their needs very well. It could be that these individuals do not engage in a heavy amount of work or play on their computers…they just need to do the basics like checking e-mail, using I.M., working with photos, etc. Another possibility is the use of virtual desktop software such as Dexpot, Yodm 3D, or Sysinternals Desktops on Windows systems. Linux systems such as Ubuntu already have that wonderful multi-desktop functionality built in. The wonderful part about virtual desktops is that a single monitor can feel equivalent to a small army of monitors. The ability to separate your open windows into “categories” and spread them out across multiple desktops is definitely nice. With each passing year dual monitor setups are becoming more common. Having twice the screen real-estate visible at the same time can be extremely convenient when you are multi-tasking. Perhaps you like to monitor your system’s stats and an e-mail account on the second monitor while working with software on the first. It certainly beats having windows popping up and down on your screen constantly while keeping on top of everything! Next we have the people who have three or more monitors in use with their computers. This may be a result of the type of work they do, an experiment to see if multiple monitors are right for them, or the cool, geeky factor that comes with having all those monitors. Needless to say these individuals can induce a good amount of envy and/or inspiration in the rest of us when we see their awesome setups. Are you perfectly content with a single monitor? Do you have two or more monitors that you use? If you have two or more monitors are they actually that useful to you? Perhaps you are getting ready even now to add additional monitors to your system. Whatever your situation may be at the moment, let us know your thoughts (and possible multi-monitor plans) in the comments! How-To Geek Polls require Javascript. Please Click Here to View the Poll. Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? Hidden Tracks Your Stolen Mac; Free Until End of January Why the Other Checkout Line Always Moves Faster World of Warcraft Theme for Windows 7 Ubuntu Font Family Now Available for Download Oh No! WikiLeaks Published Santa Claus’s Naughty List [Video] Remember the Milk Now Supports HTTPS Encryption for the Entire Session

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• Confused about modifying the sprint backlog during a sprint

  - by Maltiriel

  I've been reading a lot about scrum lately, and I've found what seem to me to be conflicting information about whether or not it's ok to change the sprint backlog during a sprint. The Wikipedia article on scrum says it's not ok, and various other articles say this as well. Also my Software Development professor taught the same thing during an overview of scrum. However, I read Scrum and XP from the Trenches and that describes a section for unplanned items on the taskboard. So then I looked up the Scrum Guide and it says that during the sprint "No changes are made that would affect the Sprint Goal" and in the discussion of the Sprint Goal "If the work turns out to be different than the Development Team expected, then they collaborate with the Product Owner to negotiate the scope of Sprint Backlog within the Sprint." It goes on to say in the discussion of the Sprint Backlog: The Sprint Backlog is a plan with enough detail that changes in progress can be understood in the Daily Scrum. The Development Team modifies Sprint Backlog throughout the Sprint, and the Sprint Backlog emerges during the Sprint. This emergence occurs as the Development Team works through the plan and learns more about the work needed to achieve the Sprint Goal. As new work is required, the Development Team adds it to the Sprint Backlog. As work is performed or completed, the estimated remaining work is updated. When elements of the plan are deemed unnecessary, they are removed. Only the Development Team can change its Sprint Backlog during a Sprint. The Sprint Backlog is a highly visible, real-time picture of the work that the Development Team plans to accomplish during the Sprint, and it belongs solely to the Development Team. So at this point I'm altogether confused. Thinking about it, it makes more sense to me to take the second approach. The individual, specific items in the backlog don't seem to me to be the most important thing, but rather the sprint goal, so not changing the sprint goal but being able to change the backlog makes sense. For instance if both the product owner and the team thought they were on the same page about a story, but as the sprint progressed they figured out there was a misunderstanding, it seems like it makes sense to change the tasks that make up that story accordingly. Or if there was some story or task that was forgotten about, but is required to reach the sprint goal, I would think it would be best to add the story or task to the backlog during the sprint. However, there are a lot of people who seem quite adamant that any change to the sprint backlog is not ok. Am I misunderstanding that position somehow? Are those folks defining the sprint backlog differently somehow? My understanding of the sprint backlog is that it consists of both the stories and the tasks they're broken down into. Anyway I would really appreciate input on this issue. I'm trying to figure out both what the idealistic scrum approach is to changing the sprint backlog during a sprint, and whether people who use scrum successfully for development allow changing the sprint backlog during a sprint.

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• Try the Oracle Database Appliance Manager Configurator - For Fun!

  - by pwstephe-Oracle

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 If you would like to get a first hand glimpse of how easy it is to configure an ODA, even if you don’t have access to one, it’s possible to download the Appliance Manager Configurator from the Oracle Technology Network, and run it standalone on your PC or Linux/Unix  workstation. The configurator is packaged in a zip file that contains the complete Java environment to run standalone. Once the package is downloaded and unzipped it’s simply a matter of launching it using the config command or shell depending on your runtime environment. Oracle Appliance Manager Configurator is a Java-based tool that enables you to input your deployment plan and validate your network settings before an actual deployment, or you can just preview and experiment with it. Simply download and run the configurator on a local client system which can be a Windows, Linux, or UNIX system. (For Windows launch the batch file config.bat for Linux/Unix environments, run  ./ config.sh). You will be presented with the very same dialogs and options used to configure a production ODA but on your workstation. At the end of a configurator session, you may save your deployment plan in a configuration file. If you were actually ready to deploy, you could copy this configuration file to a real ODA where the online Oracle Appliance Manager Configurator would use the contents to deploy your plan in production. You may also print the file’s content and use the printout as a checklist for setting up your production external network configuration. Be sure to use the actual production network addresses you intend to use it as this will only work correctly if your client system is connected to same network that will be used for the ODA. (This step is not necessary if you are just previewing the Configurator). This is a great way to get an introductory look at the simple and intuitive Database Appliance configuration interface and the steps to configure a system. /* 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; 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-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• Data breakpoints to find points where data gets broken

  - by raccoon_tim

  When working with a large code base, finding reasons for bizarre bugs can often be like finding a needle in a hay stack. Finding out why an object gets corrupted without no apparent reason can be quite daunting, especially when it seems to happen randomly and totally out of context. Scenario Take the following scenario as an example. You have defined the a class that contains an array of characters that is 256 characters long. You now implement a method for filling this buffer with a string passed as an argument. At this point you mistakenly expect the buffer to be 256 characters long. At some point you notice that you require another character buffer and you add that after the previous one in the class definition. You now figure that you don’t need the 256 characters that the first member can hold and you shorten that to 128 to conserve space. At this point you should start thinking that you also have to modify the method defined above to safeguard against buffer overflow. It so happens, however, that in this not so perfect world this does not cross your mind. Buffer overflow is one of the most frequent sources for errors in a piece of software and often one of the most difficult ones to detect, especially when data is read from an outside source. Many mass copy functions provided by the C run-time provide versions that have boundary checking (defined with the _s suffix) but they can not guard against hard coded buffer lengths that at some point get changed. Finding the bug Getting back to the scenario, you’re now wondering why does the second string get modified with data that makes no sense at all. Luckily, Visual Studio provides you with a tool to help you with finding just these kinds of errors. It’s called data breakpoints. To add a data breakpoint, you first run your application in debug mode or attach to it in the usual way, and then go to Debug, select New Breakpoint and New Data Breakpoint. In the popup that opens, you can type in the memory address and the amount of bytes you wish to monitor. You can also use an expression here, but it’s often difficult to come up with an expression for data in an object allocated on the heap when not in the context of a certain stack frame. There are a couple of things to note about data breakpoints, however. First of all, Visual Studio supports a maximum of four data breakpoints at any given time. Another important thing to notice is that some C run-time functions modify memory in kernel space which does not trigger the data breakpoint. For instance, calling ReadFile on a buffer that is monitored by a data breakpoint will not trigger the breakpoint. The application will now break at the address you specified it to. Often you might immediately spot the issue but the very least this feature can do is point you in the right direction in search for the real reason why the memory gets inadvertently modified. Conclusions Data breakpoints are a great feature, especially when doing a lot of low level operations where multiple locations modify the same data. With the exception of some special cases, like kernel memory modification, you can use it whenever you need to check when memory at a certain location gets changed on purpose or inadvertently.

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• Thinking Local, Regional and Global

  - by Apeksha Singh-Oracle

  The FIFA World Cup tournament is the biggest single-sport competition: it’s watched by about 1 billion people around the world. Every four years each national team’s manager is challenged to pull together a group players who ply their trade across the globe. For example, of the 23 members of Brazil’s national team, only four actually play for Brazilian teams, and the rest play in England, France, Germany, Spain, Italy and Ukraine. Each country’s national league, each team and each coach has a unique style. Getting all these “localized” players to work together successfully as one unit is no easy feat. In addition to $35 million in prize money, much is at stake – not least national pride and global bragging rights until the next World Cup in four years time. Achieving economic integration in the ASEAN region by 2015 is a bit like trying to create the next World Cup champion by 2018. The team comprises Brunei Darussalam, Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, Philippines, Singapore, Thailand and Vietnam. All have different languages, currencies, cultures and customs, rules and regulations. But if they can pull together as one unit, the opportunity is not only great for business and the economy, but it’s also a source of regional pride. BCG expects by 2020 the number of firms headquartered in Asia with revenue exceeding $1 billion will double to more than 5,000. Their trade in the region and with the world is forecast to increase to 37% of an estimated $37 trillion of global commerce by 2020 from 30% in 2010. Banks offering transactional banking services to the emerging market place need to prepare to repond to customer needs across the spectrum – MSMEs, SMEs, corporates and multi national corporations. Customers want innovative, differentiated, value added products and services that provide: • Pan regional operational independence while enabling single source of truth at a regional level • Regional connectivity and Cash & Liquidity  optimization • Enabling Consistent experience for their customers  by offering standardized products & services across all ASEAN countries • Multi-channel & self service capabilities / access to real-time information on liquidity and cash flows • Convergence of cash management with supply chain and trade finance While enabling the above to meet customer demands, the need for a comprehensive and robust credit management solution for effective regional banking operations is a must to manage risk. According to BCG, Asia-Pacific wholesale transaction-banking revenues are expected to triple to $139 billion by 2022 from $46 billion in 2012. To take advantage of the trend, banks will have to manage and maximize their own growth opportunities, compete on a broader scale, manage the complexity within the region and increase efficiency. They’ll also have to choose the right operating model and regional IT platform to offer: • Account Services • Cash & Liquidity Management • Trade Services & Supply Chain Financing • Payments • Securities services • Credit and Lending • Treasury services The core platform should be able to balance global needs and local nuances. Certain functions need to be performed at a regional level, while others need to be performed on a country level. Financial reporting and regulatory compliance are a case in point. The ASEAN Economic Community is in the final lap of its preparations for the ultimate challenge: becoming a formidable team in the global league. Meanwhile, transaction banks are designing their own hat trick: implementing a world-class IT platform, positioning themselves to repond to customer needs and establishing a foundation for revenue generation for years to come. Anand Ramachandran Senior Director, Global Banking Solutions Practice Oracle Financial Services Global Business Unit

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• Getting Started with Cloud Computing

  - by juanlarios

  You’ve likely heard about how Office 365 and Windows Intune are great applications to get you started with Cloud Computing. Many of you emailed me asking for more info on what Cloud Computing is, including the distinction between "Public Cloud" and "Private Cloud". I want to address these questions and help you get started. Let's begin with a brief set of definitions and some places to find more info; however, an excellent place where you can always learn more about Cloud Computing is the Microsoft Virtual Academy. Public Cloud computing means that the infrastructure to run and manage the applications users are taking advantage of is run by someone else and not you. In other words, you do not buy the hardware or software to run your email or other services being used in your organization – that is done by someone else. Users simply connect to these services from their computers and you pay a monthly subscription fee for each user that is taking advantage of the service. Examples of Public Cloud services include Office 365, Windows Intune, Microsoft Dynamics CRM Online, Hotmail, and others. Private Cloud computing generally means that the hardware and software to run services used by your organization is run on your premises, with the ability for business groups to self-provision the services they need based on rules established by the IT department. Generally, Private Cloud implementations today are found in larger organizations but they are also viable for small and medium-sized businesses since they generally allow an automation of services and reduction in IT workloads when properly implemented. Having the right management tools, like System Center 2012, to implement and operate Private Cloud is important in order to be successful. So – how do you get started? The first step is to determine what makes the most sense to your organization. The nice thing is that you do not need to pick Public or Private Cloud – you can use elements of both where it makes sense for your business – the choice is yours. When you are ready to try and purchase Public Cloud technologies, the Microsoft Volume Licensing web site is a good place to find links to each of the online services. In particular, if you are interested in a trial for each service, you can visit the following pages: Office 365, CRM Online, Windows Intune, and Windows Azure. For Private Cloud technologies, start with some of the courses on Microsoft Virtual Academy and then download and install the Microsoft Private Cloud technologies including Windows Server 2008 R2 Hyper-V and System Center 2012 in your own environment and take it for a spin. Also, keep up to date with the Canadian IT Pro blog to learn about events Microsoft is delivering such as the IT Virtualization Boot Camps and more to get you started with these technologies hands on. Finally, I want to ask for your help to allow the team at Microsoft to continue to provide you what you need. Twice a year through something we call "The Global Relationship Study" – they reach out and contact you to see how they're doing and what Microsoft could do better. If you get an email from "Microsoft Feedback" with the subject line "Help Microsoft Focus on Customers and Partners" between March 5th and April 13th, please take a little time to tell them what you think. Cloud Computing Resources: Microsoft Server and Cloud Computing site – information on Microsoft's overall cloud strategy and products. Microsoft Virtual Academy – for free online training to help improve your IT skillset. Office 365 Trial/Info page – get more information or try it out for yourself. Office 365 Videos – see how businesses like yours have used Office 365 to transition to the cloud. Windows Intune Trial/Info – get more information or try it out for yourself. Microsoft Dynamics CRM Online page – information on trying and licensing Microsoft Dynamics CRM Online. Additional Resources You May Find Useful: Springboard Series Your destination for technical resources, free tools and expert guidance to ease the deployment and management of your Windows-based client infrastructure. TechNet Evaluation Center Try some of our latest Microsoft products for free, Like System Center 2012 Pre-Release Products, and evaluate them before you buy. AlignIT Manager Tech Talk Series A monthly streamed video series with a range of topics for both infrastructure and development managers. Ask questions and participate real-time or watch the on-demand recording. Tech·Days Online Discover what's next in technology and innovation with Tech·Days session recordings, hands-on labs and Tech·Days TV.

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• Migrating VB6 to HTML5 is not a fiction - Customer success story

  - by Webgui

  All of you VB developers in the present or past would probably find it hard to believe that the old VB code can be migrated and modernized into the latest .NET based HTML5 without having to rewrite the application. But we have been working on such tools for the past couple of years and already have several real world applications that were fully 'transposed' from VB6. The solution is called Instant CloudMove and its main tool is called the TranspositionStudio. It is a unique solution that relies on the concept of transposition. Transposition comes from mathematics and music and refers to exchanging elements while everything else remains the same or moving an element as is from one environment to another. This means that we are taking the source code and put it in a modern technological environment with relatively few adjustments.The concept is based on a set of Mapping Expressions which are basically links between an element in the source environment and one in the target environment that has the same functionality. About 95% of the code is usually mapped out-of-the-box and the rest is handled with easy-to-use mapping tools designed for Visual Studio developers providing them with a familiar environment and concepts for completing the mapping and allowing them to extend and customize existing mapping expressions. The solution is also based on a circular workflow that enables developers to make any changes as required until the result is satisfying.As opposed to existing migration solutions that offer automation are usually a “black box” to the user, the transposition concept enables full visibility, flexibility and control over the code and process at all times allowing to also add/change functionalities or upgrade the UI within the process and tools.This is exactly the case with our customer’s aging VB6 PMS (Property Management System) which needed a technological update as well as a design refresh. The decision was to move the VB6 application which had about 1 million lines of code into the latest web technology. Since the application was initially written 13 years ago and had many upgrades since the code must be very patchy and includes unused sections. As a result, the company Mihshuv Group considered rewriting the entire application in Java since it already had the knowledge. Rewrite would allow starting with a clean slate and designing functionality, database architecture, UI without any constraints. On the other hand, rewrite entitles a long and detailed specification work as well as a thorough QA and this translates into a long project with high risk and costs.So the company looked for a migration solution as an alternative; the research lead to Gizmox and after examining the technology it was decided to perform a hybrid project which would include an automatic transposition of the core of the VB6 application (200,000 lines of code) while they redesigning the UI, adding new functionality, deleting unused code and rewriting about 140 reports with Crystal Reports will be done manually using Visual WebGui development tools.The migration part of the project was completed in 65 days by 3 developers from Mihshuv Group guided by Gizmox migration experts while the rewrite and UI upgrade tasks took about the same. So in only a few months period Mihshuv Group generated an up-to-date product, written in the latest Web technology with modern, friendly UI and improved functionality. Guest selection screen of the original VB6 PMS Guest selection screen on the new web–based PMS Compared to the initial plan to rewrite the entire application in Java, the hybrid migration/rewrite approach taken by Mihshuv Group using Gizmox technology proved as a great decision. In terms of time and cost there were substantial savings; from a project that was priced for at least a year (without taking into account the huge risk and uncertainty) it became a few months project only. More about this and other customer stories can be found here

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• Hopping/Tumbling Windows Could Introduce Latency.

  This is a pre-article to one I am going to be writing on adjusting an event’s time and duration to satisfy business process requirements but it is one that I think is really useful when understanding the way that Hopping/Tumbling windows work within StreamInsight.  A Tumbling window is just a special shortcut version of  a Hopping window where the width of the window is equal to the size of the hop Here is the simplest and often used definition for a Hopping Window.  You can find them all here public static CepWindowStream<CepWindow<TPayload>> HoppingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     TimeSpan hopSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   And here is the definition for a Tumbling Window public static CepWindowStream<CepWindow<TPayload>> TumblingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   These methods allow you to group events into windows of a temporal size.  It is a really useful and simple feature in StreamInsight.  One of the downsides though is that the windows cannot be flushed until an event in a following window occurs.  This means that you will potentially never see some events or see them with a delay.  Let me explain. Remember that a stream is a potentially unbounded sequence of events. Events in StreamInsight are given a StartTime.  It is this StartTime that is used to calculate into which temporal window an event falls.  It is best practice to assign a timestamp from the source system and not one from the system clock on the processing server.  StreamInsight cannot know when a window is over.  It cannot tell whether you have received all events in the window or whether some events have been delayed which means that StreamInsight cannot flush the stream for you.   Imagine you have events with the following Timestamps 12:10:10 PM 12:10:20 PM 12:10:35 PM 12:10:45 PM 11:59:59 PM And imagine that you have defined a 1 minute Tumbling Window over this stream using the following syntax var HoppingStream = from shift in inputStream.TumblingWindow(TimeSpan.FromMinutes(1),HoppingWindowOutputPolicy.ClipToWindowEnd) select new WindowCountPayload { CountInWindow = (Int32)shift.Count() };   The events between 12:10:10 PM and 12:10:45 PM will not be seen until the event at 11:59:59 PM arrives.  This could be a real problem if you need to react to windows promptly This can always be worked around by using a different design pattern but a lot of the examples I see assume there is a constant, very frequent stream of events resulting in windows always being flushed. Further examples of using windowing in StreamInsight can be found here

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• Is Visual Source Safe (The latest Version) really that bad? Why? What's the Best Alternative? Why? [closed]

  - by hanzolo

  Over the years I've constantly heard horror stories, had people say "Real Programmers Dont Use VSS", and so on. BUT, then in the workplace I've worked at two companies, one, a very well known public facing high traffic website, and another high end Financial Services "Web-Based" hosted solution catering to some very large, very well known companies, which is where I currently Reside and everything's working just fine (KNOCK KNOCK!!). I'm constantly interfacing with EXTREMELY Old technology with some of these financial institutions.. OLD LIKE YOU WOULDN'T BELIEVE.. which leads me to the conclusion that if it works "LEAVE IT", and that maybe there's some value in old technology? at least enough value to overrule a rewrite!? right?? Is there something fundamentally flawed with the underlying technology that VSS uses? I have a feeling that if i said "someone said VSS Sucks" they would beg to differ, most likely give me this look like i dont know -ish, and I'd never gain back their respect and my credibility (well, that'll be hard to blow.. lol), BUT, give me an argument that I can take to someone whose been coding for 30 years, that builds Platforms that leverage current technology (.NET 3.5 / SQL 2008 R2 ), write's their own ORM with scaffolding and is able to provide a quality platform that supports thousands of concurrent users on a multi-tenant hosted solution, and does not agree with any benefits from having Source Control Integrated, and yet uses the Infamous Visual Source Safe. I have extensive experience with TFS up to 2010, and honestly I think it's great when a team (beyond developers) can embrace it. I've worked side by side with someone whose a die hard SVN'r and from a purist standpoint, I see the beauty in it (I need a bit more, out of my SS, but it surely suffices). So, why are such smarties not running away from Visual Source Safe? surely if it was so bad, it would've have been realized by now, and I would not be sitting here with this simple old, Check In, Check Out, Version Resistant, Label Intensive system. But here I am... I would love to drop an argument that would be the end all argument, but if it's a matter of opinion and personal experience, there seems to be too much leeway for keeping VSS. UPDATE: I guess the best case is to have the VSS supporters check other people's experiences and draw from that until we (please no) experience the breaking factor ourselves. Until then, i wont be engaging in a discussion to migrate off of VSS.. UPDATE 11-2012: So i was able to convince everyone at my work place that since MS is sun downing Visual Source Safe it might be time to migrate over to TFS. I was able to convince them and have recently upgraded our team to Visual Studio 2012 and TFS 2012. The migration was fairly painless, had to run analyze.exe which found a bunch of errors (not sure they'll ever affect the project) and then manually run the VSSConverter.exe. Again, painless, except it took 16 hours to migrate 5 years worth of everything.. and now we're on TFS.. much more integrated.. much more cooler.. so all in all, VSS served it's purpose for years without hick-up. There were no horror stories and Visual Source Save as source control worked just fine. so to all the nay sayers (me included). there's nothing wrong with using VSS. i wouldnt start a new project with it, and i would definitely consider migrating to TFS. (it's really not super difficult and a new "wizard" type converter is due out any day now so migrating should be painless). But from my experience, it worked just fine and got the job done.

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• Where are my date ranges in Analytics coming from?

  - by Jeffrey McDaniel

  In the P6 Reporting Database there are two main tables to consider when viewing time - W_DAY_D and W_Calendar_FS.  W_DAY_D is populated internally during the ETL process and will provide a row for every day in the given time range. Each row will contain aspects of that day such as calendar year, month, week, quarter, etc. to allow it to be used in the time element when creating requests in Analytics to group data into these time granularities. W_Calendar_FS is used for calculations such as spreads, but is also based on the same set date range. The min and max day_dt (W_DAY_D) and daydate (W_Calendar_FS) will be related to the date range defined, which is a start date and a rolling interval plus a certain range. Generally start date plus 3 years.  In P6 Reporting Database 2.0 this date range was defined in the Configuration utility.  As of P6 Reporting Database 3.0, with the introduction of the Extended Schema this date range is set in the P6 web application. The Extended Schema uses this date range to calculate the data for near real time reporting in P6.  This same date range is validated and used for the P6 Reporting Database.  The rolling date range means if today is April 1, 2010 and the rolling interval is set to three years, the min date will be 1/1/2010 and the max date will be 4/1/2013.  1/1/2010 will be the min date because we always back fill to the beginning of the year. On April 2nd, the Extended schema services are run and the date range is adjusted there to move the max date forward to 4/2/2013.  When the ETL process is run the Reporting Database will pick up this change and also adjust the max date on the W_DAY_D and W_Calendar_FS. There are scenarios where date ranges affecting areas like resource limit may not be adjusted until a change occurs to cause a recalculation, but based on general system usage these dates in these tables will progress forward with the rolling intervals. Choosing a large date range can have an effect on the ETL process for the P6 Reporting Database. The extract portion of the process will pull spread data over into the STAR. The date range defines how long activity and resource assignment spread data is spread out in these tables. If an activity lasts 5 days it will have 5 days of spread data. If a project lasts 5 years, and the date range is 3 years the spread data after that 3 year date range will be bucketed into the last day in the date range. For the overall project and even the activity level you will still see the correct total values.  You just would not be able to see the daily spread 5 years from now. This is an important question when choosing your date range, do you really need to see spread data down to the day 5 years in the future?  Generally this amount of granularity years in the future is not needed. Remember all those values 5, 10, 15, 20 years in the future are still available to report on they would be in more of a summary format on the activity or project.  The data is always there, the level of granularity is the decision.

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• OpenGL Fast-Object Instancing Error

  - by HJ Media Studios

  I have some code that loops through a set of objects and renders instances of those objects. The list of objects that needs to be rendered is stored as a std::map, where an object of class MeshResource contains the vertices and indices with the actual data, and an object of classMeshRenderer defines the point in space the mesh is to be rendered at. My rendering code is as follows: glDisable(GL_BLEND); glEnable(GL_CULL_FACE); glDepthMask(GL_TRUE); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); for (std::map<MeshResource*, std::vector<MeshRenderer*> >::iterator it = renderables.begin(); it != renderables.end(); it++) { it->first->setupBeforeRendering(); cout << "<"; for (unsigned long i =0; i < it->second.size(); i++) { //Pass in an identity matrix to the vertex shader- used here only for debugging purposes; the real code correctly inputs any matrix. uniformizeModelMatrix(Matrix4::IDENTITY); /** * StartHere fix rendering problem. * Ruled out: * Vertex buffers correctly. * Index buffers correctly. * Matrices correct? */ it->first->render(); } it->first->cleanupAfterRendering(); } geometryPassShader->disable(); glDepthMask(GL_FALSE); glDisable(GL_CULL_FACE); glDisable(GL_DEPTH_TEST); The function in MeshResource that handles setting up the uniforms is as follows: void MeshResource::setupBeforeRendering() { glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); glEnableVertexAttribArray(2); glEnableVertexAttribArray(3); glEnableVertexAttribArray(4); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID); glBindBuffer(GL_ARRAY_BUFFER, vboID); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0); // Vertex position glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 12); // Vertex normal glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 24); // UV layer 0 glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 32); // Vertex color glVertexAttribPointer(4, 1, GL_UNSIGNED_SHORT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 44); //Material index } The code that renders the object is this: void MeshResource::render() { glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } And the code that cleans up is this: void MeshResource::cleanupAfterRendering() { glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); glDisableVertexAttribArray(2); glDisableVertexAttribArray(3); glDisableVertexAttribArray(4); } The end result of this is that I get a black screen, although the end of my rendering pipeline after the rendering code (essentially just drawing axes and lines on the screen) works properly, so I'm fairly sure it's not an issue with the passing of uniforms. If, however, I change the code slightly so that the rendering code calls the setup immediately before rendering, like so: void MeshResource::render() { setupBeforeRendering(); glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } The program works as desired. I don't want to have to do this, though, as my aim is to set up vertex, material, etc. data once per object type and then render each instance updating only the transformation information. The uniformizeModelMatrix works as follows: void RenderManager::uniformizeModelMatrix(Matrix4 matrix) { glBindBuffer(GL_UNIFORM_BUFFER, globalMatrixUBOID); glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(Matrix4), matrix.ptr()); glBindBuffer(GL_UNIFORM_BUFFER, 0); }

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• Editing files without race conditions?

  - by user2569445

  I have a CSV file that needs to be edited by multiple processes at the same time. My question is, how can I do this without introducing race conditions? It's easy to write to the end of the file without race conditions by open(2)ing it in "a" (O_APPEND) mode and simply write to it. Things get more difficult when removing lines from the file. The easiest solution is to read the file into memory, make changes to it, and overwrite it back to the file. If another process writes to it after it is in memory, however, that new data will be lost upon overwriting. To further complicate matters, my platform does not support POSIX record locks, checking for file existence is a race condition waiting to happen, rename(2) replaces the destination file if it exists instead of failing, and editing files in-place leaves empty bytes in it unless the remaining bytes are shifted towards the beginning of the file. My idea for removing a line is this (in pseudocode): filename = "/home/user/somefile"; file = open(filename, "r"); tmp = open(filename+".tmp", "ax") || die("could not create tmp file"); //"a" is O_APPEND, "x" is O_EXCL|O_CREAT while(write(tmp, read(file)); //copy the $file to $file+".new" close(file); //edit tmp file unlink(filename) || die("could not unlink file"); file = open(filename, "wx") || die("another process must have written to the file after we copied it."); //"w" is overwrite, "x" is force file creation while(write(file, read(tmp))); //copy ".tmp" back to the original file unlink(filename+".tmp") || die("could not unlink tmp file"); Or would I be better off with a simple lock file? Appender process: lock = open(filename+".lock", "wx") || die("could not lock file"); file = open(filename, "a"); write(file, "stuff"); close(file); close(lock); unlink(filename+".lock"); Editor process: lock = open(filename+".lock", "wx") || die("could not lock file"); file = open(filename, "rw"); while(contents += read(file)); //edit "contents" write(file, contents); close(file); close(lock); unlink(filename+".lock"); Both of these rely on an additional file that will be left over if a process terminates before unlinking it, causing other processes to refuse to write to the original file. In my opinion, these problems are brought on by the fact that the OS allows multiple writable file descriptors to be opened on the same file at the same time, instead of failing if a writable file descriptor is already open. It seems that O_CREAT|O_EXCL is the closest thing to a real solution for preventing filesystem race conditions, aside from POSIX record locks. Another possible solution is to separate the file into multiple files and directories, so that more granular control can be gained over components (lines, fields) of the file using O_CREAT|O_EXCL. For example, "file/$id/$field" would contain the value of column $field of the line $id. It wouldn't be a CSV file anymore, but it might just work. Yes, I know I should be using a database for this as databases are built to handle these types of problems, but the program is relatively simple and I was hoping to avoid the overhead. So, would any of these patterns work? Is there a better way? Any insight into these kinds of problems would be appreciated.

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• F# Objects &ndash; Integration with the other .Net Languages &ndash; Part 2

  - by MarkPearl

  So in part one of my posting I covered the real basics of object creation. Today I will hopefully dig a little deeper… My expert F# book brings up an interesting point – properties in F# are just syntactic sugar for method calls. This makes sense… for instance assume I had the following object with the property exposed called Firstname. type Person(Firstname : string, Lastname : string) = member v.Firstname = Firstname I could extend the Firstname property with the following code and everything would be hunky dory… type Person(Firstname : string, Lastname : string) = member v.Firstname = Console.WriteLine("Side Effect") Firstname   All that this would do is each time I use the property Firstname, I would see the side effect printed to the screen saying “Side Effect”. Member methods have a very similar look & feel to properties, in fact the only difference really is that you declare that parameters are being passed in. type Person(Firstname : string, Lastname : string) = member v.FullName(middleName) = Firstname + " " + middleName + " " + Lastname   In the code above, FullName requires the parameter middleName, and if viewed from another project in C# would show as a method and not a property. Precomputation Optimizations Okay, so something that is obvious once you think of it but that poses an interesting side effect of mutable value holders is pre-computation of results. All it is, is a slight difference in code but can result in quite a huge saving in performance. Basically pre-computation means you would not need to compute a value every time a method is called – but could perform the computation at the creation of the object (I hope I have got it right). In a way I battle to differentiate this from lazy evaluation but I will show an example to explain the principle. Let me try and show an example to illustrate the principle… assume the following F# module namespace myNamespace open System module myMod = let Add val1 val2 = Console.WriteLine("Compute") val1 + val2 type MathPrecompute(val1 : int, val2 : int) = let precomputedsum = Add val1 val2 member v.Sum = precomputedsum type MathNormalCompute(val1 : int, val2 : int) = member v.Sum = Add val1 val2 Now assume you have a C# console app that makes use of the objects with code similar to the following… using System; using myNamespace; namespace CSharpTest { class Program { static void Main(string[] args) { Console.WriteLine("Constructing Objects"); var myObj1 = new myMod.MathNormalCompute(10, 11); var myObj2 = new myMod.MathPrecompute(10, 11); Console.WriteLine(""); Console.WriteLine("Normal Compute Sum..."); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(""); Console.WriteLine("Pre Compute Sum..."); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.ReadKey(); } } } The output when running the console application would be as follows…. You will notice with the normal compute object that the system would call the Add function every time the method was called. With the Precompute object it only called the compute method when the object was created. Subtle, but something that could lead to major performance benefits. So… this post has gone off in a slight tangent but still related to F# objects.

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• Can someone explain the true landscape of Rails vs PHP deployment, particularly within the context of Reseller-based web hosting (e.g., Hostgator)?

  - by rcd

  Currently, I have a reseller account with the company HostGator. I design websites, which up until now have occasionally been wrapped in Wordpress CMSs and the like (PHP applications). I then sell hosting (of the site I've designed) to the client, which is pretty simple, in that I can simply click a button and add a new shared hosting account/site with whatever settings I want. Furthermore, I then utilize WHMCS to automate billing and account management. It's a nice package and pretty simple. I pay something like $25 a month, and can sell a hundred accounts under this (because my clients bandwidth requirements are low). Now I am finding the need to develop more customized applications, including a minimalist CMS and several proprietary things. I soon anticipate developing these apps for clients as well. Thus, I've spent the past few months learning Rails, and it's coming along well now. The thing that has nagged at me all along, though, is the deployment issue. I can't wrap my brain around it. It seems like all of the popular options (Heroku, etc) have nice automation with git and are set up in the "Rails Way". I get that (sort of). But it's terribly expensive... a single dyno, a helper, and the cheapest database (which they say is mainly suitable for testing) that isn't limited to 5MB runs $51. This is for ONE app!!! Throw in a "production" DB and you're over $200. This is like... the same prices as getting a server somewhere, right? Meanwhile, going back to what I guess is a "traditional" hosting environment with Hostgator, their server only has Ruby 1.8.7 and Rails 2.3.5... No Rails 3. AND, no Passenger (not that I really understand the difference in CGI or mod_rails or whatever, but they say Passenger is the simplest). So I'm to understand that if I build an app in Rails 3, it won't run at all on this host? But damn, I already have these accounts under my reseller account there, all running static html and/or PHP stuff, right? So what now? How do I get all of this under one simple (and affordable) roof? Forgive my ignorance, but I just don't get it. Managing a VPS is cool and all, but entails learning server admin stuff and security... And it's expensive. I get that a shared and/or reseller "server-based" (forgive the terminology) may be inadequate for large-scale apps that use a lot of bandwidth... But what about for those of us who are building real (but small and low bandwidth) apps (with Rails) and who want to deploy them simply, cheaply, using the same conceptual approach as PHP? Even after learning all of this Ruby and Rails stuff for months, I'm questioning whether it's worth it when it comes to deployment. I want to build a small app, upload it to my home directory on a shared server account, and just make it run. Why should that be so hard? Am I just choosing the wrong language/framework? Forgive my ignorance in the subject; these questions are not rhetorical; just trying to learn here. So: 1) I'd appreciate if someone could give me a good rundown of how to understand deployment in Rails vs. PHP. 2) I'd appreciate if someone could address my issue with running a hosting/web business around reseller hosting (Hostgator) while also being able to host Rails apps. Can it be done? And how can a company like Hostgator completely ignore what's current in Rails/Ruby? Thanks.

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• Delegates: A Practical Understanding

  - by samerpaul

  It's been a while since I have written on this blog, and I'm planning on reviving it this summer, since I have more time to do so again.I've also recently started working on the iPhone platform, so I haven't been as busy in .NET as before.In either case, today's blog post applies to both C# and Objective-C, because it's more about a practical understanding of delegates than it is about code. When I was learning coding, I felt like delegates was one of the hardest things to conceptually understand, and a lot of books don't really do a good job (in my opinion) of explaining it. So here's my stab at it.A Real Life Example of DelegatesLet's say there are three of you. You, your friend, and your brother. You're each in a different room in your house so you can't hear each other, even if you shout. 1)You are playing a computer game2) Friend is building a puzzle3) Brother is nappingNow, you three are going to stay in your room but you want to be informed if anything interesting is happening to the one of you. Let's say you (playing the computer game) want to know when your brother wakes up.You could keep walking to the room, checking to see if he's napping, and then walking back to your room. But that would waste a lot of time / resources, and what if you miss when he's awake before he goes back to sleep? That would be bad.Instead, you hand him a 2-way radio that works between your room and his room. And you inform him that when he wakes up, he should press a button on the radio and say "I'm awake". You are going to be listening to that radio, waiting for him to say he's awake. This, in essence, is how a delegate works.You're creating an "object" (the radio) that allows you to listen in on an event you specify. You don't want him to send any other messages to you right now, except when he wakes up. And you want to know immediately when he does, so you can go over to his room and say hi. (the methods that are called when a delegate event fires). You're also currently specifying that only you are listening on his radio.Let's say you want your friend to come into the room at the same time as you, and do something else entirely, like fluff your brother's pillow. You will then give him an identical radio, that also hooks into your brother's radio, and inform him to wait and listen for the "i'm awake" signal.Then, when your brother wakes up, he says "I'm awake!" and both you and your friend walk into the room. You say hi, and your friend fluffs the pillow, then you both exit.Later, if you decide you don't care to say hi anymore, you turn off your radio. Now, you have no idea when your brother is awake or not, because you aren't listening anymore.So again, you are each classes in this example, and each of you have your own methods. You're playing a computer game (PlayComputerGame()), your friend is building a puzzle (BuildPuzzle()) and your brother is napping (Napping()). You create a delegate (ImAwake) that you set your brother to do, when he wakes up. You listen in on that delegate (giving yourself a radio and turning it on), and when you receive the message, you fire a new method called SayHi()). Your friend is also wired up to the same delegate (using an identical radio) and fires the method FluffPillow().Hopefully this makes sense, and helps shed some light on how delegates operate. Let me know! Feel free to drop me a line at Twitter (preferred method of contact) here: samerabousalbi

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• Getting 2D Platformer entity collision Response Correct (side-to-side + jumping/landing on heads)

  - by jbrennan

  I've been working on a 2D (tile based) 2D platformer for iOS and I've got basic entity collision detection working, but there's just something not right about it and I can't quite figure out how to solve it. There are 2 forms of collision between player entities as I can tell, either the two players (human controlled) are hitting each other side-to-side (i. e. pushing against one another), or one player has jumped on the head of the other player (naturally, if I wanted to expand this to player vs enemy, the effects would be different, but the types of collisions would be identical, just the reaction should be a little different). In my code I believe I've got the side-to-side code working: If two entities press against one another, then they are both moved back on either side of the intersection rectangle so that they are just pushing on each other. I also have the "landed on the other player's head" part working. The real problem is, if the two players are currently pushing up against each other, and one player jumps, then at one point as they're jumping, the height-difference threshold that counts as a "land on head" is passed and then it registers as a jump. As a life-long player of 2D Mario Bros style games, this feels incorrect to me, but I can't quite figure out how to solve it. My code: (it's really Objective-C but I've put it in pseudo C-style code just to be simpler for non ObjC readers) void checkCollisions() { // For each entity in the scene, compare it with all other entities (but not with one it's already compared against) for (int i = 0; i < _allGameObjects.count(); i++) { // GameObject is an Entity GEGameObject *firstGameObject = _allGameObjects.objectAtIndex(i); // Don't check against yourself or any previous entity for (int j = i+1; j < _allGameObjects.count(); j++) { GEGameObject *secondGameObject = _allGameObjects.objectAtIndex(j); // Get the collision bounds for both entities, then see if they intersect // CGRect is a C-struct with an origin Point (x, y) and a Size (w, h) CGRect firstRect = firstGameObject.collisionBounds(); CGRect secondRect = secondGameObject.collisionBounds(); // Collision of any sort if (CGRectIntersectsRect(firstRect, secondRect)) { //////////////////////////////// // // // Check for jumping first (???) // // //////////////////////////////// if (firstRect.origin.y > (secondRect.origin.y + (secondRect.size.height * 0.7))) { // the top entity could be pretty far down/in to the bottom entity.... firstGameObject.didLandOnEntity(secondGameObject); } else if (secondRect.origin.y > (firstRect.origin.y + (firstRect.size.height * 0.7))) { // second entity was actually on top.... secondGameObject.didLandOnEntity.(firstGameObject); } else if (firstRect.origin.x > secondRect.origin.x && firstRect.origin.x < (secondRect.origin.x + secondRect.size.width)) { // Hit from the RIGHT CGRect intersection = CGRectIntersection(firstRect, secondRect); // The NUDGE just offsets either object back to the left or right // After the nudging, they are exactly pressing against each other with no intersection firstGameObject.nudgeToRightOfIntersection(intersection); secondGameObject.nudgeToLeftOfIntersection(intersection); } else if ((firstRect.origin.x + firstRect.size.width) > secondRect.origin.x) { // hit from the LEFT CGRect intersection = CGRectIntersection(firstRect, secondRect); secondGameObject.nudgeToRightOfIntersection(intersection); firstGameObject.nudgeToLeftOfIntersection(intersection); } } } } } I think my collision detection code is pretty close, but obviously I'm doing something a little wrong. I really think it's to do with the way my jumps are checked (I wanted to make sure that a jump could happen from an angle (instead of if the falling player had been at a right angle to the player below). Can someone please help me here? I haven't been able to find many resources on how to do this properly (and thinking like a game developer is new for me). Thanks in advance!

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