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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'd they do it: Millions of tiles in Terraria

  - by William 'MindWorX' Mariager

  I've been working up a game engine similar to Terraria, mostly as a challenge, and while I've figured out most of it, I can't really seem to wrap my head around how they handle the millions of interactable/harvestable tiles the game has at one time. Creating around 500.000 tiles, that is 1/20th of what's possible in Terraria, in my engine causes the frame-rate to drop from 60 to around 20, even tho I'm still only rendering the tiles in view. Mind you, I'm not doing anything with the tiles, only keeping them in memory. Update: Code added to show how I do things. This is part of a class, which handles the tiles and draws them. I'm guessing the culprit is the "foreach" part, which iterates everything, even empty indexes. ... public void Draw(SpriteBatch spriteBatch, GameTime gameTime) { foreach (Tile tile in this.Tiles) { if (tile != null) { if (tile.Position.X < -this.Offset.X + 32) continue; if (tile.Position.X > -this.Offset.X + 1024 - 48) continue; if (tile.Position.Y < -this.Offset.Y + 32) continue; if (tile.Position.Y > -this.Offset.Y + 768 - 48) continue; tile.Draw(spriteBatch, gameTime); } } } ... Also here is the Tile.Draw method, which could also do with an update, as each Tile uses four calls to the SpriteBatch.Draw method. This is part of my autotiling system, which means drawing each corner depending on neighboring tiles. texture_* are Rectangles, are set once at level creation, not each update. ... public virtual void Draw(SpriteBatch spriteBatch, GameTime gameTime) { if (this.type == TileType.TileSet) { spriteBatch.Draw(this.texture, this.realm.Offset + this.Position, texture_tl, this.BlendColor); spriteBatch.Draw(this.texture, this.realm.Offset + this.Position + new Vector2(8, 0), texture_tr, this.BlendColor); spriteBatch.Draw(this.texture, this.realm.Offset + this.Position + new Vector2(0, 8), texture_bl, this.BlendColor); spriteBatch.Draw(this.texture, this.realm.Offset + this.Position + new Vector2(8, 8), texture_br, this.BlendColor); } } ... Any critique or suggestions to my code is welcome. Update: Solution added. Here's the final Level.Draw method. The Level.TileAt method simply checks the inputted values, to avoid OutOfRange exceptions. ... public void Draw(SpriteBatch spriteBatch, GameTime gameTime) { Int32 startx = (Int32)Math.Floor((-this.Offset.X - 32) / 16); Int32 endx = (Int32)Math.Ceiling((-this.Offset.X + 1024 + 32) / 16); Int32 starty = (Int32)Math.Floor((-this.Offset.Y - 32) / 16); Int32 endy = (Int32)Math.Ceiling((-this.Offset.Y + 768 + 32) / 16); for (Int32 x = startx; x < endx; x += 1) { for (Int32 y = starty; y < endy; y += 1) { Tile tile = this.TileAt(x, y); if (tile != null) tile.Draw(spriteBatch, gameTime); } } } ...

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• Using WKA in Large Coherence Clusters (Disabling Multicast)

  - by jpurdy

  Disabling hardware multicast (by configuring well-known addresses aka WKA) will place significant stress on the network. For messages that must be sent to multiple servers, rather than having a server send a single packet to the switch and having the switch broadcast that packet to the rest of the cluster, the server must send a packet to each of the other servers. While hardware varies significantly, consider that a server with a single gigabit connection can send at most ~70,000 packets per second. To continue with some concrete numbers, in a cluster with 500 members, that means that each server can send at most 140 cluster-wide messages per second. And if there are 10 cluster members on each physical machine, that number shrinks to 14 cluster-wide messages per second (or with only mild hyperbole, roughly zero). It is also important to keep in mind that network I/O is not only expensive in terms of the network itself, but also the consumption of CPU required to send (or receive) a message (due to things like copying the packet bytes, processing a interrupt, etc). Fortunately, Coherence is designed to rely primarily on point-to-point messages, but there are some features that are inherently one-to-many: Announcing the arrival or departure of a member Updating partition assignment maps across the cluster Creating or destroying a NamedCache Invalidating a cache entry from a large number of client-side near caches Distributing a filter-based request across the full set of cache servers (e.g. queries, aggregators and entry processors) Invoking clear() on a NamedCache The first few of these are operations that are primarily routed through a single senior member, and also occur infrequently, so they usually are not a primary consideration. There are cases, however, where the load from introducing new members can be substantial (to the point of destabilizing the cluster). Consider the case where cluster in the first paragraph grows from 500 members to 1000 members (holding the number of physical machines constant). During this period, there will be 500 new member introductions, each of which may consist of several cluster-wide operations (for the cluster membership itself as well as the partitioned cache services, replicated cache services, invocation services, management services, etc). Note that all of these introductions will route through that one senior member, which is sharing its network bandwidth with several other members (which will be communicating to a lesser degree with other members throughout this process). While each service may have a distinct senior member, there's a good chance during initial startup that a single member will be the senior for all services (if those services start on the senior before the second member joins the cluster). It's obvious that this could cause CPU and/or network starvation. In the current release of Coherence (3.7.1.3 as of this writing), the pure unicast code path also has less sophisticated flow-control for cluster-wide messages (compared to the multicast-enabled code path), which may also result in significant heap consumption on the senior member's JVM (from the message backlog). This is almost never a problem in practice, but with sufficient CPU or network starvation, it could become critical. For the non-operational concerns (near caches, queries, etc), the application itself will determine how much load is placed on the cluster. Applications intended for deployment in a pure unicast environment should be careful to avoid excessive dependence on these features. Even in an environment with multicast support, these operations may scale poorly since even with a constant request rate, the underlying workload will increase at roughly the same rate as the underlying resources are added. Unless there is an infrastructural requirement to the contrary, multicast should be enabled. If it can't be enabled, care should be taken to ensure the added overhead doesn't lead to performance or stability issues. This is particularly crucial in large clusters.

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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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• Software Center seems to freeze system when installing, syslog has "blocked for more than 120 seconds" errors

  - by nbm

  12.04 (precise) 64-bit Kernel Linux 3.2.0-39 3.6GB memory Intel Core 2 Duo CPU @ 2.40GHz x2 WUBI-installed Ubuntu running on a MacBook Pro 7.1 with OSX running Vista via Boot Camp (hey, I like lots of OS's m'kay?) When installing from Ubuntu software center my system very frequently freezes. This has happened 4 of the last 5 installs. Most recently I was installing the Google Earth .deb from Google's website: clicking the .deb file automatically opens Software Center (otherwise I would have used Synaptic, as I've grown to expect Software Center to freeze my system and I'm rather tired of it.) By "freeze" I mean nothing works: no dash, no launcher, no mouse movement, no alt-tab, can't open terminal (keyboard does not work). Software center does show the "installing" icon but after that it greys out and I can't click anything. REISUB has no effect but a cold power-down and restart is possible. Occasionally, after 5-10 minutes, I'll be able to move the mouse / use the keyboard and run a launcher command or two, although other open apps (Chrome and Software Center) will still be greyed-out/frozen. (I've never waited longer than that - if still unresponsive after 15 minutes I just power down and restart.) Most recently, which is why I am finally posting a question, I waited about 15 minutes and was finally able to open System Monitor while this was going on. Processes tells me that System Monitor is using about 20% of CPU, and nothing else is using much (zeros mostly). In fact I didn't even see Software Center listed? However at this point the system finally partially unfroze, the installation completed, and while I wasn't about to close Software Center I was able to do a system shutdown and fresh restart and I went and took a look at the syslog. In /var/log/syslog I see a lot of ":blocked for more than 120 seconds" messages. Similar to ubuntu hang out with this message :blocked for more than 120 seconds Which has not been answered, and I'm not running a virtual machine. My full syslog with stack traces looks very, very similar to this: Why do tasks on Amazon Xen instance block for over 120 seconds causing server to hang? Note that that question was solved, but that's because the problem was being caused by Amazon and Amazon fixed the bug. I'm not running anything Amazon-related. My syslog does look very similar, however. My question is also similar to this: Troubleshooting server hang But the referenced "duplicate" in that question is about how to kill processes/restart when the system freezes. I know how to kill processes and restart. I want to figure out what is causing the problem so I can try to fix it. I realize that I could just use Synaptic instead of Ubuntu Software Center, but I'd like to try to solve the problem if possible. I'm thinking I should perhaps submit a bug report, but I wanted to first see if anyone else was having any similar problems, and if so what you all did to fix it. I see a number of questions about Software Center freezing and others, including those I linked, about the "blocked for more than 120 seconds" log error, but I didn't see any question that links the two. I did save a copy of the syslog report if anyone wants to see it, but as mentioned it's quite similar to the one posted in the Amazon-related question...and I didn't want to take up even more space unnecessarily as, my apologies - this question has already become extremely verbose!

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• Introducing the Metro User Interface on Windows 2012

  - by andywe

  Although I am a big fan of using PowerShell to do many of my server operations, that aspect is well covered by those far more knowledgeable than I, and there is vast information around the web already on that. The new Metro interface, and getting around both Windows 8 and Windows Server 2012 though is relatively new, even for those whop ran the previews. What is this? A blank Desktop!   Where did the start button go? Well, it is still there...sort of. It is hidden, and acts like an auto hidden component that appear only when the mouse is hovered over the lower left corner of the screen. Those familiar with Gnome or OSX can relate this to the "Hot Corners" functions. To get to the start button, hover your mouse in the very left corner of the task bar. Let it sit there a moment, and a small blue square with colored tiles in it called start will appear. Click it. I clicked it and now I have all the tiles..What is this?   Welcome to the Metro interface. This is a much more modern look, and although at first seems weird and cumbersome, I have actually found that it is a bit more extensible, allowing greater organization and customization than the older explorer desktop. If you look closely, you'll see each box represents either a program, or program group. First, a few basics about using the start view. First and foremost, a right mouse click will bring up a bar on the bottom, with an icon towards the right. Notice it is titled “All Apps”. An even easier way in many places is to hover your mouse in the exact opposite corner, in the upper right. A sidebar will open and expose what used to be a widget bar (remember Vista?), and there are options for Search, Start, and Settings.   Ok Great, but where is everything? It’s all there…Click the All Apps icon.   Look better? Notice the scroll bar at the bottom. Move it right..your desktop is sized to your content..so you can have a smaller, or larger amount of programs exposed. Each icon can be secondary clicked (right mouse click for most of us, and an options bar at the bottom, rather than the old small context menu, is opened with some very familiar options.   Notice the top of the Windows Explorer window has some new features. You still have your right mouse click functions, but since the shortcuts for these items already exist..just copy them. There are many ways, but here is a long way to show you more of the interface. 1. Right mouse click a program icon, and select the Open File Location option. 2. Trusty file manager opens…but if you look closely up at top edge of the window, you’ll see a nifty enhancement. An orange colored box that is titled Shortcut Tools and another lavender box Title Application tools. Each of these adds options at the top of the file manager window to make selection easy. Of course, you can still secondary click an item in the listing window too. 3. Click shortcut tools, right click your app shortcut and copy it. Then simply paste it into the desktop outside the File Explorer window Also note some of the newer features. The large icons up top below the menu that has many common operations. The options change as you select each menu item. Well, that’s it for this installment. I hope this helps you out.

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• When should I use a Process Model versus a Use Case?

  - by Dave Burke

  This Blog entry is a follow on to https://blogs.oracle.com/oum/entry/oum_is_business_process_and and addresses a question I sometimes get asked…..i.e. “when I am gathering requirements on a Project, should I use a Process Modeling approach, or should I use a Use Case approach?” Not surprisingly, the short answer is “it depends”! Let’s take a scenario where you are working on a Sales Force Automation project. We’ll call the process that is being implemented “Lead-to-Order”. I would typically think of this type of project as being “Process Centric”. In other words, the focus will be on orchestrating a series of human and system related tasks that ultimately deliver value to the business in a cost effective way. Put in even simpler terms……implement an automated pre-sales system. For this type of (Process Centric) project, requirements would typically be gathered through a series of Workshops where the focal point will be on creating, or confirming, the Future-State (To-Be) business process. If pre-defined “best-practice” business process models exist, then of course they could and should be used during the Workshops, but even in their absence, the focus of the Workshops will be to define the optimum series of Tasks, their connections, sequence, and dependencies that will ultimately reflect a business process that meets the needs of the business. Now let’s take another scenario. Assume you are working on a Content Management project that involves automating the creation and management of content for User Manuals, Web Sites, Social Media publications etc. Would you call this type of project “Process Centric”?.......well you could, but it might also fall into the category of complex configuration, plus some custom extensions to a standard software application (COTS). For this type of project it would certainly be worth considering using a Use Case approach in order to 1) understand the requirements, and 2) to capture the functional requirements of the custom extensions. At this point you might be asking “why couldn’t I use a Process Modeling approach for my Content Management project?” Well, of course you could, but you just need to think about which approach is the most effective. Start by analyzing the types of Tasks that will eventually be automated by the system, for example: Best Suited To? Task Name Process Model Use Case Notes Manage outbound calls Ö A series of linked human and system tasks for calling and following up with prospects Manage content revision Ö Updating the content on a website Update User Preferences Ö Updating a users display preferences Assign Lead Ö Reviewing a lead, then assigning it to a sales person Convert Lead to Quote Ö Updating the status of a lead, and then converting it to a sales order As you can see, it’s not an exact science, and either approach is viable for the Tasks listed above. However, where you have a series of interconnected Tasks or Activities, than when combined, deliver value to the business, then that would be a good indicator to lead with a Process Modeling approach. On the other hand, when the Tasks or Activities in question are more isolated and/or do not cross traditional departmental boundaries, then a Use Case approach might be worth considering. Now let’s take one final scenario….. As you captured the To-Be Process flows for the Sales Force automation project, you discover a “Gap” in terms of what the client requires, and what the standard COTS application can provide. Let’s assume that the only way forward is to develop a Custom Extension. This would now be a perfect opportunity to document the functional requirements (behind the Gap) using a Use Case approach. After all, we will be developing some new software, and one of the most effective ways to begin the Software Development Lifecycle is to follow a Use Case approach. As always, your comments are most welcome.

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• Using NSpec at various architectural layers

  - by nono

  Having read the quick start at nspec.org, I realized that NSpec might be a useful tool in a scenario which was becoming a bit cumbersome with NUnit alone. I'm adding an OAuth (or, DotNetOpenAuth) to a website and quickly made a mess of writing test methods such as [Test] public void UserIsLoggedInLocallyPriorToInvokingExternalLoginAndExternalLoginSucceedsAndExternalProviderIdIsNotAlreadyAssociatedWithUserAccount() { ... } ... and I wound up with maybe a dozen permutations of this theme, for the user already being logged in locally and not locally, the external login succeeding or failing, etc. Not only were the method names unwieldy, but every test needed a setup that contained parts in common with a different set of other tests. I realized that NSpec's incremental setup capabilities would work great for this, and for a while I was trucking a long wonderfully, with code like act = () => { actionResult = controller.ExternalLoginCallback(returnUrl); }; context["The user is already logged in"] = () => { before = () => identity.Setup(x => x.IsAuthenticated).Returns(true); context["The external login succeeds"] = () => { before = () => oauth.Setup(x => x.VerifyAuthentication(It.IsAny<string>())).Returns(new AuthenticationResult(true, providerName, "provideruserid", "username", new Dictionary<string, string>())); context["External login already exists for current user"] = () => { before = () => authService.Setup(x => x.ExternalLoginExistsForUser(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>())).Returns(true); it["Should add 'login sucessful' alert"] = () => { var alerts = (IList<Alert>)controller.TempData[TempDataKeys.AlertCollection]; alerts[0].Message.should_be_same("Login successful"); alerts[0].AlertType.should_be(AlertType.Success); }; it["Should return a redirect result"] = () => actionResult.should_cast_to<RedirectToRouteResult>(); }; context["External login already exists for another user"] = () => { before = () => authService.Setup(x => x.ExternalLoginExistsForAnyOtherUser(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>())).Returns(true); it["Adds an error alert"] = () => { var alerts = (IList<Alert>)controller.TempData[TempDataKeys.AlertCollection]; alerts[0].Message.should_be_same("The external login you requested is already associated with a different user account"); alerts[0].AlertType.should_be(AlertType.Error); }; it["Should return a redirect result"] = () => actionResult.should_cast_to<RedirectToRouteResult>(); }; This approach seemed to work magnificently until I prepared to write test code for my ApplicationServices layer, to which I delegate viewmodel manipulation from my MVC controllers, and which coordinates the operations of the lower data repository layer: public void CreateUserAccountFromExternalLogin(RegisterExternalLoginModel model) { throw new NotImplementedException(); } public void AssociateExternalLoginWithUser(string userName, string provider, string providerUserId) { throw new NotImplementedException(); } public string GetLocalUserName(string provider, string providerUserId) { throw new NotImplementedException(); } I have no idea what in the world to name the test class, the test methods, or even if I should perhaps include the testing for this layer into the test class from my large code snippet above, so that a single feature or user action could be tested without regard to architectural layering. I can't find any tutorials or blog posts which cover more than simple examples, so I would appreciate any recommendations or pointing in the right direction. I would even welcome "your question is invalid"-type answers as long as some explanation is provided.

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• ADF page security - the untold password rule

  - by ankuchak

  I'm kinda new to Oracle ADF. So, in this blog post I'm going to share something with you that I faced (and recovered from) recently. Initially I thought if I should at all put a blog post on this, because it's totally simple. Still, simplicity is a relative term. So without wasting further time, let's kick off.    I was exploring the ADF security aspect to secure a page through html basic authentication. The idea is very simple and the credential store etc. come into picture. But I was not able to run a successful test of this phenomenally simple thing even after trying for over 30 minutes. This is what I did.   I created a simple jsf page and put a panel in it. And I put a simple el to show the current user name.  Next I created a user that I should test with. I named the password as myuser, just to keep it simple. Then I created an enterprise role and mapped the user that I just created. Then I created an application role and mapped the enterprise role to it. Then I mapped the resource, the simple jsf page in this case, to this application role. This way, only users with the given application role can only access this page (as if you didn't know this duh!).  Of course, I had to create the page definition for the page before I could map it to an application role. What else! done! Then I hit the run menu item and it all went well...   Until... I got this message. I put the correct credentials repeatedly 2-3 times. Still I got the same error. Why? I didn't get any error message during the deployment. nope.  Then, as I said before, I spent over 30 minutes trying different things out, things like mapping only the user(not the role) to the page, changing the context root etc. Nothing worked!  Then of course, I bothered to look at the logs and found this. See the first red line. That says it all. So the problem was with that password. The password must have at least one special character and one digit in it. I think I was misled by the missing password hint/rule and the fact that the deployment didn't fail even if the user was not created properly. Well, yes, I agree that I was fool enough not to look at the logs.  Later I changed the password to something like myuser123# . And it worked. I hope it helped.

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• The long road to bug-free software

  - by Tony Davis

  The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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• High Resolution Timeouts

  - by user12607257

  The default resolution of application timers and timeouts is now 1 msec in Solaris 11.1, down from 10 msec in previous releases. This improves out-of-the-box performance of polling and event based applications, such as ticker applications, and even the Oracle rdbms log writer. More on that in a moment. As a simple example, the poll() system call takes a timeout argument in units of msec: System Calls poll(2) NAME poll - input/output multiplexing SYNOPSIS int poll(struct pollfd fds[], nfds_t nfds, int timeout); In Solaris 11, a call to poll(NULL,0,1) returns in 10 msec, because even though a 1 msec interval is requested, the implementation rounds to the system clock resolution of 10 msec. In Solaris 11.1, this call returns in 1 msec. In specification lawyer terms, the resolution of CLOCK_REALTIME, introduced by POSIX.1b real time extensions, is now 1 msec. The function clock_getres(CLOCK_REALTIME,&res) returns 1 msec, and any library calls whose man page explicitly mention CLOCK_REALTIME, such as nanosleep(), are subject to the new resolution. Additionally, many legacy functions that pre-date POSIX.1b and do not explicitly mention a clock domain, such as poll(), are subject to the new resolution. Here is a fairly comprehensive list: nanosleep pthread_mutex_timedlock pthread_mutex_reltimedlock_np pthread_rwlock_timedrdlock pthread_rwlock_reltimedrdlock_np pthread_rwlock_timedwrlock pthread_rwlock_reltimedwrlock_np mq_timedreceive mq_reltimedreceive_np mq_timedsend mq_reltimedsend_np sem_timedwait sem_reltimedwait_np poll select pselect _lwp_cond_timedwait _lwp_cond_reltimedwait semtimedop sigtimedwait aiowait aio_waitn aio_suspend port_get port_getn cond_timedwait cond_reltimedwait setitimer (ITIMER_REAL) misc rpc calls, misc ldap calls This change in resolution was made feasible because we made the implementation of timeouts more efficient a few years back when we re-architected the callout subsystem of Solaris. Previously, timeouts were tested and expired by the kernel's clock thread which ran 100 times per second, yielding a resolution of 10 msec. This did not scale, as timeouts could be posted by every CPU, but were expired by only a single thread. The resolution could be changed by setting hires_tick=1 in /etc/system, but this caused the clock thread to run at 1000 Hz, which made the potential scalability problem worse. Given enough CPUs posting enough timeouts, the clock thread could be a performance bottleneck. We fixed that by re-implementing the timeout as a per-CPU timer interrupt (using the cyclic subsystem, for those familiar with Solaris internals). This decoupled the clock thread frequency from timeout resolution, and allowed us to improve default timeout resolution without adding CPU overhead in the clock thread. Here are some exceptions for which the default resolution is still 10 msec. The thread scheduler's time quantum is 10 msec by default, because preemption is driven by the clock thread (plus helper threads for scalability). See for example dispadmin, priocntl, fx_dptbl, rt_dptbl, and ts_dptbl. This may be changed using hires_tick. The resolution of the clock_t data type, primarily used in DDI functions, is 10 msec. It may be changed using hires_tick. These functions are only used by developers writing kernel modules. A few functions that pre-date POSIX CLOCK_REALTIME mention _SC_CLK_TCK, CLK_TCK, "system clock", or no clock domain. These functions are still driven by the clock thread, and their resolution is 10 msec. They include alarm, pcsample, times, clock, and setitimer for ITIMER_VIRTUAL and ITIMER_PROF. Their resolution may be changed using hires_tick. Now back to the database. How does this help the Oracle log writer? Foreground processes post a redo record to the log writer, which releases them after the redo has committed. When a large number of foregrounds are waiting, the release step can slow down the log writer, so under heavy load, the foregrounds switch to a mode where they poll for completion. This scales better because every foreground can poll independently, but at the cost of waiting the minimum polling interval. That was 10 msec, but is now 1 msec in Solaris 11.1, so the foregrounds process transactions faster under load. Pretty cool.

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• Dynamics CRM error "A currency is required if a value exists in a money field" after converting Acti

  - by Evgeny

  We have a Dynamics CRM 4.0 instance with some custom attributes of type "money" on the Case entity and on all Activity entities (Email, Phone Call, etc.) When I use the built-in "Convert Activity to Case" functionality I find that the resulting Case does not have a Currency set, even if the Activity it was created from does have it. Whenever the case is opened the user then gets this JavaScript error: A currency is required if a value exists in a money field. Select a currency and try again. This is extremely annoying! How do I fix it? Is there any way I can set the currency? It needs to be done synchronously, because the Case is opened immediately when it's created from an Activity. So even if I started a workflow to set the currency the user would still get that error at least once. Alterntatively, can I just suppress the warning somehow? I don't really care about setting the Currency, I just want the error gone. Thanks in advance for any help!

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• WPF - LayoutUpdated event firing repeatedly

  - by Drew Noakes

  I've been adding a bit of animation to my WPF application. Thanks to Dan Crevier's unique solution to animating the children of a panel combined with the awesome WPF Penner animations it turned out to be fairly straightforward to make one of my controls look great and have its children move about with some nice animation. Unfortunately this all comes with a performance overhead. I'm happy to have the performance hit when items are added/removed or the control is resized, but it seems that this perf hit occurs consistently throughout the application's lifetime, even when items are completely static. The PanelLayoutAnimator class uses an attached property to hook the UIElement.LayoutUpdated.aspx) event. When this event fires, render transforms are animated to cause the children to glide to their new positions. Unfortunately it seems that the LayoutUpdated event fires every second or so, even when nothing is happening in the application (at least I don't think my code's doing anything -- the app doesn't have focus and the mouse is steady.) As the reason for the event is not immediately apparent to the event handler, all children of the control have to be reevaluated. This event is being called about once a second when idle. The frequency increases when actually using the app. So my question is, how can I improve the performance here? Any answer that assists would be appreciated, but I'm currently stuck on these sub-questions: What causes the LayoutUpdated event to fire so frequently? Is this supposed to happen, and if not, how can I find out why it's firing and curtail it? Is there a more convenient way within the handler to know whether something has happened that might have moved children? If so, I could bail out early and avoid the overhead of looping each child. For now I will work around this issue by disabling animation when there are more than N children in the panel.

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• Working with Subversion the same as with Visual Source Safe in Visual Studio

  - by Para

  Hi, At work I just started using subversion with ankhsvn instead of visual source safe. I managed to integrate it well enough but it doesn't seem the same. Using VSS the following would happen: A user check out a file by right clicking and selecting "check out" or by editing it. If another user tried to modify the same file he would get an error. No 2 users could edit the same file at the same time. No fancy merging. No conflicts and no conflict resolutions. I understand the the philosophy behind subversion is different but is there any way that this behavior described above could be duplicated with subversion? There is an option in ankhSVN called "Automatically lock files on change..." but even if I activate this option when I edit a file it never gets automatically locked. Even if this option worked the other users wouldn't see the lock until they comited the file. They wouldn't get an error when they tried to edit it like they would in Visual Source Safe. So basically: can Visual Source Safe's behavior be duplicated using Subversion and ankhSVN?

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• Using Word COM objects in .NET, WinWord process won't quit after calling Word.Documents.Add

  - by Keith

  I'm running into the classic scenario where, when creating Word COM objects in .NET (via the Microsoft.Office.Interop.Word assembly), the WinWord process won't exit even though I'm properly closing and releasing the objects. I've narrowed it down to the use of the Word.Documents.Add() method. I can work with Word in other ways without a problem (opening documents, modifying contents, etc) and WinWord.exe quits when I tell it to. It's once I use the Add() method that the process is left running. Here is a simple example which reproduces the problem: Dim oWord As New Word.Application() oWord.Visible = False Dim oDocuments As Word.Documents = oWord.Documents Dim oDoc As Word.Document = oDocuments.Add(Template:=CObj(sTemplatePath), NewTemplate:=False, DocumentType:=Word.WdNewDocumentType.wdNewBlankDocument, Visible:=False) ' dispose objects oDoc.Close() While (Marshal.ReleaseComObject(oDoc) < 0) End While oDoc = Nothing oWord.Quit() While (Marshal.ReleaseComObject(oWord) < 0) End While oWord = Nothing As you can see I'm creating and disposing the objects properly, even taking the extra step to loop Marsha.ReleaseComObject until it returns the proper code. Working with the Word objects is fine in other regards, it's just that pesky Documents.Add that is causing me grief. Is there another object that gets created in this process that I need to reference and dispose of? Is there another disposal step I need to follow? Something else? Your help is much appreciated :)

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• Uploadify & Integrated Windows Authentication

  - by vdh_ant

  Hi guys I'm running into an issue with Uploadify and I hope someone can help. I have put Uploadify into my app and all works fine in dev (using the VS web server). All worked fine and checked until I deployed the app into my test environment which uses Integrated Windows Authentication. When I actually go to upload the file, the browser brings up a login prompt. At this point, even if you type in the correct username and password, the request seems not to complete and even if you tell the browser to remember the password it still brings up the login prompt. When this started to occur, I decided to spin up Fiddler and see what was going on. But guess what, when ever Fiddler is running the issue doesn't occur. Unfortunately I can't make running Fiddler a reuqierment for running the app. Hence does anyone have any ideas. I know there are some issues with Uploadify/flash when using forms authentication but I didn't think they carried across to Integrated Windows Authentication. Cheers Anthony

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• iPhone: image in table cell - wrong position & not scaled correctly in iPhone 3.0

  - by Karsten Silz

  Hi, I have a custom table cell in an iPhone 3.x app to show basketball player data, including a picture. Here's my code from the table controller: UIImageView *theImage = (UIImageView *) [cell viewWithTag:0]; theImage.image = [manager getSmallImageForPlayer: data.number]; theImage.frame = CGRectMake(14, 0, 30, 44); theImage.clipsToBounds = YES; theImage.contentMode = UIViewContentModeScaleAspectFit; theImage.autoresizingMask = UIViewAutoresizingFlexibleHeight && UIViewAutoresizingFlexibleWidth; theImage.autoresizesSubviews = YES; Here's what it looks like in the iPhone SDK 3.0 simulator: Here's what it looks like in the iPhone SDK 3.1.3 simulator: So I have two problems: In both versions, the image view starts at position (0,0) in the table cell, even though I set the frame to start at (14,0). In the 3.0 simulator (and 3.0 device), the image is not shrunk down correctly, even though I set the image view content mode to "UIViewContentModeScaleAspectFit". But the same code works fine in the 3.1.3 simulator / device. Who can help me with either of these two problems?

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• Hidden Features of C#?

  - by Serhat Özgel

  This came to my mind after I learned the following from this question: where T : struct We, C# developers, all know the basics of C#. I mean declarations, conditionals, loops, operators, etc. Some of us even mastered the stuff like Generics, anonymous types, lambdas, linq, ... But what are the most hidden features or tricks of C# that even C# fans, addicts, experts barely know? Here are the revealed features so far: Keywords yield by Michael Stum var by Michael Stum using() statement by kokos readonly by kokos as by Mike Stone as / is by Ed Swangren as / is (improved) by Rocketpants default by deathofrats global:: by pzycoman using() blocks by AlexCuse volatile by Jakub Šturc extern alias by Jakub Šturc Attributes DefaultValueAttribute by Michael Stum ObsoleteAttribute by DannySmurf DebuggerDisplayAttribute by Stu DebuggerBrowsable and DebuggerStepThrough by bdukes ThreadStaticAttribute by marxidad FlagsAttribute by Martin Clarke ConditionalAttribute by AndrewBurns Syntax ?? operator by kokos number flaggings by Nick Berardi where T:new by Lars Mæhlum implicit generics by Keith one-parameter lambdas by Keith auto properties by Keith namespace aliases by Keith verbatim string literals with @ by Patrick enum values by lfoust @variablenames by marxidad event operators by marxidad format string brackets by Portman property accessor accessibility modifiers by xanadont ternary operator (?:) by JasonS checked and unchecked operators by Binoj Antony implicit and explicit operators by Flory Language Features Nullable types by Brad Barker Currying by Brian Leahy anonymous types by Keith __makeref __reftype __refvalue by Judah Himango object initializers by lomaxx format strings by David in Dakota Extension Methods by marxidad partial methods by Jon Erickson preprocessor directives by John Asbeck DEBUG pre-processor directive by Robert Durgin operator overloading by SefBkn type inferrence by chakrit boolean operators taken to next level by Rob Gough pass value-type variable as interface without boxing by Roman Boiko programmatically determine declared variable type by Roman Boiko Static Constructors by Chris Easier-on-the-eyes / condensed ORM-mapping using LINQ by roosteronacid Visual Studio Features select block of text in editor by Himadri snippets by DannySmurf Framework TransactionScope by KiwiBastard DependantTransaction by KiwiBastard Nullable<T> by IainMH Mutex by Diago System.IO.Path by ageektrapped WeakReference by Juan Manuel Methods and Properties String.IsNullOrEmpty() method by KiwiBastard List.ForEach() method by KiwiBastard BeginInvoke(), EndInvoke() methods by Will Dean Nullable<T>.HasValue and Nullable<T>.Value properties by Rismo GetValueOrDefault method by John Sheehan Tips & Tricks nice method for event handlers by Andreas H.R. Nilsson uppercase comparisons by John access anonymous types without reflection by dp a quick way to lazily instantiate collection properties by Will JavaScript-like anonymous inline-functions by roosteronacid Other netmodules by kokos LINQBridge by Duncan Smart Parallel Extensions by Joel Coehoorn

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• "The calling thread cannot access this object because a different thread owns it." While using Dispa

  - by Sdry

  I have an application, that I want to load additional xaml files, being resourcedictionaries controling the style of the application. Yet when trying to add a loaded ResourceDictionary to the mergeddictionaries I get an InvalidOperationException saying "The calling thread cannot access this object because a different thread owns it." at a point where I am not even using multiple threads. The application contains a usercontrol which loads the xaml file through a background worker, adding the loaded ResourceDictionaries to an Observablecollection. When I pass on a selected theme(=ResourceDictionary) to a function in the mainwindow of the application, it goes wrong. public void LoadTheme(Theme theme) {//sdry 2010-4-22 if(theme !=null){ this._dispatcher.Invoke(DispatcherPriority.Normal, (Action)(() => { MessageBox.Show("SKIN TEST: " + theme.Name); //> oke #if (SHOWDEBUGINFO) _selectedTheme = theme.Name; //>oke #endif Application.Current.Resources.MergedDictionaries.Clear(); //>oke Application.Current.Resources.MergedDictionaries.Add(theme.ResourceDictionary); //> InvalidOperationException //the theme object has a property named ResourceDictionary of type ResourceDictionary containing the loaded xaml })); } } My first reaction was to use the Disatcher.Invoke, even not knowing how I would not be on the gui thread, which doesn't solve a thing. So maybe my loaded theme belongs to a different thread ? but its originating from a property of a usercontrol, which should be the same thread. And its accesable untill trying to use the ResourceDictionary. This makes me confused, and not very aware of how to proceed, any help is appreciated.

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• How can I sort a DataGridTemplateColumn on a WPF Toolkit DataGrid?

  - by Kilhoffer

  I have a WPF Toolkit DataGrid with one DataGridTemplateColumn. I've specified in a grid attribute that I wish all columns to be sortable, but the DataGridTemplateColumn won't allow it. All other columns do allow sorting. I've even tried explicitly setting CanUserSort to true for that column, but no luck. Is it even possible to sort a template column? I've provided a custom sorter that works for all columns, but the header won't allow a sort click. <Controls:DataGrid ItemsSource="{Binding Events}" AutoGenerateColumns="False" CanUserSortColumns="True" CanUserReorderColumns="False" Sorting="DataGrid_Sorting" x:Name="EventsGrid"> <Controls:DataGrid.Columns> <Controls:DataGridTemplateColumn Header="Type" Width="42" CanUserResize="False"> <Controls:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Image Source="{Binding EventTypeImage, Mode=OneWay}" HorizontalAlignment="Center" Width="16"/> </DataTemplate> </Controls:DataGridTemplateColumn.CellTemplate> </Controls:DataGridTemplateColumn> <Controls:DataGridTextColumn Header="Source" Binding="{Binding Source, Mode=OneWay}" /> <Controls:DataGridTextColumn Header="Details" MinWidth="175" Binding="{Binding Details, Mode=OneWay}" /> <Controls:DataGridTextColumn Header="Timestamp" MinWidth="175" Binding="{Binding Timestamp, Mode=OneWay}" IsReadOnly="True"/> </Controls:DataGrid.Columns> </Controls:DataGrid>

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• FileSystemWatcher.Changed fires immediately when Excel 2007 opens XLS file in compatibility mode

  - by Rick Mogstad

  We use a FileSystemWatcher to monitor documents opened from our Document Management system, and if the user saves the document, we ask if they would also like them updated in our system. We have a problem with XLS files in Excel 2007 (have not verified that the problem does not exist in 2003, but it only seems to be files that open in compatibility mode in 2007) where the Changed event fires immediately upon opening the file, and then once more upon closing the file, even if nothing has changed or the user chooses not to save upon closing. This same behavior does not exist when opening XLSX files. I wrote a test app to verify the behavior, which you can find at (http://www.just2guys.net/SOFiles/FSWExcel.zip). In the app, there is one FileSystemWatcher for each NotifyFilter type, so that it is apparent why the Changed event was fired. Any way you can think of to only prompt the user when the document is actually saved in some way by the user? I can start monitoring the file after Process.Start is called, which allows me to skip the message upon opening the document, but I still get one upon closing the document, even when nothing was changed.

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• UISplitViewController and complex view heirarchy

  - by Jasconius

  I'm doing an iPad tech demo and I'm running into a serious technical problem. I have an app concept that leverages UISplitViewController, but NOT as the primary controller for the entire app. The app flow could be described roughly as this: Home screen (UIViewController) List-Detail "Catalog" (UISplitViewController) Super Detail Screen (UIViewController but could conceivable also be a child of SplitView). The problem is in the flow between Home and Catalog. Once a UISplitViewController view is added to the UIWindow, it starts to throw hissy fits. The problem can be summarized at this: When a UISplitView generates a popover view, it appears to then be latched to its parent view. Upon removing the UISplitView from the UIWindow subviews, you will get a CoreGraphics exception and the view will fail to be removed. When adding other views (presumably in this case, the home screen to which you are returning), they do not autorotate, instead, the UISplitView, which has failed to be removed due to a CG exception, continues to respond to the rotation instead, causing horrible rendering bugs that can't be just "dealt with". At this point, adding any views, even re-adding the SplitView, causes a cascade of render bugs. I then tried simply to leave the SplitView ever present as the "bottom" view, and keeping adding and removing the Home Screen from on top of it, but this fails as SplitView dominates the Orientation change calls, and Home Screen will not rotate, even if you call [homeScreen becomeFirstResponder] You can't put SplitView into a hierarchy like UINavigationController, you will get an outright runtime error, so that option is off the table. Modals just look bad and are discourages anyway. My presumption at this moment is that the only proper way to deal with this problem is so somehow "disarm" UISplitViewController so that it can be removed from its parent view without throwing an unhandled exception, but I have no idea how. If you want to see an app that does exactly what I need to do, check out GILT Groupe in the iPad app store. They pulled it off, but they seem to have programmed an entire custom view transition set. Help would be greatly appreciated.

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• Visual C# GUI Designer - Recommended way of removing generated event handler-code & basic tutorial

  - by cusack

  Hi, I'm new to the Visual C# designer so these are general and pretty basic question on how to work with the designer. When we for instance add a label to a form and then double-click on it in the Visual C# designer (I'm using Microsoft Visual C# 2008 Express Edition), the following things happen: The designer generates code within Form1.Designer.cs (assume default names for simplicity) to add the label, then with the double-click it will add the event handler label1_Click to the label within Form1.Designer.cs, using the following code this.label1.Click += new System.EventHandler(this.label1_Click); and it adds the event handler method to Form1.cs private void label1_Click(object sender, EventArgs e) { } If I now remove the label only the code within Form1.Designer.cs will be removed but the label1_Click method will stay within Form1.cs even if it isn't used by anything else. But if I'm using reset within Properties-Events for the Click-event from within the designer even the label1_Click method in Form1.cs will be removed. 1.) Isn't that a little inconsistent behavior? 2.) What is the recommended way of removing such generated event handler-code? 3.) What is the best "mental approach"/best practice for using the designer? I would approach it by mental separation in the way that Form1.cs is 100% my responsibility and that on the other hand I'm not touching the code in Form1.Designer.cs at all. Does that make sense or not? Since sometimes the designer removes sth. from Form1.cs I'm not sure about this. 4.) Can you recommend a simple designer tutorial that assumes no Visual C# designer knowledge but expects/doesn't explain C#. The following one is an example of what I would not want it explains what a c#-comment is and I'd prefer text over video as well: http://msdn.microsoft.com/en-us/beginner/bb964631.aspx

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• FusionCharts vs GoogleCharts vs HighCharts suggestions required for commercial use

  - by Forte

  I find that FusionCharts v3 evaluation and HighCharts cannot be used for commercial purpose. Google charts is the best option but those are not as good looking as any of the above. They don't even have 3d charts although their visualization API does support 3D which i cannot find. Is there any open source graphing or charting solution available which can be used in commercial products? I even looked in to Open Flash Charts 2 but found that the developer had left the project long time a go and the currently out libs are way too buggy. I had to fix more than 50 bugs to get their 1 chart working. I tried to fix others but couldn't get Pie charts etc. working. What i'm looking for is - 1. Attractive 3d column chart. 2. 3d Pie Chart. 3. Spline Chart. 4. Geographical Chart. Does anyone knows any open source or free solution which can be used for commercial products? Cheers!

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• shouldAutorotateToInterfaceOrientation called several times in a row without any rotation

  - by Mike

  I am trying to implement some interface changes in my app, based on the device rotation. My app is a view based app. So, its main view controller has a didload method. The app starts in portrait. Almost all changes on the device orientation triggers the shouldAutorotateToInterfaceOrientation method but this method is not called when the device is put on portrait, after coming from any landscape orientation. While debugging the app, I have put a NSLog(@"orientation=%d", interfaceOrientation); on my shouldAutorotateToInterfaceOrientation method, and what I see is quite strange: When I run the app, shouldAutorotateToInterfaceOrientation is called 6 times before the app's interface even appears. Every time it runs, it reports a different number for the orientation: the order it reports on console is: portrait, portrait, portrait, landscape right, landscape left, upside down) (????). During this time the app is just beginning. All 6 times the debugger reports the method being run by the app's delegate. So, here comes the questions: WHy shouldAutorotateToInterfaceOrientation is not being called when the device enters on portrait? Why is this method running 6 times called by the delegate even before the app starts and shows its interface if no rotation is being done? thanks.

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