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• Private Cloud: Putting some method behind the madness

  - by Sudip Datta

  Finally, I decided to join the blogging community. And what could be a better time to start than the week after OpenWorld 2012. 50K+ attendees, demonstrations, speaker sessions and a whole lot of buzz on Oracle Cloud..It was raining clouds in this year's Openworld. I am not here to write about Oracle's cloud strategy in general, but on Enterprise Manager's cloud management capabilities. This year's Openworld was the first after we announced the 12c Cloud Control and we were happy to share the stage with quite a few early adopters. Stay tuned for videos from our customers and partners, I will post them as they get published. I met a number of platform administrators in Oracle-DBAs, Middleware Admins, SOA Admins...The cloud has affected them all, at least to the point where it beckoned more than just curiosity..Most IT infrastructure are already heavily virtualized (on VMWare and on others including Oracle VM), and some would claim they are already on “cloud” (at least their Sysadmins told them so). But none of them were confident of the benefits because their pain points continued to grow.. Isn't cloud supposed to ease those? Instead, they were chasing hundreds of databases running on hundreds of VMs, often with as much certainty propounded by Heisenberg. What happened to the age-old IT discipline around administration, compliance, configuration management? VMs are great for what they are. I personally think they have opened the doors to new approaches in which an application stack gets provisioned and updated. In fact, Enterprise Manager 12c is possibly the only tool out there that can provision full-fledged application as VM Assemblies. In this year's Openworld, customers talked on how they provisioned RAC and Siebel assemblies, which as the techies out there know, are not trivial (hearing provisioning time for Siebel down from weeks to hours was gratifying indeed). However, I do have an issue with a "one-size fits all" approach to cloud. In a week's span, I met several personas: Project owners requiring an EC2 like VM instance for their projects Admins needing the same for Sparc-Solaris. DBAs requiring dedicated databases for new projects APEX Developers needing just a ready-to-consume schema as a service Java Developers looking for a runtime platform QA engineers needing a fast clone of their production environment If you drill down further, you will end up peeling more layers of the details. For example, the requirements for Load testing and Functional testing are very different. For Load testing the test environment should ideally be the same as the production. You shouldn't run production on Exadata and load test on a VM; they will just not be good representations of one another. For Functional testing it does not possibly matter. DBAs seem to be at the worst affected of the lot. It seems they have been asked to choose between agile provisioning and  faster runtime performance. And in some cases, it is really a Hobson's choice, because their infrastructure provider made no distinction between the OLTP application and the Virtual desktop! Sad indeed. When one looks at the portfolio of services that we already offer (vanilla IaaS, VM Assembly based PaaS, DBaaS) or have announced (Java PaaS, Instant Cloning, Schema-aaS), one can possibly think that we are trying to be the "renaissance man" ! Well I would have possibly digested that had it not been for the various personas that I described above. Getting the use cases right is very important for an application such as cloud management. We iterate and iterate over these over and over again and re-validate them in CABs (Customer Advisory Boards). We consider over the major aspects of tenancy: service placement, resource isolation (can a tenant execute an expensive SQL and run away with all the resources), quota and security. We, in Engineering, keep reminding ourselves that we are dealing with enterprise clouds. We owe it to our customer base ! In the coming posts, I will drill down more into each of the services. In the meanwhile, here are some collateral and  demos for starters with EM 12c. http://www.oracle.com/technetwork/oem/cloud-mgmt/index.html Sudip Datta The views expressed here are my own and do not necessarily reflect the views of Oracle. Stay Connected: Twitter | Facebook | YouTube | Linkedin | Newsletter --

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• 2D Particle Explosion

  - by TheBroodian

  I'm developing a 2D action game, and in said game I've given my primary character an ability he can use to throw a fireball. I'm trying to design an effect so that when said fireball collides (be it with terrain or with an enemy) that the fireball will explode. For the explosion effect I've created a particle that once placed into game space will follow random, yet autonomic behavior based on random variables. Here is my question: When I generate my explosion (essentially 90 of these particles) I get one of two behaviors, 1) They are all generated with the same random variables, and don't resemble an explosion at all, more like a large mass of clumped sprites that all follow the same randomly generated path. 2) If I assign each particle a unique seed to its random number generator, they are a little bit -more- spread out, yet clumping is still visible (they seem to fork out into 3 different directions) Does anybody have any tips for producing particle-based 2D explosions? I'll include the code for my particle and the event I'm generating them in. Fire particle class: public FireParticle(xTile.Dimensions.Location StartLocation, ContentManager content) { worldLocation = StartLocation; fireParticleAnimation = new FireParticleAnimation(content); random = new Random(); int rightorleft = random.Next(0, 3); int upordown = random.Next(1, 3); int xVelocity = random.Next(0, 101); int yVelocity = random.Next(0, 101); Vector2 tempVector2 = new Vector2(0,0); if (rightorleft == 1) { tempVector2 = new Vector2(xVelocity, tempVector2.Y); } else if (rightorleft == 2) { tempVector2 = new Vector2(-xVelocity, tempVector2.Y); } if (upordown == 1) { tempVector2 = new Vector2(tempVector2.X, -yVelocity); } else if (upordown == 2) { tempVector2 = new Vector2(tempVector2.X, yVelocity); } velocity = tempVector2; scale = random.Next(1, 11); upwardForce = -10; dead = false; } public FireParticle(xTile.Dimensions.Location StartLocation, ContentManager content, int seed) { worldLocation = StartLocation; fireParticleAnimation = new FireParticleAnimation(content); random = new Random(seed); int rightorleft = random.Next(0, 3); int upordown = random.Next(1, 3); int xVelocity = random.Next(0, 101); int yVelocity = random.Next(0, 101); Vector2 tempVector2 = new Vector2(0, 0); if (rightorleft == 1) { tempVector2 = new Vector2(xVelocity, tempVector2.Y); } else if (rightorleft == 2) { tempVector2 = new Vector2(-xVelocity, tempVector2.Y); } if (upordown == 1) { tempVector2 = new Vector2(tempVector2.X, -yVelocity); } else if (upordown == 2) { tempVector2 = new Vector2(tempVector2.X, yVelocity); } velocity = tempVector2; scale = random.Next(1, 11); upwardForce = -10; dead = false; } #endregion #region Update and Draw public void Update(GameTime gameTime) { elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; fireParticleAnimation.Update(gameTime); Vector2 moveAmount = velocity * elapsed; xTile.Dimensions.Location newPosition = new xTile.Dimensions.Location(worldLocation.X + (int)moveAmount.X, worldLocation.Y + (int)moveAmount.Y); worldLocation = newPosition; velocity.Y += upwardForce; if (fireParticleAnimation.finishedPlaying) { dead = true; } } public void Draw(SpriteBatch spriteBatch) { spriteBatch.Draw( fireParticleAnimation.image.Image, new Rectangle((int)drawLocation.X, (int)drawLocation.Y, scale, scale), fireParticleAnimation.image.SizeAndsource, Color.White * fireParticleAnimation.image.Alpha); } Fireball explosion event: public override void Update(GameTime gameTime) { if (enabled) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; foreach (Heart_of_Fire.World_Objects.Particles.FireParticle particle in explosionParticles.ToList()) { particle.Update(gameTime); if (particle.Dead) { explosionParticles.Remove(particle); } } collisionRectangle = new Microsoft.Xna.Framework.Rectangle((int)wrldPstn.X, (int)wrldPstn.Y, 5, 5); explosionCheck = exploded; if (!exploded) { coreGraphic.Update(gameTime); tailGraphic.Update(gameTime); Vector2 moveAmount = velocity * elapsed; moveAmount = horizontalCollision(moveAmount, layer); moveAmount = verticalCollision(moveAmount, layer); Vector2 newPosition = new Vector2(wrldPstn.X + moveAmount.X, wrldPstn.Y + moveAmount.Y); if (hasCollidedHorizontally || hasCollidedVertically) { exploded = true; } wrldPstn = newPosition; worldLocation = new xTile.Dimensions.Location((int)wrldPstn.X, (int)wrldPstn.Y); } if (explosionCheck != exploded) { for (int i = 0; i < 90; i++) { explosionParticles.Add(new World_Objects.Particles.FireParticle( new Location( collisionRectangle.X + random.Next(0, 6), collisionRectangle.Y + random.Next(0, 6)), contentMgr)); } } if (exploded && explosionParticles.Count() == 0) { //enabled = false; } } }

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• Identity Globe Trotters (Sep Edition): The Social Customer

  - by Tanu Sood

  Welcome to the inaugural edition of our monthly series - Identity Globe Trotters. Starting today, the last Friday of every month, we will explore regional commentary on Identity Management. We will invite guest contributors from around the world to share their opinions and experiences around Identity Management and highlight regional nuances, specific drivers, solutions and more. Today's feature is contributed by Michael Krebs, Head of Business Development at esentri consulting GmbH, a (SOA) specialized Oracle Gold Partner based in Ettlingen, Germany. In his current role, Krebs is dealing with the latest developments in Enterprise Social Networking and the Integration of Social Media within business processes.  By Michael Krebs The relevance of "easy sign-on" in the age of the "Social Customer" With the growth of Social Networks, the time people spend within those closed "eco-systems" is growing year by year. With social networks looking to integrate search engines, like Facebook announced some weeks ago, their relevance will continue to grow in contrast to the more conventional search engines. This is one of the reasons why social network accounts of the users are getting more and more like a virtual fingerprint. With the growing relevance of social networks the importance of a simple way for customers to get in touch with say, customer care or contract departments, will be crucial for sales processes in critical markets. Customers want to have one single point of contact and also an easy "login-method" with no dedicated usernames, passwords or proprietary accounts. The golden rule in the future social media driven markets will be: The lower the complexity of the initial contact, the better a company can profit from social networks. If you, for example, can generate a smart way of how an existing customer can use self-service portals, the cost in providing phone support can be lowered significantly. Recruiting and Hiring of "Digital Natives" Another particular example is "social" recruiting processes. The so called "digital natives" don´t want to type in their profile facts and CV´s in proprietary systems. Why not use the actual LinkedIn profile? In German speaking region, the market in the area of professional social networks is dominated by XING, the equivalent to LinkedIn. A few weeks back, this network also opened up their interfaces for integrating social sign-ons or the usage of profile data for recruiting-purposes. In the European (and especially the German) employment market, where the number of young candidates is shrinking because of the low birth rate in the region, it will become essential to use social-media supported hiring processes to find and on-board the rare talents. In fact, you will see traditional recruiting websites integrated with social hiring to attract the best talents in the market, where the pool of potential candidates has decreased dramatically over the years. Identity Management as a key factor in the Customer Experience process To create the biggest value for customers and also future employees, companies need to connect their HCM or CRM-systems with powerful Identity management solutions. With the highly efficient Oracle (social & mobile enabling) Identity Management solution, enterprises can combine easy sign on with secure connections to the backend infrastructure. This combination enables a "one-stop" service with personalized content for customers and talents. In addition, companies can collect valuable data for the enrichment of their CRM-data. The goal is to enrich the so called "Customer Experience" via all available customer channels and contact points. Those systems have already gained importance in the B2C-markets and will gradually spread out to B2B-channels in the near future. Conclusion: Central and "Social" Identity management is key to Customer Experience Management and Talent Management For a seamless delivery of "Customer Experience Management" and a modern way of recruiting the best talent, companies need to integrate Social Sign-on capabilities with modern CX - and Talent management infrastructure. This lowers the barrier for existing and future customers or employees to get in touch with sales, support or human resources. Identity management is the technology enabler and backbone for a modern Customer Experience Infrastructure. Oracle Identity management solutions provide the opportunity to secure Social Applications and connect them with modern CX-solutions. At the end, companies benefit from "best of breed" processes and solutions for enriching customer experience without compromising security. About esentri: esentri is a provider of enterprise social networking and brings the benefits of social network communication into business environments. As one key strength, esentri uses Oracle Identity Management solutions for delivering Social and Mobile access for Oracle’s CRM- and HCM-solutions. …..End Guest Post…. With new and enhanced features optimized to secure the new digital experience, the recently announced Oracle Identity Management 11g Release 2 enables organizations to securely embrace cloud, mobile and social infrastructures and reach new user communities to help further expand and develop their businesses. Additional Resources: Oracle Identity Management 11gR2 release Oracle Identity Management website Datasheet: Mobile and Social Access (pdf) IDM at OOW: Focus on Identity Management Facebook: OracleIDM Twitter: OracleIDM We look forward to your feedback on this post and welcome your suggestions for topics to cover in Identity Globe Trotters. Last Friday, every month!

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• BizTalk: namespaces

  - by Leonid Ganeline

  BizTalk team did a good job hiding the .NET guts from developers. Developers are working with editors and hardly with .NET code. The Orchestration editor, the Mapper, the Schema editor, the Pipeline editor, all these editors hide what is going on with artifacts created and deployed. Working with the BizTalk artifacts year after year brings us some knowledge which could help to understand more about the .NET guts. I would like to highlight the .NET namespaces. What they are, how they influence our everyday tasks in the BizTalk application development. What is it? Most of the BizTalk artifacts are compiled into the NET classes. Not all of them… but I will show you later. Classes are placed inside the namespaces. I will not describe here why we need namespaces and what is it. I assume you all know about it more then me. Here I would like to emphasize that almost each BizTalk artifact is implemented as a .NET class within a .NET namespace. Where to see the namespaces in development? The namespaces are inconsistently spread across the artifact parameters. Let’s start with namespace placement in development. Then we go with namespaces in deployment and operations. I am using pictures from the BizTalk Server 2013 Beta and the Visual Studio 2012 but there was no changes regarding the namespaces starting from the BizTalk 2006. Default namespace When a new BizTalk project is created, the default namespace is set up the same as a name of a project. This namespace would be used for all new BizTalk artifacts added to this project. Orchestrations When we select a green or a red markers (the Begin and End orchestration shapes) we will see the orchestration Properties window. We also can click anywhere on the space between Port Surfaces to see this window.   Schemas The only way to see the NET namespace for map is selecting the schema file name into the Solution Explorer. Notes: We can also see the Type Name parameter. It is a name of the correspondent .NET class. We can also see the Fully Qualified Name parameter. We cannot see the schema namespace when selecting any node on the schema editor surface. Only selecting a schema file name gives us a namespace parameter. If we select a <Schema> node we can get the Target Namespace parameter of the schema. This is NOT the .NET namespace! It is an XML namespace. See this XML namespace inside the XML schema, it is shown as a special targetNamespace attribute Here this XML namespace appears inside the XML document itself. It is shown as a special xmlns attribute.   Maps It is similar to the schemas. The only way to see the NET namespace for map is selecting a map file name into the Solution Explorer. Pipelines It is similar to the schemas. The only way to see the NET namespace for pipeline is selecting a pipeline file name into the Solution Explorer. z Ports, Policies and Tracking Profiles The Send and Receive Ports, the Policies and the BAM Tracking Profiles do not create the .NET classes and they do not have the associated .NET namespaces. How to copy artifacts? Since the new versions of the BizTalk Server are going to production I am spending more and more time redesigning and refactoring the BizTalk applications. It is good to know how the refactoring process copes with the .NET namespaces. Let see what is going on with the namespaces when we copy the artifacts from one project to another. Here is an example: I am going to group the artifacts under the project folders. So, I have created a Group folder, have run the Add / Existing Item.. command and have chosen all artifacts in the project root. The artifact copies were created in the Group folder: What was happened with the namespaces of the artifacts? As you can see, the folder name, the “Group”, was added to the namespace. It is great! When I added a folder, I have added one more level in the name hierarchy and the namespace change just reflexes this hierarchy change.  The same namespace adjustment happens when we copy the BizTalk artifacts between the projects. But there is an issue with the namespace of an orchestration. It was not changed. The namespaces of the schemas, maps, pipelines are changed but not the orchestration namespace. I have to change the orchestration namespace manually. Now another example: I am creating a new Project folder and moving the artifacts there from the project root by drag and drop. We will mention the artifact namespaces are not changed. Another example: I am copying the artifacts from the project root by (drag and drop) + Ctrl. We will mention the artifact namespaces are changed. It works exactly as it was with the Add / Existing Item.. command. Conclusion: The namespace parameter is put inconsistently in different places for different artifacts Moving artifacts changes the namespaces of the schemas, maps, pipelines but not the orchestrations.

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• How to Hashtag (Without Being #Annoying)

  - by Mike Stiles

  The right tool in the wrong hands can be a dangerous thing. Giving a chimpanzee a chain saw would not be a pretty picture. And putting Twitter hashtags in the hands of social marketers who were never really sure how to use them can be equally unattractive. Boiled down, hashtags are for search and organization of tweets. A notch up from that, they can also be used as part of a marketing strategy. In terms of search, if you’re in the organic apple business, you want anyone who searches “organic” on Twitter to see your posts about your apples. It’s keyword tactics not unlike web site keyword search tactics. So get a clear idea of what keywords are relevant for your tweet. It’s reasonable to include #organic in your tweet. Is it fatal if you don’t hashtag the word? It depends on the person searching. If they search “organic,” your tweet’s going to come up even if you didn’t put the hashtag in front of it. If the searcher enters “#organic,” your tweet needs the hashtag. Err on the side of caution and hashtag it so it comes up no matter how the searcher enters it. You’ll also want to hashtag it for the second big reason people hashtag, organization. You can follow a hashtag. So can the rest of the Twitterverse. If you’re that into organic munchies, you can set up a stream populated only with tweets hashtagged #organic. If you’ve established a hashtag for your brand, like #nobugsprayapples, you (and everyone else) can watch what people are tweeting about your company. So what kind of hashtags should you include? They should be directly related to the core message of your tweet. Ancillary or very loosely-related hashtags = annoying. Hashtagging your brand makes sense. Hashtagging your core area of interest makes sense. Creating a specific event or campaign hashtag you want others to include and spread makes sense (the burden is on you to promote it and get it going). Hashtagging nearly every word in the tweet is highly annoying. Far and away, the majority of hashtagged words in such tweets have no relevance, are not terms that would be searched, and are not terms needed for categorization. It looks desperate and spammy. Two is fine. One is better. And it is possible to tweet with --gasp-- no hashtags! Make your hashtags as short as you can. In fact, if your brand’s name really is #nobugsprayapples, you’re burning up valuable, limited characters and risking the inability of others to retweet with added comments. Also try to narrow your topic hashtag down. You’ll find a lot of relevant users with #organic, but a lot of totally uninterested users with #food. Just as you can join online forums and gain credibility and a reputation by contributing regularly to that forum, you can follow hashtagged topics and gain the same kind of credibility in your area of expertise. Don’t just parachute in for the occasional marketing message. And if you’re constantly retweeting one particular person, stop it. It’s kissing up and it’s obvious. Which brings us to the king of hashtag annoyances, “hashjacking.” This is when you see what terms are hot and include them in your marketing tweet as a hashtag, even though it’s unrelated to your content. Justify it all you want, but #justinbieber has nothing to do with your organic apples. Equally annoying, piggybacking on a popular event’s hashtag to tweet something not connected to the event. You’re only fostering ill will and mistrust toward your account from the people you’ve tricked into seeing your tweet. Lastly, don’t @ mention people just to make sure they see your tweet. If the tweet’s not for them or about them, it’s spammy. What I haven’t covered is use of the hashtag for comedy’s sake. You’ll see this a lot and is a matter of personal taste. No one will search these hashtagged terms or need to categorize then, they’re just there for self-expression and laughs. Twitter is, after all, supposed to be fun.  What are some of your biggest Twitter pet peeves? #blogsovernow

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• The architecture and technologies to use for a secure, fast, reliable and easily scalable web application

  - by DSoul

  ^ For actual questions, skip to the lists down below I understand, that his is a vague topic, but please, before you turn the other way and disregard me, hear me out. I am currently doing research for a web application(I don't know if application is the correct word for it, but I will proceed w/ that for now), that one day might need to be everything mentioned in the title. I am bound by nothing. That means that every language, OS and framework is acceptable, but only if it proves it's usefulness. And if you are going to say, that scalability and speed depend on the code I write for this application, then I agree, but I am just trying to find something, that wouldn't stand in my way later on. I have done quite a bit reading on this subject, but I still don't have a clear picture, to what suits my needs, so I come to you, StackOverflow, to give me directions. I know you all must be wondering what I'm building, but I assure you, that it doesn't matter. I have heard of 12 factor app though, if you have any similar guidelines or what is, to suggest the please, go ahead. For the sake of keeping your answers as open as possible, I'm not gonna provide you my experience regarding anything written in this question. ^ Skippers, start here First off - the weights of the requirements are probably something like that (on a scale of 10): Security - 10 Speed - 5 Reliability (concurrency) - 7.5 Scalability - 10 Speed and concurrency are not a top priority, in the sense, that the program can be CPU intensive, and therefore slow, and only accept a not-that-high number of concurrent users, but both of these factors must be improvable by scaling the system Anyway, here are my questions: How many layers should the application have, so it would be future-proof and could best fulfill the aforementioned requirements? For now, what I have in mind is the most common version: Completely separated front end, that might be a web page or an MMI application or even both. Some middle-ware handling communication between the front and the back end. This is probably a server that communicates w/ the front end via HTTP. How the communication w/ the back end should be handled is probably dependent on the back end. The back end. Something that handles data through resources like DB and etc. and does various computations w/ the data. This, as the highest priority part of the software, must be easily spread to multiple computers later on and have no known security holes. I think ideally the middle-ware should send a request to a queue from where one of the back end processes takes this request, chops it up to smaller parts and buts these parts of the request back onto the same queue as the initial request, after what these parts will be then handled by other back end processes. Something *map-reduce*y, so to say. What frameworks, languages and etc. should these layers use? The technologies used here are not that important at this moment, you can ignore this part for now I've been pointed to node.js for this part. Do you guys know any better alternatives, or have any reasons why I should (not) use node.js for this particular job. I actually have no good idea, what to use for this job, there are too many options out there, so please direct me. This part (and the 2. one also, I think) depend a lot on the OS, so suggest any OSs alongside w/ the technologies/frameworks. Initially, all computers (or 1 for starters) hosting the back end are going to be virtual machines. Please do give suggestions to any part of the question, that you feel you have comprehensive knowledge and/or experience of. And also, point out if you feel that any part of the current set-up means an instant (or even distant) failure or if I missed a very important aspect to consider. I'm not looking for a definitive answer for how to achieve my goals, because there certainly isn't one, for I haven't provided you w/ all the required information. I'm just looking for recommendations and directions on what to look into. Also, bare in mind, that this isn't something that I have to get done quickly, to sell and let it be re-written by the new owner (which, I've been told for multiple times, is what I should aim for). I have all the time in the world and I really just want to learn doing something really high-end. Also, excuse me if my language isn't the best, I'm not a native. Anyway. Thanks in advance to anyone, who takes the time to help me out here. PS. When I do seem to come up w/ a good architecture/design for this project, I will certainly make it an open project and keep you guys up to date w/ it's development. As in what you could have told me earlier and etc. For obvious reasons the very same question got closed on SO, but could you guys still help me?.

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• Notes from AT&T ARO Session at Oredev 2013

  - by Geertjan

  The mobile internet is 12 times bigger than internet was 12 years ago. Explosive growth, faster networks, and more powerful devices. 85% of users prefer mobile apps, while 56% have problems. Almost 60% want less than 2 second mobile app startup. App with poor mobile experience results in not buying stuff, going to competitor, not liking your company. Battery life. Bad mobile app is worse than no app at all because it turns people away from brand, etc. Apps didn't exist 10 years ago, 72 billion dollars a year in 2013, 151 billion in 2017.Testing performance. Mobile is different than regular app. Need to fix issues before customers discover them. ARO is free and open source AT&T tool for identifying mobile app performance problems. Mobile data is different -- radio resource control state machine. Radio resource control -- radio from idle to continuous reception -- drains battery, sends data, packets coming through, after packets come through radio is still on which is tail time, after 10 seconds of no data coming through radio goes off. For example, YouTube, e.g., 10 to 15 seconds after every connection, can be huge drain on battery, app traffic triggers RRC state. Goal. Balance fast network connectivity against battery usage. ARO is free and open source and test any platform and won awards. How do I test my app? pcap or tcdump network. Native collector: Android and iOS. Android rooted device is needed. Test app on phone, background data, idle for ads and analytics. Graded against 25 best practices. See all the processes, all network traffic mapped to processes, stats about trace, can look just at your app, exlude Facebook, etc. Many tests conducted, e.g., file download, HTML (wrapped applications, e.g., cordova). Best Practices. Make stuff smaller. GZIP, smaller files, download faster, best for files larger than 800 bytes, minification -- remove tabs and commenting -- browser doesn't need that, just give processor what it needs remove wheat from chaff. Images -- make images smaller, 1024x1024 image for a checkmark, swish it, make it 33% smaller, ARO records the screen, probably could be 9 times smaller. Download less stuff. 17% of HTTP content on mobile is duplicate data because of caching, reloading from cache is 75% to 99% faster than downloading again, 75% possible savings which means app will start up faster because using cache -- everyone wants app starting up 2 seconds. Make fewer HTTP requests. Inline and combine CSS and JS when possible reduces the number of requests, spread images used often. Fewer connections. Faster and use less battery, for example, download an image every 60 secs, download an add every 60 seconds, send analytics every 60 seconds -- instead of that, use transaction manager, download everything at once, reduce amount of time connected to network by 40% also -- 80% of applications do NOT close connections when they are finished, e.g., download picture, 10 seconds later the radio turns off, if you do not explicitly close, eventually server closes, 38% more tail time, 40% less energy if you close connection right away, background data traffic is 27% of data and 55% of network time, this kills the battery. Look at redirection. Adds 200 to 600 ms on each connection, waterfall diagram to all the requests -- e.g., xyz.com redirect to www.xyz.com redirect to xyz.mobi to www.xyz.com, waterfall visualization of packets, minimize redirects but redirects are fine. HTML best practices. Order matters and hiding code (JS downloading blocks rendering, always do CSS before JS or JS asynchronously, CSS 'display:none' hides images from user but the browser downloads them which adds latency to application. Some apps turn on GPS for no reason. Tell network when down, but maybe some other app is using the radio at the same time. It's all about knowing best practices: everyone wins with ARO (carriers, e.g., AT&T, developers, customers). Faster apps, better battery usage, network traffic better, better app reviews, happier customers. MBTA app, referenced as an example.ARO is free, open source, can test all platforms.

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• Interesting issue with WCF wsHttpBinding through a Firewall

  - by Marko

  I have a web application deployed in an internet hosting provider. This web application consumes a WCF Service deployed at an IIS server located at my company’s application server, in order to have data access to the company’s database, the network guys allowed me to expose this WCF service through a firewall for security reasons. A diagram would look like this. [Hosted page] --- (Internet) --- |Firewall <Public IP>:<Port-X >| --- [IIS with WCF Service <Comp. Network Ip>:<Port-Y>] link text I also wanted to use wsHttpBinding to take advantage of its security features, and encrypt sensible information. After trying it out I get the following error: Exception Details: System.ServiceModel.EndpointNotFoundException: The message with To 'http://<IP>:<Port>/service/WCFService.svc' cannot be processed at the receiver, due to an AddressFilter mismatch at the EndpointDispatcher. Check that the sender and receiver's EndpointAddresses agree. Doing some research I found out that wsHttpBinding uses WS-Addressing standards, and reading about this standard I learned that the SOAP header is enhanced to include tags like ‘MessageID’, ‘ReplyTo’, ‘Action’ and ‘To’. So I’m guessing that, because the client application endpoint specifies the Firewall IP address and Port, and the service replies with its internal network address which is different from the Firewall’s IP, then WS-Addressing fires the above message. Which I think it’s a very good security measure, but it’s not quite useful in my scenario. Quoting the WS-Addressing standard submission (http://www.w3.org/Submission/ws-addressing/) "Due to the range of network technologies currently in wide-spread use (e.g., NAT, DHCP, firewalls), many deployments cannot assign a meaningful global URI to a given endpoint. To allow these ‘anonymous’ endpoints to initiate message exchange patterns and receive replies, WS-Addressing defines the following well-known URI for use by endpoints that cannot have a stable, resolvable URI. http://schemas.xmlsoap.org/ws/2004/08/addressing/role/anonymous" HOW can I configure my wsHttpBinding Endpoint to address my Firewall’s IP and to ignore or bypass the address specified in the ‘To’ WS-Addressing tag in the SOAP message header? Or do I have to change something in my service endpoint configuration? Help and guidance will be much appreciated. Marko. P.S.: While I find any solution to this, I’m using basicHttpBinding with absolutely no problem of course.

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• WPF Formatting Issues - Automatically stretching and resizing?

  - by Adam S

  I'm very new to WPF and XAML. I am trying to design a basic data entry form. I have used a stack panel holding four more stack panels to get the layout I want. Perhaps a grid would be better for this, I am not sure. Here is an image of my form in action: http://yfrog.com/7gscreenshot1impp And here is the XAML code that generates it: <Window x:Class="Test1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="224" Width="536.762"> <StackPanel Height="Auto" Name="stackPanel1" Width="Auto" Orientation="Horizontal"> <StackPanel Height="Auto" Name="stackPanel2" Width="Auto"> <Label Height="Auto" Name="label1" Width="Auto">Patient Name:</Label> <Label Height="Auto" Name="label2" Width="Auto">Physician:</Label> <Label Height="Auto" Name="label3" Width="Auto">Insurance:</Label> <Label Height="Auto" Name="label4" Width="Auto">Therapy Goals:</Label> </StackPanel> <StackPanel Height="Auto" Name="stackPanel3" Width="Auto"> <TextBox Height="Auto" Name="textBox1" Width="Auto" Padding="3" Margin="1" /> <TextBox Height="Auto" Name="textBox2" Width="Auto" Padding="3" Margin="1" /> <TextBox Height="Auto" Name="textBox3" Width="Auto" Padding="3" Margin="1" /> <TextBox Height="Auto" Name="textBox4" Width="Auto" Padding="3" Margin="1" /> </StackPanel> <StackPanel Height="Auto" Name="stackPanel4" Width="Auto"> <Label Height="Auto" Name="label5" Width="Auto">Date:</Label> <Label Height="Auto" Name="label6" Width="Auto">Patient Phone:</Label> <Label Height="Auto" Name="label7" Width="Auto">Facility:</Label> <Label Height="Auto" Name="label8" Width="Auto">Referring Physician:</Label> </StackPanel> <StackPanel Height="Auto" Name="stackPanel5" Width="Auto"> <TextBox Height="Auto" Name="textBox5" Width="Auto" Padding="3" Margin="1" /> <TextBox Height="Auto" Name="textBox6" Width="Auto" Padding="3" Margin="1" /> <TextBox Height="Auto" Name="textBox7" Width="Auto" Padding="3" Margin="1" /> <TextBox Height="Auto" Name="textBox8" Width="Auto" Padding="3" Margin="1" /> </StackPanel> </StackPanel> </Window> What I really want is for the text boxes to stretch equally to fill up the space horizontally. I would also like for the controls in each vertical stackpanel to 'spread out' evenly as the window is resized vertically. Can any of you experts out there help me out?

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• How to Practice Unix Programming in C?

  - by danben

  After five years of professional Java (and to a lesser extent, Python) programming and slowly feeling my CS education slip away, I decided I wanted to broaden my horizons / general usefulness to the world and do something that feels more (to me) like I really have an influence over the machine. I chose to learn C and Unix programming since I feel like that is where many of the most interesting problems are. My end goal is to be able to do this professionally, if for no other reason than the fact that I have to spend 40-50 hours per week on work that pays the bills, so it may as well also be the type of coding I want to get better at. Of course, you don't get hired to do things you haven't dont before, so for now I am ramping up on my own. To this end, I started with K&R, which was a great resource in part due to the exercises spread throughout each chapter. After that I moved on to Computer Systems: A Programmer's Perspective, followed by ten chapters of Advanced Programming in the Unix Environment. When I am done with this book, I will read Unix Network Programming. What I'm missing in the Stevens books is the lack of programming problems; they mainly document functionality and provide examples, with a few end-of-chapter questions following. I feel that I would benefit much more from being challenged to use the knowledge in each chapter ala K&R. I could write some test program for each function, but this is a less desirable method as (1) I would probably be less motivated than if I were rising to some external challenge, and (2) I will naturally only think to use the function in the ways that have already occurred to me. So, I'd like to get some recommendations on how to practice. Obviously, my first choice would be to find some resource that has Unix programming challenges. I have also considered finding and attempting to contribute to some open source C project, but this is a bit daunting as there would be some overhead in learning to use the software, then learning the codebase. The only open-source C project I can think of that I use regularly is Python, and I'm not sure how easy that would be to get started on. That said, I'm open to all kinds of suggestions as there are likely things I haven't even thought of.

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• Maven best practice for generating multiple jars with different/filtered classes ?

  - by jaguard

  I developed a Java utility library (similarly to Apache Commons) that I use in various projects. Additionally to fat clients I also use it for mobile clients (PDA with J9 Foundation profile). In time the library that started as a single project spread over multiple packages. As a result I end up with a lot of functionality but not really needed in all the projects. Since this library is also used inside some mobile/PDA projects I need a way to collect just the used classes and generate the actual specialized jars Currently in the projects that area using this library, I have Ant jar tasks that generate (from the utility project) the specialized jar files (ex: my-util-1.0-pda.jar, my-util-1.0-rcp.jar) using include/exclude jar task features. This is mostly needed due to the generated jar size constraints for the mobile projects. Migrating now to Maven I just wonder if there are any best practices to arrive to something similar so I consider the following scenarios: [1] - additionally to the main jar artifact (my-lib-1.0.jar) also generating inside my-lib project the separate/specialized artifacts using classifiers (ex: my-lib-1.0-pda.jar) using Maven Jar Plugin or Maven Assembly Plugin filtering/includes ... I'm not very comfortable with this approach since it pollute the library with library consumers demands (filters) [2] - Create additional Maven projects for all the specialized clients/projects, that will "wrap" the "my-lib" and generate the filtered jar artifacts (ex: my-lib-wrapper-pda-1.0 ...etc). As a result, these wrapper projects will include the filtering (to generate the filtered artifact) and will depend just on the "my-lib" project and the client projects will depend on my-lib-wrapper-xxx-1.0 instead of my-lib-1.0. This approach my look problematic since even that will let "my-lib" project intact (with no additional classifiers & artifacts), basically will double the number of projects since for every client project I'll have one just to collect the needed classes from the "my-util" library ("my-pda-app" project will need a "my-lib-wrapper-for-my-pda-app" project/dependency) [3] - Into the every client project that use the library (ex: my-pda-app) add some specialized Maven plugins to trim - out (when generating the final artifact/package) the un-needed classes (ex: maven-assembly-plugin, maven-jar-plugin, proguard-maven-plugin) What is the best practice for solving this kind of problems in the "Maven way" ?!

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• Why does PostgresQL query performance drop over time, but restored when rebuilding index

  - by Jim Rush

  According to this page in the manual, indexes don't need to be maintained. However, we are running with a PostgresQL table that has a continuous rate of updates, deletes and inserts that over time (a few days) sees a significant query degradation. If we delete and recreate the index, query performance is restored. We are using out of the box settings. The table in our test is currently starting out empty and grows to half a million rows. It has a fairly large row (lots of text fields). We are search is based of an index, not the primary key (I've confirmed the index is being used, at least under normal conditions) The table is being used as a persistent store for a single process. Using PostgresQL on Windows with a Java client I'm willing to give up insert and update performance to keep up the query performance. We are considering rearchitecting the application so that data is spread across various dynamic tables in a manner that allows us to drop and rebuild indexes periodically without impacting the application. However, as always, there is a time crunch to get this to work and I suspect we are missing something basic in our configuration or usage. We have considered forcing vacuuming and rebuild to run at certain times, but I suspect the locking period for such an action would cause our query to block. This may be an option, but there are some real-time (windows of 3-5 seconds) implications that require other changes in our code. Additional information: Table and index CREATE TABLE icl_contacts ( id bigint NOT NULL, campaignfqname character varying(255) NOT NULL, currentstate character(16) NOT NULL, xmlscheduledtime character(23) NOT NULL, ... 25 or so other fields. Most of them fixed or varying character fiel ... CONSTRAINT icl_contacts_pkey PRIMARY KEY (id) ) WITH (OIDS=FALSE); ALTER TABLE icl_contacts OWNER TO postgres; CREATE INDEX icl_contacts_idx ON icl_contacts USING btree (xmlscheduledtime, currentstate, campaignfqname); Analyze: Limit (cost=0.00..3792.10 rows=750 width=32) (actual time=48.922..59.601 rows=750 loops=1) - Index Scan using icl_contacts_idx on icl_contacts (cost=0.00..934580.47 rows=184841 width=32) (actual time=48.909..55.961 rows=750 loops=1) Index Cond: ((xmlscheduledtime < '2010-05-20T13:00:00.000'::bpchar) AND (currentstate = 'SCHEDULED'::bpchar) AND ((campaignfqname)::text = '.main.ee45692a-6113-43cb-9257-7b6bf65f0c3e'::text)) And, yes, I am aware there there are a variety of things we could do to normalize and improve the design of this table. Some of these options may be available to us. My focus in this question is about understanding how PostgresQL is managing the index and query over time (understand why, not just fix). If it were to be done over or significantly refactored, there would be a lot of changes.

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• SaaS Architecture Question from Newbie

  - by user226767

  I have developed a number of departmental client-server applications, and am now ready to begin working on moving one of these applications to a SaaS model. I have done some basic web development, but I'm a newbie when it comes to SaaS architectures. One of the first questions that comes to mind as I try to design the architecture is the question of single vs. multi tenancy. The pros and cons of each vary significantly depending on the type of application and scale required, so I'd like to describe my application and scale needs below, and hope others can comment on how I should get started with the architecture. The client-server application currently consists of a Firebird database and a Windows application. The database contains about 20 tables containing a few thousand records in 4 primary tables, and a few hundred records in various lookup and related tables. Although the number of records is small, the size can get large, as the database can contain large BLOBS. Each customer sets up their own database and has a handful of users within the organization connected to it. When I update the db schema, a new windows application is released, and it checks the db schema and then applies the updates as needed. For the SaaS application, I am designing for 100's (not 1000's or millions) of new customers per year. My first thought was to go with a multi tenancy model to make updates easy (shut down apply the updates to one database, and then start up). On the other hand, a single tenancy model would provide a means to roll updates out to a group of customers at a time, and spread the risk of data corruption - i.e. if something goes wrong with a database, it will impact one customer instead of all customers. With this idea, I was thinking of having a single web front-end which would connect to a single customer database upon login. Thus, when a new customer creates an account, a new database would be created (each customer would have their own db with multiple users as needed for the customer). In this model, a db update would require either a process to go through each db to apply schema changes, or a trigger upon logging in to initiate a schema update similar to the client-server model currently in use. Can anyone point me to information for similar applications which have been ported from client-server to SaaS? Or provide any pointers to consider? Basically I'm looking for architecture examples of taking a departmental application and making it available as a self service website for multiple customers. Thanks for any suggestions, resources, etc.

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• How to I serialize a large graph of .NET object into a SQL Server BLOB without creating a large bu

  - by Ian Ringrose

  We have code like: ms = New IO.MemoryStream bin = New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bin.Serialize(ms, largeGraphOfObjects) dataToSaveToDatabase = ms.ToArray() // put dataToSaveToDatabase in a Sql server BLOB But the memory steam allocates a large buffer from the large memory heap that is giving us problems. So how can we stream the data without needing enough free memory to hold the serialized objects. I am looking for a way to get a Stream from SQL server that can then be passed to bin.Serialize() so avoiding keeping all the data in my processes memory. Likewise for reading the data back... Some more background. This is part of a complex numerical processing system that processes data in near real time looking for equipment problems etc, the serialization is done to allow a restart when there is a problem with data quality from a data feed etc. (We store the data feeds and can rerun them after the operator has edited out bad values.) Therefore we serialize the object a lot more often then we de-serialize them. The objects we are serializing include very large arrays mostly of doubles as well as a lot of small “more normal” objects. We are pushing the memory limit on a 32 bit system and make the garage collector work very hard. (Effects are being made elsewhere in the system to improve this, e.g. reusing large arrays rather then create new arrays.) Often the serialization of the state is the last straw that courses an out of memory exception; our peak memory usage is while this serialization is being done. I think we get large memory pool fragmentation when we de-serialize the object, I expect there are also other problem with large memory pool fragmentation given the size of the arrays. (This has not yet been investigated, as the person that first looked at this is a numerical processing expert, not a memory management expert.) Are customers use a mix of Sql Server 2000, 2005 and 2008 and we would rather not have different code paths for each version of Sql Server if possible. We can have many active models at a time (in different process, across many machines), each model can have many saved states. Hence the saved state is stored in a database blob rather then a file. As the spread of saving the state is important, I would rather not serialize the object to a file, and then put the file in a BLOB one block at a time. Other related questions I have asked How to Stream data from/to SQL Server BLOB fields? Is there a SqlFileStream like class that works with Sql Server 2005?

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• Rails 3.1 text_field form helper and jQuery datepicker date format

  - by DanyW

  I have a form field in my Rails view like this: <%= f.text_field :date, :class => "datepicker" %> A javascript function converts all input fields of that class to a jQueryUI datepicker. $(".datepicker").datepicker({ dateFormat : "dd MM yy", buttonImageOnly : true, buttonImage : "<%= asset_path('iconDatePicker.gif') %>", showOn : "both", changeMonth : true, changeYear : true, yearRange : "c-20:c+5" }) So far so good. I can edit the record and it persists the date correctly all the way to the DB. My problem is when I want to edit the record again. When the form is pre-populated from the record it displays in 'yyyy-mm-dd' format. The javascript only formats dates which are selected in the datepicker control. Is there any way I can format the date retrieved from the database? At which stage can I do this? Thanks, Dany. Some more details following the discussion below, my form is spread across two files, a view and a partial. Here's the view: <%= form_tag("/shows/update_individual", :method => "put") do %> <% for show in @shows %> <%= fields_for "shows[]", show do |f| %> <%= render "fields", :f => f %> <% end %> <% end %> <%= submit_tag "Submit"%> <% end %> And here's the _fields partial view: <p> <%= f.label :name %> <%= f.text_field :name %> </p> <p> <%= f.date %> <%= f.label :date %> <%= f.text_field :date, :class => "datepicker" %> </p> Controller code: def edit_individual @shows = Show.find(params[:show_ids]) end

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• Why is this OpenGL ES code slow on iPhone?

  - by f3r3nc

  I've slightly modified the iPhone SDK's GLSprite example while learning OpenGL ES and it turns out to be quite slow. Even in the simulator (on the hw worst) so I must be doing something wrong since it's only 400 textured triangles. const GLfloat spriteVertices[] = { 0.0f, 0.0f, 100.0f, 0.0f, 0.0f, 100.0f, 100.0f, 100.0f }; const GLshort spriteTexcoords[] = { 0,0, 1,0, 0,1, 1,1 }; - (void)setupView { glViewport(0, 0, backingWidth, backingHeight); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(0.0f, backingWidth, backingHeight,0.0f, -10.0f, 10.0f); glMatrixMode(GL_MODELVIEW); glClearColor(0.3f, 0.0f, 0.0f, 1.0f); glVertexPointer(2, GL_FLOAT, 0, spriteVertices); glEnableClientState(GL_VERTEX_ARRAY); glTexCoordPointer(2, GL_SHORT, 0, spriteTexcoords); glEnableClientState(GL_TEXTURE_COORD_ARRAY); // sprite data is preloaded. 512x512 rgba8888 glGenTextures(1, &spriteTexture); glBindTexture(GL_TEXTURE_2D, spriteTexture); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, spriteData); free(spriteData); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glEnable(GL_TEXTURE_2D); glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); glEnable(GL_BLEND); } - (void)drawView { .. glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glTranslatef(tx-100, ty-100,10); for (int i=0; i<200; i++) { glTranslatef(1, 1, 0); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); } .. } drawView is called every time the screen is touched or the finger on the screen is moved and tx,ty are set to the x,y coordinates where that touch happened. I've also tried using GLBuffer, when translation was pre-generated and there was only one DrawArray but gave the same performance (~4 FPS). ===EDIT=== Meanwhile I've modified this so that much smaller quads are used (sized: 34x20) and much less overlapping is done. There are ~400 quads-800 triangles spread on the whole screen. Texture size is 512x512 atlas and RGBA_8888 while the texture coordinates are in float. The code is very ugly in terms of API efficiency: there are two MatrixMode change along with two loads and two translation then a drawarrays for a triangle strip (quad). Now this produces ~45 FPS.

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• Exception: attempt to acquire a reference on a close SQLiteClosable

  - by CommonsWare

  I posted this back in May on the [android-developers] Google Group. I never heard back and was not able to reproduce the problem until one of my students did last week. I figured I'd post it here and see if it rang any bells for anyone. In one of my code samples, I have the following method: static Cursor getAll(SQLiteDatabase db, String orderBy) { return(db.rawQuery("SELECT * FROM restaurants "+orderBy, null)); } When I run it, sporadically, I get this: 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): java.lang.IllegalStateException: attempt to acquire a reference on a close SQLiteClosable 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:31) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:56) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:49) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1118) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1092) 05-01 14:45:05.849: ERROR/AndroidRuntime(1145): at apt.tutorial.Restaurant.getAll(Restaurant.java:14) This makes no sense to me. The database is definitely open. The SQLiteClosable is the SQLiteQuery created by SQLiteQueryDriver, and I see no evidence that there is an object pool or something going on here that might explain how a "new" SQLiteClosable is already closed. The fact that it is sporadic (meaning the same UI operations sometimes trigger the exception, but not always) suggests some sort of pool, race condition, or something...but I'm not sure where. Thoughts? Thanks! UPDATE: The code in question is from the LunchList tutorials out of my Android Programming Tutorials book. It's a bit spread out and not terribly suitable for posting directly in SO. You can download the code for that book from the above link if you want to take a look at it. I do not recall exactly which edition of the tutorial the student was working on at the time, though it was in the Tutorial 12-Tutorial 16 range. I was mostly hoping to run across somebody who had tripped over this problem before and had a likely culprit. I'm fairly certain my database is open. Thanks again!

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• How do you prevent IDisposable from spreading to all your classes?

  - by GrahamS

  Start with these simple classes... Let's say I have a simple set of classes like this: class Bus { Driver busDriver = new Driver(); } class Driver { Shoe[] shoes = { new Shoe(), new Shoe() }; } class Shoe { Shoelace lace = new Shoelace(); } class Shoelace { bool tied = false; } A Bus has a Driver, the Driver has two Shoes, each Shoe has a Shoelace. All very silly. Add an IDisposable object to Shoelace Later I decide that some operation on the Shoelace could be multi-threaded, so I add an EventWaitHandle for the threads to communicate with. So Shoelace now looks like this: class Shoelace { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; // ... other stuff .. } Implement IDisposable on Shoelace Buit now FxCop will complain: "Implement IDisposable on 'Shoelace' because it creates members of the following IDisposable types: 'EventWaitHandle'." Okay, I implement IDisposable on Shoelace and my neat little class becomes this horrible mess: class Shoelace : IDisposable { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; private bool disposed = false; public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } ~Shoelace() { Dispose(false); } protected virtual void Dispose(bool disposing) { if (!this.disposed) { if (disposing) { if (waitHandle != null) { waitHandle.Close(); waitHandle = null; } } // No unmanaged resources to release otherwise they'd go here. } disposed = true; } } Or (as pointed out by commenters) since Shoelace itself has no unmanaged resources, I might use the simpler dispose implementation without needing the Dispose(bool) and Destructor: class Shoelace : IDisposable { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; public void Dispose() { if (waitHandle != null) { waitHandle.Close(); waitHandle = null; } GC.SuppressFinalize(this); } } Watch in horror as IDisposable spreads Right that's that fixed. But now FxCop will complain that Shoe creates a Shoelace, so Shoe must be IDisposable too. And Driver creates Shoe so Driver must be IDisposable. and Bus creates Driver so Bus must be IDisposable and so on. Suddenly my small change to Shoelace is causing me a lot of work and my boss is wondering why I need to checkout Bus to make a change to Shoelace. The Question How do you prevent this spread of IDisposable, but still ensure that your unmanaged objects are properly disposed?

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• Which programming language to choose? (for a specific problem/domain, details inside)

  - by Bijan

  I am building a trading portfolio management system that is responsible for production, optimization, and simulation of non-high frequency trading portfolios (dealing with 1min or 3min bars of data, not tick data). I plan on employing Amazon web services to take on the entire load of the application. I have four choices that I am considering as language. a) Java b) C++ c) C# d) Python Here is the scope of the extremes of the project scope. This isn't how it will be, maybe ever, but it's within the scope of the requirements: Weekly simulation of 10,000,000 trading systems. (Each trading system is expected to have its own data mining methods, including feature selection algorithms which are extremely computationally-expensive. Imagine 500-5000 features using wrappers. These are not run often by any means, but it's still a consideration) Real-time production of portfolio w/ 100,000 trading strategies Taking in 1 min or 3 min data from every stock/futures market around the globe (approx 100,000) Portfolio optimization of portfolios with up to 100,000 strategies. (rather intensive algorithm) Speed is a concern, but I believe that Java can handle the load. I just want to make sure that Java CAN handle the above requirements comfortably. I don't want to do the project in C++, but I will if it's required. The reason C# is on there is because I thought it was a good alternative to Java, even though I don't like Windows at all and would prefer Java if all things are the same. Python - I've read somethings on PyPy and pyscho that claim python can be optimized with JIT compiling to run at near C-like speeds.... That's pretty much the only reason it is on this list, besides that fact that Python is a great language and would probably be the most enjoyable language to code in, which is not a factor at all for this project, but a perk. To sum up: - real time production - weekly simulations of a large number of systems - weekly/monthly optimizations of portfolios - large numbers of connections to collect data from There is no dealing with millisecond or even second based trades. The only consideration is if Java can possibly deal with this kind of load when spread out of a necessary amount of EC2 servers. Thank you guys so much for your wisdom.

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• Xcode + Perforce: it frequently shows me the spinning wheel for no reason! What can i do?

  - by GamingHorror

  While working on an Xcode project i keep getting the spinning wheel while switching files, scrolling, searching, typing, debugging, removing breakpoints, switching back from another app or saving. It also happens before compiling but usually it just happens from time to time for no apparent reason. This is the second time this started happening in a Xcode project and it's driving me nuts. It completely breaks my flow of work to have to wait for the spinning wheel to go away (2-5 seconds). What on earth could i possibly do to ... figure out what's causing the problem? resolve the problem? More details: When any project is small, everything is super-smooth with Xcode and Perforce. Two of my projects eventually had this spinning wheel problem after about 4 weeks of work. It only happened with those two projects so far. They consist of around 1000-1200 files in source control, most of them assets. The problem occurs even if i manually check out the whole project in Perforce. The problem is gone when i copy the project directory and work in the copy which is no longer under source control, or if i create a branch in Perforce and work in the branch (under source control). One of these projects i shared with a colleague, and he had exactly the same issues on his Mac. We eventually switched to Subversion and the spinning-wheel issue immediately went away. Now that i've received an updated copy of the project and simply put it under Perforce as a new project, the problem also went away (so far it did not resurface). It leads me to think that it may be caused by a larger number of file revisions. The server itself (version 2009.1) is on a different (Windows) machine on my LAN, so there's definetely no Internet lag involved. The complete repository is just 1 GB in size spread over a dozen projects or so. I'm sorry if the question seems more like a support inquiry for Perforce. However i'm using the free version of Perforce so i'm not entitled to get support from them. I hope no one minds me asking here. I'm really bummed out by this. I don't want to have to create a new branch for the project each time the spinning wheel problem surfaces.

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• Efficiently fetching and storing tweets from a few hundred twitter profiles?

  - by MSpreij

  The site I'm working on needs to fetch the tweets from 150-300 people, store them locally, and then list them on the front page. The profiles sit in groups. The pages will be showing the last 20 tweets (or 21-40, etc) by date, group of profiles, single profile, search, or "subject" (which is sort of a different group.. I think..) a live, context-aware tag cloud (based on the last 300 tweets of the current search, group of profiles, or single profile shown) various statistics (group stuffs, most active, etc) which depend on the type of page shown. We're expecting a fair bit of traffic. The last, similar site peaked at nearly 40K visits per day, and ran intro trouble before I started caching pages as static files, and disabling some features (some, accidently..). This was caused mostly by the fact that a page load would also fetch the last x tweets from the 3-6 profiles which had not been updated the longest.. With this new site I can fortunately use cron to fetch tweets, so that helps. I'll also be denormalizing the db a little so it needs less joins, optimize it for faster selects instead of size. Now, main question: how do I figure out which profiles to check for new tweets in an efficient manner? Some people will be tweeting more often than others, some will tweet in bursts (this happens a lot). I want to keep the front page of the site as "current" as possible. If it comes to, say, 300 profiles, and I check 5 every minute, some tweets will only appear an hour after the fact. I can check more often (up to 20K) but want to optimize this as much as possible, both to not hit the rate limit and to not run out of resources on the local server (it hit mysql's connection limit with that other site). Question 2: since cron only "runs" once a minute, I figure I have to check multiple profiles each minute - as stated, at least 5, possibly more. To try and spread it out over that minute I could have it sleep a few seconds between batches or even single profiles. But then if it takes longer than 60 seconds altogether, the script will run into itself. Is this a problem? If so, how can I avoid that? Question 3: any other tips? Readmes? URLs?

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• Recommendations for distributed processing/distributed storage systems

  - by Eddie

  At my organization we have a processing and storage system spread across two dozen linux machines that handles over a petabyte of data. The system right now is very ad-hoc; processing automation and data management is handled by a collection of large perl programs on independent machines. I am looking at distributed processing and storage systems to make it easier to maintain, evenly distribute load and data with replication, and grow in disk space and compute power. The system needs to be able to handle millions of files, varying in size between 50 megabytes to 50 gigabytes. Once created, the files will not be appended to, only replaced completely if need be. The files need to be accessible via HTTP for customer download. Right now, processing is automated by perl scripts (that I have complete control over) which call a series of other programs (that I don't have control over because they are closed source) that essentially transforms one data set into another. No data mining happening here. Here is a quick list of things I am looking for: Reliability: These data must be accessible over HTTP about 99% of the time so I need something that does data replication across the cluster. Scalability: I want to be able to add more processing power and storage easily and rebalance the data on across the cluster. Distributed processing: Easy and automatic job scheduling and load balancing that fits with processing workflow I briefly described above. Data location awareness: Not strictly required but desirable. Since data and processing will be on the same set of nodes I would like the job scheduler to schedule jobs on or close to the node that the data is actually on to cut down on network traffic. Here is what I've looked at so far: Storage Management: GlusterFS: Looks really nice and easy to use but doesn't seem to have a way to figure out what node(s) a file actually resides on to supply as a hint to the job scheduler. GPFS: Seems like the gold standard of clustered filesystems. Meets most of my requirements except, like glusterfs, data location awareness. Ceph: Seems way to immature right now. Distributed processing: Sun Grid Engine: I have a lot of experience with this and it's relatively easy to use (once it is configured properly that is). But Oracle got its icy grip around it and it no longer seems very desirable. Both: Hadoop/HDFS: At first glance it looked like hadoop was perfect for my situation. Distributed storage and job scheduling and it was the only thing I found that would give me the data location awareness that I wanted. But I don't like the namename being a single point of failure. Also, I'm not really sure if the MapReduce paradigm fits the type of processing workflow that I have. It seems like you need to write all your software specifically for MapReduce instead of just using Hadoop as a generic job scheduler. OpenStack: I've done some reading on this but I'm having trouble deciding if it fits well with my problem or not. Does anyone have opinions or recommendations for technologies that would fit my problem well? Any suggestions or advise would be greatly appreciated. Thanks!

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• Postfix logs missing information on delivery status (postfix/smtp message)

  - by hegemon

  I noticed a problem with postfix logs, that information on some of emails delivery status is missing. The issue affects about 1% of emails. "Healthy" log: <server># grep 8EB992EFBB44 postfix_log/mail04.log Jun 5 03:09:29 mail04 postfix/smtpd[8537]: 8EB992EFBB44: client=xxx.xxx.xxx[xxx.xxx.xxx.xxx] Jun 5 03:09:29 mail04 postfix/cleanup[34349]: 8EB992EFBB44: message-id=<[email protected]> Jun 5 03:12:02 mail04 postfix/qmgr[76377]: 8EB992EFBB44: from=<[email protected]>, size=48845, nrcpt=1 (queue active) Jun 5 03:15:12 mail04 postfix/smtp[35058]: 8EB992EFBB44: to=<[email protected]>, relay=mx.baz.com[xxx.xxx.xxx.xxx]:25, conn_use=70, delay=343, delays=153/190/0/0.24, dsn=2.0.0, status=sent (250 ok) Jun 5 03:15:12 mail04 postfix/qmgr[76377]: 8EB992EFBB44: removed "Broken" log: <server># grep F3C362EF37CA postfix_log/mail04.log Jun 5 04:03:27 mail04 postfix/smtpd[39666]: F3C362EF37CA: client=xxx.xxx.xxx[xxx.xxx.xxx.xxx] Jun 5 04:03:27 mail04 postfix/cleanup[41287]: F3C362EF37CA: message-id=<[email protected]> Jun 5 04:03:28 mail04 postfix/qmgr[76377]: F3C362EF37CA: from=<[email protected]>, size=48892, nrcpt=1 (queue active) ** here should be a log line from postfix/smtp but there is none ** Jun 5 04:03:29 mail04 postfix/qmgr[76377]: F3C362EF37CA: removed Background information: system: FreeBSD xxx.xxx.xxx 8.2-RELEASE FreeBSD 8.2-RELEASE #0: Thu Feb 17 02:41:51 UTC 2011 [email protected]:/usr/obj/usr/src/sys/GENERIC amd64 Postfix is installed inside jail. Logs are on the same machine, log dir is mounted thru nullfs. The site has spikes of heavy load, causing disks (local) to run at 100%. Update The log is rotated daily, current size is ~ 500MB. I made a test by queuing 99000 messages to same destination (in order to rule out dns/network/mx issues). 5715 messages don't have any DSN record. Failed messages queue time is spread evenly over time, i don't see any time-bound issues. Some undelivered emails: envelopeid | processed_time --------------+---------------------------- 8D7652EF3BAE | 2012-06-06 13:19:11.072715 DD53A2EF3C5C | 2012-06-06 13:33:24.374783 8C52F2EF4E3F | 2012-06-06 13:39:15.810616 BBC572EF525C | 2012-06-06 13:44:22.762812 E95822EF54D1 | 2012-06-06 13:52:01.134533 839DD2EF4FBB | 2012-06-06 14:13:48.511236 017EE2EF6234 | 2012-06-06 15:04:48.618963 Those are a few picks, such records of undelivered email occur almost every second. <server># egrep '(8D7652EF3BAE|BBC572EF525C|017EE2EF6234)' mail04.log Jun 6 13:19:10 mail04 postfix/smtpd[20350]: 8D7652EF3BAE: client=xxx.xxx.xxx[xxx.xxx.xxx.xxx] Jun 6 13:19:10 mail04 postfix/cleanup[21024]: 8D7652EF3BAE: message-id=<[email protected]> Jun 6 13:19:10 mail04 postfix/qmgr[7939]: 8D7652EF3BAE: from=<[email protected]>, size=63718, nrcpt=1 (queue active) Jun 6 13:19:11 mail04 postfix/qmgr[7939]: 8D7652EF3BAE: removed Jun 6 13:44:22 mail04 postfix/smtpd[20346]: BBC572EF525C: client=xxx.xxx.xxx[xxx.xxx.xxx.xxx] Jun 6 13:44:22 mail04 postfix/cleanup[24811]: BBC572EF525C: message-id=<[email protected]> Jun 6 13:44:22 mail04 postfix/qmgr[7939]: BBC572EF525C: from=<[email protected]>, size=63758, nrcpt=1 (queue active) Jun 6 15:04:49 mail04 postfix/smtpd[20344]: 017EE2EF6234: client=xxx.xxx.xxx[xxx.xxx.xxx.xxx] Jun 6 15:04:49 mail04 postfix/cleanup[35585]: 017EE2EF6234: message-id=<[email protected]> Jun 6 15:04:49 mail04 postfix/qmgr[7939]: 017EE2EF6234: from=<[email protected]>, size=63706, nrcpt=1 (queue active) <server># <server># find /var/spool/postfix/active/ -type f -print | wc -l 1 <server># IMPORTANT: As you can see above some of emails doesn't event have the removed line.

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• Choice of an OS for a home ZFS NAS

  - by OlafM

  I am preparing a home NAS with an old Athlon 64 X2 3800+, 4 GB ECC RAM, Asus M2V MX motherboard, and a single 3 TB WDC Green (another one as mirror may be installed in the future). It's the cheapest solution I found that includes ECC memory and the higher energy consumption is offset by the lower (zero) cost of acquisition. The system will be used for: music storage and stream to other desktop computers; storage of the scanned dia slides (3-4k slides, 180 MB TIFF each one plus reduced quality JPEG version); stream of these photos to a local iPad 2 (maybe Plex App? not yet sure); (one additional) remote backup via rsync/ssh or ZFS send/receive. It will be controlled via remote ssh, maybe VNC, no monitor attached. Absolute requirement is a reliable ZFS solution, plus the ability to easily install packets/software/virtual machines and to update remotely (I will be the admin and I don't live near the NAS). I have mainly three options: NAS4free/FreeNAS OpenIndiana Solaris Express 11 (yeah yeah I know the license requirements, I will write a perl script on it to count it as development machine). Problems: NAS4free/FreeNAS (I tested only NAS4free) required embedded installation for remote upgrading, but full install for easy addition of software packets. Since I need at least AirVideo Server (linux/win) and Plex App (win/linux) to stream the photos and some videos to iPad (they both require virtualbox), but I cannot be there to install updates, NAS4free/FreeNAS are excluded. http://www.nas4free.org/general_information.html explains the issue: embedded can be remotely updated, full cannot. Solaris has also another advantage: Crashplan client supports Solaris and I'm already using it for other backups. I would like to leave the option open, even if I will be doing backups probably through zfs send/receive. NexentaStor was left out because zfs send/receive are not included in the free version. The question is now Solaris 11 Express over OpenIndiana. To ease the management, I will be using http://www.napp-it.org Which one would you suggest and why? I found lots of informations and it's difficult for me to decide. I think (from the napp-it manual) that Solaris has some additional options for SMB shares, but are they really needed at home? I think I won't even use ACLs, since normal unix-style permissions are enough. OpenIndiana has maybe more frequent updates (Solaris offers only security updates between releases), but again, do I need them? I don't think so. Moreover, this is a NAS that has to work and nothing else, I cannot risk having problems that require me to access the server. Isn't OpenIndiana a bit more... cutting edge (in the Solaris world)? I'm just asking, no need to focus on this for the answer :-) I would limit myself to these two options (SE11.1/OI) also because I will be making a NAS for me in the future (where high performances with Mac shares are also required) and Solaris has kernel support for AFP. I will use this server to gather experience as well. After this long question, thanks in advance! If you need additional info, let me know and I will update this post. UPDATES Given the first answers, I will strongly suggest the person paying the hardware to insert a second HD. Better 2x2TB than 1x3TB (3 TB is oversized anyway). I was trying to keep the initial costs down to spread them over a longer period, but better having something good from the beginning.

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• Week in Geek: FBI Back Door in OpenBSD Edition

  - by Asian Angel

  This week we learned how to migrate bookmarks from Delicious to Diigo, fix annoying arrows, play old-school DOS games, schedule smart computer shutdowns, use breaks in Microsoft Word to better format documents, check the condition of hard-disks using Linux disk utilities, & what the Linux fstab is and how it works. Photo by Jameson42. Random Geek Links Another week with extra news link goodness to help keep you up to date. Photo by justmakeit. Report of FBI back door roils OpenBSD community Allegations that the FBI surreptitiously placed a back door into the OpenBSD operating system have alarmed the computer security community, prompting calls for an audit of the source code and claims that the charges must be a hoax. Fortinet: Job outlook improving for cybercrooks In an ironic twist in the job market, more positions will open up for developers who can write customized malware packers, people who can break CAPTCHA codes, and distributors who can spread malicious code, according to Fortinet. Enisa: Malware for smartphones is a ’serious risk’ Businesses and consumers are at risk of data breaches through smartphone use, according to the European Network and Information Security Agency. The trick with the f: Google and Microsoft web sites distribute malware Last week, Google’s DoubleClick advertising platform and Microsoft’s rad.msn.com online ad network briefly distributed malware to other web sites in the form of advertising banners. New scam tactic: Fake disk defraggers It would appear that scammers are trying out new programs to see which might best confuse potential victims and evade detection by legitimate antivirus software. Microsoft closes IE and Stuxnet holes As previously announced, Microsoft has released 17 security updates to close 40 security holes. All four Windows holes so far disclosed in connection with Stuxnet have now been closed. Microsoft Offers H.264 Support to Firefox on Windows via Add-On The new HTML5 Extension for Windows Media Player Firefox Plug-in add-on from Microsoft offers users that are running Firefox on Windows 7 H.264 support for HTML5 video playback. Google proclaims Chrome business-ready Google has announced that Chrome is ready for corporate use. Microsoft Tells Exchange Customers to Think Twice Before Opting for Google Message Continuity This week, Microsoft is telling companies still running Exchange 2010’s precursors that they should carefully consider the implications of embracing Google Message Continuity. Who Google has in mind for its Chrome OS users Steven Vaughan-Nichols explains why he feels that Chrome OS will be ideal for either office-workers or people who need a computer, but do not know the first thing about how to use one safely. Oracle takes office suite to the cloud Oracle has introduced Cloud Office 1.0, a cloud-based version of its office suite, which is aimed at web and mobile users. Mozilla pays premiums for reports of vulnerabilities The Mozilla Foundation has followed Google’s example by expanding its rewards program for reports of vulnerabilities in its Web applications. Who bought those 882 Novell patents? Not just Microsoft The mysterious CPTN Holdings — the organization that bought the 882 Novell patents as part of the terms of the Attachmate acquisition of Novell – has been unmasked (Microsoft, Apple, EMC and Oracle). Appeals court: Feds need warrants for e-mail Police must obtain search warrants before perusing Internet users’ e-mail records, a federal appeals court ruled today in a landmark decision that struck down part of a 1986 law allowing warrantless access. Geek Video of the Week What happens when someone plays a wicked prank by shoveling crazy snow paths that lead to dead ends or turn back on themselves? Watch to find out! Photo by CollegeHumor. Janitor Snow Shoveling Prank Random TinyHacker Links The Oatmeal on Cat vs Internet What lengths will our poor neglected kitty hero have to go to in order to get some attention? Guide On Using JoliCloud With Windows JoliCloud is a nifty operating system that’s made for people who need a light-weight OS that’s mostly cloud based. Check this guide on using it with Windows. Use Cameyo to Easily Create Portable Programs Here’s a nifty tool to make portable apps out of programs in Windows. Check out the guide to do it. Better Family Tech Support A nice new site by Google to help members of family understand how computers work. Track Your Stolen Mobile Phone With F-Secure A useful anti-theft tool for your mobile phone. Super User Questions Another week with great answers to popular questions from Super User. What Chrome password manager fits my requirements? What’s the best way to be able to reimage windows computers? Could you suggest feature-rich disk-based personal backup program for linux (and I’ve seen a few)? What is IPv6 and why should I care? Is there any way to find out what programs are trying to connect to Internet on windows? How-To Geek Weekly Article Recap Here are our hottest articles full of geeky goodness from this past week at HTG. 20 OS X Keyboard Shortcuts You Might Not Know Microsoft Security Essentials 2.0 Kills Viruses Dead. Download It Now. Is Your Desktop Printer More Expensive Than Printing Services? Ask the Readers: Would You Be Willing to Give Windows Up and Use a Different O.S.? The Twelve Days of Geekmas One Year Ago on How-To Geek Enjoy reading through our latest batch of retro-geek goodness from one year ago. Macrium Reflect is a Free and Easy To Use Backup Utility How To Turn a Physical Computer Into A Virtual Machine with Disk2vhd How To Restore Windows 7 from a System Image How To Manage Hard Drive Space Used by Windows 7 Backup and Restore How To Manage Hibernate Mode in Windows 7 The Geek Note That is all we have for you this week, so see you back here again after the holidays! Got a great tip? Send it in to us at [email protected]. Photo by mitjamavsar. Latest Features How-To Geek ETC The Complete List of iPad Tips, Tricks, and Tutorials The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Deathwing the Destroyer – WoW Cataclysm Dragon Wallpaper Drag2Up Lets You Drag and Drop Files to the Web With Ease The Spam Police Parts 1 and 2 – Goodbye Spammers [Videos] Snow Angels Theme for Windows 7 Exploring the Jungle Ruins Wallpaper Protect Your Privacy When Browsing with Chrome and Iron Browser

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