Search Results

Search found 23603 results on 945 pages for 'non technical manager'.

Page 383/945 | < Previous Page | 379 380 381 382 383 384 385 386 387 388 389 390  | Next Page >

• Ways to use your skills as a developer to give back to the community/charities.

  - by Ryan Hayes

  Recently I came upon a community event called GiveCamp. GiveCamp is a weekend-long event where technology professionals from designers, developers and database administrators to marketers and web strategists donate their time to provide solutions for non-profit organizations. Since its inception in 2007, the GiveCamp program has provided benefits to over 150 charities, with a value of developer and designer time exceeding $1,000,000 in services! Coming from a very rural part of the country where there is a huge opportunity for charity events like this, it got me wondering. Are there other large movements like GiveCamp that are out there? GiveCamp is sponsored by Microsoft, so of course most are run through .NET user groups. Are there other flavors of it? Different types? Java/Python/other open source charity movements? If not, how do you give back?

  Read the article

• "Software sources" crashes since unbuntu updated from 12.04 to 12.10

  - by Jean-Sebastien

  First of all, sorry for my English, I is not my native language. I recently updated my PC from ubuntu 12.04 to 12.10. Now “Software sources” crashes when I try to open it directly from Unity or from Ubuntu Software Center ? Software sources. When I try to open “Update manager”, I get the following error message. Note that the internet connection WROKS! W:Failed to fetch http://ppa.launchpad.net/rye/ubuntuone-extras/ubuntu/dists/quantal/main/source/Sources 404 Not Found, ... ... ... E:Some index files failed to download. They have been ignored, or old ones used instead. Please, can somebody help me on this? JS

  Read the article

• A Graduate&rsquo;s Journey at Oracle &ndash; Bhaskar Ghosh From Oracle India

  - by david.talamelli

  I am Bhaskar Ghosh, and I work as an Applications Engineer with Oracle. Well, it was three years ago when my journey with one of the largest software companies started. It was a fine day and a decisive moment, when I was placed in Oracle as a campus recruit from College of Engineering Guindy, Anna University, Chennai! I always thought of looking back, the time that helped me learn beyond my boundaries, think broader and ahead, and grow – technically, professionally and personally. Hmmn! Let me recall the eventful moments once again. My first day as an intern at Oracle started in late 2007. I met one of the Oracle Managers at the Oracle Campus in Hyderabad and on the same day I also met another Oracle employee who was to later to become my first manager. I was charged and thrilled with the environment and the wonderful people around me! I was joined by two other interns, who also had a Masters in Computer Applications. We formed a very friendly group with all the interns and the new hires, and shared our excitement and learning. Myself and one of the other Graduates started working on a very interesting project on Semantic technology. We finally had our names added as co-developers for this very project. This phase of five months was the time and we learnt tremendously and worked very hard, partly because we had to travel back and forth to our colleges to submit reports and present for the Masters in Computer Applications final year project reviews. After completing my MCA, I joined as a full-time employee in 2008. During the next year, we worked on interesting and bleeding edge technologies - OWL, RDF, SPARQL, Visualization, J2EE, Social Web features, Semantic Web technologies, Web Services and many more! We developed cool, rich internet and desktop applications. Little did I know at that time, that this learning would help me tremendously for my the next project in Oracle. The following year saw me being assigned a role in a different project that my other team members were working on for the last two years. It took me two months to understand and get into a flow with this new task. I was fortunate that this phase helped me enhance my inter-personal and communication skills, as much as it helped me grow professionally with better ability to tackle multiple priorities and switch between tasks based on the team’s requirements. I was made the POC for all communications with our team and other product teams. I personally feel that this time enhanced me tremendously in technologies like Oracle Forms, J2EE, and Java and Web Services. The last six months, saw myself becoming an Institute of Electrical and Electronics Engineer member, and continuing my higher education International Institute of Information Technology, Hyderabad. Oracle supports its employees becoming members of professional bodies, and higher studies are supported by management, I think it is tremendously helpful in the professional and technical growth of the employees. Last three months, I have been working on great and useful enhancements to our product. Ah beautiful! All these years, there have been other moments and events of fun that are too worth mentioning. Clubs and groups at Oracle such as Employee Club, Oracle Volunteers, Football Club, etc. have always kept on organizing numerous events and competitions, full of fun and entertainment. I really enjoyed participating, even if it was small, in the intra-Oracle football tourney, Oracle Volunteer Days, OraFora, OraOvations, and a few more. Those ‘Seasons of Sharing’, those ‘Blood Donation camps’, those ‘Diwali and Christmas gifts and events’, those ‘fun events at the annual function called OraOvations’, those ‘books and cycle stalls’, and those so many other things… It only fills my mind with pleasure. The last three years have been very eventful:they have been full of learning and growth, and under the very able and encouraging guidance of my manager. I have got the opportunity to know about and/or interact with many wonderful personalities, and learn from them, here at Oracle. The environment, the people, and the fellow developers have been so friendly, and always ever ready to help, when we were in doubt.. I really love the big office space, and the flexible timings, and the caring people around. I look forward to a beautiful, learning and motivating journey with Oracle.

  Read the article

• ASP.NET Web API and Simple Value Parameters from POSTed data

  - by Rick Strahl

  In testing out various features of Web API I've found a few oddities in the way that the serialization is handled. These are probably not super common but they may throw you for a loop. Here's what I found. Simple Parameters from Xml or JSON Content Web API makes it very easy to create action methods that accept parameters that are automatically parsed from XML or JSON request bodies. For example, you can send a JavaScript JSON object to the server and Web API happily deserializes it for you. This works just fine:public string ReturnAlbumInfo(Album album) { return album.AlbumName + " (" + album.YearReleased.ToString() + ")"; } However, if you have methods that accept simple parameter types like strings, dates, number etc., those methods don't receive their parameters from XML or JSON body by default and you may end up with failures. Take the following two very simple methods:public string ReturnString(string message) { return message; } public HttpResponseMessage ReturnDateTime(DateTime time) { return Request.CreateResponse<DateTime>(HttpStatusCode.OK, time); } The first one accepts a string and if called with a JSON string from the client like this:var client = new HttpClient(); var result = client.PostAsJsonAsync<string>(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, "Hello World").Result; which results in a trace like this: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 13Expect: 100-continueConnection: Keep-Alive "Hello World" produces… wait for it: null. Sending a date in the same fashion:var client = new HttpClient(); var result = client.PostAsJsonAsync<DateTime>(http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime, new DateTime(2012, 1, 1)).Result; results in this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 30Expect: 100-continueConnection: Keep-Alive "\/Date(1325412000000-1000)\/" (yes still the ugly MS AJAX date, yuk! This will supposedly change by RTM with Json.net used for client serialization) produces an error response: The parameters dictionary contains a null entry for parameter 'time' of non-nullable type 'System.DateTime' for method 'System.Net.Http.HttpResponseMessage ReturnDateTime(System.DateTime)' in 'AspNetWebApi.Controllers.AlbumApiController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Basically any simple parameters are not parsed properly resulting in null being sent to the method. For the string the call doesn't fail, but for the non-nullable date it produces an error because the method can't handle a null value. This behavior is a bit unexpected to say the least, but there's a simple solution to make this work using an explicit [FromBody] attribute:public string ReturnString([FromBody] string message) andpublic HttpResponseMessage ReturnDateTime([FromBody] DateTime time) which explicitly instructs Web API to read the value from the body. UrlEncoded Form Variable Parsing Another similar issue I ran into is with POST Form Variable binding. Web API can retrieve parameters from the QueryString and Route Values but it doesn't explicitly map parameters from POST values either. Taking our same ReturnString function from earlier and posting a message POST variable like this:var formVars = new Dictionary<string,string>(); formVars.Add("message", "Some Value"); var content = new FormUrlEncodedContent(formVars); var client = new HttpClient(); var result = client.PostAsync(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, content).Result; which produces this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/x-www-form-urlencodedHost: rasxpsContent-Length: 18Expect: 100-continue message=Some+Value When calling ReturnString:public string ReturnString(string message) { return message; } unfortunately it does not map the message value to the message parameter. This sort of mapping unfortunately is not available in Web API. Web API does support binding to form variables but only as part of model binding, which binds object properties to the POST variables. Sending the same message as in the previous example you can use the following code to pick up POST variable data:public string ReturnMessageModel(MessageModel model) { return model.Message; } public class MessageModel { public string Message { get; set; }} Note that the model is bound and the message form variable is mapped to the Message property as would other variables to properties if there were more. This works but it's not very dynamic. There's no real easy way to retrieve form variables (or query string values for that matter) in Web API's Request object as far as I can discern. Well only if you consider this easy:public string ReturnString() { var formData = Request.Content.ReadAsAsync<FormDataCollection>().Result; return formData.Get("message"); } Oddly FormDataCollection does not allow for indexers to work so you have to use the .Get() method which is rather odd. If you're running under IIS/Cassini you can always resort to the old and trusty HttpContext access for request data:public string ReturnString() { return HttpContext.Current.Request.Form["message"]; } which works fine and is easier. It's kind of a bummer that HttpRequestMessage doesn't expose some sort of raw Request object that has access to dynamic data - given that it's meant to serve as a generic REST/HTTP API that seems like a crucial missing piece. I don't see any way to read query string values either. To me personally HttpContext works, since I don't see myself using self-hosted code much.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

  Read the article

• Egy DBA napja - Utópia, vagy sem?

  - by lsarecz

  Ma délelott a HOUG BI/DW és DB szakmai napján tartottam egy eloadást arról, hogyan kellene egy DBA-nak dolgoznia manapság. A lényeg az volt, hogy az üzlet legjobb kiszolgálása érdekében célszeru a felhasználók és az alkalmazás oldaláról megközelíteni a kérdést. Azaz monitorozzuk a felhasználók elégedettségét, majd ha valami nem stimmel fúrjunk le alsóbb rétegekbe (MW, DB, OS, HW, Storage, Network), és ott folytassuk a diagnosztikát. Meglepetésemre az eloadást követoen a DB szakosztály vezetoje úgy kommentálta az eloadást, hogy ez még utópisztikus. Ma délután egy a hallgatók között ülo üzemeltetési igazgató e-mail-ben jelezte, hogy ezzel o sem ért egyet, mert ok már most is így üzemeltetnek, még ha nem is minden elemében a Grid Control-t használják. És mi sem bizonyítja jobban, hogy ez az üzemeltetési model nem utópia, mint hogy az Oracle Enterprise Manager 11g tökéletes támogatást ad minderre. Akit ezek után érdekel az eloadásom, az innen letöltheti: 1. fele, 2. fele.

  Read the article

• How do I recover a BTRFS filesystem with "parent transid verify failed" errors?

  - by Evan P.

  I've got an external USB disk running btrfs. I use it for backups, and each time I do a backup I take a snapshot. However, it's giving me this error now: parent transid verify failed on 109973766144 wanted 1823 found 1821 parent transid verify failed on 109973766144 wanted 1823 found 1821 Obviously, this is a non-critical disk, but I have a few files on here that aren't available elsewhere. Is there any way to recover data from this disk? Maybe by mounting one of the snapshots as root?

  Read the article

• I Start!

  - by andyleonard

  I originally titled this post "I Quit!" but decided that doesn't set the proper tone and definitely does not match my feelings about the upcoming transitions in my life. "I Start!" is much more appropriate! Introduction I've tendered my resignation from the position of Manager, ETL Team, Data Management Group, Molina Medicaid Solutions effective Friday 14 Jan 2011. "There I Was..." In 2008 my consultant billable-days - the metric I use to determine how business is going - dropped from 20 / month...(read more)

  Read the article

• Google présente le Nexus S fabriqué par Samsung, tournant sous Android 2.3 et équipé du NFC

  Google présente le Nexus S fabriqué par Samsung, au design épuré et équipé du NFC Mise à jour du 07.12.2010 par Katleen Cette fois-ci, c'est officiel. Le Nexus One aura un successeur, et c'est bel et bien cet appareil qu'Eric Schmidt avait furtivement montré il y a quelques semaines lors d'une conférence. Le second smartphone estampillé Google a été fabriqué par Samsung, qui a du le fabriquer en respectant scrupuleusement un cahier des charges très précis, en matière de hardware et de design. Son exclusivité ? Etre le premier à tourner sous Android 2.3 (Gingerbread) en version "pure" (non remodelée par les opérateurs, ni par Samsung). Autre grand pas en avant : l'inclusion d...

  Read the article

• Defining the Features we would like to see

  - by Patrick Liekhus

  OK, now that we have a very rough idea of what we are building, let’s get a list of the top features that this application needs to allow us to do.  In this next list we are not prioritizing them yet, just getting on paper the high level backlog of items that this system must do. Add a new task to my work queue Change the status of the task Print a hard copy of the task list by day for my records Log a phone conversation A manager should be able to assign tasks to another user How do we login? Change the Covey roles per user Manage the statuses used Manage the Covey quadrants Can we make this available on the following user interfaces? Windows Desktop Web Browser Sliverlight (WPF) Excel Add-in Outlook Add-in Android Devices iPhone Devices Windows Mobile Devices Blackberry Devices While this looks like a simple spread sheet, it can get pretty complex and busy quickly.  Next time we will work on making this into a Product Backlog and prioritizing the features we would like to see.

  Read the article

• AJI Report 14 &ndash; Brian Lagunas on XAML and Windows 8

  - by Jeff Julian

  We sat down with Brian at the Iowa Code Camp to talk about his sessions, WPF, Application Design, and what Infragistics has to offer developers. Infragistics is a huge supporter of regional events like Iowa Code Camp and we want to thank them for their support of the Midwest region. Brian is a sharp guy and it was great to meet him and learn more about what makes him tick. Brian Lagunas is an INETA Community Speaker, co-leader of the Boise .Net Developers User Group (NETDUG), and original author of the Extended WPF Toolkit. He is a multi-recipient of the Microsoft Community Contributor Award and can be found speaking at a variety of user groups and code camps around the nation. Brian currently works at Infragistics as a Product Manager for the award winning NetAdvantage for WPF and Silverlight components. Before geeking out, Brian served his country in the United States Army as an infantryman and later served his local community as a deputy sheriff.   Listen to the Show   Site: http://brianlagunas.com Twitter: @BrianLagunas

  Read the article

• How do I share files with someone who does not have a ubuntu one account

  - by Bob

  I tried to search for an answer, except that, uhhh there is no search. I want to share a Ubuntu One folder with people who do not have a Ubuntu One account. Is that possible? I found this answer in the faq, "Yes! Since Ubuntu 10.04 LTS, Ubuntu One supports sharing files publicly. Right click on a file already synchronized by Ubuntu One and select "Publish via Ubuntu One". Right-click on the file again and select "Copy Ubuntu One public URL". You can now paste the URL and share it with whoever you want." That doesn't seem to help me with 11.04. There is no 'Publish via Ubuntu One' button in 11.04. Does anyone know if there is a way to share files with non-ubuntu users? If so, how? Thanks In Advance, Bob

  Read the article

• OTN Architect Day Headed to Reston, VA - May 16

  - by Bob Rhubart

  In 2011 OTN Architect Day made stops in Chicago, Denver, Phoenix, Redwood Shores, and Toronto. The 2012 series begins with OTN Architect Day in Reston, VA on Wednesday May 16. Registration is now open for this free event, but don't get caught napping -- seating is limited, and the event is just 5 weeks away. The information below reflects the most recent updates to the event agenda, including the addition of Oracle ACE Director Kai Yu as the guest keynote speaker. Kai is Senior System Engineer / Architect at Dell, Inc., and has been very busy of late as a speaker at various industry and Oracle User Group events. I'm very happy Kai has agreed to make the trek from his hometown in Austin, TX to share his insight at the Architect Day event in Reston.  If you're in the area, put this one on your calendar. You won't be sorry.   Venue Sheraton Reston Hotel 11810 Sunrise Valley Drive Reston, VA 20191 Event Agenda 8:30 am - 9:00 am Registration and Continental Breakfast 9:00 am - 9:15 am Welcome and Opening Comments 9:15 am - 10:00 am Engineered Systems: Oracle's Vision for the Future | Ralf Dossman Oracle's Exadata and Exalogic are impressive products in their own right. But working in combination they deliver unparalleled transaction processing performance with up to a 30x increase over existing legacy systems, with the lowest cost of ownership over a 3 or 5 year basis than any other hardware. In this session you'll learn how to leverage Oracle's Engineered Systems within your enterprise to deliver record-breaking performance at the lowest TCO. 10:00 am - 10:30 am High Availability Infrastructure for Cloud Computing | Kai Yu Infrastructure high availability is extremely critical to Cloud Computing. In a Cloud system that hosts a large number of databases and applications with different SLAs, any unplanned outage can be devastating, and even a small planned downtime may be unacceptable. This presentation will discuss various technology solutions and the related best practices that system architects should consider in cloud infrastructure design to ensure high availability. 10:30 am - 10:45 am Break 10:45 am - 11:30 am Breakout Sessions: (pick one) Innovations in Grid Computing with Oracle Coherence | Bjorn Boe Learn how Coherence can increase the availability, scalability and performance of your existing applications with its advanced low-latency data-grid technologies. Also hear some interesting industry-specific use cases that customers had implemented and how Oracle is integrating Coherence into its Enterprise Java stack. Cloud Computing - Making IT Simple | Scott Mattoon The road to Cloud Computing is not without a few bumps. This session will help to smooth out your journey by tackling some of the potential complications. We'll examine whether standardization is a prerequisite for the Cloud. We'll look at why refactoring isn't just for application code. We'll check out deployable entities and their simplification via higher levels of abstraction. And we'll close out the session with a look at engineered systems and modular clouds. 11:30 pm - 12:15 pm Breakout Sessions: (pick one) Oracle Enterprise Manager | Joe Diemer Oracle Enterprise Manager (EM) provides complete lifecycle management for the cloud - from automated cloud setup to self-service delivery to cloud operations. In this session you'll learn how to take control of your cloud infrastructure with EM features including Consolidation Planning and Self-Service provisioning with Metering and Chargeback. Come hear how Oracle is expanding its management capabilities into the cloud! Rationalization and Defense in Depth - Two Steps Closer to the Clouds | Dave Chappelle Security represents one of the biggest concerns about cloud computing. In this session we'll get past the FUD with a real-world look at some key issues. We'll discuss the infrastructure necessary to support rationalization and security services, explore architecture for defense -in-depth, and deal frankly with the good, the bad, and the ugly in Cloud security. 12:15 pm - 1:15 pm Lunch 1:40 pm - 2:00 pm Panel Discussion - Q&A 2:00 pm - 2:45 pm Breakout Sessions: (pick one) 21st Century SOA | Peter Belknap Service Oriented Architecture has evolved from concept to reality in the last decade. The right methodology coupled with mature SOA technologies has helped customers demonstrate success in both innovation and ROI. In this session you will learn how Oracle SOA Suite's orchestration, virtualization, and governance capabilities provide the infrastructure to run mission critical business and system applications. And we'll take a special look at the convergence of SOA & BPM using Oracle's Unified technology stack. Track B: Oracle Cloud Reference Architecture | Anbu Krishnaswamy Cloud initiatives are beginning to dominate enterprise IT roadmaps. Successful adoption of Cloud and the subsequent governance challenges warrant a Cloud reference architecture that is applied consistently across the enterprise. This presentation gives an overview of Oracle's Cloud Reference Architecture, which is part of the Cloud Enterprise Technology Strategy (ETS). Concepts covered include common management layer capabilities, service models, resource pools, and use cases. 2:45 pm - 3:00 pm Break 3:00 pm - 4:00 pm Roundtable Discussions 4:00 pm - 4:15 pm Closing Comments & Readouts from Roundtable 4:15 pm - 5:00 pm Cocktail Reception / Networking Session schedule and content subject to change.

  Read the article

• RT3290 Bluetooth not pairing in Ubuntu 14.04

  - by Nashhole

  I recently followed the instructions listed in the following link to get my RT3290 bluetooth working on my laptop. These instructions have yielded the most progress I have had in the year I have had this laptop. My machine now sees my bluetooth, I can scan for and see devices, and other devices and see my laptop, but pairing continually fails. Ralink RT 3290 Bluetooth Problem on Ubuntu 14.04 -lscpi reads 04:00.1 Bluetooth: Ralink corp. RT3290 Bluetooth -rfkill list reads 0: hci0: Bluetooth Soft blocked: no Hard blocked: no -dmesg | grep Blue reads [ 5.965811] Bluetooth: Core ver 2.17 [ 5.965833] Bluetooth: HCI device and connection manager initialized [ 5.965840] Bluetooth: HCI socket layer initialized [ 5.965842] Bluetooth: L2CAP socket layer initialized [ 5.965847] Bluetooth: SCO socket layer initialized [ 6.038085] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [ 6.038088] Bluetooth: BNEP filters: protocol multicast [ 6.038096] Bluetooth: BNEP socket layer initialized [ 6.058013] Bluetooth: RFCOMM TTY layer initialized [ 6.058024] Bluetooth: RFCOMM socket layer initialized [ 6.058029] Bluetooth: RFCOMM ver 1.11 Any one have any thoughts or ideas I could try? Thanks in advance for your time and assistance.

  Read the article

• C# 4.0: Covariance And Contravariance In Generics

  - by Paulo Morgado

  C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

  Read the article

• OSB/OSR/OER in One Domain - QName violates loader constraints

  - by John Graves

  For demos, testing and prototyping, I wanted a single domain which contained three servers:OSB - Oracle Service BusOSR - Oracle Service RegistryOER - Oracle Enterprise Repository These three can work together to help with service governance in an enterprise.  When building out the domain, I found errors in the OSR server due to some conflicting classes from the OSB.  This wouldn't be an issue if each server was given a unique classpath setting with the node manager, but I was having the node manager use the standard startup scripts. The domain's bin/setDomainEnv.sh script has a large set of extra libraries added for OSB which look like this: if [ "${POST_CLASSPATH}" != "" ] ; then POST_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jrf_11.1.1/jrf.jar${CLASSPATHSEP}${POST_CLASSPATH}" export POST_CLASSPATH else POST_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jrf_11.1.1/jrf.jar" export POST_CLASSPATH fi if [ "${PRE_CLASSPATH}" != "" ] ; then PRE_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jdbc_11.1.1/ojdbc6dms.jar${CLASSPATHSEP}${PRE_CLASSPATH}" export PRE_CLASSPATH else PRE_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jdbc_11.1.1/ojdbc6dms.jar" export PRE_CLASSPATH fi POST_CLASSPATH="${POST_CLASSPATH}${CLASSPATHSEP}/oracle/fmwhome/Oracle_OSB1/soa/modules/oracle.soa.common.adapters_11.1.1/oracle.soa.common.adapters.jar\ ${CLASSPATHSEP}${ALSB_HOME}/lib/version.jar\ ${CLASSPATHSEP}${ALSB_HOME}/lib/alsb.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-ant.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-common.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-core.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-dameon.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/classes${CLASSPATHSEP}\ ${ALSB_HOME}/lib/external/log4j_1.2.8.jar${CLASSPATHSEP}\ ${DOMAIN_HOME}/config/osb" I didn't take the time to sort out exactly which jar was causing the problem, but I simply surrounded this block with a conditional statement: if [ "${SERVER_NAME}" == "osr_server1" ] ; then POST_CLASSPATH=""else if [ "${POST_CLASSPATH}" != "" ] ; then POST_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jrf_11.1.1/jrf.jar${CLASSPATHSEP}${POST_CLASSPATH}" export POST_CLASSPATH else POST_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jrf_11.1.1/jrf.jar" export POST_CLASSPATH fi if [ "${PRE_CLASSPATH}" != "" ] ; then PRE_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jdbc_11.1.1/ojdbc6dms.jar${CLASSPATHSEP}${PRE_CLASSPATH}" export PRE_CLASSPATH else PRE_CLASSPATH="${COMMON_COMPONENTS_HOME}/modules/oracle.jdbc_11.1.1/ojdbc6dms.jar" export PRE_CLASSPATH fi POST_CLASSPATH="${POST_CLASSPATH}${CLASSPATHSEP}/oracle/fmwhome/Oracle_OSB1/soa/modules/oracle.soa.common.adapters_11.1.1/oracle.soa.common.adapters.jar\ ${CLASSPATHSEP}${ALSB_HOME}/lib/version.jar\ ${CLASSPATHSEP}${ALSB_HOME}/lib/alsb.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-ant.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-common.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-core.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/lib/j2ssh-dameon.jar\ ${CLASSPATHSEP}${ALSB_HOME}/3rdparty/classes${CLASSPATHSEP}\ ${ALSB_HOME}/lib/external/log4j_1.2.8.jar${CLASSPATHSEP}\ ${DOMAIN_HOME}/config/osb" fi I could have also just done an if [ ${SERVER_NAME} = "osb_server1" ], but I would have also had to include the AdminServer because they are needed there too.  Since the oer_server1 didn't mind, I did the negative case as shown above. To help others find this post, I'm including the error that was reported in the OSR server before I made this change. ####<Mar 30, 2012 4:20:28 PM EST> <Error> <HTTP> <localhost.localdomain> <osr_server1> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <11d1def534ea1be0:30e96542:13662023753:-8000-000000000000001c> <1333084828916> <BEA-101017> <[ServletContext@470316600[app:registry module:registry.war path:/registry spec-version:null]] Root cause of ServletException. java.lang.LinkageError: Class javax/xml/namespace/QName violates loader constraints at com.idoox.wsdl.extensions.PopulatedExtensionRegistry.<init>(PopulatedExtensionRegistry.java:84) at com.idoox.wsdl.factory.WSDLFactoryImpl.newDefinition(WSDLFactoryImpl.java:61) at com.idoox.wsdl.xml.WSDLReaderImpl.parseDefinitions(WSDLReaderImpl.java:419) at com.idoox.wsdl.xml.WSDLReaderImpl.readWSDL(WSDLReaderImpl.java:309) at com.idoox.wsdl.xml.WSDLReaderImpl.readWSDL(WSDLReaderImpl.java:272) at com.idoox.wsdl.xml.WSDLReaderImpl.readWSDL(WSDLReaderImpl.java:198) at com.idoox.wsdl.util.WSDLUtil.readWSDL(WSDLUtil.java:126) at com.systinet.wasp.admin.PackageRepositoryImpl.validateServicesNamespaceAndName(PackageRepositoryImpl.java:885) at com.systinet.wasp.admin.PackageRepositoryImpl.registerPackage(PackageRepositoryImpl.java:807) at com.systinet.wasp.admin.PackageRepositoryImpl.updateDir(PackageRepositoryImpl.java:611) at com.systinet.wasp.admin.PackageRepositoryImpl.updateDir(PackageRepositoryImpl.java:643) at com.systinet.wasp.admin.PackageRepositoryImpl.update(PackageRepositoryImpl.java:553) at com.systinet.wasp.admin.PackageRepositoryImpl.init(PackageRepositoryImpl.java:242) at com.idoox.wasp.ModuleRepository.loadModules(ModuleRepository.java:198) at com.systinet.wasp.WaspImpl.boot(WaspImpl.java:383) at org.systinet.wasp.Wasp.init(Wasp.java:151) at com.systinet.transport.servlet.server.Servlet.init(Unknown Source) at weblogic.servlet.internal.StubSecurityHelper$ServletInitAction.run(StubSecurityHelper.java:283) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120) at weblogic.servlet.internal.StubSecurityHelper.createServlet(StubSecurityHelper.java:64) at weblogic.servlet.internal.StubLifecycleHelper.createOneInstance(StubLifecycleHelper.java:58) at weblogic.servlet.internal.StubLifecycleHelper.<init>(StubLifecycleHelper.java:48) at weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubImpl.java:539) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:244) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:184) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3732) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3696) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2273) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1490) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256) at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)

  Read the article

• On StringComparison Values

  - by Jesse

  When you use the .NET Framework’s String.Equals and String.Compare methods do you use an overloStringComparison enumeration value? If not, you should be because the value provided for that StringComparison argument can have a big impact on the results of your string comparison. The StringComparison enumeration defines values that fall into three different major categories: Culture-sensitive comparison using a specific culture, defaulted to the Thread.CurrentThread.CurrentCulture value (StringComparison.CurrentCulture and StringComparison.CurrentCutlureIgnoreCase) Invariant culture comparison (StringComparison.InvariantCulture and StringComparison.InvariantCultureIgnoreCase) Ordinal (byte-by-byte) comparison of  (StringComparison.Ordinal and StringComparison.OrdinalIgnoreCase) There is a lot of great material available that detail the technical ins and outs of these different string comparison approaches. If you’re at all interested in the topic these two MSDN articles are worth a read: Best Practices For Using Strings in the .NET Framework: http://msdn.microsoft.com/en-us/library/dd465121.aspx How To Compare Strings: http://msdn.microsoft.com/en-us/library/cc165449.aspx Those articles cover the technical details of string comparison well enough that I’m not going to reiterate them here other than to say that the upshot is that you typically want to use the culture-sensitive comparison whenever you’re comparing strings that were entered by or will be displayed to users and the ordinal comparison in nearly all other cases. So where does that leave the invariant culture comparisons? The “Best Practices For Using Strings in the .NET Framework” article has the following to say: “On balance, the invariant culture has very few properties that make it useful for comparison. It does comparison in a linguistically relevant manner, which prevents it from guaranteeing full symbolic equivalence, but it is not the choice for display in any culture. One of the few reasons to use StringComparison.InvariantCulture for comparison is to persist ordered data for a cross-culturally identical display. For example, if a large data file that contains a list of sorted identifiers for display accompanies an application, adding to this list would require an insertion with invariant-style sorting.” I don’t know about you, but I feel like that paragraph is a bit lacking. Are there really any “real world” reasons to use the invariant culture comparison? I think the answer to this question is, “yes”, but in order to understand why we should first think about what the invariant culture comparison really does. The invariant culture comparison is really just a culture-sensitive comparison using a special invariant culture (Michael Kaplan has a great post on the history of the invariant culture on his blog: http://blogs.msdn.com/b/michkap/archive/2004/12/29/344136.aspx). This means that the invariant culture comparison will apply the linguistic customs defined by the invariant culture which are guaranteed not to differ between different machines or execution contexts. This sort of consistently does prove useful if you needed to maintain a list of strings that are sorted in a meaningful and consistent way regardless of the user viewing them or the machine on which they are being viewed. Example: Prototype Names Let’s say that you work for a large multi-national toy company with branch offices in 10 different countries. Each year the company would work on 15-25 new toy prototypes each of which is assigned a “code name” while it is under development. Coming up with fun new code names is a big part of the company culture that everyone really enjoys, so to be fair the CEO of the company spent a lot of time coming up with a prototype naming scheme that would be fun for everyone to participate in, fair to all of the different branch locations, and accessible to all members of the organization regardless of the country they were from and the language that they spoke. Each new prototype will get a code name that begins with a letter following the previously created name using the alphabetical order of the Latin/Roman alphabet. Each new year prototype names would start back at “A”. The country that leads the prototype development effort gets to choose the name in their native language. (An appropriate Romanization system will be used for countries where the primary language is not written in the Latin/Roman alphabet. For example, the Pinyin system could be used for Chinese). To avoid repeating names, a list of all current and past prototype names will be maintained on each branch location’s company intranet site. Assuming that maintaining a single pre-sorted list is not feasible among all of the highly distributed intranet implementations, what string comparison method would you use to sort each year’s list of prototype names so that the list is both meaningful and consistent regardless of the country within which the list is being viewed? Sorting the list with a culture-sensitive comparison using the default configured culture on each country’s intranet server the list would probably work most of the time, but subtle differences between cultures could mean that two different people would see a list that was sorted slightly differently. The CEO wants the prototype names to be a unifying aspect of company culture and is adamant that everyone see the the same list sorted in the same order and there’s no way to guarantee a consistent sort across different cultures using the culture-sensitive string comparison rules. The culture-sensitive sort would produce a meaningful list for the specific user viewing it, but it wouldn’t always be consistent between different users. Sorting with the ordinal comparison would certainly be consistent regardless of the user viewing it, but would it be meaningful? Let’s say that the current year’s prototype name list looks like this: Antílope (Spanish) Babouin (French) Cahoun (Czech) Diamond (English) Flosse (German) If you were to sort this list using ordinal rules you’d end up with: Antílope Babouin Diamond Flosse Cahoun This sort is no good because the entry for “C” appears the bottom of the list after “F”. This is because the Czech entry for the letter “C” makes use of a diacritic (accent mark). The ordinal string comparison does a byte-by-byte comparison of the code points that make up each character in the string and the code point for the “C” with the diacritic mark is higher than any letter without a diacritic mark, which pushes that entry to the bottom of the sorted list. The CEO wants each country to be able to create prototype names in their native language, which means we need to allow for names that might begin with letters that have diacritics, so ordinal sorting kills the meaningfulness of the list. As it turns out, this situation is actually well-suited for the invariant culture comparison. The invariant culture accounts for linguistically relevant factors like the use of diacritics but will provide a consistent sort across all machines that perform the sort. Now that we’ve walked through this example, the following line from the “Best Practices For Using Strings in the .NET Framework” makes a lot more sense: One of the few reasons to use StringComparison.InvariantCulture for comparison is to persist ordered data for a cross-culturally identical display That line describes the prototype name example perfectly: we need a way to persist ordered data for a cross-culturally identical display. While this example is 100% made-up, I think it illustrates that there are indeed real-world situations where the invariant culture comparison is useful.

  Read the article

• Best way of storing voxels

  - by opiop65

  This should be a pretty easy question to answer, and I'm not looking for how to store the voxels data wise, I'm looking for the theory. Currently, my voxel engine has no global list of tiles. Each chunk has it's own list, and its hard to do things like collision detection or anything that may use tiles that are outside of its own chunk. I recently worked on procedural terrain with a non voxel engine. Now, I want to start using heightmaps in my voxel engine. But, I have a problem. If each chunk has its own list, then it will be pretty difficult to implement the heightmaps. My real question is, is should I store a global list of voxels independent of the chunks? And then I can just easily perform collision detection and terrain generation. However, it would probably be harder to do things such as frustum culling. So how should I store them?

  Read the article

• Can't get TRIM test to work

  - by Matthew Marcus

  So I'm attempting to install TRIM using the walkthrough here: How to enable TRIM? But everytime I attempt to run the hdparm command, I get the following when I try to run it w/ sda: reading sector 5805056: FAILED: Input/output error and I get this when running it with sda1: /dev/sda1: Device /dev/sda1 has non-zero LBA starting offset of 2048. Please use an absolute LBA with the /dev/ entry for the full device, rather than a partition name. /dev/sda1 is probably a partition of /dev/sda (?) The absolute LBA of sector 5807104 from /dev/sda1 should be 5809152 Aborting. I'm running Natty in a VBox on Windows 7. Someone PLEASE help.. I keep getting this "consistency check" message on boot of my machine and I think it's because Ubuntu is writing to the same sectors on the VHD too much.. need to get trim working on this thing.. Thanks.

  Read the article

• Low disk space: home/user folder occupies 94GB

  - by tedtoy

  I am low on disk space and when I check the Disk Usage analyzer (using gksudo baobab) it indicates that my home/teddy folder is using 94GB, but when I browse through its contents I can only account for about 1gb of that usage. I've tried sudo apt-get clean and deleting the cached package files from Synaptic Package Manager, emptied trash but that has not changed the amount of free space I have. It seems similar to this problem But using the root disk usage analyzer has not given any insight into what is consuming so much space. Any ideas?

  Read the article

• HDFC Bank's Journey to Oracle Private Database Cloud

  - by Nilesh Agrawal

  One of the key takeaways from a recent post by Sushil Kumar is the importance of business initiative that drives the transformational journey from legacy IT to enterprise private cloud. The journey that leads to a agile, self-service and efficient infrastructure with reduced complexity and enables IT to deliver services more closely aligned with business requirements. Nilanjay Bhattacharjee, AVP, IT of HDFC Bank presented a real-world case study based on one such initiative in his Oracle OpenWorld session titled "HDFC BANK Journey into Oracle Database Cloud with EM 12c DBaaS". The case study highlighted in this session is from HDFC Bank’s Lending Business Segment, which comprises roughly 50% of Bank’s top line. Bank’s Lending Business is always under pressure to launch “New Schemes” to compete and stay ahead in this segment and IT has to keep up with this challenging business requirement. Lending related applications are highly dynamic and go through constant changes and every single and minor change in each related application is required to be thoroughly UAT tested certified before they are certified for production rollout. This leads to a constant pressure in IT for rapid provisioning of UAT databases on an ongoing basis to enable faster time to market. Nilanjay joined Sushil Kumar, VP, Product Strategy, Oracle, during the Enterprise Manager general session at Oracle OpenWorld 2012. Let's watch what Nilanjay had to say about their recent Database cloud deployment. “Agility” in launching new business schemes became the key business driver for private database cloud adoption in the Bank. Nilanjay spent an hour discussing it during his session. Let's look at why Database-as-a-Service(DBaaS) model was need of the hour in this case  - Average 3 days to provision UAT Database for Loan Management Application Silo’ed UAT environment with Average 30% utilization Compliance requirement consume UAT testing resources DBA activities leads to $$ paid to SI for provisioning databases manually Overhead in managing configuration drift between production and test environments Rollout impact/delay on new business initiatives The private database cloud implementation progressed through 4 fundamental phases - Standardization, Consolidation, Automation, Optimization of UAT infrastructure. Project scoping was carried out and end users and stakeholders were engaged early on right from planning phase and including all phases of implementation. Standardization and Consolidation phase involved multiple iterations of planning to first standardize on infrastructure, db versions, patch levels, configuration, IT processes etc and with database level consolidation project onto Exadata platform. It was also decided to have existing AIX UAT DB landscape covered and EM 12c DBaaS solution being platform agnostic supported this model well. Automation and Optimization phase provided the necessary Agility, Self-Service and efficiency and this was made possible via EM 12c DBaaS. EM 12c DBaaS Self-Service/SSA Portal was setup with required zones, quotas, service templates, charge plan defined. There were 2 zones implemented - Exadata zone  primarily for UAT and benchmark testing for databases running on Exadata platform and second zone was for AIX setup to cover other databases those running on AIX. Metering and Chargeback/Showback capabilities provided business and IT the framework for cloud optimization and also visibility into cloud usage. More details on UAT cloud implementation, related building blocks and EM 12c DBaaS solution are covered in Nilanjay's OpenWorld session here. Some of the key Benefits achieved from UAT cloud initiative are - New business initiatives can be easily launched due to rapid provisioning of UAT Databases [ ~3 hours ] Drastically cut down $$ on SI for DBA Activities due to Self-Service Effective usage of infrastructure leading to  better ROI Empowering  consumers to provision database using Self-Service Control on project schedule with DB end date aligned to project plan submitted during provisioning Databases provisioned through Self-Service are monitored in EM and auto configured for Alerts and KPI Regulatory requirement of database does not impact existing project in queue This table below shows typical list of activities and tasks involved when a end user requests for a UAT database. EM 12c DBaaS solution helped reduce UAT database provisioning time from roughly 3 days down to 3 hours and this timing also includes provisioning time for database with production scale data (ranging from 250 G to 2 TB of data) - And it's not just about time to provision,  this initiative has enabled an agile, efficient and transparent UAT environment where end users are empowered with real control of cloud resources and IT's role is shifted as enabler of strategic services instead of being administrator of all user requests. The strong collaboration between IT and business community right from planning to implementation to go-live has played the key role in achieving this common goal of enterprise private cloud. Finally, real cloud is here and this cloud is accompanied with rain (business benefits) as well ! For more information, please go to Oracle Enterprise Manager  web page or  follow us at :  Twitter | Facebook | YouTube | Linkedin | Newsletter

  Read the article

• Visualize flowchart diagram with multiple end symbols

  - by platzhirsch

  I am looking for a standardize way to visualize the following hierarchical logic: The state of the thread is represented by the answers to the hierarchical set of question You can read this listing like a flowchart, you iterate over the questions decide, go one step deeper and so on. Therefore I thought the best way to visualize it, using a flowchart. The problem is, in this hierarchical set it is possible to end in more than one state and its totally valid. I have never seen a flowchart where you can enter more than one state. Is it still possible and I am missing the right symbol to present this logic or are flowchart not fitting anyway? What other graphical representation could I use, is there something fitting in UML? A non-deterministic state machine seems not to be intuitive enough, transfering it into a deterministic state machine would result in to many states, and so on.

  Read the article

• Incorrect colour blending when using a pixel shader with XNA

  - by MazK

  I'm using XNA 4.0 to create a 2D game and while implementing a layer tinting pixel shader I noticed that when the texture's alpha value is anything between 1 or 0 the end result is different than expected. The tinting works from selecting a colour and setting the amount of tint. This is achieved via the shader which works out first the starting colour (for each r, g, b and a) : float red = texCoord.r * vertexColour.r; and then the final tinted colour : output.r = red + (tintColour.r - red) * tintAmount; The alpha value isn't tinted and is left as : output.a = texCoord.a * vertexColour.a; The picture in the link below shows different backdrops against an energy ball object where it's outer glow hasn't blended as I would like it to. The middle two are incorrect as the second non tinted one should not show a glow against a white BG and the third should be entirely invisible. The blending function is NonPremultiplied. Why the alpha value is interfering with the final colour?

  Read the article

• New Exadata Book Available Soon

  - by Rob Reynolds

  Oracle Press is set to released the first book on data warehouse performance and Exadata on March 14th. Achieving Extreme Performance with Oracle Exadata , by my colleagues Rick Greenwald, Robert Stackowiak, Maqsood Alam, and Mans Bhuller will be available at your favorite booksellers next week. I've seen a sneak peak of the content in this book and its a great way to fully grasp the power of Exadata and how to best apply it to achieve extreme data warehouse performance. From the publisher's description: Achieving Extreme Performance with Oracle Exadata and the Sun Oracle Database Machine is filled with best practices for deployments, hardware sizing, architecting the database machine environments for maximum availability, and backup and recovery. Oracle Database 11gR2 features used within these offerings, as well as migration options and paths for Oracle and non-Oracle databases to Oracle Exadata are covered. This Oracle Press guide also discusses architecture, administration, maintenance, monitoring, and tuning of Oracle Exadata Storage Servers and the Sun Oracle Database Machine. If your company is considering Exadata, or if you need more horsepower out of your data warehouse, I highly recommend grabbing a copy of this book next week.

  Read the article

• Optimizing collision engine bottleneck

  - by Vittorio Romeo

  Foreword: I'm aware that optimizing this bottleneck is not a necessity - the engine is already very fast. I, however, for fun and educational purposes, would love to find a way to make the engine even faster. I'm creating a general-purpose C++ 2D collision detection/response engine, with an emphasis on flexibility and speed. Here's a very basic diagram of its architecture: Basically, the main class is World, which owns (manages memory) of a ResolverBase*, a SpatialBase* and a vector<Body*>. SpatialBase is a pure virtual class which deals with broad-phase collision detection. ResolverBase is a pure virtual class which deals with collision resolution. The bodies communicate to the World::SpatialBase* with SpatialInfo objects, owned by the bodies themselves. There currenly is one spatial class: Grid : SpatialBase, which is a basic fixed 2D grid. It has it's own info class, GridInfo : SpatialInfo. Here's how its architecture looks: The Grid class owns a 2D array of Cell*. The Cell class contains two collection of (not owned) Body*: a vector<Body*> which contains all the bodies that are in the cell, and a map<int, vector<Body*>> which contains all the bodies that are in the cell, divided in groups. Bodies, in fact, have a groupId int that is used for collision groups. GridInfo objects also contain non-owning pointers to the cells the body is in. As I previously said, the engine is based on groups. Body::getGroups() returns a vector<int> of all the groups the body is part of. Body::getGroupsToCheck() returns a vector<int> of all the groups the body has to check collision against. Bodies can occupy more than a single cell. GridInfo always stores non-owning pointers to the occupied cells. After the bodies move, collision detection happens. We assume that all bodies are axis-aligned bounding boxes. How broad-phase collision detection works: Part 1: spatial info update For each Body body: Top-leftmost occupied cell and bottom-rightmost occupied cells are calculated. If they differ from the previous cells, body.gridInfo.cells is cleared, and filled with all the cells the body occupies (2D for loop from the top-leftmost cell to the bottom-rightmost cell). body is now guaranteed to know what cells it occupies. For a performance boost, it stores a pointer to every map<int, vector<Body*>> of every cell it occupies where the int is a group of body->getGroupsToCheck(). These pointers get stored in gridInfo->queries, which is simply a vector<map<int, vector<Body*>>*>. body is now guaranteed to have a pointer to every vector<Body*> of bodies of groups it needs to check collision against. These pointers are stored in gridInfo->queries. Part 2: actual collision checks For each Body body: body clears and fills a vector<Body*> bodiesToCheck, which contains all the bodies it needs to check against. Duplicates are avoided (bodies can belong to more than one group) by checking if bodiesToCheck already contains the body we're trying to add. const vector<Body*>& GridInfo::getBodiesToCheck() { bodiesToCheck.clear(); for(const auto& q : queries) for(const auto& b : *q) if(!contains(bodiesToCheck, b)) bodiesToCheck.push_back(b); return bodiesToCheck; } The GridInfo::getBodiesToCheck() method IS THE BOTTLENECK. The bodiesToCheck vector must be filled for every body update because bodies could have moved meanwhile. It also needs to prevent duplicate collision checks. The contains function simply checks if the vector already contains a body with std::find. Collision is checked and resolved for every body in bodiesToCheck. That's it. So, I've been trying to optimize this broad-phase collision detection for quite a while now. Every time I try something else than the current architecture/setup, something doesn't go as planned or I make assumption about the simulation that later are proven to be false. My question is: how can I optimize the broad-phase of my collision engine maintaining the grouped bodies approach? Is there some kind of magic C++ optimization that can be applied here? Can the architecture be redesigned in order to allow for more performance? Actual implementation: SSVSCollsion Body.h, Body.cpp World.h, World.cpp Grid.h, Grid.cpp Cell.h, Cell.cpp GridInfo.h, GridInfo.cpp

  Read the article

• How to Fix the “Firefox Is Already Running” Error

  - by Chris Hoffman

  The “Firefox is already running, but is not responding” error has haunted Firefox users for years. You don’t have to restart your computer when you see this error – you can usually fix it with a quick trip to the Task Manager. This error occurs when Firefox is closed but is still running in the background. Firefox is either in the process of closing or is frozen and hasn’t quit properly. In rare situations, there may be a problem with your profile. Secure Yourself by Using Two-Step Verification on These 16 Web Services How to Fix a Stuck Pixel on an LCD Monitor How to Factory Reset Your Android Phone or Tablet When It Won’t Boot

  Read the article

< Previous Page | 379 380 381 382 383 384 385 386 387 388 389 390  | Next Page >