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• Corsair Hackers Reboot

  It wasn't easy for me to attend but it was absolutely worth to go. The Linux User Group of Mauritius (LUGM) organised another get-together for any open source enthusiast here on the island. Strangely named "Corsair Hackers Reboot" but it stands for a positive cause: "Corsair Hackers Reboot Event A collaborative activity involving LUGM, UoM Computer Club, Fortune Way Shopping Mall and several geeks from around the island, striving to put FOSS into homes & offices. The public is invited to discover and explore Free Software & Open Source." And it was a good opportunity for me and the kids to visit the east coast of Mauritius, too. Perfect timing It couldn't have been better... Why? Well, for two important reasons (in terms of IT): End of support for Microsoft Windows XP - 08.04.2014 Release of Ubuntu 14.04 Long Term Support - 17.04.2014 Quite funnily, those two IT dates weren't the initial reasons and only during the weeks of preparations we put those together. And therefore it was even more positive to promote the use of Linux and open source software in general to a broader audience. Getting there ... Thanks to the new motor way M3 and all the additional road work which has been completed recently it was very simple to get across the island in a very quick and relaxed manner. Compared to my trips in the early days of living in Mauritius (and riding on a scooter) it was very smooth and within less than an hour we hit Centrale de Flacq. Well, being in the city doesn't necessarily mean that one has arrived at the destination. But thanks to modern technology I had a quick look on Google Maps, and we finally managed to get a parking behind the huge bus terminal in Flacq. From there it was just a short walk to Fortune Way. The children were trying to count the number of buses... Well, lots and lots of buses - really impressive actually. What was presented? There were different areas set up. Right at the entrance one's attention was directly drawn towards the elevated hacker's stage. Similar to rock stars performing their gig there was bunch of computers, laptops and networking equipment in order to cater the right working conditions for coding/programming challenge(s) on the one hand and for the pen-testing or system hacking competition on the other hand. Personally, I was very impresses that actually Nitin took care of the pen-testing competition. He hardly started one year back with Linux in general, and Kali Linux specifically. Seeing his personal development from absolute newbie to a decent Linux system administrator within such a short period of time, is really impressive. His passion to open source software made him a living. Next, clock-wise seen, was the Kid's Corner with face-painting as the main attraction. Additionally, there were numerous paper print outs to colour. Plus a decent workstation with the educational suite GCompris. Of course, my little ones were into that. They already know GCompris since a while as they are allowed to use it on an IGEL thin client terminal here at home. To simplify my life, I set up GCompris as full-screen guest session on the server, and they can pass the login screen without any further obstacles. And because it's a thin client hooked up to a XDMCP remote session I don't have to worry about the hardware on their desk, too. The next section was the main attraction of the event: BYOD - Bring Your Own Device Well, compared to the usual context of BYOD the corsairs had a completely different intention. Here, you could bring your own laptop and a team of knowledgeable experts - read: geeks and so on - offered to fully convert your system on any Linux distribution of your choice. And even though I came later, I was told that the USB pen drives had been in permanent use. From being prepared via dd command over launching LiveCD session to finally installing a fresh Linux system on bare metal. Most interestingly, I did a similar job already a couple of months ago, while upgrading an existing Windows XP system to Xubuntu 13.10. So far, the female owner is very happy and enjoys her system almost every evening to go shopping online, checking mails, and reading latest news from the Anime world. Back to the Hackers event, Ish told me that they managed approximately 20 conversion during the day. Furthermore, Ajay and others gladly assisted some visitors with some tricky issues and by the end of the day you can call is a success. While I was around, there was a elderly male visitor that got a full-fledged system conversion to a Linux system running completely in French language. A little bit more to the centre it was Yasir's turn to demonstrate his Arduino hardware that he hooked up with an experimental electrical circuit board connected to an LCD matrix display. That's the real spirit of hacking, and he showed some minor adjustments on the fly while demo'ing the system. Also, very interesting there was a thermal sensor around. Personally, I think that platforms like the Arduino as well as the Raspberry Pi have a great potential at a very affordable price in order to bring a better understanding of electronics as well as computer programming to a broader audience. It would be great to see more of those experiments during future activities. And last but not least there were a small number of vendors. Amongst them was Emtel - once again as sponsor of the general internet connectivity - and another hardware supplier from Riche Terre shopping mall. They had a good collection of Android related gimmicks, like a autonomous web cam that can convert any TV with HDMI connector into an online video chat system given WiFi. It's actually kind of awesome to have a Skype or Google hangout video session on the big screen rather than on the laptop. Some pictures of the event LUGM: Great conversations on Linux, open source and free software during the Corsair Hackers Reboot LUGM: Educational workstation running GCompris suite attracted the youngest attendees of the day. Of course, face painting had to be done prior to hacking... LUGM: Nadim demoing some Linux specifics to interested visitors. Everyone was pretty busy during the whole day LUGM: The hacking competition, here pen-testing a wireless connection and access point between multiple machines LUGM: Well prepared workstations to be able to 'upgrade' visitors' machines to any Linux operating system Final thoughts Gratefully, during the preparations of the event I was invited to leave some comments or suggestions, and the team of the LUGM did a great job. The outdoor banner was a eye-catcher, the various flyers and posters for the event were clearly written and as far as I understood from the quick chats I had with Ish, Nadim, Nitin, Ajay, and of course others all were very happy about the event execution. Great job, LUGM! And I'm already looking forward to the next Corsair Hackers Reboot event ... Crossing fingers: Very soon and hopefully this year again :) Update: In the media The event had been announced in local media, too. L'Express: Salon informatique: Hacking Challenge à Flacq

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• PostSharp, Obfuscation, and IL

  - by Simon Cooper

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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• Windows Phone 7 Development Updates &ndash; March 8th 2011

  - by Nikita Polyakov

  Here are the latest update from the Windows Phone 7 Developer Worlds that went live this month. Here are some of the latest numbers: Windows Phone Marketplace currently offers more than 9,000 quality apps and games and enjoys a base of over 32,000 registered developers, delivering an average of 100 new apps every day. There have been over 1 million downloads of the developers tools for Windows Phone 7. Trial version help you sell more Trials result in higher sales by the numbers: Users like trials  - paid apps with trial functionality are downloaded 70 times more than paid apps that don’t Nearly 1 out of 10 trial apps downloaded convert to a purchase and generate 10 times more revenue on average than paid apps that don’t include trial functionality. Trial downloads convert to paid downloads quickly. More than half of trial downloads that convert to a sale do so within the 1st 24 hours of trial download, and mostly within 2 hours of trial download. Microsoft Ad Control is gaining traction By the numbers - ad supported Windows Phone 7 apps are: Roughly ¼ of all registered U.S. WP7 developers have downloaded the free Ad SDK for Silverlight and XNA Of ad funded apps, over 95 percent use the free Microsoft Advertising Ad Control Monthly impressions from our Ad Exchange has continued to grow by double digits – impressions increased by 376 percent since January Ad Control, the first wave of “How Do I” videos are now available on MSDN: Create an Ad in a Windows Phone 7 XNA Game App Register Ad-Enabled Windows Phone 7 Apps Measure Ad Performance of Windows Phone 7 Apps Boarder International App submission for Free Apps through Yalla Apps As of today you can start submitting your free applications in developer markets that are currently not covered by Microsoft. To submit your Free application if you DO NOT belong to one of the Marketplace supported countries, go to: Yalla Apps Marketplace Policy Updates: Free App Marketplace Submission upped to 100 and other news Microsoft has been revisiting a few of our Marketplace policies based on feedback from developers to reduce friction and cost, word for word: 1. We have raised the limit on the number of certifications that can be performed for FREE apps at no cost to the registered developer from five to 100. This was a common request from developers which we are glad to implement after building alternate methods to ensure that users can find and download high quality apps. 2. We have converted policy 5.6 - related to the inclusion of contact information for support - from a mandatory to an optional policy. This is still a strongly recommended best practice, but we recognized and responded to developer feedback that this policy was creating excessive drag on the certification process for developers without commensurate user benefit for all apps. 3. We also understand the desire for clarification with regard to our policy on applications distributed under open source licenses.  The Marketplace Application Provider Agreement (APA) already permits applications under the BSD, MIT, Apache Software License 2.0 and Microsoft Public License.  We plan to update the APA shortly to clarify that we also permit applications under the Eclipse Public License, the Mozilla Public License and other, similar licenses and we continue to explore the possibility of accommodating additional OSS licenses. Enjoy and happy coding! Official Blog Post for reference.

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• Transform Your Application Integration with Best Practices from Oracle Customers

  - by Lionel Dubreuil

  You want to transform your application integration into an environment based on a service-oriented architecture (SOA). You also want to utilize business process management (BPM) to improve efficiency, deliver business agility, lower total cost of ownership, and increase business visibility. And you want to hear directly from like-minded professionals who have made those types of transformations. Easy enough. Attend this Webcast series to learn from customers who have successfully integrated with Oracle SOA and BPM solutions.Join us for this series and discover how to: Use a single unified platform for all types of processes Increase real-time process visibility Improve efficiency of existing IT investments Lower up-front costs and achieve faster time to market Gain greater benefit from SOA with the addition of BPM Here's the list of upcoming webcasts: “Migrating to SOA at Choice Hotels” on Thurs., June 21, 2012 — 10 a.m. PT / 1 p.m. ET Hear how Choice Hotels successfully made the transition from a complex legacy environment into a SOA-based shared services infrastructure that accelerated time to market as the company implemented its event-driven Google API project. “San Joaquin County—Optimizing Justice and Public Safety with Oracle BPM and Oracle SOA” on Thurs., July 26, 2012 — 10 a.m. PT / 1 p.m. ET Learn how San Joaquin County moved to a service-oriented architecture foundation and business process management platform to gain efficiency and greater visibility into mission-critical information for public safety. “Streamlining Order to Cash with SOA at Eaton” on Thurs., August 23, 2012 — 10 a.m. PT / 1 p.m. ET Discover how Eaton transitioned from a legacy TIBCO infrastructure. Learn about the company’s reference architecture for a SOA-based Oracle Fusion Distributed Order Orchestration (DOO). “Fast BPM Implementation with Fusion: Production in Five Months” on Thurs., September 13, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Nets Denmark A/S implemented Oracle Unified Business Process Management Suite in just five months. The Webcast will cover the implementation from start to production, including integration with legacy systems. “SOA Implementation at Farmers Insurance” on Thurs., October 18, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Farmers Insurance Group lowered application infrastructure costs, reduced time to market, and introduced flexibility by transforming to a SOA-based infrastructure with SOA governance. Register today!

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• Transform Your Application Integration with Best Practices from Oracle Customers

  - by Lionel Dubreuil

  You want to transform your application integration into an environment based on a service-oriented architecture (SOA). You also want to utilize business process management (BPM) to improve efficiency, deliver business agility, lower total cost of ownership, and increase business visibility. And you want to hear directly from like-minded professionals who have made those types of transformations. Easy enough. Attend this Webcast series to learn from customers who have successfully integrated with Oracle SOA and BPM solutions.Join us for this series and discover how to: Use a single unified platform for all types of processes Increase real-time process visibility Improve efficiency of existing IT investments Lower up-front costs and achieve faster time to market Gain greater benefit from SOA with the addition of BPM Here's the list of upcoming webcasts: “Migrating to SOA at Choice Hotels” on Thurs., June 21, 2012 — 10 a.m. PT / 1 p.m. ET Hear how Choice Hotels successfully made the transition from a complex legacy environment into a SOA-based shared services infrastructure that accelerated time to market as the company implemented its event-driven Google API project. “San Joaquin County—Optimizing Justice and Public Safety with Oracle BPM and Oracle SOA” on Thurs., July 26, 2012 — 10 a.m. PT / 1 p.m. ET Learn how San Joaquin County moved to a service-oriented architecture foundation and business process management platform to gain efficiency and greater visibility into mission-critical information for public safety. “Streamlining Order to Cash with SOA at Eaton” on Thurs., August 23, 2012 — 10 a.m. PT / 1 p.m. ET Discover how Eaton transitioned from a legacy TIBCO infrastructure. Learn about the company’s reference architecture for a SOA-based Oracle Fusion Distributed Order Orchestration (DOO). “Fast BPM Implementation with Fusion: Production in Five Months” on Thurs., September 13, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Nets Denmark A/S implemented Oracle Unified Business Process Management Suite in just five months. The Webcast will cover the implementation from start to production, including integration with legacy systems. “SOA Implementation at Farmers Insurance” on Thurs., October 18, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Farmers Insurance Group lowered application infrastructure costs, reduced time to market, and introduced flexibility by transforming to a SOA-based infrastructure with SOA governance. Register today!

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• Transform Your Application Integration with Best Practices from Oracle Customers

  - by Lionel Dubreuil

  You want to transform your application integration into an environment based on a service-oriented architecture (SOA). You also want to utilize business process management (BPM) to improve efficiency, deliver business agility, lower total cost of ownership, and increase business visibility. And you want to hear directly from like-minded professionals who have made those types of transformations. Easy enough. Attend this Webcast series to learn from customers who have successfully integrated with Oracle SOA and BPM solutions.Join us for this series and discover how to: Use a single unified platform for all types of processes Increase real-time process visibility Improve efficiency of existing IT investments Lower up-front costs and achieve faster time to market Gain greater benefit from SOA with the addition of BPM Here's the list of upcoming webcasts: “Migrating to SOA at Choice Hotels” on Thurs., June 21, 2012 — 10 a.m. PT / 1 p.m. ET Hear how Choice Hotels successfully made the transition from a complex legacy environment into a SOA-based shared services infrastructure that accelerated time to market as the company implemented its event-driven Google API project. “San Joaquin County—Optimizing Justice and Public Safety with Oracle BPM and Oracle SOA” on Thurs., July 26, 2012 — 10 a.m. PT / 1 p.m. ET Learn how San Joaquin County moved to a service-oriented architecture foundation and business process management platform to gain efficiency and greater visibility into mission-critical information for public safety. “Streamlining Order to Cash with SOA at Eaton” on Thurs., August 23, 2012 — 10 a.m. PT / 1 p.m. ET Discover how Eaton transitioned from a legacy TIBCO infrastructure. Learn about the company’s reference architecture for a SOA-based Oracle Fusion Distributed Order Orchestration (DOO). “Fast BPM Implementation with Fusion: Production in Five Months” on Thurs., September 13, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Nets Denmark A/S implemented Oracle Unified Business Process Management Suite in just five months. The Webcast will cover the implementation from start to production, including integration with legacy systems. “SOA Implementation at Farmers Insurance” on Thurs., October 18, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Farmers Insurance Group lowered application infrastructure costs, reduced time to market, and introduced flexibility by transforming to a SOA-based infrastructure with SOA governance. Register today!

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• Transform Your Application Integration with Best Practices from Oracle Customers

  - by Lionel Dubreuil

  You want to transform your application integration into an environment based on a service-oriented architecture (SOA). You also want to utilize business process management (BPM) to improve efficiency, deliver business agility, lower total cost of ownership, and increase business visibility. And you want to hear directly from like-minded professionals who have made those types of transformations. Easy enough. Attend this Webcast series to learn from customers who have successfully integrated with Oracle SOA and BPM solutions.Join us for this series and discover how to: Use a single unified platform for all types of processes Increase real-time process visibility Improve efficiency of existing IT investments Lower up-front costs and achieve faster time to market Gain greater benefit from SOA with the addition of BPM Here's the list of upcoming webcasts: “Migrating to SOA at Choice Hotels” on Thurs., June 21, 2012 — 10 a.m. PT / 1 p.m. ET Hear how Choice Hotels successfully made the transition from a complex legacy environment into a SOA-based shared services infrastructure that accelerated time to market as the company implemented its event-driven Google API project. “San Joaquin County—Optimizing Justice and Public Safety with Oracle BPM and Oracle SOA” on Thurs., July 26, 2012 — 10 a.m. PT / 1 p.m. ET Learn how San Joaquin County moved to a service-oriented architecture foundation and business process management platform to gain efficiency and greater visibility into mission-critical information for public safety. “Streamlining Order to Cash with SOA at Eaton” on Thurs., August 23, 2012 — 10 a.m. PT / 1 p.m. ET Discover how Eaton transitioned from a legacy TIBCO infrastructure. Learn about the company’s reference architecture for a SOA-based Oracle Fusion Distributed Order Orchestration (DOO). “Fast BPM Implementation with Fusion: Production in Five Months” on Thurs., September 13, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Nets Denmark A/S implemented Oracle Unified Business Process Management Suite in just five months. The Webcast will cover the implementation from start to production, including integration with legacy systems. “SOA Implementation at Farmers Insurance” on Thurs., October 18, 2012 — 10 a.m. PT / 1 p.m. ET Learn how Farmers Insurance Group lowered application infrastructure costs, reduced time to market, and introduced flexibility by transforming to a SOA-based infrastructure with SOA governance. Register today!

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• Oracle is Sponsoring LinuxCon Europe 2012

  - by Zeynep Koch

  Architecture is amazing in Barcelona but you will also be impressed with Oracle Linux sessions in LinuxCon Europe as well.  Oracle is one of the key sponsors in LinuxCon Europe and we have great sessions to show you why Oracle Linux is best for your "IT architecture"! We also have a booth where you can pick up latest Oracle Linux and Oracle VM DVD Kit and Virtualization for Dummies booklet. Don't forget to visit us at technology showcase Booth #19. Oracle Sessions at LinuxCon Europe 2012:  1. OCFS2: Status and Overview - Lenz Grimmer, Oracle Wednesday November 7, 2012 10:40am - 11:25am Venue: Diamant OCFS2, Oracle's general-purpose shared-disk cluster file system for Linux has come a long way since its development started in 2003. Distributed under the GPL and part of the mainline Linux Kernel, it is also included in Oracle Linux and plays a vital role in products like Oracle VM, Oracle RAC or E-Business Suite. This presentation will provide a general technical overview as well as an update on the latest developments. Attendees will learn about the features and improvements that set OCFS2 apart from other Linux-based cluster file systems, including: Heartbeat implementation: global vs. local heartbeats Storage optimizations: Extent-based Allocations, Hole punching, Reflinks 2. Status of Linux Tracing - Elena Zannoni, Oracle Wednesday November 7, 2012 11:35am - 12:20am Venue: Diamant There have been many developments recently in the Linux tracing area. The tracing infrastructure in the kernel is getting more robust, with  the recent introduction of uprobes to allow the implementation of user  space tracing, and new features of perf. There are many tracing tools to choose from, including the newest kid on the block, DTrace for Linux.  This talk will take the audience through the main tracing facilities  available today whether more tightly integrated with the kernel code, or maintained stand alone. 3. MySQL Security Model and Pluggable Authentication - Kristofer Pettersson, Oracle Wednesday November 7, 2012 1:50pm - 2:35pm Venue: Diamant With an increasing security awareness among web and cloud developers, knowing how to secure your database from unauthorized or malicious access has become important. This talk explains the MySQL security model, pluggable authentication, new auditing features and rounds off with some pointers on how to securely integrate your database into your Linux web stack. We look forward to seeing you in Barcelona, Spain on November 5-9, 2012. Register today 

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• Tech Cast Live - Java and Oracle, One Year Later - February 15th 10AM PST

  - by Cassandra Clark

  Join us for a special live conversation with Ajay Patel, Vice President of Product Development for Application Grid Products and Justin Kestelyn, Director of the Oracle Technology Network. Justin and Ajay will discuss the changes that have come to Java and Oracle since the Sun acquisition, just over a year ago. This live broadcast conversation will include discussion on: - Highlights, challenges and what we learned over the past year - The Future of Java and its importance to Oracle and the community - Oracle's Application Grid product portfolio today Watch Live Event February 15th Watch Archived TechCast Lives You will also have the chance to submit questions to the speakers live on the show, for real-time feedback by using #techcastlive. If your question is read on air we will send you a Free I am the Future of Java t-shirt* *Promotion Details After you have submitted your question and it is read on the live TechCast held February 15th your shirt should arrive in two to four weeks while supplies last. No purchase, payments, or fees are required to receive the gift. Limit one thank you gift per person, and the offer is available only while supplies last. Oracle reserves the right to modify or terminate this offer at any time, for any reason. This offer is not available to Oracle employees or residents of countries subject to U.S. embargo (including Cuba, Iran, Iraq, Libya, North Korea, Sudan, and Syria). Due to Federal Government regulations, this offer is not available to Federal Government customers. Those residing in India or Brazil will be given a substitute gift as we can not ship t-shirts to your country. You are responsible for complying with your employer's policies regarding acceptance of promotional items, and for government laws, regulations and agency policies, if you are a government employee you will not be able to participate. Must be 18 years of age or older. Void where prohibited. Neither Oracle nor any third party assisting Oracle with this offer is responsible for any problems, errors, delays, or technical malfunction related to or impacting this offer. Oracle respects your right to privacy and your information will not be distributed or used for any other purpose. For more information on Oracle's privacy policy, please review our http://www.oracle.com/html/privacy-policy.html. If you have any questions, please contact us at [email protected].

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• PostSharp, Obfuscation, and IL

  - by simonc

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day! Cross posted from Simple Talk.

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• Planning Bulletin for JRE 7: What EBS Customers Can Do Today

  - by Steven Chan (Oracle Development)

  An initiative to certify Oracle E-Business Suite with JRE 7 desktop clients is underway.  We have tested EBS 11.5.10.2, 12.0, and 12.1 with JRE 7. We have fixes for nearly all of the compatibility issues now, and are working hard to produce the remaining fixes quickly. A. When will JRE 7 be certified with Oracle E-Business Suite? We will announce the certification of the E-Business Suite with JRE 7 once all fixes are available, verified, and documented.  Certification announcements will be distributed through My Oracle Support, My Oracle Support Community Forums, Oracle Technology Network Forums, newsletters, and user group news outlets. Oracle's Revenue Recognition rules prohibit us from discussing certification and release dates.  In addition to the standard communication channels listed above, customers are encouraged to monitor or subscribe to this blog.    B. What can customers do to prepare for the JRE 7 certification? Customers should ensure that they are on the latest available JRE 6 update. Of the compatibility issues identified so far with JRE 7, the most critical is an issue that prevents E-Business Suite Forms-based products from launching on Windows desktops that are running JRE 7.  Customers can prevent this issue today by ensuring that they have applied the latest certified patches documented for JRE 6 configurations to their EBS application tier servers: Apply Forms patch 14615390 to EBS 11i environments (Note 125767.1) Apply Forms patch 14614795 to EBS 12.0 and 12.1 environments (Note 437878.1) These patches are compatible with JRE 6 and 7, production ready, and fully-tested with the E-Business Suite.  These patches may be applied immediately to all E-Business Suite environments. All other Forms prerequisites documented in the Notes above should also be applied now. C. What else will be required by the final certified configuration? Oracle expects that all other compatibility issues will be resolved by installing a specific JRE 7 release, at minimum.  That specific release has not been finalized yet, and this is subject to change. D.  Where will the official patch requirements be documented? All patches required for ensuring full compatibility of the E-Business Suite with JRE 7 will be documented in updates to these published Notes: For EBS 11i: Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 11i (Note 290807.1) Upgrading Developer 6i with Oracle E-Business Suite 11i (Note 125767.1) For EBS 12 Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 12 (Note 393931.1) Upgrading OracleAS 10g Forms and Reports in Oracle E-Business Suite Release 12 (Note 437878.1) Disclaimer The preceding is intended to outline our general product direction.  It is intended for information purposes only, and may not be incorporated into any contract.   It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decision.  The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.

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• Survey results: Open source developer preferences

  We recently conducted a survey of open source developers to learn about their current preferences around hosting sites and source control systems.  The survey was primarily advertised via Twitter, and we tried to avoid pushing the survey among audiences that would be specifically oriented towards a particular site (for example we did not advertise the survey from the CodePlex twitter account). In total there were just under 500 responses, so a reasonable sample size although not necessarily enough to guarantee fully representative results.  One of the survey questions was what is your preferred operating system for development, and looking at the results they are particularly interesting when split by operating system preference because of how significant the difference is:   Table 1 - Preferences by what is preferred operating system for development   As you can see, the preferences among developers which prefer Windows is very different from Linux and Mac oriented developers.  Again, the question was on what operating system they prefer to use for development, and didn’t ask what type of applications they create, so presumably many create things like websites which are cross-platform from a user perspective regardless of the operating system they prefer developing with. For hosting site preference, CodePlex and GitHub are roughly tied for first place among Windows developers and combined are preferred by over 75%.  However with Linux and Mac developers, GitHub has a runaway lead over the other sites.  Perhaps not particularly surprising, CodePlex has negligible mindshare among Linux and Mac developers.  It is somewhat surprising how low SourceForge and Google Code are given historically they used to rank much higher. Looking at version control preferences is also interesting.  Among Windows developers TFS, Mercurial, Subversion, and Git all have a sizable following.  While for Linux and Mac developers it is almost all Git and Mercurial, with Git having a substantial lead.  Git is generally considered to run better on Linux and have more of a Unix feel, so not really surprising to see it more popular there compared to Windows developers.  It is surprising how low Subversion has dropped since it was the dominant preference not long ago for open source developers.  Around a quarter of Windows developers still prefer Subversion, but Linux and Mac developers have largely abandoned it.  The trend towards distributed version control systems (e.g. Mercurial and Git) is strong, with over 50% of Windows developers now prefer DVCS, and over 80% of Linux and Mac developers.

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• Super constructor must be a first statement in Java constructor [closed]

  - by Val

  I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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• The Buzz at the JavaOne Bookstore

  - by Janice J. Heiss

  I found my way to the JavaOne bookstore, a hub of activity. Who says brick and mortar bookstores are dead? I asked what was hot and got two answers: Hadoop in Practice by Alex Holmes was doing well. And Scala for the Impatient by noted Java Champion Cay Horstmann also seemed to be a fast seller. Hadoop in PracticeHadoop is a framework that organizes large clusters of computers around a problem. It is touted as especially effective for large amounts of data, and is use such companies as  Facebook, Yahoo, Apple, eBay and LinkedIn. Hadoop in Practice collects nearly 100 Hadoop examples and presents them in a problem/solution format with step by step explanations of solutions and designs. It’s very much a participatory book intended to make developers more at home with Hadoop.The author, Alex Holmes, is a senior software engineer with more than 15 years of experience developing large-scale distributed Java systems. For the last four years, he has gained expertise in Hadoop solving Big Data problems across a number of projects. He has presented at JavaOne and Jazoon and is currently a technical lead at VeriSign.At this year’s JavaOne, he is presenting a session with VeriSign colleague, Karthik Shyamsunder called “Java: A Perfect Platform for Data Science” where they will explain how the Java platform has emerged as a perfect platform for practicing data science, and also talk about such technologies as Hadoop, Hive, Pig, HBase, Cassandra, and Mahout. Scala for the ImpatientSan Jose State University computer science professor and Java Champion Cay Horstmann is the principal author of the highly regarded Core Java. Scala for the Impatient is a basic, practical introduction to Scala for experienced programmers. Horstmann has a presentation summarizing the themes of his book on at his website. On the final page he offers an enticing summary of his conclusions:* Widespread dissatisfaction with Java + XML + IDEs               --Don't make me eat Elephant again * A separate language for every problem domain is not efficient               --It takes time to master the idioms* ”JavaScript Everywhere” isn't going to scale* Trend is towards languages with more expressive power, less boilerplate* Will Scala be the “one ring to rule them”?* Maybe              --If it succeeds in industry             --If student-friendly subsets and tools are created The popularity of both books echoed comments by IBM Distinguished Engineer Jason McGee who closed his part of the Sunday JavaOne keynote by pointing out that the use of Java in complex applications is increasingly being augmented by a host of other languages with strong communities around them – JavaScript, JRuby, Scala, Python and so forth. Java developers increasingly must know the strengths and weaknesses of such languages going forward.

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• Wireframing: A Day In the Life of UX Workshop at Oracle

  - by ultan o'broin

  The Oracle Applications User Experience team's Day in the Life (DITL) of User Experience (UX) event was run in Oracle's Redwood Shores HQ for Oracle Usability Advisory Board (OUAB) members. I was charged with putting together a wireframing session, together with Director of Financial Applications User Experience, Scott Robinson (@scottrobinson). Example of stunning new wireframing visuals we used on the DITL events. We put on a lively show, explaining the basics of wireframing, the concepts, what it is and isn't, considerations on wireframing tool choice, and then imparting some tips and best practices. But the real energy came when the OUAB customers and partners in the room were challenge to do some wireframing of their own. Wireframing is about bringing your business and product use cases to life in real UX visual terms, by creating a low-fidelity drawing to iterate and agree on in advance of prototyping and coding what is to be finally built and rolled out for users. All the best people wireframe. Leonardo da Vinci used "cartoons" on some great works, tracing outlines first and using red ochre or charcoal dropped through holes in the tracing parchment onto the canvas to outline the subject. (Image distributed under Wikimedia commons license) Wireframing an application's user experience design enables you to: Obtain stakeholder buy-in. Enable faster iteration of different designs. Determine the task flow navigation paths (in Oracle Fusion Applications navigation is linked with user roles). Develop a content strategy (readability, search engine optimization (SEO) of content, and so on) Lay out the pages, widgets, groups of features, and so on. Apply usability heuristics early (no replacement for usability testing, but a great way to do some heavy-lifting up front). Decide upstream which functional user experience design patterns to apply (out of the box solutions that expedite productivity). Assess which Oracle Application Development Framework (ADF) or equivalent technology components can be used (again, developer productivity is enhanced downstream). We ran a lively hands-on exercise where teams wireframed a choice of application scenarios using the time-honored tools of pen and paper. Scott worked the floor like a pro, pointing out great use of features, best practices, innovations, and making sure that the whole concept of wireframing, the gestalt, transferred. "We need more buttons!" The cry of the energized. Not quite. The winning wireframe session (online shopping scenario) from the Applications UX DITL event shown. Great fun, great energy, and great teamwork were evident in the room. Naturally, there were prizes for the best wireframe. Well, actually, prizes were handed out to the other attendees too! An exciting, slightly different aspect to delivery of this session made the wireframing event one of the highlights of the day. And definitely, something we will repeat again when we get the chance. Thanks to everyone who attended, contributed, and helped organize.

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• Data structures for a 2D multi-layered and multi-region map?

  - by DevilWithin

  I am working on a 2D world editor and a world format subsequently. If I were to handle the game "world" being created just as a layered set of structures, either in top or side views, it would be considerably simple to do most things. But, since this editor is meant for 3rd parties, I have no clue how big worlds one will want to make and I need to keep in mind that eventually it will become simply too much to check, handling and comparing stuff that are happening completely away from the player position. I know the solution for this is to subdivide my world into sub regions and stream them on the fly, loading and unloading resources and other data. This way I know a virtually infinite game area is achievable. But, while I know theoretically what to do, I really have a few questions I'd hoped to get answered for some hints about the topic. The logic way to handle the regions is some kind of grid, would you pick evenly distributed blocks with equal sizes or would you let the user subdivide areas by taste with irregular sized rectangles? In case of even grids, would you use some kind of block/chunk neighbouring system to check when the player transposes the limit or just put all those in a simple array? Being a region a different data structure than its owner "game world", when streaming a region, would you deliver the objects to the parent structures and track them for unloading later, or retain the objects in each region for a more "hard-limit" approach? Introducing the subdivision approach to the project, and already having a multi layered scene graph structure on place, how would i make it support the new concept? Would you have the parent node have the layers as children, and replicate in each layer node, a node per region? Or the opposite, parent node owns all the regions possible, and each region has multiple layers as children? Or would you just put the region logic outside the graph completely(compatible with the first suggestion in Q.3) When I say virtually infinite worlds, I mean it of course under the contraints of the variable sizes and so on. Using float positions, a HUGE world can already be made. Do you think its sane to think beyond that? Because I think its ok to stick to this limit since it will never be reached so easily.. As for when to stream a region, I'm implementing it as a collection of watcher cameras, which the streaming system works with to know what to load/unload. The problem here is, i will be needing some kind of warps/teleports built in for my game, and there is a chance i will be teleporting a player to a unloaded region far away. How would you approach something like this? Is it sane to load any region to memory which can be teleported to by a warp within a radius from the player? Sorry for the huge question, any answers are helpful!

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• How granular should a command be in a CQ[R]S model?

  - by Aaronaught

  I'm considering a project to migrate part of our WCF-based SOA over to a service bus model (probably nServiceBus) and using some basic pub-sub to achieve Command-Query Separation. I'm not new to SOA, or even to service bus models, but I confess that until recently my concept of "separation" was limited to run-of-the-mill database mirroring and replication. Still, I'm attracted to the idea because it seems to provide all the benefits of an eventually-consistent system while sidestepping many of the obvious drawbacks (most notably the lack of proper transactional support). I've read a lot on the subject from Udi Dahan who is basically the guru on ESB architectures (at least in the Microsoft world), but one thing he says really puzzles me: As we get larger entities with more fields on them, we also get more actors working with those same entities, and the higher the likelihood that something will touch some attribute of them at any given time, increasing the number of concurrency conflicts. [...] A core element of CQRS is rethinking the design of the user interface to enable us to capture our users’ intent such that making a customer preferred is a different unit of work for the user than indicating that the customer has moved or that they’ve gotten married. Using an Excel-like UI for data changes doesn’t capture intent, as we saw above. -- Udi Dahan, Clarified CQRS From the perspective described in the quotation, it's hard to argue with that logic. But it seems to go against the grain with respect to SOAs. An SOA (and really services in general) are supposed to deal with coarse-grained messages so as to minimize network chatter - among many other benefits. I realize that network chatter is less of an issue when you've got highly-distributed systems with good message queuing and none of the baggage of RPC, but it doesn't seem wise to dismiss the issue entirely. Udi almost seems to be saying that every attribute change (i.e. field update) ought to be its own command, which is hard to imagine in the context of one user potentially updating hundreds or thousands of combined entities and attributes as it often is with a traditional web service. One batch update in SQL Server may take a fraction of a second given a good highly-parameterized query, table-valued parameter or bulk insert to a staging table; processing all of these updates one at a time is slow, slow, slow, and OLTP database hardware is the most expensive of all to scale up/out. Is there some way to reconcile these competing concerns? Am I thinking about it the wrong way? Does this problem have a well-known solution in the CQS/ESB world? If not, then how does one decide what the "right level" of granularity in a Command should be? Is there some "standard" one can use as a starting point - sort of like 3NF in databases - and only deviate when careful profiling suggests a potentially significant performance benefit? Or is this possibly one of those things that, despite several strong opinions being expressed by various experts, is really just a matter of opinion?

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• Compiling for T4

  - by Darryl Gove

  I've recently had quite a few queries about compiling for T4 based systems. So it's probably a good time to review what I consider to be the best practices. Always use the latest compiler. Being in the compiler team, this is bound to be something I'd recommend But the serious points are that (a) Every release the tools get better and better, so you are going to be much more effective using the latest release (b) Every release we improve the generated code, so you will see things get better (c) Old releases cannot know about new hardware. Always use optimisation. You should use at least -O to get some amount of optimisation. -xO4 is typically even better as this will add within-file inlining. Always generate debug information, using -g. This allows the tools to attribute information to lines of source. This is particularly important when profiling an application. The default target of -xtarget=generic is often sufficient. This setting is designed to produce a binary that runs well across all supported platforms. If the binary is going to be deployed on only a subset of architectures, then it is possible to produce a binary that only uses the instructions supported on these architectures, which may lead to some performance gains. I've previously discussed which chips support which architectures, and I'd recommend that you take a look at the chart that goes with the discussion. Crossfile optimisation (-xipo) can be very useful - particularly when the hot source code is distributed across multiple source files. If you're allowed to have something as geeky as favourite compiler optimisations, then this is mine! Profile feedback (-xprofile=[collect: | use:]) will help the compiler make the best code layout decisions, and is particularly effective with crossfile optimisations. But what makes this optimisation really useful is that codes that are dominated by branch instructions don't typically improve much with "traditional" compiler optimisation, but often do respond well to being built with profile feedback. The macro flag -fast aims to provide a one-stop "give me a fast application" flag. This usually gives a best performing binary, but with a few caveats. It assumes the build platform is also the deployment platform, it enables floating point optimisations, and it makes some relatively weak assumptions about pointer aliasing. It's worth investigating. SPARC64 processor, T3, and T4 implement floating point multiply accumulate instructions. These can substantially improve floating point performance. To generate them the compiler needs the flag -fma=fused and also needs an architecture that supports the instruction (at least -xarch=sparcfmaf). The most critical advise is that anyone doing performance work should profile their application. I cannot overstate how important it is to look at where the time is going in order to determine what can be done to improve it. I also presented at Oracle OpenWorld on this topic, so it might be helpful to review those slides.

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• Fixing a NoClassDefFoundError

  - by Chris Okyen

  I have some code: package ftc; import java.util.Scanner; public class Fer_To_Cel { public static void main(String[] argv) { // Scanner object to get the temp in degrees Farenheit Scanner keyboard = new Scanner(System.in); boolean isInt = true; // temporarily put as true in case the user enters a valid int the first time int degreesF = 0; // initialy set to 0 do { try { // Input the temperature text. System.out.print("\nPlease enter a temperature (integer number, no fractional part) in degrees Farenheit: "); degreesF = Integer.parseInt(keyboard.next()); // Get user input and Assign the far. temperature variable, which is casted from String to int. } // Let the user know in a user friendly notice that the value entered wasnt an int ( give int value range ) , and then give error log catch(java.lang.Exception e) { System.out.println("Sorry but you entered a non-int value ( needs to be between ( including ) -2,147,483,648 and 2,147,483,647 ).. \n"); e.printStackTrace(); isInt = false; } } while(!isInt); System.out.println(""); // print a new line. final int degreesC = (5*(degreesF-32)/9); // convert the degrees from F to C and store the resulting expression in degreesC // Print out a newline, then print what X degrees F is in Celcius. System.out.println("\n" + degreesF + " degrees Farenheit is " + degreesC + " degrees Celcius"); } } And The following error: C:\Program Files\Java\jdk1.7.0_06\bin>java Fer_To_Cel Exception in thread "main" java.lang.NoClassDefFoundError: Fer_To_Cel (wrong name: ftc/Fer_To_Cel) at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:791) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:14 at java.net.URLClassLoader.defineClass(URLClassLoader.java:449) at java.net.URLClassLoader.access$100(URLClassLoader.java:71) at java.net.URLClassLoader$1.run(URLClassLoader.java:361) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:423) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at java.lang.ClassLoader.loadClass(ClassLoader.java:356) at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:480) The code compiled without compile errors, but presented errors during execution. Which leads me to two questions. I know Errors can be termed Compiler, Runtime and Logic Errors, but the NoClassDefFoundError inherits java.lang.LinkageError. Does that make it a Linker error, being niether of the three types of errors I listed, If I am right this is the answer. For someone else who obtains the singular .java file and compiles it, would this be the only way to solve this problem? Or can I (should I ) do/have done something to fix this problem? Basically, based on a basis of programming, is this a fault of me as the writer? Could this be done once on, my half and be distributed and not needed be done again?

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• JavaOne 2012: Camel, Twitter, Coherence, Wicket and GlassFish

  - by Bruno.Borges

  Before joining Oracle as Product Manager for WebLogic and GlassFish for Latin America, at the beggining of this year I proposed two talks to JavaOne USA that I had been presenting in Brazil for quite a while. One of them I presented last year at ApacheCon in Vancouver, Canada as well in JavaOne Brazil. In June I got the news that they were accepted as Alternate Sessions. Surprisingly enough, few weeks later and at the same time I joined Oracle, I received the news that they were officially accepted and put on schedule. Tomorrow I'll be flying to San Francisco, to my first JavaOne in the United States, and I wanted to share with you what I'm going to present there. My two sessions are these ones: Wed, 10/03, 4:30pm - CON2989 Leverage Enterprise Integration Patterns with Apache Camel and TwitterOn this one, you will be introducted to the Apache Camel framework that I had been talking about in Brazil at conferences, before joining Oracle, and to a component I contributed to integrate with Twitter. Also, you will have a preview of a new component I've been working on to integrate Camel with the Oracle Coherence distributed cache. Thu, 10/04, 3:30pm - CON3395 How Scala, Wicket, and Java EE Can Improve Web DevelopmentThis one I've been working on for quite a while. It was based on an idea to have an architecture that could be as agile as frameworks and technologies such as Ruby on Rails, PHP or Python, for rapid web development. You will be introduced to the Apache Wicket framework, another Apache project I enjoy working with and gave lots of talks at Brazilian conferences, including JavaOne Brazil, JustJava, QCon SP, and The Developers Conference. You will also be introduced to the Scala language and how to create nice DSLs to boost productiveness. And last but not least, the Java EE 6 platform, that offers an awesome improvement from previous versions with its CDI, JPA, EJB3 and JAX-RS features for web development. Other events I will be participating during my stay in SF: Geeks Bike Ride GlassFish Community Event GlassFish and Friends Party    If you have any other event to suggest, please do suggest! It's my first JavaOne and I'm really looking forward to enjoying everything. See you guys in a few days!!

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• RTS Game Style Application [closed]

  - by Daniel Wynand van Wyk

  My question may seem somewhat odd, but I hope that my specifications will clarify EXACTLY what it is that I am after. I need some help choosing the right tooling for a particular endeavour. My background is in desktop application development and large back-end systems. I have worked primarily on the Microsoft stack using C# and the .Net framework. My goal is to develop a 2D, RTS style, interactive office simulation. The simulation will model various office spaces, office equipment, employees and their interactions with one another. The idea is to abstract the concept of an office completely. Under the hood the application will do many things that are nothing like a game. This includes P2P networking, VPN tunnelling, streaming video, instant messaging, document collaboration, remote screen sharing, file-sharing, virus scanning, VOIP, document scanning, faxing, emailing, distributed computing, content management and much more! A somewhat similar thing has been attempted by IBM, where they created a virtual office in second life. If their attempt was a game, the game-play would be notably horrible, to say the least! The users/players will drive and control my application through the various objects modelled in the simulation. A single application capable of performing all of these various tasks would be a nightmare to navigate for even the most expert user. Using the concept of a game, I can easily separate functionality by assigning them to objects that relate 1-1 with their real world counter-parts. This can greatly simplify computing for novice users, with many added benefits in terms of visibility, transparency of process and centralized configuration. My hope is to make complex computing tasks accessible to all kinds of users and to greatly reduce the cognitive load associated with using the many different utilities and applications inside office settings. The complexity is therefore limited to the complexity of the space in which you find yourself. I want the application to target as many platforms as possible and run on computers that have no accelerated graphics capabilities. The simulation won't contain any of the fancy eye-candy you find in modern games, to the contrary, my "game" will purposefully be clean and simple. The closest thing I could imagine would be an old game like "Theme Hospital" or the first instalment of "The Sims". All the content will be pre-created and not user-generated like Second Life. New functionality will be added via a plugin system. Given my background and nature of my "game", I would like to spend most of my time writing code that does not have to do with the simulated office, as the "game" is really just a glorified application menu. I have done much reading about existing engines, frameworks and tools. I need the help of an experienced game developer who has tried and tested various products over the years who can guide me in the right direction given my very particular needs. I would appreciate any help I can get!

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• Draw images with warped triangles on a web server [migrated]

  - by epologee

  The scenario The Flash front end of my current project produces images that a web server needs to combine into a video. Both frame-rate and frame-resolution are sizeable enough that sending an image sequence to the back end is not feasible (in both time and client bandwidth). Instead, we're trying to recreate the image drawing on the back end as well. Correct and slow, or incorrect and fast The problem is that this involves quite a bit of drawing textured triangles, and two solutions we found in Python (here and there) are so inefficient, that the drawing takes about 60 seconds per frame, resulting in a whopping 7,5 hours of processing time for a 30 second clip. Unacceptable. When using a PHP-module to send commands to ImageMagick for image manipulation, the whole process is super fast (tenths of a second per frame), but ImageMagick seems to be unable to draw triangles the way we do it in the front end, so the final results do not match. Unacceptable. What I'm asking here, is if there's someone who would know a way to solve this issue, by any means necessary that would run on a web server. Warping an image Let me explain the process of the front end: Perform a Delaunay calculation on points in an image to get an evenly distributed mesh of triangles. Offset the points/vertices in the mesh, distorting or warping the image. Draw the warped triangles on a new bitmap. We can send the results (coordinates) of steps 1 and 2 to the back end, to then draw the warped triangles and save it to an image on disk (or append as a frame to the video). But that last step is what I need help with. The Question Is there an alternative to ImageMagick that can draw triangles in a bitmap? Is there some other library, like a C library, that would allow us to do this? Or could we achieve this effect more easily by switching back end technologies, like Ruby? (.Net and Java are, unfortunately, not really options right now) Many thanks. EP. P.S. I'd appreciate re-tagging efforts, I don't quite know what labels to put on this question. Thanks!

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• Movement prediction for non-shooters

  - by ShadowChaser

  I'm working on an isometric (2D) game with moderate-scale multiplayer - 20-30 players. I've had some difficulty getting a good movement prediction implementation in place. Right now, clients are authoritative for their own position. The server performs validation and broad-scale cheat detection, and I fully realize that the system will never be fully robust against cheating. However, the performance and implementation tradeoffs work well for me right now. Given that I'm dealing with sprite graphics, the game has 8 defined directions rather than free movement. Whenever the player changes their direction or speed (walk, run, stop), a "true" 3D velocity is set on the entity and a packet it sent to the server with the new movement state. In addition, every 250ms additional packets are transmitted with the player's current position for state updates on the server as well as for client prediction. After the server validates the packet, it gets automatically distributed to all of the other "nearby" players. Client-side, all entities with non-zero velocity (ie/ moving entities) are tracked and updated by a rudimentary "physics" system - basically nothing more than changing the position by the velocity according to the elapsed time slice (40ms or so). What I'm struggling with is how to implement clean movement prediction. I have the nagging suspicion that I've made a design mistake somewhere. I've been over the Unreal, Half-life, and all other movement prediction/lag compensation articles I could find, but they all seam geared toward shooters: "Don't send each control change, send updates every 120ms, server is authoritative, client predicts, etc". Unfortunately, that style of design won't work well for me - there's no 3D environment so each individual state change is important. 1) Most of the samples I saw tightly couple movement prediction right into the entities themselves. For example, storing the previous state along with the current state. I'd like to avoid that and keep entities with their "current state" only. Is there a better way to handle this? 2) What should happen when the player stops? I can't interpolate to the correct position, since they might need to walk backwards or another strange direction if their position is too far ahead. 3) What should happen when entities collide? If the current player collides with something, the answer is simple - just stop the player from moving. But what happens if two entities take up the same space on the server? What if the local prediction causes a remote entity to collide with the player or another entity - do I stop them as well? If the prediction had the misfortune of sticking them in front of a wall that the player has gone around, the prediction will never be able to compensate and once the error gets to high the entity will snap to the new position.

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• How to avoid oscillation by async event based systems?

  - by inf3rno

  Imagine a system where there are data sources which need to be kept in sync. A simple example is model - view data binding by MVC. Now I intend to describe these kind of systems with data sources and hubs. Data sources are publishing and subscribing for events and hubs are relaying events to data sources. By handling an event a data source will change it state described in the event. By publishing an event the data source puts its current state to the event, so other data sources can use that information to change their state accordingly. The only problem with this system, that events can be reflected from the hub or from the other data sources, and that can put the system into an infinite oscillation (by async or infinite loop by sync). For example A -- data source B -- data source H -- hub A -> H -> A -- reflection from the hub A -> H -> B -> H -> A -- reflection from another data source By sync it is relatively easy to solve this issue. You can compare the current state with the event, and if they are equal, you don't change the state and raise the same event again. By async I could not find a solution yet. The state comparison does not work by async event handling because there is eventual consistency, and new events can be published in an inconsistent state causing the same oscillation. For example: A(*->x) -> H -> B(y->x) -- can go parallel with B(*->y) -> H -> A(x->y) -- so first A changes to x state while B changes to y state -- then B changes to x state while A changes to y state -- and so on for eternity... What do you think is there an algorithm to solve this problem? If there is a solution, is it possible to extend it to prevent oscillation caused by multiple hubs, multiple different events, etc... ? update: I don't think I can make this work without a lot of effort. I think this problem is just the same as we have by syncing multiple databases in a distributed system. So I think what I really need is constraints if I want to prevent this problem in an automatic way. What constraints do you suggest?

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• Replacing DropBox with: Amazon S3 + SSL + GPG/TrueCrypt + Mounting on OSX ??

  - by Matt Rogish

  So, right now we're using DropBox to share various data files around between approximately 10 Mac OS X systems. However, we already have an S3 account and everyone on the lowest DropBox plan of $10/mo seems too expensive. We'd like to avoid any kind of local storage (share a disk on a desktop or something) since we're a geographically distributed team). So, I am contemplating something that would allow us to replace DropBox with our own home-grown solution. We are all fairly technical people and/or smart enough to follow some steps, so if it's not as "user friendly" as DropBox we're all comfortable with that. There are plenty of docs out there that have bits and pieces of what I want but some of the tools don't seem to fit the requirements: Transport security via SSL to the bucket Encryption of bucket contents Bi-directional syncing Most of the scripts I can find on the internet use "duplicity" which appears to fail #1 (it doesn't look like duplicity supports SSL to S3 - the docs don't state but the protocol looks plain old http http://www.nongnu.org/duplicity/duplicity.1.html#sect6 ) Many scripts use gpg to encrypt files. This seems like it could work, however I have to make sure that each OSX client is able to use the same key to encrypt and decrypt files (key management is left to me to manage). FTP and other client-based apps don't seem to support this at all. Finally, most of the scripts use one-way replication, e.g. using Amazon S3 as a simple backup store. As we'd be using Amazon S3 as the "repository" they fail this one. Whew. So, I'd love a single tool that does this but after an exhaustive search I don't think one exists. In my mind, the magical tool would be some combination of TrueCrypt and rsync. I'd be happy just knowing which tools out there can fulfill my 3 requirements, after that I can stitch together the rest. Any thoughts? THANKS!

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