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• SEO to ensure visibility for a narrow, non-competitive, non-commercial site

  - by hen3ry

  I'm webmaster of a non-commercial site in English. A non-native-English speaker asked me why our site doesn't produce hits in Google searches she conducts for relevant keywords in her native language. I asked her for a list of keywords in her native language, and I naively tried inserting those into the META info in the page headers and waited a couple of weeks. No help. A little searching informed me that Google doesn't use the META info, and has not done so for a very long time. D'oh! To be entirely concrete, suppose the StackExchange folks want Russian speakers to find this site, Pro Webmasters. The direct translation in Russian of "webmaster" --thanks, Google Translator-- is: "?????????". (Not sure this will render properly, but that's not essential to my question.) Assuming Pro Webmasters has a common template for all pages it generates, inserting "?????????" into the Keywords META for that template won't help, it seems. What could StackExchange do to make this site visible to users searching with the Russian keyword "?????????" ? Pretty much all the advice I've seen boils down to this, if I understand correctly: use the desired search term often (but not too often) among site content, and the problem will be solved. That's great, but I don't think sprinkling "?????????" visibly all over Pro Webmasters is going to fly. Just for completeness, crawlers must be long immune to the invisible-to-visitors scheme, e.g, format "?????????" in a tiny text size in a color the same as an existing background, e.g. white-over-white. Or, put that text inside a div styled: ' style="visibility: hidden" '. Probably some other equivalents. I can only think of one slightly effective method, along these lines: place an unobtrusive link on the common template to a page titled "for international users" , and on that page list desired synonyms for "webmaster" in various languages on that page. A test case --admittedly, just one-- using my site implies that a Google search for "international users" ????????? will produce a hit for this page, and thus make the site minimally visible, despite the fact that the page will almost never be visited. At the moment, anyway. Note: All the SEO discussions I have found so far are about competitive and --almost certainly-- commercial sites. To repeat: my site is non-commercial, and it is about an obscure, narrow topic that is of interest to only a small number of people worldwide. This isn't about clawing our way to the top of competitive rankings, just making this content minimally visible to interested non-native-English speakers. Ideas? TIA

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• Is there a pedagogical game engine?

  - by K.G.

  I'm looking for a book, website, or other resource that gives modern 3D game engines the same treatment as Operating Systems: Design and Implementation gave operating systems. I have read Jason Gregory's Game Engine Architecture, which I enjoyed. However, by intent the author treated components of the architecture as atomic units, whereas what I'm interested in is the plumbing between those units that makes a coherent whole out of ideally loosely coupled parts. In books such as these, one usually reads that "that's academic," but that's the point! I have also read Julian Gold's Object-oriented Game Development, which likewise was good, but I feel is beginning to show its age. Since even mobile platforms these days are multicore and have fast video memory, those kinds of things (concurrency, display item buffering) would ideally be covered. There are other resources, such as the Doom 3 source code, which is highly instructive for its being a shipped product. The problem with those is as follows: float Q_rsqrt( float number ) { long i; float x2, y; const float threehalfs = 1.5F; x2 = number * 0.5F; y = number; i = * ( long * ) &y; // evil floating point bit level hacking i = 0x5f3759df - ( i >> 1 ); // what the f***? y = * ( float * ) &i; y = y * ( threehalfs - ( x2 * y * y ) ); // 1st iteration // y = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, this can be removed return y; } To wit, while brilliant, this kind of source requires more enlightenment than I can usually muster upon first read. In summary, here's my white whale: For an adult reader with experience in programming. I wish I could save all the trees killed by every. Single. Game Programming book ever devoting the first two chapters to "Now just what is a variable anyway?" In C or C++, very preferably C++. Languages that are more concise are fantastic for teaching, except for when what you want to learn is how to cope with a verbose language. There is also the benefit of the guardrails that C++ doesn't provide, such as garbage collection. Platform agnostic. I'm sincerely afraid that this book is out there and it's Visual C++/DirectX oriented. I'm a Linux guy, and I'd do what it takes, but I would very much like to be able to use OpenGL. Thanks for everything! Before anyone gets on my case about it, Fast inverse square root was from Quake III Arena, not Doom 3!

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• MS in Computer Science after BE in electronics

  - by Abhinav

  I am doing my 3rd year Bachelors in Electronics and Electrical Communication but from the first year I have been interested in Computer Science. But at that time it was just my hobby. But in second year when I joined robotics my love for computer science rose. I with my team came in top three in 2 National Competition (Technical fests of different IITs) where we used Image Processing, Hardware interfacing etc. But then I realised that Computer Science is not just about coding. I took many lectures from online free schools like Udacity, Coursera in subjects related to Artificial Intelligence, Building a Search Engine, Design and Analysis of Algorithm, Programming a Robotic Car, Programming Languages, Machine Learning, Software Engineering as a Service, WebApps Engineering, Compilers, Applied Crypotography etc. I also did some courses in Core and Advanced Java in my second year from training institute. I will also be taking course in Statistics, Databases, Discrete Mathematics from 25th June. Now I realized how vast is the field of Computer Science and how efficient you become on deciding algorithms and classifying problems into different subfields which have been thoroughly researched so you don't always do brute force thing or naive programming. Now this field has become kind of passion for me. Adding to the fact I am also doing my 6 months internship in software field in Texas Instruments where I am working on Automation and Algorithms. I also have some 5-6 good college level projects in Softwares and Robotics. I also like Electronics but only some fields like Operating System(this subject was there in Electronics also), Micro Processor, Digital, Computer Architecture, DSPs etc. I really want to pursue MS in some field of Computer Science. I am giving GRE in October/November. Till now I have good CG of around 9.4/10 and my 1 year in college is still left. Do I have any chance that some good University in US will consider me for MS in field related to computer science or Robotics. Also Can you suggest somethings that I can do during this 1 year to increase my chances for MS or should I apply for EECS(Electrical Engineering and Computer Science) and then I can shift more towards Computer Science as my major option. My main aim is to do Phd after Ms in CS if I am able to do that somehow. I know that I have to put much extra effort to understand things in MS than CS undergraduates but I will do that with my full dedication, also when I communicate with my college CS students or during my internship period I didn't feel that I am missing very much stuff that they know and was very comfortable during my internship with software employees.

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• 3 Reasons You Need To Know Something About Every Technology

  - by Tim Murphy

  I make my living as a consultant and a general technologist.  I credit my success to the fact that I have never been afraid to pick up any product, language or platform needed to get the job done.  While Microsoft technologies I my mainstay, I have done work on mainframe and UNIX platforms and have worked with a wide variety of database engines.  Each one has it’s use and most times it is less expensive to find a way to communicate with an existing system than to replace it. So what are the main benefits of expending the effort to learn a new technology? New ways to solve problems Accelerate development Advise clients and get new business opportunities By new technology I mean ones that you haven’t had experience with before.  They don’t have to be the the one that just came out yesterday.  As they say, those who do not learn from history are bound to repeat it.  If you can learn something from an older technology it can be just as valuable as the shiny new one.  Either way, when you add another tool to your kit you get a new view on each problem you face.  This makes it easier to create a sound solution. The next thing you can learn from working with different products and techniques is how to more efficiently develop solve problems.  Many times if you are working with a new language you will find that there are specific design patterns that are used with it in normal use.  These can usually be applied with most languages.  You just needed to be exposed to them. The last point is about helping your clients and helping yourself.  If you can get in on technologies early you will have advantage over your competition in the market.  You will also be able to honestly advise you client on why they should or should not go with a new product.  Being able to compare products and their features is always an ability that stake holders appreciate. You don’t need to learn every detail of a product.  Learn enough to function and get an idea of how to use the technology.  Keep eating those technology Wheaties and you will be ready to go the distance in any project. del.icio.us Tags: Technology,technologists,technology generalist,Software Architecture

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• Making A Photo-Sharing App For Android In Eclipse [on hold]

  - by user3694394

  I've only just started developing mobile apps, which is something that I've been wanting to learn for a while now. I'm from an indie games studio, making PC games for around the last 3 years, and I finally decided to move into android app development. The only problem I'm having is that I don't know where to start. The project which I'm aiming to create will be something similar to Instagram, basically a photo-sharing app which allows users to take new photos, or pull them from their device, and add filters to them, before posting them. I have a rough idea of how I could go about doing this, but I need pointing towards any tutorials available for each specific step. So, here's my idea: Create a UI in eclipse (this wont be a problem for me, I should be able to do this fine through xml files) Setup a server-side database to store all user info and uploaded images (the images will need to be converted into byte arrays, and I have no idea how to do this through a database). My best idea would be to use a MySQL database to do this. Add user interactions (likes, favourites, reposts, etc.). This would, again, have to be stored in the database (or, at least, i think it would). Add the ability to take new photos using the phone's camera (I can probably do this anyway, using the Camera API). Add the ability to pull existing photos from the device (again, pretty simple to do). Add the ability to add filters to any photos (I had a look around, and there are some repos and resources which allow you to do this, but they're mainly for iOS development). Add facebook/twitter integration (possibly) to allow phots to be shared to other social networks. Create a news feed which shows users all of the latest photos from their friends, and allows them to post their own images to it. Give all registered users their own wall/page which has their latest posts/images displayed on it. Add the ability to allow users to follow other users, and display their followed users posts on their news feed. Yep. It's not going to be easy, and I don't even know if it's possible for me to do alone in Eclipse. However, this is the plan, and I'm going to do my best to learn everything I need to know to do this successfully. My actual question would be how should I start doing this- where do I begin learning how to do all of this? I've had a look at snapify, which can be edited via Parse, but I won't be spending hundreds of dollars (since I'm 15 and just don't have the available funds) on software. I have extensive knowledge of Java (again, I've been making games for around 3 years, mainly in Java), and various scripting languages. So, hopefully, this will be of some use here. Thanks in advance, Josh.

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• What algorithms can I use to detect if articles or posts are duplicates?

  - by michael

  I'm trying to detect if an article or forum post is a duplicate entry within the database. I've given this some thought, coming to the conclusion that someone who duplicate content will do so using one of the three (in descending difficult to detect): simple copy paste the whole text copy and paste parts of text merging it with their own copy an article from an external site and masquerade as their own Prepping Text For Analysis Basically any anomalies; the goal is to make the text as "pure" as possible. For more accurate results, the text is "standardized" by: Stripping duplicate white spaces and trimming leading and trailing. Newlines are standardized to \n. HTML tags are removed. Using a RegEx called Daring Fireball URLs are stripped. I use BB code in my application so that goes to. (ä)ccented and foreign (besides Enlgish) are converted to their non foreign form. I store information about each article in (1) statistics table and in (2) keywords table. (1) Statistics Table The following statistics are stored about the textual content (much like this post) text length letter count word count sentence count average words per sentence automated readability index gunning fog score For European languages Coleman-Liau and Automated Readability Index should be used as they do not use syllable counting, so should produce a reasonably accurate score. (2) Keywords Table The keywords are generated by excluding a huge list of stop words (common words), e.g., 'the', 'a', 'of', 'to', etc, etc. Sample Data text_length, 3963 letter_count, 3052 word_count, 684 sentence_count, 33 word_per_sentence, 21 gunning_fog, 11.5 auto_read_index, 9.9 keyword 1, killed keyword 2, officers keyword 3, police It should be noted that once an article gets updated all of the above statistics are regenerated and could be completely different values. How could I use the above information to detect if an article that's being published for the first time, is already existing within the database? I'm aware anything I'll design will not be perfect, the biggest risk being (1) Content that is not a duplicate will be flagged as duplicate (2) The system allows the duplicate content through. So the algorithm should generate a risk assessment number from 0 being no duplicate risk 5 being possible duplicate and 10 being duplicate. Anything above 5 then there's a good possibility that the content is duplicate. In this case the content could be flagged and linked to the article's that are possible duplicates and a human could decide whether to delete or allow. As I said before I'm storing keywords for the whole article, however I wonder if I could do the same on paragraph basis; this would also mean further separating my data in the DB but it would also make it easier for detecting (2) in my initial post. I'm thinking weighted average between the statistics, but in what order and what would be the consequences...

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• How to become a good team player?

  - by Nick

  I've been programming (obsessively) since I was 12. I am fairly knowledgeable across the spectrum of languages out there, from assembly, to C++, to Javascript, to Haskell, Lisp, and Qi. But all of my projects have been by myself. I got my degree in chemical engineering, not CS or computer engineering, but for the first time this fall I'll be working on a large programming project with other people, and I have no clue how to prepare. I've been using Windows all of my life, but this project is going to be very unix-y, so I purchased a Mac recently in the hopes of familiarizing myself with the environment. I was fortunate to participate in a hackathon with some friends this past year -- both CS majors -- and excitingly enough, we won. But I realized as I worked with them that their workflow was very different from mine. They used Git for version control. I had never used it at the time, but I've since learned all that I can about it. They also used a lot of frameworks and libraries. I had to learn what Rails was pretty much overnight for the hackathon (on the other hand, they didn't know what lexical scoping or closures were). All of our code worked well, but they didn't understand mine, and I didn't understand theirs. I hear references to things that real programmers do on a daily basis -- unit testing, code reviews, but I only have the vaguest sense of what these are. I normally don't have many bugs in my little projects, so I have never needed a bug tracking system or tests for them. And the last thing is that it takes me a long time to understand other people's code. Variable naming conventions (that vary with each new language) are difficult (__mzkwpSomRidicAbbrev), and I find the loose coupling difficult. That's not to say I don't loosely couple things -- I think I'm quite good at it for my own work, but when I download something like the Linux kernel or the Chromium source code to look at it, I spend hours trying to figure out how all of these oddly named directories and files connect. It's a programming sin to reinvent the wheel, but I often find it's just quicker to write up the functionality myself than to spend hours dissecting some library. Obviously, people who do this for a living don't have these problems, and I'll need to get to that point myself. Question: What are some steps that I can take to begin "integrating" with everyone else? Thanks!

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• best way to "introduce" OOP/OOD to team of experienced C++ engineers

  - by DXM

  I am looking for an efficient way, that also doesn't come off as an insult, to introduce OOP concepts to existing team members? My teammates are not new to OO languages. We've been doing C++/C# for a long time so technology itself is familiar. However, I look around and without major infusion of effort (mostly in the form of code reviews), it seems what we are producing is C code that happens to be inside classes. There's almost no use of single responsibility principle, abstractions or attempts to minimize coupling, just to name a few. I've seen classes that don't have a constructor but get memset to 0 every time they are instantiated. But every time I bring up OOP, everyone always nods and makes it seem like they know exactly what I'm talking about. Knowing the concepts is good, but we (some more than others) seem to have very hard time applying them when it comes to delivering actual work. Code reviews have been very helpful but the problem with code reviews is that they only occur after the fact so to some it seems we end up rewriting (it's mostly refactoring, but still takes lots of time) code that was just written. Also code reviews only give feedback to an individual engineer, not the entire team. I am toying with the idea of doing a presentation (or a series) and try to bring up OOP again along with some examples of existing code that could've been written better and could be refactored. I could use some really old projects that no one owns anymore so at least that part shouldn't be a sensitive issue. However, will this work? As I said most people have done C++ for a long time so my guess is that a) they'll sit there thinking why I'm telling them stuff they already know or b) they might actually take it as an insult because I'm telling them they don't know how to do the job they've been doing for years if not decades. Is there another approach which would reach broader audience than a code review would, but at the same time wouldn't feel like a punishment lecture? I'm not a fresh kid out of college who has utopian ideals of perfectly designed code and I don't expect that from anyone. The reason I'm writing this is because I just did a review of a person who actually had decent high-level design on paper. However if you picture classes: A - B - C - D, in the code B, C and D all implement almost the same public interface and B/C have one liner functions so that top-most class A is doing absolutely all the work (down to memory management, string parsing, setup negotiations...) primarily in 4 mongo methods and, for all intents and purposes, calls almost directly into D. Update: I'm a tech lead(6 months in this role) and do have full support of the group manager. We are working on a very mature product and maintenance costs are definitely letting themselves be known.

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• Why is multithreading often preferred for improving performance?

  - by user1849534

  I have a question, it's about why programmers seems to love concurrency and multi-threaded programs in general. I'm considering 2 main approaches here: an async approach basically based on signals, or just an async approach as called by many papers and languages like the new C# 5.0 for example, and a "companion thread" that manages the policy of your pipeline a concurrent approach or multi-threading approach I will just say that I'm thinking about the hardware here and the worst case scenario, and I have tested this 2 paradigms myself, the async paradigm is a winner at the point that I don't get why people 90% of the time talk about multi-threading when they want to speed up things or make a good use of their resources. I have tested multi-threaded programs and async program on an old machine with an Intel quad-core that doesn't offer a memory controller inside the CPU, the memory is managed entirely by the motherboard, well in this case performances are horrible with a multi-threaded application, even a relatively low number of threads like 3-4-5 can be a problem, the application is unresponsive and is just slow and unpleasant. A good async approach is, on the other hand, probably not faster but it's not worst either, my application just waits for the result and doesn't hangs, it's responsive and there is a much better scaling going on. I have also discovered that a context change in the threading world it's not that cheap in real world scenario, it's in fact quite expensive especially when you have more than 2 threads that need to cycle and swap among each other to be computed. On modern CPUs the situation it's not really that different, the memory controller it's integrated but my point is that an x86 CPUs is basically a serial machine and the memory controller works the same way as with the old machine with an external memory controller on the motherboard. The context switch is still a relevant cost in my application and the fact that the memory controller it's integrated or that the newer CPU have more than 2 core it's not bargain for me. For what i have experienced the concurrent approach is good in theory but not that good in practice, with the memory model imposed by the hardware, it's hard to make a good use of this paradigm, also it introduces a lot of issues ranging from the use of my data structures to the join of multiple threads. Also both paradigms do not offer any security abut when the task or the job will be done in a certain point in time, making them really similar from a functional point of view. According to the X86 memory model, why the majority of people suggest to use concurrency with C++ and not just an async approach ? Also why not considering the worst case scenario of a computer where the context switch is probably more expensive than the computation itself ?

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• Should I go back to college and graduate with a poor GPA or try to jump into an entry-level development position? [closed]

  - by jshin47

  I once attended a top-10 American university but I am currently not in school for several different reasons. Chief among them is that I did very poorly two semesters and even failed one of them (got two F's) which put me in automatic suspension. My major is not CS but math. I am in a pickle at the moment. After I was suspended I got a job at a niche IT company in the area. I am employed as something of an IT generalist; my primary responsibilities are Windows systems administration/networking but I also do some Android, iOS, and .NET development. I have released a few apps to the app store under my name and my company's name, and we have done work for a few big clients. I started working at my job about 1.5 years ago and I am somewhat happily employed but I do not see it as a long-term fit because it is a small company with little opportunity to advance. I would like to move out to California and particularly to the Bay Area to get a job at a more reputable or exciting company, even at a lower rate of pay, but I am not sure if I should do that or try to go back to school. If I went back to school, it would take 1-1.5 years to graduate and some $. Best case scenario I would graduate with a 2.9 or 3.0 GPA. It is a top-10 school, but that's a crappy GPA. If I do not go back to school, I will be a field where most people have degrees, without a degree. If anything goes wrong I could be really screwed as I feel I will get no respect without a degree. On the other hand I really would like to get started in the field and get more serious about developing good development practices, learning new languages/frameworks, and working with people who know a lot more than I so I can learn and grow as a developer and eventually do my own thing. Basically, I am wondering: Should I just go back to school? How much does the bad GPA / good school reputation weigh in? What about the fact that I am a Math major and not a CS major (have never taken a CS course)? Does my skill set as something of a generalist bode well for me finding work at a start up in the Bay Area? If not (2), should I hunker down and focus on producing a really good (or a few medicore) iOS apps? Android apps? etc... How would you look at someone who did great in HS, kind of goofed off in college and eventually quit, and got into development? Thanks for any thoughts or input.

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• Take Two: Comparing JVMs on ARM/Linux

  - by user12608080

  Although the intent of the previous article, entitled Comparing JVMs on ARM/Linux, was to introduce and highlight the availability of the HotSpot server compiler (referred to as c2) for Java SE-Embedded ARM v7,  it seems, based on feedback, that everyone was more interested in the OpenJDK comparisons to Java SE-E.  In fact there were two main concerns: The fact that the previous article compared Java SE-E 7 against OpenJDK 6 might be construed as an unlevel playing field because version 7 is newer and therefore potentially more optimized. That the generic compiler settings chosen to build the OpenJDK implementations did not put those versions in a particularly favorable light. With those considerations in mind, we'll institute the following changes to this version of the benchmarking: In order to help alleviate an additional concern that there is some sort of benchmark bias, we'll use a different suite, called DaCapo.  Funded and supported by many prestigious organizations, DaCapo's aim is to benchmark real world applications.  Further information about DaCapo can be found at http://dacapobench.org. At the suggestion of Xerxes Ranby, who has been a great help through this entire exercise, a newer Linux distribution will be used to assure that the OpenJDK implementations were built with more optimal compiler settings.  The Linux distribution in this instance is Ubuntu 11.10 Oneiric Ocelot. Having experienced difficulties getting Ubuntu 11.10 to run on the original D2Plug ARMv7 platform, for these benchmarks, we'll switch to an embedded system that has a supported Ubuntu 11.10 release.  That platform is the Freescale i.MX53 Quick Start Board.  It has an ARMv7 Coretex-A8 processor running at 1GHz with 1GB RAM. We'll limit comparisons to 4 JVM implementations: Java SE-E 7 Update 2 c1 compiler (default) Java SE-E 6 Update 30 (c1 compiler is the only option) OpenJDK 6 IcedTea6 1.11pre 6b23~pre11-0ubuntu1.11.10.2 CACAO build 1.1.0pre2 OpenJDK 6 IcedTea6 1.11pre 6b23~pre11-0ubuntu1.11.10.2 JamVM build-1.6.0-devel Certain OpenJDK implementations were eliminated from this round of testing for the simple reason that their performance was not competitive.  The Java SE 7u2 c2 compiler was also removed because although quite respectable, it did not perform as well as the c1 compilers.  Recall that c2 works optimally in long-lived situations.  Many of these benchmarks completed in a relatively short period of time.  To get a feel for where c2 shines, take a look at the first chart in this blog. The first chart that follows includes performance of all benchmark runs on all platforms.  Later on we'll look more at individual tests.  In all runs, smaller means faster.  The DaCapo aficionado may notice that only 10 of the 14 DaCapo tests for this version were executed.  The reason for this is that these 10 tests represent the only ones successfully completed by all 4 JVMs.  Only the Java SE-E 6u30 could successfully run all of the tests.  Both OpenJDK instances not only failed to complete certain tests, but also experienced VM aborts too. One of the first observations that can be made between Java SE-E 6 and 7 is that, for all intents and purposes, they are on par with regards to performance.  While it is a fact that successive Java SE releases add additional optimizations, it is also true that Java SE 7 introduces additional complexity to the Java platform thus balancing out any potential performance gains at this point.  We are still early into Java SE 7.  We would expect further performance enhancements for Java SE-E 7 in future updates. In comparing Java SE-E to OpenJDK performance, among both OpenJDK VMs, Cacao results are respectable in 4 of the 10 tests.  The charts that follow show the individual results of those four tests.  Both Java SE-E versions do win every test and outperform Cacao in the range of 9% to 55%. For the remaining 6 tests, Java SE-E significantly outperforms Cacao in the range of 114% to 311% So it looks like OpenJDK results are mixed for this round of benchmarks.  In some cases, performance looks to have improved.  But in a majority of instances, OpenJDK still lags behind Java SE-Embedded considerably. Time to put on my asbestos suit.  Let the flames begin...

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• CPU Usage in Very Large Coherence Clusters

  - by jpurdy

  When sizing Coherence installations, one of the complicating factors is that these installations (by their very nature) tend to be application-specific, with some being large, memory-intensive caches, with others acting as I/O-intensive transaction-processing platforms, and still others performing CPU-intensive calculations across the data grid. Regardless of the primary resource requirements, Coherence sizing calculations are inherently empirical, in that there are so many permutations that a simple spreadsheet approach to sizing is rarely optimal (though it can provide a good starting estimate). So we typically recommend measuring actual resource usage (primarily CPU cycles, network bandwidth and memory) at a given load, and then extrapolating from those measurements. Of course there may be multiple types of load, and these may have varying degrees of correlation -- for example, an increased request rate may drive up the number of objects "pinned" in memory at any point, but the increase may be less than linear if those objects are naturally shared by concurrent requests. But for most reasonably-designed applications, a linear resource model will be reasonably accurate for most levels of scale. However, at extreme scale, sizing becomes a bit more complicated as certain cluster management operations -- while very infrequent -- become increasingly critical. This is because certain operations do not naturally tend to scale out. In a small cluster, sizing is primarily driven by the request rate, required cache size, or other application-driven metrics. In larger clusters (e.g. those with hundreds of cluster members), certain infrastructure tasks become intensive, in particular those related to members joining and leaving the cluster, such as introducing new cluster members to the rest of the cluster, or publishing the location of partitions during rebalancing. These tasks have a strong tendency to require all updates to be routed via a single member for the sake of cluster stability and data integrity. Fortunately that member is dynamically assigned in Coherence, so it is not a single point of failure, but it may still become a single point of bottleneck (until the cluster finishes its reconfiguration, at which point this member will have a similar load to the rest of the members). The most common cause of scaling issues in large clusters is disabling multicast (by configuring well-known addresses, aka WKA). This obviously impacts network usage, but it also has a large impact on CPU usage, primarily since the senior member must directly communicate certain messages with every other cluster member, and this communication requires significant CPU time. In particular, the need to notify the rest of the cluster about membership changes and corresponding partition reassignments adds stress to the senior member. Given that portions of the network stack may tend to be single-threaded (both in Coherence and the underlying OS), this may be even more problematic on servers with poor single-threaded performance. As a result of this, some extremely large clusters may be configured with a smaller number of partitions than ideal. This results in the size of each partition being increased. When a cache server fails, the other servers will use their fractional backups to recover the state of that server (and take over responsibility for their backed-up portion of that state). The finest granularity of this recovery is a single partition, and the single service thread can not accept new requests during this recovery. Ordinarily, recovery is practically instantaneous (it is roughly equivalent to the time required to iterate over a set of backup backing map entries and move them to the primary backing map in the same JVM). But certain factors can increase this duration drastically (to several seconds): large partitions, sufficiently slow single-threaded CPU performance, many or expensive indexes to rebuild, etc. The solution of course is to mitigate each of those factors but in many cases this may be challenging. Larger clusters also lead to the temptation to place more load on the available hardware resources, spreading CPU resources thin. As an example, while we've long been aware of how garbage collection can cause significant pauses, it usually isn't viewed as a major consumer of CPU (in terms of overall system throughput). Typically, the use of a concurrent collector allows greater responsiveness by minimizing pause times, at the cost of reducing system throughput. However, at a recent engagement, we were forced to turn off the concurrent collector and use a traditional parallel "stop the world" collector to reduce CPU usage to an acceptable level. In summary, there are some less obvious factors that may result in excessive CPU consumption in a larger cluster, so it is even more critical to test at full scale, even though allocating sufficient hardware may often be much more difficult for these large clusters.

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• Can working exclusively with niche apps or tech hurt your career in software development? How to get out of the cycle? [closed]

  - by Keoma

  I'm finding myself in a bit of a pickle. I've been at a pretty comfortable IT group for almost a decade. I got my start here working on web development, mostly CRUD, but have demonstrated the ability to figure out more complex problems. I'm not a rock star, but I have received many compliments on my programming aptitude, and technologists and architects have commented on my ability to pick things up (for example, I recently learned a very popular web framework that shall remain nameless since I don’t want to be identified). My problem is that, over time, my responsibilities have been shifting towards work such as support or ‘development’ with some rather niche products (afraid to mention here due to potential for being identified). Some of this work, if it includes anything resembling coding, is very menial scripting in languages such as Powershell or VBScript. The vast majority of the time, however, a typical day consists of going back and forth with the product’s vendor support to send them logs and apply configuration changes or patches they recommend. I’m basically starved for some actual software development. However, even though I’m more than capable of doing that development work (and actually do a much better job at it than anything else), our boss is more interested in the kind of work I mentioned above, her reasoning being that since no one else in the organization wants to do it, it must mean job security. This has been going on for close to 3 years, and the only reason I have held on is on the promise that we would eventually get more development projects assigned to us. Well, that turned out not to be true at all. A recent talk with the boss has just made it more explicitly clear, as she told me in no uncertain terms that it’s very likely that development work (web or otherwise) would go to another group. The reason given to me is that our we don’t have enough resources in our group to handle that. So now I find myself in the position that I either have to stay in what has essentially become a dead end IT job that is tied to the fortunes of a niche stack of apps, or try to find a position that will be better for my long term career. My problem (is it a problem?), however, is that compared to others, my development projects in the last three years are very sparse in number. To compound things, projects using the latest and most popular frameworks, amount to the big fat number of just one—with no work of that kind in the foreseeable future. I am very concerned that this sparseness in my resume is a deficit, and that it will hurt my chances of landing a different job. I’m also wondering how much it will hurt me, and whether that can be ameliorated with hobby projects of my own. I guess I’m looking for opinions. Thank you very much for reading.

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• Common SOA Problems by C2B2

  - by JuergenKress

  SOA stands for Service Oriented Architecture and has only really come together as a concrete approach in the last 15 years or so, although the concepts involved have been around for longer. Oracle SOA Suite is based around the Service Component Architecture (SCA) devised by the Open SOA collaboration of companies including Oracle and IBM. SCA, as used in SOA suite, is designed as a way to crystallise the concepts of SOA into a standard which ensures that SOA principles like the separation of application and business logic are maintained. Orchestration or Integration? A common thing to see with many people who are beginning to either build a new SOA based infrastructure, or move an old system to be service oriented, is confusion in the purpose of SOA technologies like BPEL and enterprise service buses. For a lot of problems, orchestration tools like BPEL or integration tools like an ESB will both do the job and achieve the right objectives; however it’s important to remember that, although a hammer can be used to drive a screw into wood, that doesn’t mean it’s the best way to do it. Service Integration is the act of connecting components together at a low level, which usually results in a single external endpoint for you to expose to your customers or other teams within your organisation – a simple product ordering system, for example, might integrate a stock checking service and a payment processing service. Process Orchestration, however, is generally a higher level approach whereby the (often externally exposed) service endpoints are brought together to track an end-to-end business process. This might include the earlier example of a product ordering service and couple it with a business rules service and human task to handle edge-cases. A good (but not exhaustive) rule-of-thumb is that integrations performed by an ESB will usually be real-time, whereas process orchestration in a SOA composite might comprise processes which take a certain amount of time to complete, or have to wait pending manual intervention. BPEL vs BPMN For some, with pre-existing SOA or business process projects, this decision is effectively already made. For those embarking on new projects it’s certainly an important consideration for those using Oracle SOA software since, due to the components included in SOA Suite and BPM Suite, the choice of which to buy is determined by what they offer. Oracle SOA suite has no BPMN engine, whereas BPM suite has both a BPMN and a BPEL engine. SOA suite has the ESB component “Mediator”, whereas BPM suite has none. Decisions must be made, therefore, on whether just one or both process modelling languages are to be used. The wrong decision could be costly further down the line. Design for performance: Read the complete article here. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Technorati Tags: C2B2,SOA best practice,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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• SQL 2014 does data the way developers want

  - by Rob Farley

  A post I’ve been meaning to write for a while, good that it fits with this month’s T-SQL Tuesday, hosted by Joey D’Antoni (@jdanton) Ever since I got into databases, I’ve been a fan. I studied Pure Maths at university (as well as Computer Science), and am very comfortable with Set Theory, which undergirds relational database concepts. But I’ve also spent a long time as a developer, and appreciate that that databases don’t exactly fit within the stuff I learned in my first year of uni, particularly the “Algorithms and Data Structures” subject, in which we studied concepts like linked lists. Writing in languages like C, we used pointers to quickly move around data, without a database in sight. Of course, if we had a power failure all this data was lost, as it was only persisted in RAM. Perhaps it’s why I’m a fan of database internals, of indexes, latches, execution plans, and so on – the developer in me wants to be reassured that we’re getting to the data as efficiently as possible. Back when SQL Server 2005 was approaching, one of the big stories was around CLR. Many were saying that T-SQL stored procedures would be a thing of the past because we now had CLR, and that obviously going to be much faster than using the abstracted T-SQL. Around the same time, we were seeing technologies like Linq-to-SQL produce poor T-SQL equivalents, and developers had had a gutful. They wanted to move away from T-SQL, having lost trust in it. I was never one of those developers, because I’d looked under the covers and knew that despite being abstracted, T-SQL was still a good way of getting to data. It worked for me, appealing to both my Set Theory side and my Developer side. CLR hasn’t exactly become the default option for stored procedures, although there are plenty of situations where it can be useful for getting faster performance. SQL Server 2014 is different though, through Hekaton – its In-Memory OLTP environment. When you create a table using Hekaton (that is, a memory-optimized one), the table you create is the kind of thing you’d’ve made as a developer. It creates code in C leveraging structs and pointers and arrays, which it compiles into fast code. When you insert data into it, it creates a new instance of a struct in memory, and adds it to an array. When the insert is committed, a small write is made to the transaction to make sure it’s durable, but none of the locking and latching behaviour that typifies transactional systems is needed. Indexes are done using hashes and using bw-trees (which avoid locking through the use of pointers) and by handling each updates as a delete-and-insert. This is data the way that developers do it when they’re coding for performance – the way I was taught at university before I learned about databases. Being done in C, it compiles to very quick code, and although these tables don’t support every feature that regular SQL tables do, this is still an excellent direction that has been taken. @rob_farley

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• Professional immigration

  - by etranger

  Hello all, Does anyone here have a practical advice on professional relocation from Russia to Europe? The reasons behind making such a decision are far beyond the subject, perhaps, so I'll stick to the practical part. Having done some of the "common stuff" for finding a job, I am now facing two serious problems: I am a "dual-class" person, with university degree in marketing, and multiple years of self-studied computer competence (hence my writing here). Have professional experience in both areas. I don't currently hold a European work permit. From what I can see, this results in normal HR person throwing out my CV as either being "overqualified" or "too much trouble with making the permit". I do have the skills and character to start my own business, but it requires start-up capital that I don't have, over the last years I had to pay high bills for medical treatment of my family member, who had deceased. Now, I'm almost out of debts. As you can probably guess, English is not a problem, and I'm open to new languages, but first steps of entering the market, or the society, is the problematic part. I live close to Norway, and am trying to get some professional contacts there, but it hasn't got me any practical perspective so far. Any advice is greatly appreciated. EDIT: I am currently making my living off web site development, and occasional consulting services both in IT and marketing. For purely geographic reasons I'm dealing with clients that reside in the same city where I live, pop. 350 000. Being quite local, market requirements for web sites are simple and stable — clients need to control navigation, write articles in a word-like editor, upload illustrations and place ad banners, all with no additional programming. As many web developers do, I'm using my own content management system that fits these expectations. I have also started developing a newer version of this system that has better support for international environments, but I'm too distant from the real market demand in Europe to speak of the right track here. Technically it's based on php/mysql and uses xslt for templating. It allows for quick website deployment, and has architectural neatness, lack of which made me abandon similar opensource solutions (Joomla and the like). Deploying time from rasterized design proofs is normally under 6-8 working hours, don't know how that compares to the world practice. EDIT 2: Can anyone share what Norwegian (Scandinavian) web solutions market currently demands?

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• Best Practices for serializing/persisting String Object Dictionary entities

  - by Mark Heath

  I'm noticing a trend towards using a dictionary of string to object (or sometimes string to string), instead of strongly typed objects. For example, the new Katana project makes heavy use of IDictionary<string,object>. This approach avoids the need to continually update your entity classes/DTOs and the database tables that persist them with new properties. It also avoids the need to create new derived entity types to support new types of entity, since the Dictionary is flexible enough to store any arbitrary properties. Here's a contrived example: class StorageDevice { public int Id { get; set; } public string Name { get; set; } } class NetworkShare : StorageDevice { public string Path { get; set; } public string LoginName { get; set; } public string Password { get; set; } } class CloudStorage : StorageDevice { public string ServerUri { get; set } public string ContainerName { get; set; } public int PortNumber { get; set; } public Guid ApiKey { get; set; } } versus: class StorageDevice { public IDictionary<string, object> Properties { get; set; } } Basically I'm on the lookout for any talks, books or articles on this approach, so I can pick up on any best practices / difficulties to avoid. Here's my main questions: Does this approach have a name? (only thing I've heard used so far is "self-describing objects") What are the best practices for persisting these dictionaries into a relational database? Especially the challenges of deserializing them successfully with strongly typed languages like C#. Does it change anything if some of the objects in the dictionary are themselves lists of strongly typed entities? Should a second dictionary be used if you want to temporarily store objects that are not to be persisted/serialized across a network, or should you use some kind of namespacing on the keys to indicate this?

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• What's about Java?

  - by Silviu Turuga

  What is Java? In very short words, Java is a programming language that let you make an application that can be run on different operating systems, no matter we are talking about Windows, Mac OS, Linux or even embedded devices, such as RaspberryPi. When you compile a Java program, instead of getting a binary output as you get on other programming languages, you'll get a Java intermediate code, called Java bytecode. This is interpreted at run time, by a virtual machine that is specifically for the hardware and operating system you are using. What Java do i need? There are 5 major versions of Java: Java SE(Standard Edition) - this is what I'll use on most of my tutorials. Most of the examples will run on Java 6, but for others you'll need Java 7. Java EE (Enterprise Edition) - used for enterprise development Java ME (Micro Edition) - for running Java on mobile and different embedded devices such as PDAs, TV set-top boxes, printers, etc. Java Embedded - for some embedded devices such as Raspberry Pi, where the resources are limited JavaFX - to develop rich content User Interfaces. This is also something that will use a lot. More detailed information can be found on Oracle's website If you just want to run java applications you'll need the JRE (Java Runtime Environment) installed. If you want to program and create new applications, then you'll need the JDK (Java Development Kit).  How to check if Java is already installed? From command line, if you are on Windows, or from Terminal on Mac enter the following: java -version You should get something like this, if you have java installed on your system: java version "1.6.0_37" Java(TM) SE Runtime Environment (build 1.6.0_37-b06-434-11M3909) Java HotSpot(TM) 64-Bit Server VM (build 20.12-b01-434, mixed mode) Note: your current Java version might be different from mine. More information https://www.java.com/en/download/faq/whatis_java.xml http://en.wikipedia.org/wiki/Java_(programming_language) Next steps Install Java SDK Chose an IDE. I recommend NetBeans as it is very easy to use and also let you quickly create the GUI of your application Alternatives are Eclipse, Komodo Edit (for Mac), etc. There are plenty of solutions both free or paid. Resources on web Oracle Tutorials - lot of tutorials and useful resources JavaRanch - forum about java

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• Where does a "Technical Programmer" fit in, and what does the title mean? [closed]

  - by Mike E

  Was: "What is a 'Technical Programmer'"? I've noticed in job posting boards a few postings, all from European companies in the games industry, for a "Technical Programmer". The job description was similar, having to do with tools development, 3d graphics programming, etc. It seems to be somewhere between a Technical Artist who's more technical than artist or who can code, and a Technical Director but perhaps without the seniority/experience. Information elsewhere on the position is sparse. The title seems redundant and I haven't seen any American companies post jobs by that name, exactly. One example is this job posting on gamedev.net which isn't exactly thorough. In case the link dies: Subject: Technical Programmer Frictional Games, the creators of Amnesia: The Dark Descent and the Penumbra series, are looking for a talented programmer to join the company! You will be working for a small team with a big focus on finding new and innovating solutions. We want you who are not afraid to explore uncharted territory and constantly learn new things. Self-discipline and independence are also important traits as all work will be done from home. Some the things you will work with include: 3D math, rendering, shaders and everything else related. Console development (most likely Xbox 360). Hardware implementations (support for motion controls, etc). All coding is in C++, so great skills in that is imperative. Revised Summarised Question: So, where does a programmer of this nature fit in to software development team? If I had these on my team, what tasks am I expecting them to complete? Can I ask one to build a new level editor, or optimize the rendering engine? It doesn't seem to be a "tools programmer" which focuses on producing artist tools, often in high-level languages like C#, Python, or Java. Nor does it seem to be working directly on the engine, nor a graphics programmer, as such. Yet, a strong C++ requirement, which was mirrored in other postings besides this one I quoted. Edited To Add As far as it being a low-level programmer, I had considered that but lacking from the posting was a requirement of Assembly. Instead, they tend to require familiarity with higher-level hardware APIs such as DirectX, or DirectInput. I wasn't fully clear in my original post. I think, however, that Mathew Foscarini has it right in his answer, so barring someone who definitely works with or as a "Technical Programmer" stepping in to provide a clearer explanation, I'll go with that. A generalist, which also fits the description of a more-technical-than-artist TA.

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• Organization &amp; Architecture UNISA Studies &ndash; Chap 13

  - by MarkPearl

  Learning Outcomes Explain the advantages of using a large number of registers Discuss the way in which compilers optimize register usage Discuss the evolution of CISC machines Describe the characteristics of RISC architecture Discuss the RISC vs. CISC controversy Describe the way in which RISC and CISC design principles can be combined Instruction Execution Characteristics To understand the the line of reasoning of RISC advocates, we need a brief overview of instruction execution characteristics. These include… Operations Operands Procedure Calls These three sections can be studied in depth in the textbook at pages 503 - 505 A number of groups have come up with the conclusion that the attempt to make the instruction set architecture closer to HLLs (High Level Languages) is not the most effective design strategy. Rather HLL’s can be best supported by optimizing performance of the most time-consuming features of typical HLL programs. Generally 3 main characteristics came up to improve performance… Use a large number of registers or use a compiler to optimize register usage Careful attention needs to be paid to the design of instruction pipelines A simplified (reduced) instruction set is indicated The use of a large register optimization One of the most important design principles of RISC machines is the use of a large number of registers. The concept of register windows and the use of a large register file versus the use of cache memory are discussed. On the face of it, the use of a large set of registers should decrease the need to access memory. The design task is to organize the registers in such a fashion that this goal is realized. Read page 507 – 510 for a detailed explanation. Compiler-based register optimization   Reduced Instructions Set Architecture There are two advantages to smaller programs… Because the program takes up less memory, there is a savings in that resource (this was more compelling when memory was more expensive) Smaller programs should improve performance, and this will happen in two ways – fewer instructions means fewer instruction bytes to be fetched and in a paging environment smaller programs occupy fewer pages, reducing page faults. Certain characteristics are common to RISC processors… One instruction per cycle Register-to-register operations Simple addressing modes Simple instruction formats RISC vs. CISC After initial enthusiasm for RISC machines, there has been a growing realization that RISC designs may benefit from the inclusion of some CISC features CISC designs may benefit from the inclusion of some RISC features

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• Data Source Security Part 4

  - by Steve Felts

  So far, I have covered Client Identity and Oracle Proxy Session features, with WLS or database credentials.  This article will cover one more feature, Identify-based pooling.  Then, there is one more topic to cover - how these options play with transactions.Identity-based Connection Pooling An identity based pool creates a heterogeneous pool of connections.  This allows applications to use a JDBC connection with a specific DBMS credential by pooling physical connections with different DBMS credentials.  The DBMS credential is based on either the WebLogic user mapped to a database user or the database user directly, based on the “use database credentials” setting as described earlier. Using this feature enabled with “use database credentials” enabled seems to be what is proposed in the JDBC standard, basically a heterogeneous pool with users specified by getConnection(user, password). The allocation of connections is more complex if Enable Identity Based Connection Pooling attribute is enabled on the data source.  When an application requests a database connection, the WebLogic Server instance selects an existing physical connection or creates a new physical connection with requested DBMS identity. The following section provides information on how heterogeneous connections are created:1. At connection pool initialization, the physical JDBC connections based on the configured or default “initial capacity” are created with the configured default DBMS credential of the data source.2. An application tries to get a connection from a data source.3a. If “use database credentials” is not enabled, the user specified in getConnection is mapped to a DBMS credential, as described earlier.  If the credential map doesn’t have a matching user, the default DBMS credential is used from the datasource descriptor.3b. If “use database credentials” is enabled, the user and password specified in getConnection are used directly.4. The connection pool is searched for a connection with a matching DBMS credential.5. If a match is found, the connection is reserved and returned to the application.6. If no match is found, a connection is created or reused based on the maximum capacity of the pool: - If the maximum capacity has not been reached, a new connection is created with the DBMS credential, reserved, and returned to the application.- If the pool has reached maximum capacity, based on the least recently used (LRU) algorithm, a physical connection is selected from the pool and destroyed. A new connection is created with the DBMS credential, reserved, and returned to the application. It should be clear that finding a matching connection is more expensive than a homogeneous pool.  Destroying a connection and getting a new one is very expensive.  If you can use a normal homogeneous pool or one of the light-weight options (client identity or an Oracle proxy connection), those should be used instead of identity based pooling. Regardless of how physical connections are created, each physical connection in the pool has its own DBMS credential information maintained by the pool. Once a physical connection is reserved by the pool, it does not change its DBMS credential even if the current thread changes its WebLogic user credential and continues to use the same connection. To configure this feature, select Enable Identity Based Connection Pooling.  See http://docs.oracle.com/cd/E24329_01/apirefs.1211/e24401/taskhelp/jdbc/jdbc_datasources/EnableIdentityBasedConnectionPooling.html  "Enable identity-based connection pooling for a JDBC data source" in Oracle WebLogic Server Administration Console Help. You must make the following changes to use Logging Last Resource (LLR) transaction optimization with Identity-based Pooling to get around the problem that multiple users will be accessing the associated transaction table.- You must configure a custom schema for LLR using a fully qualified LLR table name. All LLR connections will then use the named schema rather than the default schema when accessing the LLR transaction table.  - Use database specific administration tools to grant permission to access the named LLR table to all users that could access this table via a global transaction. By default, the LLR table is created during boot by the user configured for the connection in the data source. In most cases, the database will only allow access to this user and not allow access to mapped users. Connections within Transactions Now that we have covered the behavior of all of these various options, it’s time to discuss the exception to all of the rules.  When you get a connection within a transaction, it is associated with the transaction context on a particular WLS instance. When getting a connection with a data source configured with non-XA LLR or 1PC (using the JTS driver) with global transactions, the first connection obtained within the transaction is returned on subsequent connection requests regardless of the values of username/password specified and independent of the associated proxy user session, if any. The connection must be shared among all users of the connection when using LLR or 1PC. For XA data sources, the first connection obtained within the global transaction is returned on subsequent connection requests within the application server, regardless of the values of username/password specified and independent of the associated proxy user session, if any.  The connection must be shared among all users of the connection within a global transaction within the application server/JVM.

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• 2012 EC Election Ballot open; Meet the Candidates Call tomorrow

  - by heathervc

  The JCP Executive Committee (EC) Election ballot is now open and all of the candidates' nominations materials are now available on JCP.org -- note that two new candidates were nominated late last week:  Liferay and North Sixty-One. It is shaping up to be an exciting election this year! The ratified candidates are:  Cinterion, Credit Suisse, Fujitsu and HP.The elected candidates are (9 candidates, 2 open seats):  Cisco Systems, CloudBees, Giuseppe Dell'Abate, Liferay, London Java Community, MoroccoJUG, North Sixty-One, Software AG, and Zero Turnaround. Tomorrow, 18 October, we will hold an open teleconference for the Java Community to meet the candidates and ask questions regarding their nomination.  We hope you will be able to participate in the call.  Should the time be inconvenient, a recording will be made available for download, and candidate questions may be posted on this blog entry or sent to [email protected]. Topic: Meet the EC Candidates Date: Thursday, October 18, 2012 Time: 9:30 am, Pacific Daylight Time (San Francisco, GMT-07:00) Meeting Number: 807 818 225 Meeting Password: MeetEC ------------------------------------------------------- To join the online meeting (Now from mobile devices) ------------------------------------------------------- 1. Go to https://jcp.webex.com/jcp/j.php?ED=186721592&UID=0&PW=NMmUzNjY5ZTMw&RT=MiM0 2. If requested, enter your name and email address. 3. If a password is required, enter the meeting password: MeetEC 4. Click "Join". To view in other time zones or languages, please click the link: https://jcp.webex.com/jcp/j.php?ED=186721592&UID=0&PW=NMmUzNjY5ZTMw&ORT=MiM0 ------------------------------------------------------- To join the audio conference only -------------------------------------------------------     +1 (866) 682-4770     Outside the US: global access numbers  https://www.intercallonline.com/portlets/scheduling/viewNumbers/listNumbersByCode.do?confCode=6279803 or +1 (408) 774-4073     Conference code: 9454597     Security code: JCPEC (52732)------------------------------------------------------- For assistance ------------------------------------------------------- 1. Go to https://jcp.webex.com/jcp/mc 2. On the left navigation bar, click "Support".

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• ADF Mobile Released!!

  - by Denis T

  ADFmfAnnounce We are pleased to announce the general availability of the newest version of Oracle’s ADF Mobile framework. This new framework provides the much anticipated on-device capabilities that the latest mobile applications require.  Feature Highlights Java - Oracle brings a Java VM embedded with each application so you can develop all your business logic in the platform neutral language you know and love! (Yes, even iOS!) JDBC - Since we give you Java, we also provide JDBC along with a SQLite driver and engine that also supports encryption out of the box. Multi-Platform - Truly develop your application only once and deploy to multiple platforms. iOS and Android platforms are supported for both phone and tablet. Flexible - You can decide how to implement the UI: (a) Use existing server-based UI framework like JSF. (b) Use your own favorite HTML5 framework like JQuery. (c) Use our declarative HTML5 component set provided with the framework. ADF Mobile XML or AMX for short, provides all the normal input and layout controls you expect and we also add charts/maps/gauges along with it to provide a very comprehensive UI controls. You can also mix and match any of the three for ultimate flexibility! Device Feature Access - You can get access to device features from either Java or JavaScript to invoke features like camera, GPS, email, SMS, contacts, etc. Secure - ADF Mobile provides integrated security that works with your server back-end as well. Whether you’re using remote URLs, local HTML or AMX, you can secure any/all of your features with a single consistent login page. Since we also give you SQLite encryption, we are assured that your data is safe. Rapid - Using the same development techniques that ADF developers are already used to, you can quickly create mobile applications without ever learning another language! Architecture ADF Mobile is a “hybrid” architecture that employs a natively built “container” on each platform that hosts a number of browser windows that are used to display the application content. We add the Java VM as a natively built library to the container for business logic.   How To Get Started ADF Mobile is an extension to the recently released JDeveloper version 11.1.2.3.0. Simple get the latest JDeveloper from Oracle Technology Network and use the Check for Updates feature to get the ADF Mobile extension. Note: ADF Mobile does not require developers to learn any other languages or frameworks but to build/deploy to iOS, you must be on an Apple MacintoshTM and have Xcode installed. To build/deploy to Android™ you must have the Android SDK installed.

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• Using XA Transactions in Coherence-based Applications

  - by jpurdy

  While the costs of XA transactions are well known (e.g. increased data contention, higher latency, significant disk I/O for logging, availability challenges, etc.), in many cases they are the most attractive option for coordinating logical transactions across multiple resources. There are a few common approaches when integrating Coherence into applications via the use of an application server's transaction manager: Use of Coherence as a read-only cache, applying transactions to the underlying database (or any system of record) instead of the cache. Use of TransactionMap interface via the included resource adapter. Use of the new ACID transaction framework, introduced in Coherence 3.6.   Each of these may have significant drawbacks for certain workloads. Using Coherence as a read-only cache is the simplest option. In this approach, the application is responsible for managing both the database and the cache (either within the business logic or via application server hooks). This approach also tends to provide limited benefit for many workloads, particularly those workloads that either have queries (given the complexity of maintaining a fully cached data set in Coherence) or are not read-heavy (where the cost of managing the cache may outweigh the benefits of reading from it). All updates are made synchronously to the database, leaving it as both a source of latency as well as a potential bottleneck. This approach also prevents addressing "hot data" problems (when certain objects are updated by many concurrent transactions) since most database servers offer no facilities for explicitly controlling concurrent updates. Finally, this option tends to be a better fit for key-based access (rather than filter-based access such as queries) since this makes it easier to aggressively invalidate cache entries without worrying about when they will be reloaded. The advantage of this approach is that it allows strong data consistency as long as optimistic concurrency control is used to ensure that database updates are applied correctly regardless of whether the cache contains stale (or even dirty) data. Another benefit of this approach is that it avoids the limitations of Coherence's write-through caching implementation. TransactionMap is generally used when Coherence acts as system of record. TransactionMap is not generally compatible with write-through caching, so it will usually be either used to manage a standalone cache or when the cache is backed by a database via write-behind caching. TransactionMap has some restrictions that may limit its utility, the most significant being: The lock-based concurrency model is relatively inefficient and may introduce significant latency and contention. As an example, in a typical configuration, a transaction that updates 20 cache entries will require roughly 40ms just for lock management (assuming all locks are granted immediately, and excluding validation and writing which will require a similar amount of time). This may be partially mitigated by denormalizing (e.g. combining a parent object and its set of child objects into a single cache entry), at the cost of increasing false contention (e.g. transactions will conflict even when updating different child objects). If the client (application server JVM) fails during the commit phase, locks will be released immediately, and the transaction may be partially committed. In practice, this is usually not as bad as it may sound since the commit phase is usually very short (all locks having been previously acquired). Note that this vulnerability does not exist when a single NamedCache is used and all updates are confined to a single partition (generally implying the use of partition affinity). The unconventional TransactionMap API is cumbersome but manageable. Only a few methods are transactional, primarily get(), put() and remove(). The ACID transactions framework (accessed via the Connection class) provides atomicity guarantees by implementing the NamedCache interface, maintaining its own cache data and transaction logs inside a set of private partitioned caches. This feature may be used as either a local transactional resource or as logging XA resource. However, a lack of database integration precludes the use of this functionality for most applications. A side effect of this is that this feature has not seen significant adoption, meaning that any use of this is subject to the usual headaches associated with being an early adopter (greater chance of bugs and greater risk of hitting an unoptimized code path). As a result, for the moment, we generally recommend against using this feature. In summary, it is possible to use Coherence in XA-oriented applications, and several customers are doing this successfully, but it is not a core usage model for the product, so care should be taken before committing to this path. For most applications, the most robust solution is normally to use Coherence as a read-only cache of the underlying data resources, even if this prevents taking advantage of certain product features.

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• Does OO, TDD, and Refactoring to Smaller Functions affect Speed of Code?

  - by Dennis

  In Computer Science field, I have noticed a notable shift in thinking when it comes to programming. The advice as it stands now is write smaller, more testable code refactor existing code into smaller and smaller chunks of code until most of your methods/functions are just a few lines long write functions that only do one thing (which makes them smaller again) This is a change compared to the "old" or "bad" code practices where you have methods spanning 2500 lines, and big classes doing everything. My question is this: when it call comes down to machine code, to 1s and 0s, to assembly instructions, should I be at all concerned that my class-separated code with variety of small-to-tiny functions generates too much extra overhead? While I am not exactly familiar with how OO code and function calls are handled in ASM in the end, I do have some idea. I assume that each extra function call, object call, or include call (in some languages), generate an extra set of instructions, thereby increasing code's volume and adding various overhead, without adding actual "useful" code. I also imagine that good optimizations can be done to ASM before it is actually ran on the hardware, but that optimization can only do so much too. Hence, my question -- how much overhead (in space and speed) does well-separated code (split up across hundreds of files, classes, and methods) actually introduce compared to having "one big method that contains everything", due to this overhead? UPDATE for clarity: I am assuming that adding more and more functions and more and more objects and classes in a code will result in more and more parameter passing between smaller code pieces. It was said somewhere (quote TBD) that up to 70% of all code is made up of ASM's MOV instruction - loading CPU registers with proper variables, not the actual computation being done. In my case, you load up CPU's time with PUSH/POP instructions to provide linkage and parameter passing between various pieces of code. The smaller you make your pieces of code, the more overhead "linkage" is required. I am concerned that this linkage adds to software bloat and slow-down and I am wondering if I should be concerned about this, and how much, if any at all, because current and future generations of programmers who are building software for the next century, will have to live with and consume software built using these practices. UPDATE: Multiple files I am writing new code now that is slowly replacing old code. In particular I've noted that one of the old classes was a ~3000 line file (as mentioned earlier). Now it is becoming a set of 15-20 files located across various directories, including test files and not including PHP framework I am using to bind some things together. More files are coming as well. When it comes to disk I/O, loading multiple files is slower than loading one large file. Of course not all files are loaded, they are loaded as needed, and disk caching and memory caching options exist, and yet still I believe that loading multiple files takes more processing than loading a single file into memory. I am adding that to my concern.

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